I first published this article on 10.2.2022 but as usual it was not final. I had written the Vision, Needs and Observations of the current situation, evaluated how it works and possibilities to tweak. 

I came back to the design in September 2023. Now I decided I need to narrow down the scope from "Buildings and Energy systems" to "Energy at Iso-orvokkiniitty". Possible spin-offs (i.e. other designs) are "Water and Hygiene" (essentially the same as "Household water system at Iso-orvokkiniitty" which was a spin-off from Design 1) and "Food".  

We had an assessment meeting with Andreas on 6.11.2023 and I did some tweaks to the text in order to move it from "nearly ready" to "ready". 

Last edit 19.11.2023 

APPROVED 13.1.2024 (no edits after that) 
VOBREDIMET Design Framework

This article is building heavily on previous articles, especially those about the site and the article about the House which are basically the observation part of this design. 


  • Design Framework
  • Vision
    • The original vision of the house
    • Off-grid
    • Our Energy-system Vision
  • Our Needs
  • Observation
    • Borders and resources
  • Evaluate how it works
  • Tweak
    • Tweak table
    • Tweaking the electricity system
      • Short term
      • Solar panels and wind mills
      • Further improvements
      • Experiences withe the “Mobile battery pack”
  • Implementation
  • Maintenance
  • Evaluate against Holmgren design principles
    • Functions – Elements analysis
  • How does the Design relate to Planetary Boundaries?
  • Have we realized our Vision?
  • Have we met our needs?
  • Integration with other designs
  • What tools did I use?
  • The learning pathway
  • References

Tweaking the OBREDIM to circular.

This is the Design of our House (including other buildings) from the perspective of the Main System Energy (see The Permaculture Pathway). The Design Framework is VOBREDIMET (Vision, Observation, Boundaries, Resources, Evaluation, Design, Implementation, Maintenance, (Re)Evaluation, and Tweaking).

Designing a house and buildings is very much about Needs so I added that as a separate box in the graph although it would normally fall under Observation. I have named the Design box Tweak, as my aim here is to start from what has already been done until now (instead of trying to reconstruct the design process from 5 years back). So the result of this Design are the Tweaks that we need to do now. The original design process is described in the separate article about the House, which in this case falls under Observation. Let’s see how it works.


I will go from our original vision regarding the house in 2016-17 to a broader vision based on Permaculture Ethics to the specific vision concerning this design: the Off-grid Vision.

Our original vision regarding the house in 2016-17

In 2017 I wrote: "To us natural building means dynamic breathing structures, natural materials, ecological energy solutions and based on permaculture principles local, self-sufficiency and closed loops. Of course a traditional log house would be natural building but we chose straw bale-clay construction, which enables good insulation and dynamic structures. 
Key principles in our house are: 
- natural and breathing materials, i.e. avoiding by all means use of plastics and styrofoam. 
  - the only exception to this is electric coils and water piping etc
  - the clay is from our own field and the bales from an organic farm
  - the floor and roof insulation is borax-free cellulose with clay powder (fire prevention)
  - the foundation is insulated with Leca gravel and the earth cellar with glass foam gravel 
- Location in a SW facing slope protected from the N by forest and the slope
- Gravitational ventilation
- Heating with wood (fireplaces) supplemented with solar collectors. Firewood from our forest. 
- Off-grid electricity with solar panels and windmill
- Traditional well for water
- Willow waste water treatment to keep nutrients on the site.  

I think the Values and our Vision have remained largely the same over the years since we bought the place. Our values and visions were and are very much based on environmental concerns, our long history in the organic farming movement, naturalness and broadly speaking ecological Green political ideas.

Here I will define our Vision about the House based on Permaculture Ethics:

    • Use natural materials and construction technologies with as small an environmental footprint as possible.
    • Enable an ecological lifestyle with a high degree of self-sufficiency in energy, food and materials.
    • Minimise waste
    • Create a healthy and inspiring living environment for ourselves
    • Enable social life and living according to our values
    • Share our experiences
    • Hospitality


An important choice we made in the beginning was to be off-grid. That was based the self-sufficiency vision and Earth Care Ethics (see above). I wrote about the reasons for this choice in November 2014 in: “Own energy and electricity” (Googlenglish, original in Finnish). In the article I refer

  1. To the fact that the use of fossil fuels has led to climate change and is destroying our possibilities to live on this planet but nevertheless nothing is done about stopping usage of fossil fuels.
  2. Nuclear energy is not a solution and even nuclear fusion power would lead to disaster (for several reasons) – even though it might be clean.
  3. We need to take responsibility ourselves for an energy descent.
  4. It is not possible to connect to the grid and only be supplied with renewable sustainable electricity (in practise wind). You get electricity from your socket even if the windmills are standing still.

So this part of our vision was pretty radical but still included the idea of a more or less normal lifestyle in terms of having electricity for all kinds of modern appliances. Basically all the technology we need for this (solar panels, wind mills, chargers, inverters etc) are linked to the economic system that is leading to the demise of humankind as we know it. So what we envision here is still some kind of high-tech driven but de-centralised society that is able to descend to a sustainable level of consumption. Are off-grid homes a part of that vision? Already in my November 2014 article I concluded that if there was a de-centralised and smart energy system based on local energy sources it would make sense to connect – but as it does not exist we don’t want to connect.

This brings us to the thinking of David Holmgren in “Permaculture. Principles & Pathways Beyond Sustainability” (2002). As a part of the principle “Catch and store energy” he suggested in Chapter “Appropriate Use of Non-Renewable Resources” (p 48) that “The transition to declining energy availability provides unique strategic opportunity to make the best use of existing wealth and non-renewable resources to rebuild natural and human capital”. This could be used as justification to build an off-grid system even if it does not make short-term economical sense. However Holmgren continues (p 50) in Chapter “Idealism versus Pragmatism” to describe how they are at Melliodora connected to the grid – although using only 20% of the electricity a typical household would use – and concludes “for the present we can make better use of the money that would be required to develop other aspects of our property”. According to Holmgren the most important thing is to use as little electricity as possible. Of course that is easiest to achieve if energy supply is limited (i.e. if one is off-grid).

Our Energy System Vision

Based on the above our Vision became to be as self-sufficient in energy at Iso-orvokkiniitty as possible.

This vision led us to building an off-grid house and installing solar panels and a wind mill to cover our electricity needs. Heating is based on firewood with additional energy coming from solar collectors.

The aim of this design is to Tweak the design in order to meet the Vision even better.


The observation part of the Site is covered in previous articles:

The article “House” contains a detailed description of the house planning and the house in early January 2021. If nothing else, read it before going further in this article. Building the house is quite well documented: see links to our blog in the House article. Here I am observing what was already done (and the proposed Design will be Tweaks to the existing.

Summary of the timeline of the buildings:

Firewood sheds on the left, the storage building on the right and house in the background. 30.1.2022.
  • The dry toilet was built 2015
  • The summer kitchen was built 2015-16
  • The main house was build 2016-18 and we moved in spring 2018. Official final inspection was done in December 2021.
  • I built the first firewood shed in 2019.
  • In 2020 we started several projects which were more or less finalised during 2021:
    • storage building for the generator, beekeeping and mushroom growing equipment, gardening equipment and car and bicycle related stuff.
    • earth cellar
    • sauna
  • In January 2022 I built the 2nd firewood shed.

Borders and resources

A general description of the site including site borders and resources can be found in Iso-orvokkiniitty: the site. Relating to the Buildings and Energy systems and how to tweak them borders and resources relate to

  • Financial limitations and resources
  • Human resources
  • Material resources on-site and off-site
  • Limitations created by our choices (mainly the off-grid system).

Our financial position is pretty good. Erkki’s business is creating cash-flow and Marja’s business in ecological landscape design has got a good start and is creating some income for her. We expect to pay our house loan by the end of 2028 and try not to take on more loan in the meantime. Cashflow allows us to do some investments year by year as long as Erkki is in business.

Erkki is in good health and physical condition but of course as 63 year old it will not be true for ever. Marja has had some health challenges in the recent years but she is better now. Help can be got in the form of “talkoo” (gathering together at each others places or common projects for communal work), volunteers, help from family and friends, workshops, hiring school children for summer work or hiring professionals for specific tasks.

Material resources on-site are (for constructions)

  • wood for firewood

Professionals for off-grid electricity systems and small scale power plants are scarce and apart from solar panels commercial solutions are not readily available.

Evaluate how it works

The “House” article contains also evaluation – most importantly:

  • “Permaculture construction checklist” inspired by Paul Jennings (2) and my thoughts and comments to the raised points.
  • Functions-Elements analysis of the House
  • Functions-Elements analysis of the Energy system
Sources of electricity in Finland 2021: starting from the orange: Nuclear 26,3%, Combined heat power stations, Combined industry power stations, Electricity power stations, Import, Water, Wind, Sun. Source: Finnish Energy.

Update 2023: There has been significant changes since the above statistic (10):

  1. Import from Russia has stopped in May 2022.
  2. The Olkiluoto 3 nuclear power station finally went online in April 2023 and since then Finland has been a net exporter of energy. In June 2023 55% of electricity in Finland was nuclear.
  3. Heavy investments in wind power have continued (3 billion € in 2022) and wind power has covered 19,4% of electricity consumption in January to June 2023. Wind mill capacity will be over 7000 MW by the end of 2023.
  4. Solar power is still a very small part of the total but almost doubled from summer 2022 to summer 2023.
  5. “Clean” electricity (this includes nuclear) covered 97% of electricity production in Finland in June 2023.


Energy is not normally recognised as a separate need but it is needed for the satisfaction of most basic needs. This design focuses on energy at Iso-orvokkiniitty.


We wanted to design an off-grid system for electricity in our house. See blog posting in November 2014: In Googlenglish or original in Finnish.

This was in line with Earth Care “Enable an ecological lifestyle with a high degree of self-sufficiency in energy, food and materials“. In Finland over 50% of produced electricity was with renewables in 2020, including renewable fuel, wind and water. However Nuclear is the biggest single source (and increasing) and 20% of electricity was imported (2021) which could be Russian nuclear or Norwegian water power (import from Russia stopped in 2022). Even though renewables are growing, Finland relies heavily on nuclear so we didn’t want to connect to that kind of grid.

In 2015 we asked Janne Käpylehto to consult us in designing the off-grid electricity system. He gave us a proposal which you can see below (the whole report was 14 pages). The system was implemented by REPS Oy in 2016-17 with the solar panels installed on the darkest possible day 21.12.2016. (Unfortunately REPS Oy has stopped their activities shortly after so we have not had proper support for the system.)

The main differences between the plan and how it was implemented were:

  1. more solar panels (12 x 260 W)
  2. less battery capacity (32 kWh of which 50% usable)
  3. No 12V system, i.e. everything is built with 230V
  4. The Windmill is a 2,6 kW Skystream.
  5. The generator is missing in the illustration but it was proposed also in Janne’s plan.
Our electricity design 2015 (Janne Käpylehto).

All our home appliances are high quality with lowest possible energy consumption at time of purchase.

Overall the electricity system works well from March to October. Electricity (and hot water) are in abundance in the summer. The main challenge is insufficient electricity production in the winter months (November until mid February) and as a consequence lack of water in the house. We have adapted to this with some changes in behaviour in the winter months compared to summer when electricity is in abundance. From a modern urban lifestyle point of view our summer is when we can behave “normally”.

In the winter months we have these adaptations (situation in 2021):

  • If the wind is not blowing, we power the house with the 3 kW Honda generator, usually 2-3 hours per day in the morning which means 3-4 kWh power per day. That is only half of what we calculate we would normally use. We run the generator most days in November, December and January. Windy days give us a break but solar panels don’t produce enough even on a sunny day until first week of February – and sunny days are scarce in November – January anyway. In summer 2021 I finalised the storage building which has one room for the generator (+ other equipment which use fuel, mainly the chain saws). I installed fire protective walls inside and an exhaust pipe through the wall with an exhaust silencer to reduce the outside noise level. We have 2 Honda generators (2nd for backup).
  • Prepare food and boil water only on the wood fired stove (electric stove and water boiler are put away October – March – both use 2kW max power)
  • Dishwashing by hand, water heated in 10L kettle on the stove (we have a dishwasher – when it heats water it uses 2 kW so we use it only in summer)
  • Washing laundry with washing machine more seldom, necessary to use generator if it’s not a very windy day (heating water takes 2 kW)
  • Often fast showers (the colder it is outside the more hot water we have)
  • Use battery powered lights in the evening and morning if electricity is off (so we have electricity every day but not necessarily all the time)(Candles decrease inside air quality.)
  • Store water for the periods when we don’t have the power on.
  • Use rainwater to flush the toilet (not possible if freezing).
  • We have 2 extra 200 Ah batteries which are used to run some vital functions:
    • the pump for the floor heating system. this is vital because it keeps the cellar from freezing so the incoming water pipe does not freeze.
    • wifi and weather station
  • The fridge does not have an electricity back-up so electricity shouldn’t be off more than 10 hours at a time (overnight). In the original electric plan the fridge was not supposed to be cut off electricity but that has not been implemented.
January Wind Rose at 50m altitude at Iso-orvokkiniitty according to Tuuliatlas.

So there are quite a few adaptations which may or may not be acceptable to someone striving to develop self sufficiency In their lifestyle. In our case we are 2 adults living in the house so it is acceptable – if we were a family with kids it would be more challenging. Living in an energy-squeezed situation is acceptable but the main irritation is the need to run the generator most of the days in the 3-4 winter months. For that we use 150-200 litres of petrol (benzin) per winter with current prices a cost of up to 400 €/year. It’s not a huge amount of petrol – if you compare f.ex. to a car, but still definitely a fault in the design.

The bottomline is that I was way too optimistic regarding how much power the wind mill would produce in the winter months. In my posting in November 2014 I estimated 270-400 kWh per month production. The estimate in Janne Käpylehto’s report was more realistic at 1300 kWh/year (110 kWh/month) with a 3kW wind turbine. We don’t have a meter for following cumulative power production but my estimate based on how many days we have not needed the generator is 40-50 kWh per month. I presume Janne Käpylehto’s estimate could be correct in more optimal wind conditions.

July Wind Rose at 50m altitude at Iso-orvokkiniitty.

Analysing reasons why the wind mill did not meet expectations:

Location in general: Wind speeds inland at accessible height (for small wind mills) are much lower than on the sea coast or archipelago. It is questionable if it makes sense to install a small mill inland unless it can be located on a very high spot in the landscape. (I wasn’t willing to believe this back in 2015-16.)

Map from kartta.paikkatietoikkuna.fi with wind rose (blue = winter, red = summer)

Location in the landscape: We originally considered 2 locations for the wind mill: Down on the field or in the eastern corner of our property in the forest, which is the highest point on our property. I still presume the chosen location in the forest was correct as it is over 10m higher than the field. However the location is problematic because it is in the forest and trees certainly cause a lot of turbulence. The mast is 24 meters high which is not enough when tree tops are at 16-17 meters beside the wind mill and 20 meters in the old spruce forest to the NW (I believe there should be 10 meters between treetops and turbine). NW to W winds hit the mill well and 4-5m/s wind speed is sufficient to revolve the mill although it takes 6m/s to produce reasonable amount of electricity (energy production increases exponentially in 3rd power compared to wind speed). But winds from W to NW which are also typical in the winter come from the direction of the old spruce forest and it requires a 7-8m/s wind for the mill to revolve. N and NE winds work ok at least at 6-7 m/s wind speeds but they are not so common. E winds seem to be blocked by the hill to the east but east winds are also not common.

Photo taken on 24.4.2017 showing the wind turbine appr. 8 meters above the surrounding tree tops. In SE individual higher trees and in SW the old spruce forest.
Photo taken 1.1.2022 from similar angle. It doesn’t look like 5 years of forest growth would have made any significant difference (not sure if the photo angle is exactly the same). I have taken down the tall birch on the east of the turbine.

To summarise:

  • Wind conditions inland are not ideal for small wind mills that cannot be raised high enough.
  • The windmill is a Skystream 3.7 with a rated power of 2,6 kW which it reaches at 11 m/s wind speed. The swept area of the rotor is 10,9 m2 (diameter 3,7m) which is the most important parameter especially in low wind situations (a mill could have a similar rated power with smaller swept area if it is meant for high wind speed conditions). In general the wind speeds are not sufficient to generate excess electricity to fill up the batteries. The turbine should be bigger.
  • The mast is 24 meters. It is difficult to go higher with reasonable cost, but it would certainly improve the situation.
  • If the turbine was bigger, also the battery capacity should be bigger to store energy for the days with no wind.

SWOC of off-grid electricity: 2021 situation

– Abundance of electricity in the summer months.
– Low maintenance cost.
– Develops consciousness of energy and electricity usage and natural availability when it is in limited supply.
– Possibility for energy self-sufficiency
– Insulated from problems in the grid (electricity outages due to storms etc)
– Cheap to run
– Lack of electricity in winter months.
– External energy in the form of f.ex. a generator running on fossil fuel could totally offset the benefits in terms of CO2, particle emissions and noise.
– Starting the generator not automised. Starting the backup generator requires “manpower” (in 2022 switched to generator with electric start).
– Solar energy is available at relatively low investment level
– Cover electricity need in the buildings and mobility.
– In winter months some form of external electricity generation is needed.
– High investment cost to cover electricity gap in the winter.
– Feasible small scale electricity solutions are not available for the winter period.


Heating is a key part of meeting our Physiological and Environmental needs. It is needed for heating the house (target about 20°C inside), heating water for hygiene use and for processing food and beverages. The main fuel for heating in Finland has traditionally been wood and burning firewood is still the easiest way to achieve a high degree of self-sufficiency in heating energy. The other standard heating solutions in Finnish countryside today are oil and electricity. Increasingly thermal energy systems, heat exchangers and air conditioners (air heat pump for heating) are installed to save energy. Why don’t we have any of those?

  • Oil is obviously a fossil fuel so a no-go.
  • Electricity as an external resource could be produced with fossil, nuclear, peat or also renewable sources. In an off-grid setting there is no way enough electricity could be produced in a sensible way for heating in the winter.
  • A thermal heating system can save 2/3 of the energy needed for heating. 1/3 is still a lot of energy and it needs to be electricity. Not possible in an off-grid system.
  • Heat exchangers capture heat from the outflowing air into the inflowing air in the ventilation pipes. It requires electricity to run, it makes a noise, gets dirty and it requires maintenance. It is a no-go in a house with traditional gravitational ventilation.
  • An air conditioner requires electricity, makes a noise and doesn’t produce a lot in the coldest weathers.

In January 2016 I posted on our blog about Energy design more from the heating point of view (in Googlenglish, and original in Finnish). The Elements and Functions (energy) analysis is in the “House” article. I am not repeating it here.

Below I try to illustrate the energy system.

Our Energy system: electricity and heating.
Thinning out mainly birch north from our house. I cut and chopped it in the woods.

Overall I think the energy system works well for us. The main physical challenge is the firewood production but in this kind of a lifestyle you need to get more or less addicted to forest works and chopping firewood. It requires you to be in good condition and at the same time offers the exercise you need for that goal. Some external resources are needed. Making firewood includes these steps:

Cleaning the field edge. These were taken with car trailer to the house. Tapio was a great help.
Cut and chopped at the house.
  • Trees need to be felled. For this I am using a chainsaw that runs on petrol.
    • It would be possible to use a hand saw but to me it seems a bit extreme. Petrol consumption is quite low – I think I’m not using more than 15-20 litres per year.
    • Battery driven chainsaws are developing fast. Probably the best ones would already do the job. However I have invested in a good chainsaw so I will probably wait for a few years before investing in a battery-driven chainsaw. Anyway the chainsaw is used mainly in the winter when we are not self-sufficient in electricity. I have a small electric chainsaw for summer use.
  • I either cut and chop the wood into appr. 40 cm pieces in the woods or bring them to the house as longer trunks.
  • Bringing to the house depends on where I am logging.
    • If in the forest without access with tractor, I chop the wood in the forest and bring them to the house with a battery-driven wheelbarrow. The distance should be less than 100 meters from the house – preferably less that 50 m.
    • If logging close to the field with access with tractor or car I either ask our neighbour to help with tractor or pull them with our car trailer.
    • A horse would be nice for this job but not sufficient justification to get a horse (need to feed the horse etc).
  • If I didn’t cut and chop the wood in the forest I do it at the house. Cutting with chainsaw and chopping with ax (alternatives exist but I am old-school and enjoy chopping with ax).
  • I have built 2 sheds for firewood and there is a smaller shelter next to the sauna. I’m not sure yet how much firewood we need but I presume 8-10 m3 for the house and 3 m3 for the sauna. I now have space for some 25 m3 so in the spring optimally we should have enough firewood for 2 years. 10m3 chopped and piled mixed firewood is about 15000 kWh worth of energy (6)
Bringing firewood down the hill with the battery driven wheelbarrow.
Zone 4 is where firewood can be harvested by thinning the forest or cleaning the field edges. Behind the 100 meter distance line it is however unpractical. Zone 5 is not touched.

I am trying to avoid investing into any heavier equipment like tractors, ATV, chopping machines etc. If those are necessary for the job I might as well buy the firewood. When it comes to machine work professionals are for sure doing it more efficiently than I could ever do. Firewood costs in our region appr. 60 €/m3 so our annual cost for buying it would be 700-800 €/year (that was in 2021 – now they are 90 €/m3 so now it would be >1000 €/year). I’ve invested that much just in one chainsaw so economically the whole operation is questionable (becoming less questionable).

The Zone 4 forest that we can harvest for fire wood is appr. 3 ha. As it is young mixed forest we can presume forest growth to be up to 8-10 m3/ha so our need of 15 m3 is possibly only half of the growth on that 3 hectares.

Use of firewood

The use of firewood in the house depends mainly on outside temperature. Once we can’t use electricity for cooking (October-March = 6 months) we fire the kitchen stove in average 2 times per day using average 15 kg fire wood per day (7 m3) and thereby generating about 60 kWh heat per day or 10000 kWh per winter. In the winter 2019-20 we fired either one of the big ovens 35 times but in 2020-21 67 times and in 2021-22 it looks to be appr 50 times. If average is 50 times and we burn 15 kg per time it means 750 kg (almost 2 m3) and appr 3000 kWh. So total heating of the house is 9-10 m3 per winter and 13000 kWh of heating energy which includes heating the water. We heat the sauna once a week using 35 kg per heating meaning an additional 4,5 m3 fire wood bringing the total to 14-15 m3 per year.

A 100 m2 house is estimated to need 20000 kWh heating energy per year. In our case the calculated 13000 kWh covers October to March but there is heating energy needed also earlier in the autumn and later in the spring and for hot water the year round. This is covered by the solar collectors and passive solar energy coming in from the windows.

Our baking oven from the side. The wood is burned on the backside of the massive oven (facing our study) while the baking oven opens to the kitchen/dining room. The oven is insulated so I can bake several batches of bread with one heating (we heat the oven first, close the chimney and then bake). Therefore heat release into the house is slow. © Heikki Hyytiäinen

Finnish Massive Fireplaces

A typical fireplace in Central or Southern Europe is an open fireplace with a chimney directly up through the roof. Sometimes the chimney is on the outside wall of the house. It seems that the purpose is to ventilate out both the smoke and the heat as effectively as possible – so totally contrary to why we build fireplaces here in the north. That kind of fireplace is not for heating.

Our baking oven from the front. From the tertiary chamber the hot air enters the cheeks going down to floor level where it enters the chimney. © Heikki Hyytiäinen

A Finnish Massive Fireplace has an efficiency of 85% or more. The main idea is to burn efficiently and cleanly in high temperature and to store the heat in the masonry. This is achieved by regulating the air inflow, secondary air fed above the flame to ensure sufficient oxygen for the flame and a secondary burning chamber above the primary chamber. After the fire is off the chimney is closed in order not to ventilate the heat out. Here I am illustrating the design of our baking oven but the same principles apply for all massive ovens. It burns not only efficiently but has low emissions. Our ovens were designed by architect Heikki Hyytiäinen from Tulisydän. You can read about the workshop where our ovens were built in our blog.

SWOC of our heating system

– Possible to be self-sufficient in heating the house.
– Wood based heating is carbon neutral when need is less than forest growth.
– Solar collectors provide hot water from April to October without any effort or cost.
– Passive house format (big windows to the south) provides heating in Spring and Autumn months when the sun shines.
– Possibility for physical exercise in forest, chopping wood and carrying it inside.
– A sizeable material flow has to be managed.
– Firewood is readily available locally if need to buy.
– External inputs in the form of chainsaw and fuel.
– Good physical health required

Fossil Fuels

Fossil fuels should be avoided by all means. However we use some fossil fuels (2021 situation):

  • The generator we need for electricity in the winter uses 120 – 200 litres petrol per year depending on how windy it is and our electricity need. A little bit machine oil.
  • The chainsaw I use for firewood work runs on petrol but uses only 15-20 litres per year. The chain oil is bio-based. The chainsaw is mainly used in the winter months when forest work is mostly done. A battery driven chainsaw wouldn’t have a positive impact if the electricity is generated with the generator.
  • We don’t have a tractor but we occasionally ask our neighbour to do tractor work for us. In the winter the snow ploughing is done by tractor. Occasional excavation work.
  • Mobility: Cars are a necessity in the countryside. So far we have had 1 car and a van but it looks like we are going to have 2 cars and a van. (August 2023: planning to sell the van)
    • The van is a gas VW Caddy that we leased new in 2015. It runs almost purely on biogas which in Finland we can consider zero-emission as biogas here is produced from sidestreams of food industry that earlier was waste and other methane emissions of waste. We estimate the van uses less than 50 litres of petrol per year.
    • We had a diesel car until 2019. Biodiesel is available only in Helsinki so it was mostly run with regular diesel. I changed to a petrol car in 2019 with the plan to convert it to biogas. However this was never done for various reasons. In January 2022 we changed to a used 2015 bifuel Volvo V70 that runs on biogas. The aim is to run it purely on biogas but of course some petrol will be consumed. However the Volvo will probably decrease milage on the Caddy, so 60-70 litres of petrol per year for both cars is a realistic estimate.
    • I have placed an order for an electric car which has V2L; i.e. it is possible to get electricity out of the car for other uses. In the summer we can charge the car at home for free with solar. In the winter we can charge it elsewhere and use it as a mobile battery pack. Obviously an electric car has a huge environmental footprint but common thinking seems to be that it is offset already with 10000 km drive compared to a petrol / diesel car if the electricity is renewable (?).

Alternative or additional electricity sources

Obviously I have put quite a lot of though into how to solve the winter electricity deficit. I can group possible solutions in three groups:

  1. More solar and wind
  2. Electricity from wood
  3. External sources
1st January 2022 at noon. Our solar panels are getting sun but any panels on ground level would be in the shadow.

More solar and wind and battery capacity

Theoretically solar panels produce in December 10% of what they produce in June. So one option would be just to add more solar panels. Those could be installed vertically on the top of the house roof to catch the winter sun as efficiently as possible. The house roof is the only practical spot on our property which is high enough to catch the December sun. Ground level installations would be in the shadow.

Even now we have excess electricity in the summer. I am presuming we have so much that we can charge the to-be electric car in the summer but that remains to be seen. If this is not true it would make sense to install more solar panels.

More solar panels
Relatively easy to install and well-known technology.
Suppliers easy to find.
Relatively high cost relative to produced power in the winter.
On cloudy days no amount of solar panels can help. (Especially November and December are mostly cloudy.)
Even on a sunny day the panels would have only 3-4 hours to produce the needed electrity in winter. Doubling the current amount of panels would not suffice.
Lengthen the time (spring, autumn) we are electricity self sufficient including charging an electric car.
Integration to existing system.
The only spot for installation that makes sense is vertical on the roof ridge (the roof itself is already full)

In our conditions our current wind mill is too small. The aim should be that on a windy day the batteries would be filled from empty (50%) to full, i.e. 16 kWh. My estimate is that that would require 3-4 times more swiping area, i.e. 30-40 m2 so the windmill diameter should be 6-7 meters and nominal power 8-10 kW.

More wind power
Well known technology
Power on cloudy days (if there is wind)
If big enough gives sufficient power.
Relatively high cost
Existing tower probably not sufficient for a bigger mill.
If there is no wind even a bigger mill can not help.
Potential electricity self sufficiency in the winter.
Excess electricity in the winter can be used for warming the house (5kW resistant cord already installed in the hot water tank) or charging the electric car.
Integration to existing system.
Requires more batteries to match the max power output.
Almost no local suppliers for small wind mills in 8-10 kW range.
Higher tower.

With a quick look in the internet it seems that a 10 kW turbine could be purchased at roughly 10000€. The cost of tower and installation could be an other 10000€, so total cost would be 20000€. For comparison – with an other quick search in the internet it seems that a big industrial 2-3 MW windmill requires an investment of 1,1 M€/MW (5), so the investment is roughly half of a small wind mill per kW power.

More battery capacity
Catch and store energy
Bridge over the winter days when there is neither sun nor wind.
Battery prices are decreasing and f.ex. used electric car batteries are becoming available.

Integration to existing system.
Only makes sense with more power generation

Overall the biggest challenge is cost – the technology is available.

Additionally Hydrogen Fuel technology is a potential way to store summer solar energy as hydrogen and back to electricity. An example from Sweden: Bränslecell i källaren: ”Nu är det vätgasdrift som gäller” and Skippar elnätet – med bränsleceller I källaren. This technology is however not readily available.

Electricity from wood

Finland has an abundance of wood and anyone who owns land in Finland almost inevitably owns forest. So transforming wood into electricity would be the natural choice for self sufficient electricity production. There are three different technologies that come up in this context.

  1. Thermoelectric generators. These can be pretty much dismissed because of very low efficiency and low power output (could be used for charging a mobile phone).
  2. Biomass gasifiers
  3. Stirling motors
Biomass gasifiers
– Produce gas that can run a generator for electricity.
– DIY and commercial solutions available.
– Biochar as a sidestream
– Small DIY solutions are extremely laborious, inefficient and cause high level of emissions (air pollution). (They can’t be considered a sustainable solution.)
– Professional versions are very expensive (35000 € and up) and small solutions for single house needs are not available.
– Must be fed with wood chips or pellets so they need to be purchased or a machine chain created for producing them (fossil fuels difficult to avoid).
– Integrate the gasifier to the house heating system (50-80% of energy is heat)
– Difficult efficiently retrofit in existing house heating system.
– Commercial solutions not available

It is easy to find information about gasifiers with google but difficult to find serious information without picking up the phone. F.ex Q Power in Finland has interesting technology but these are not single house solutions. There are several DIY experts in Finland and even books written about the subject (including gasifier powered cars).

Conclusion: not realistic to implement.

Stirling generators

Basic information about Stirling generators: https://www.stirlingengine.com/generators. A Swedish company Inresol has developed small scale Stirling generators but I suspect the company is not operating anymore. I tried to buy a 5 kW version some years ago but they would not offer it saying the technology was not ready. The Austrian company Ökofen now offers a combined pellet boiler (for heating) and Stirling Engine which they call Ökofen_e. Less than 10% of the energy output is electricity (10 kW heat, 600W electricity).

– Renewable energy (wood)
– Automatic system.
– Generates electricity with Stinger engine.
– Uses wood pallets: they must be bought.
– Connect to our hot water tank and floor heating system (would probably eliminate most need for using fireplaces)
– Use excess heat to heat some other building, f.ex hen house.
– Proportion heat/electricity is too high (15 to 1): to generate sufficient electricity will generate too much heat.
– We probably need to fire the kitchen stove anyway resulting in even more excess heat.
– Difficult to retrofit: No space in/under the house for the Ökofen boiler (even though they are quite compact)

We have floor heating piping in the house which is largely unused currently as we are unable to drive sufficient heat into the hot water tank. The Ökofen boiler could be connected to our existing hot water tank and thereby we could produce enough heat to run the floor heating system, largely eliminating the need to use the fireplaces. At the same time the Stinger engine would produce electricity.

On the negative side is that the Ökofen runs on wood pallets, which – while renewable – is a purely external resource as we can not produce it ourselves (it’s not even available locally). If it would run on wood chips we could theoretically produce it ourselves in the summer with solar panel powered equipment (Catch and store energy). Or at least buy the wood chips locally.

The other main problem is that the proportion electricity/heat is too low. On the other hand excess heat opens up other opportunities, i.e. heating some other space like a hen house.

And finally, we have made a rather big investment in fireplaces which would not be needed anymore.

Conclusion: not realistic to implement.

External sources

The simplest solution of course would be to connect to the grid. At the moment that is a no-go just for the simple reason that we have built an off-grid house and want to keep it that way.

An other external source that has become possible only recently is a “”mobile battery pack” aka electric car with V2L (vehicle to load). Until now you could not get electricity out of an electric car for other uses (or not in a simple way) but some recent models have V2L, i.e. a standard socket which in the case of Hyundai Ioniq5 and Kia EV6 (the first models that enable this) gives you 3,6 kW power for other uses. So if you make the comparison:

  • our house at the moment has 16 kWh usable battery capacity and the inverter gives 3,6 kW
  • a Kia EV6 has 77 kWh usable battery capacity and the inverter gives 3,6 kW

you realise that this gives some possibilities to develop a solution that is not perfect in terms of self sufficiency but is better than running a petrol powered generator.

Electric car with V2L
– In the summer the car can be charged with our solar panels for free (this electricity is otherwise lost because we cannot sell it to the grid).
– The car can store a high amount of electricity.
– In the winter the car can be charged elsewhere and thereby electricity can be “imported” to the house.
– Design Principle; Integrate rather than segregate. The V2L car has several functions: apart from the above listed it is a car and provides mobility.
– Eliminate fossil fuels in driving a car.
– Limited power from the house inverter for charging the car in the summer (currently 100 km requires 20 hours charging).
– The car can’t charge the house when it is needed for driving (Mobility).
– In the summer plug the car to the house in order to charge the car batteries from the solar panels.
– In the winter plug the car to the house in order to charge the house batteries from the car.
– Use electric appliances (f.ex. a garden shredder) at locations that are too far from the house for extension cords.
– Avoid fossil fuels in cars (Mobility)
– Cost of the electric car
– Slow charging of car from house (1 kW power). However max 100 km driving per day is sufficient in almost all situations.
– High ecological footprint in manufacturing an electric car.

The electric car is a big investment but after all it is a car, not only a mobile battery pack. I probably wouldn’t have bought a new car otherwise but now the electric car is a solution for our winter electricity challenge. I am aware about the sustainability issues of electric cars and especially the batteries which use materials that need to be mined. Finland is one of the countries that will be affected as many of the rare metals can be found here. Obviously I don’t want an open mine in my backyard (NIMBY) but – even if we forget about carbon emissions – it is also not ethical to forget about the environmental and social problems caused by fossil fuel extraction around the world. All that is happening somewhere else far away and we only get the benefit of cheap energy. If and as we still need cars electricity is the way to go for personal cars. Biogas is also good and essentially zero-emission (we also have a biogas car) but there is not enough production potential for sustainable biogas to transform all traffic into biogas (although there is potential for much more than is produced today). (7)(8)

Zoning Mobility

Above I am considering an electric vehicle (EV) so it is relevant to integrate with our Mobility. In the background article “Evaluation and site analysis 1: Sectors” I have analysed our mobility pre-covid19. I am updating that map below.


  • Koti = Iso-orvokkiniitty
  • Sale Saukkola = currently the closest charging station (>100kW) + small supermarket & hardwarestore
  • ABC Lohja supercharger
  • Lohja = city center of Lohja municipality
  • K-Citymarket Lohja = hypermarket with supercharger
  • ABC Karjaa supercharger

Most of my driving happens in this sphere and it is mainly linked to services that are not available in Karjalohja village. I go to Helsinki region on an irregular approximately monthly basis and drive in south-west Finland for business or private irregularly. Since I work from my home office and travel much less than pre-covid19 times my driving is relatively limited. I have now had the Kia EV6 for 11 months and have driven 16000 km (including a trip to Denmark and to Norway. If we calculate 18000 km/year it would mean approximately 4000 kWh/year consumption.

Marja goes regularly every week to Helsinki and drives with biogas.

Water & Hygien

Water will be discussed in a separate Design. In the below picture I am showing the Water System connected to the House.

The Water System connected to the House

Here I would like to discuss the main challenges related to water in the house and energy. The summer does not pose challenges in this respect as electricity is in abundance. Here I am thinking of the winter period.

  • In the winter we are squeezed for electricity. The water system in the house relies on pumps that run on electricity. When the electricity is off we don’t get water in the house. Back-ups are:
    • store water in the kitchen and bathroom
    • use the dry toilet outside to avoid need to flush the toilet
    • hand pump and carry water from the well (at the moment the hand pump is not installed)
  • The efficient production period of solar collectors (hot water) is shorter than for solar panels. Hot water can be expected from April until October. In the summer there is an abundance of hot water.
    • solar collectors stop being effective for heating household water before the heating season starts in the autumn. It means that in October – November there is either no hot water or the living room massive oven needs to be heated just for the water even if heating the house is not yet necessary.
    • In the spring the situation is similar but for a shorter period. After the winter the house structures are cold so heating is necessary at higher outside temperatures than in the autumn when the house structures are warm.
  • The energy consumption of the washing machine and dishwashing machine are high so we avoid using them in the winter period. Dishwashing is mostly done by hand and water heated on the stove. Washing machines in most cases require running the generator.


Food and drink are one of the key basic needs of humans. We normally eat and drink several times per day. Therefor a kitchen is a key part of any living quarters at least in our part of the world where it is considered normal to prepare food and eat at home most of the times. If striving for some degree of self-sufficiency you also need to process and conserve food as well as store it. I will do a separate design about our “Food system” so here I will only briefly touch on the connections between food and energy.

  • Water (energy to move it) is needed in the kitchen for food preparation, washing and drinking. Water is discussed above.
  • A stove is needed for preparing food.
    • In the summer we have a small electric induction stove and a water boiler. The limitation is that there is place only for one kettle. The wood stove can also be used but it creates excess heat.
    • In the winter we use the wood stove, which has the secondary function to heat the house. If the outside temperature is above 0°C heating the stove twice a day is sufficient to keep the house warm. Firewood needs to be carried in.
    • Store hot water in the termos for coffee later.
  • In the winter months I bake bread 2-3 times per month. The bakery oven has the secondary function to heat the house. If the outside temperature is below -10°C either big oven needs to be heated almost every day anyway. When the oven is warm, food can be prepared in the oven.
  • Dishwasher has been mentioned earlier (not used in the winter).
  • Other appliances in the kitchen that need electricity
    • stone mill: the traditional Finnish sour rye bread is 100% wholemeal. I mill the flour just before making the dough.
    • kitchen universal machine. It is not used on a daily basis – mainly for larger food preparation.
    • Fridge + freezer.
  • We have an extra full-size fridge under the house for summer use. Mainly for storing shiitake or other larger harvested volumes and it is used by volunteers in the summer.
  • Earth cellar is not connected to electricity.

Again the biggest challenge is the water in the winter period. Other than that a few things stick out if compared to a “normal” Finnish or western lifestyle:

  • A wood fired stove requires a different mentality. You can’t just press the button to get the water boiling. In the summer we can do that but in the winter it has to be “slow life”.
  • The induction stove has a single cooking spot so it is limiting food preparation in the summer. The stove’s max power input is 2000 W. Bigger induction stoves with 3-4 cooking spots typically use 6000 W which exceeds our inverter capacity.
  • Hand washing dishes in the winter.
  • We don’t have a big freezer for food storage due to lack of electricity. However placing the freezer in our cold veranda would mean that energy consumption would be very low in the winter.
  • You need a headlight when going to the earth cellar (or outside in general in winter).


The house was designed in 2015 and we built it 2016-18. Outside buildings (storage, earth cellar, sauna) were build in 2020-21. This design is about the tweaks that could help us meet our vision and needs better than the current situation. The need to tweak goes mainly around lack of electricity in the winter. Some of the possible ways to solve that have been evaluated above and I am listing some possible tweaks below.

Need to tweakHow to tweak
Electricity I will write about the electricity system below.
– lack of electricity from solar and wind in the winter months Different options are evaluated above (more wind, Stirling engine etc) but finally none of these options seems possible to implement at this point. The main limiting factors are cost of implementation compared to generated electricity, low efficiency and high need of external resources even after installation (wood chips).
– need to generate electricity with the generator in November, December, January, early February The most realistic way to eliminate the regular need for the generator is the electric car which is a cleaner and more efficient way of bringing in external electricity to the house when the solar panels and wind mill are not producing enough. The generator remains as a backup but the 2nd generator which we had for back-up can be sold.
– need to have 200 Ah back-up batteriesPossible to take electricity for prioritised appliances from the main batteries when electricity is otherwise off. Needs an electrician to do it.
– chainsaw runs on petrol Replace with battery driven chainsaw when winter electricity is sufficient and sustainable.
– requires a lot of physical work That’s ok as long as I am in good health.
– transporting wood from the forest to the house Currently using a battery driven wheal-barrow, car trailer or asking neighbours help with a tractor. I don’t want to buy a tractor or ATV so no tweak foreseen for the moment.
Water & hygiene
– lack of water in the winterSolved when winter electricity challenge solved.
Hand pump at well is the backup if there is no electricity. We also use rainwater for flushing the toilet if outside temperature is above freezing.
– need to store water in kitchen and bathroom in the winterSolved when winter electricity challenge solved.
– need to restrict use of washing machine (laundry) in the winter Solved when winter electricity challenge solved.
– lack of hot water especially autumn and spring (limited hot water in the winter)Heating the living room oven anyway.
A gas water heater could be installed but I think we’ll just adapt to cold showers periodically.
– saunaWe have build a very traditional log sauna with single-fired wood stove, which means the sauna experience is perfect but it takes 3-4 hours to heat the sauna up. A quicker continuous-fired sauna would be more flexible as it can be heated up in 30 minutes and decrease the problem of lacking hot water for shower in the house. Might sound crazy but in Finland it is quite normal for a sauna enthusiast to have 3-4 different saunas on a property. No plans to implement more sauna’s however.
– freezer: limited capacityPut box freezer in the cold veranda. Electricity consumption in the winter will be very limited.
– limited space for cooking in the summer A multispot electric stove is not an option because it needs more power than the inverter can generate (2kW per spot). Could use a gas cooker on the wood stove in the summer. Challenge where to put the gas bottle.
– dish washing in the winter by hand Solved when winter electricity challenge solved.
– fridge doesn’t get backup electricity when power is off Solved when winter electricity challenge solved.
– petrol carWas finally changed to a biogas car in January 2022.
Electric car is coming. (It arrived in December 2022)

Tweaking the electricity system

Our biggest frustration is lack of electricity in the winter which has various other effects as described above. I have analysed different options for solutions. The concrete question is how to eliminate the need to regularly generate electricity with the generator. We want to find a short term solution that functions already in the winter 2022-23 and explore longer term solutions.

Short term (this chapter was written in February 2022)

As described above a quick fix to the situation is an electric car with V2L (vehicle to load). I envision that this enables a situation where we need to go shopping to Lohja once a week and at the same time charge the car at the hypermarket parking lot. The full car battery should run the house for a week even if there is no wind (most weeks there is some wind). For the time being there are no charging stations in Karjalohja but on the other hand we pretty regularly go to Lohja anyway for services or shopping that is not available here (and new charging stations are popping up). I have placed the order for a Kia EV6 which at the same time will serve as a good quality car for my “business-self”. Lead times for cars are long, I hope to receive it in May 2022 (it arrived in December).

Of course, how this solution will work in practice is not completely clear. Questions I already have that can be answered only by observing once the car is here are:

  • Summer: Do we have enough power from the solar panels and wind mill in summer to charge the car?
  • Will it become a problem for our everyday life if we are charging the car most of the time with 1kW power, leaving other needs with only 2,6 kW (inverter is 3,6 kW)?
  • Can we charge the car 24/7 without depleting the house batteries in the night (summer nights are short)?
  • Winter: For how long can we in practise run the house with the car and will it allow us a more relaxed usage of electricity without going to charge the car in Lohja more than once a week?

How would this compare to the current situation? Now we are running the generator with 160-200 litres of petrol per winter producing some 300 kWh electricity and emitting 360 kg CO2 (3).

If we make the calculation for the Kia EV6 we get the following numbers:

  • battery capacity 77 kWh but recommendation is not to repeatedly charge to 100%. Also the last 15-20% charging is slower. So we can calculate in practise with 65 kWh when the car is charged (85%).
  • Consumption of the car in the winter is 25 kWh per 100 km so we nead 8 kWh for the 30 km distance to Lohja (closest charging station at the moment).
  • There should be some reserve when we start from home so let’s say 15-20 kWh left.
  • So when we are back from Lohja we have 57 kWh charge and we need to go get more when 15 kWh is left so 42 kWh is usable .
  • With the calculated 8 kWh/day consumption that would last us 5 days but if we squeeze a bit we could make it for a week. Also most weeks there is some day with wind.
  • In the course of the roughly 100 days of electricity deficiency we would import some 600 kWh into the house.
  • Average CO2 emission of electricity in Finland is 131 kg CO2/MWh (4). So 600 kWh equals 79 kg or appr. 20% of what we emit with the generator. The car will be charged with wind power so the difference is actually much bigger.
  • In the fast charging stations electricity is pretty expensive but can vary widely. To be on the safe side we can calculate 0,35€/kWh. Then the cost of 600 kWh would be 210 €.
  • Even if the period when we need to import electricity to the house is only 3 months the period when the car needs to charged elsewhere is much longer. Probably only the 4-5 summer months we produce enough electricity to load the car at home. If we calculate 20000 km/year and 8 months loading elsewhere (16000 km) we need to buy an additional 4000 kWh for the car at a cost of c 1400 €.

So the conclusion is that we still need to be conscious about our electricity consumption but we could use double the electricity in the winter compared to now.

The electric car charging stations usually declare that they are using 100% wind power. So all the electricity we use would be renewable. Of course it doesn’t mean that it is without an environmental footprint. Both the car and industrial size windmills have a pretty heavy footprint.

Solar panels and wind mills.

If the above works as planned the rest becomes an economical calculation. Does it make economic sense to try to eliminate the 1100-1200 €/year cost of buying electricity for the car and house? This is the kind of calculation that depends on the pay-back time and interest rate that we choose. If we calculate with 20 years payback and 4% interest rate we could invest 15000 € to save 1100 €/year cost (presuming there are no running costs in 20 years). If we presume 30 years payback and 3% interest rate we could invest 20000 € so let’s consider that the absolute maximum.

Would it be possible to totally eliminate the need to buy electricity to the house and car with 15000-20000€ investment? What would be the best way to do that? In the above analysis the conclusion was that only a big enough windmill (10 kW nominal power) and more batteries could be a realistic solution. It also shows that 20000€ most probably would not be enough. We also noted that a big industrial windmill is half the price relative to power generation – probably much less because they are located in optimal location and high enough to reach the winds. What if we made an investment in a tiny piece of an industrial windmill to cover our external electricity need? The investment would even pay a part of the cost we have in charging the car.

Further improvements (longer term)

The possibility to import electricity in the winter solves the problem we had in a satisfactory way. A possible improvement would be to invest in a bigger wind mill, but that is not topical for the moment.

For charging the car in the summer, currently there are 3 bottlenecks:

  1. overall power production is not sufficient
  2. the inverter is too small
  3. the charger of the EV is too small

The charger would be ok if we could charge 24/7. That requires solving 1. and 2. The current battery capacity should be sufficient but charging 24/7 would mean that the batteries go through a full charging cycle every day (full in the evening, 50% empty in the morning) and that would affect the longevity of the batteries.

So the plan is to double the solar panel system, i.e. solar panels, charger, batteries, inverter. This requires a more detailed technical plan and offers that I will not include here. For economical reasons it is not realistic to implement before 2024-25.

Experiences with the “Mobile battery pack” (September 2023)

So the tweak I did was to buy the Kia EV6 electric car with V2L. The car finally arrived in December 2022 – 16 months after placing the order. So now we have experience of the car for most of last winter and also this summer.

The situation in the winter was more or less as expected above. A new 100 kW power charging station was opened at the Sale supermarket in Saukkola 26 km from here which means about 14 kWh power consumption to drive back and forth. Of course mostly I would charge the car on my way home from somewhere but I did drive to Saukkola just for charging quite a few times. When there was no other need for mobility we could run the house for 4-5 days with the car. As expected electricity use became more relaxed when it was more easily available than before. Overall the system worked well. Electricity cost is c. 30c/kWh.

Obviously the failed cell had to be in the left back corner so I had to move the other 3-cell packs out of the way. Each one weighs 140 kg.

In March 2023 we had a problem. One 2V cell in house battery pack failed and therefore the batteries could not be charged or used. Fortunately the external electricity source (car or generator) bypasses the battery pack but as soon as the car was disconnected the house was without electricity. It took until end of May until we received the repalcement cell and could fix the problem, so the car had to be hooked to the house even though the sun was already shining. Fortunately we had the car – otherwise we would have had to run the generator practically all the time, which would have been a nightmare.

The situation in the summer was more mixed. Until now the feeling has been that we have more electricity in the summer than we could ever use. But the situation changes if you are charging the car with 1,2 kW power most of the time. We never ran out of electricity but I also did not charge the car 24/7. 24 x 1,2 kW = 28,8 kWh so that would be most of the electricity we have on a sunny day. So I could charge the car only during daytime on sunny days approximately 10 hours per day gaining 50 km driving distance per day. In practice it meant that I could cover my local mobility (Karjalohja, Lohja, Karjaa) with our own solar energy but any trips further out would require charging the car elsewhere. F.ex driving to Helsinki and back would require that I charge the car for 4-5 days before the trip. Also the time period when the car can be charged from the house is quite short covering mainly June, July and August. Then there is the spring period March, April, May and autumn period September, October, first part of November when we don’t need external electricity in the house but most of the time it is not possible to charge the car and finally the winter months late November, December, January first half of February when we need external sources of electricity.

Charging the car takes 1/3 of the capacity of our inverter which means that exceeding the inverter capacity becomes even more a risk than before. The charging needs to be interrupted if other bigger consumption is happening, fex. preparing food with the electric stove. So it requires quite a lot of consciousness about what electric appliances are needed and used at any given time.


This design includes a lot of evaluation about different options for tweaking our energy system in order to better meet our vision of high energy self-sufficiency. The evaluations serve the purpose of understanding what is possible, what is realistic and what would make sense when taking existing limiting factors into account. Compared to the evaluations there is actually not so much that has been implemented in terms of tweaking the system. See below:

Kia EV6Use EV to “import” electricity to charge the house batteriesImplemented (car received) Dec. 2022 and working as planned.
KIA EV6Charge EV with house solar panels to increase self-sufficiency in mobilityImplemented summer 2023
BypassPrioritised circulation pump for cellar heating from the main batteries when electricity is otherwise off (critical in the winter so that pipes don’t freeze).Implemented by electrician in November 2023
Additional solar panel systemIncrease capacity of solar panels, batteries and inverter in order to be able to charge the EV in the summer in a higher degree. Planned 2025-26
Electric chainsawNeeded for felling and cutting trees for firewood. Replaces the chainsaw that runs on petrol. Planned 2024-25


ElementMaintanence needWhen
Solar panelsNo maintenance. A gradual decrease in power (0,5%/year) can be expected (9). Industry standard is 25-30 years lifespan.
WindmillNo Maintenance. In our mill the only “moving parts” in the turbine are the bearings. A lifespan of 20-30 can be expected before bearings need to be changed.
BatteriesAdd distilled water.

1 cell has failed so far and had to be replaced.
Appr. every other month.
Battery lifespan according to seller should. be 15+ years.
Other electronics related to above (chargers, inverters etc)No maintenance. Lifespan?
Kia EV6Used to charge batteries. Drive to closest supercharger. Every 4-5 days if no sun or wind.
Lifespan of the car: 7 year warranty.
GeneratorAdd petrol.
Service engine.
Every 20 hours of use.
FireplacesSweeping chimneysAnnual.

Evaluating against Holmgren Design Principles

DESIGN PRINCIPLE (Holmgren)Evaluation September 2023
Off-grid systems in households are still not common, so it was difficult to get information about how it could work. Building the system and interacting with it has given us a lot of information that was not available and that we can now use for developing the system further and share with others.
Catching and storing energy is the essence of the whole design. Can we catch and store the energy we need? It can be done in a reasonable way in the summer but the winter is challenging and the cost of 100% self-sufficiency would become very high – or electricity consumption should be decreased more than we are currently willing to do. The more basic need of keeping the house warm over the winter can be covered with firewood.
The yield is energy in the form of heat and electricity.
The grid is an “infinite” source of low-cost electricity. Only recently has a feedback loop emerged in the form or price fluctuations. In an off-grid system the feedback loop is more concrete: if there is no sun or wind the batteries will soon run empty and there is no electricity to use. You have to adapt: self-regulate your consumption.
– firewood from our forest
– purchased firewood
– solar energy from our solar collectors (hot water)
– solar energy from our solar panels (electricity)
– wind power from our wind mill (electricity)
– purchased wind power imported via our EV (electricity)

Even if these are all renewable energy sources they definitely have an ecological footprint. It would be challenging to do an exact calculation but I imagine the list above is in order of how heavy the footprint is. The order would change if we forget about the ecological cost of the investment in each system. In that case the purchased firewood contains the highest fossil fuel load.
Burning firewood produces ash that can be used in the garden as nutrients and for increasing soil pH. Burning firewood also causes emissions into the air – even if our fireplaces are low-emission designs.

On the long run waste from the different systems is largely a question of the lifespan of the systems (as long as possible) and how those materials can eventually be circulated. All the electricity related systems include materials that can not be circulated on the farm.
The patterns:
– the seasons: warm and sunny in the summer, cold and dark in the winter
– heating mainly in the winter (warm water also in the summer)
– electricity production higher in the summer and lower in the winter
the main challenges of the design concern the winter
See separate Functions – Elements analysis below.
Our energy solutions are small in the sense that they fit a single house situation. They are slow in the sense that winter electricity supply is limited and we adapt to that.
There is a diversity of sources of energy and elements that supply it.
The house roof was used to install the solar panels and collectors.
CREATIVELY USE AND RESPOND TO CHANGE. Using an EV for “Importing” electricity in the winter was not an option or even a thought when the house was designed.

Functions – Elements analysis

As the illustration shows, most functions are served with several alternative elements. However some elements – especially those with the purpose to produce electricity, serve only one function. Some elements are used mainly in the winter and some in the summer. Some functions, most notably heating the house, are needed only in the winter. A critical factor in the winter is not to let the incoming water pipe freeze. This requires that the circulation pump feeding the cellar chamber with heat through hot water piping. It only requires 10W power but it still requires that the power is on in the house in the winter. Until now that has been solved with a spare battery connected to the circulation pump but the system will be fixed with a priority output from the main batteries. This was already in the original design but has never been implemented until now (November 2023).

Moving water is a key reason why it is difficult to be without electricity for a longer period.

It is good to point out also some elements that we don’t have. We have gravitational ventilation so we don’t have a mechanical ventilation and heat recovery system. That means we loose some heat in the winter but we don’t depend on electricity for our ventilation which is a vital function in a house.

How does the Design relate to Planetary Boundaries?

Earth-system processWhat can we do? Evaluation
1. Climate changeAvoid use of non-renewable energy sources. The case could be made that we use only renewable energy sources and therefore we are climate neutral in our energy use. When it comes to heating the house with wood I think the case is valid as we can at the same time block our 6 hectares of forest of other logging. The electricity story is more complex as it has required a sizable use of natural resources to build up the system. Would it have been better to stick to the grid and wait for the electricity in the grid to gradually get cleaner? Our second main argument against the grid was nuclear energy which is not directly addressed in planetary boundaries.
2. Biodiversity lossFirewood can be harvested in a way that enhances biodiversity in the forest.
3. BiogeochemicalNo real connection to N and P cycling.
4. Ocean acidificationNo real connection.
5. Land useThe house itself takes up land but the energy system doesn’t much add to this. Solar panels and collectors are on the roof. The windmill required some clearing of trees but essentially it is inside the forest and no service road was built. Everything was carried up.
Indirect effect in land use for mining etc especially regarding building the EV.
6. FreshwaterHousehold water is a separate design and it should not have any negative impact on freshwater.
7. Ozone depletionNo real connection.
8. Atmospheric aerosolsNo real connection.
9. Chemical pollutionThe house was built almost only with natural materials to avoid chemical load. The energy system does link to mining. Therefore indirect effect through manufacture of EV’s and off-grid equipment.

When it comes to energy management in a private house the main planetary boundary to consider is climate change. Climate change mitigation should be realized without harming the other planetary boundaries. The main concerns with clean electricity are land use and chemical pollution.

Have we realised our Vision?

Our Vision became to be as self-sufficient in energy at Iso-orvokkiniitty as possible.

I think we are doing pretty well.

Have we met our needs?

I discussed Our Needs in a separate article. That discussion was much broader than just Energy. The Vision regarding physiological needs was to “Enable an ecological lifestyle with a high degree of self-sufficiency in energy, food and materials.” While only energy was the focus of this design it can also be stated that energy is the only sector where “a high degree of self-sufficiency” has been reached. We don’t have the data to do an exact calculation but my crude estimate is that on annual basis we produce 90% of our electricity usage of 4200kWh/year, but in November-December-January we produce only 20% with solar or wind and cover 80% from external sources. The value 90% comes from using more electricity in the summer when it is in abundance and less in the winter when it is scarce. However 25-30% of the year we are heavily dependent on an external source – be it the generator or the electric car.

On the other hand the electric car enables us to cover some of our energy needs for mobility from the solar panels in the 3-4 summer months. If we calculate 10 kWh per day every second day for 3 months that would be 450 kWh so in par with what we need from external sources in the winter.

Electricity source or sinkkWh
Electricity consumption in the house (estimate) (4mx5kWh/d+4mx10kWh/d+4mx20kWh/d)4200 kWh
Electricity consumption for mobility (EV6: 22 kWh/100km) 4400 kWh
Electricity imported to the house (winter)600 kWh
Electricity charged from the house into the EV (summer)450 kWh

Evaluating our Vision in a broader sense than just energy:

EARTH CARE Evaluation
Use natural materials and construction technologies with as small an environmental footprint as possible.In the house itself – yes.
Burning firewood for heating – yes.
Equipment related to electricity supply – materials are definitely not natural but the overall ecological footprint is hopefully smaller than in the grid. But I cannot be sure.
Enable an ecological lifestyle with a high degree of self-sufficiency in energy, We have a high degree of energy self sufficiency (see more detailed discussion below). Mobility is a challenge in the countryside but biogas and electricity should be a way forward although not perfect when the whole lifecycle is taken into account. (Perfect would be no mobility.)
Take responsibility for an energy descent.Yes, but how much we directly use energy in a household is only one part of the story. A big part of our energy footprint is in the products and services we buy and consume. Decreasing consumption and increasing self-sufficiency is a big part of the equation.
FoodThe house and buildings enable us to develop a high food self sufficiency. We have space for preparation, dry storage in the kitchen, earth cellar for potatoes and root vegetables and preserves. The earth cellar does not require external energy. Food deserves its own design.
and materials.Self sufficiency in other materials is low and difficult to achieve. Fiber for textiles could be grown (Marja is interested). Wood works can be done from own material. A lot of modern gear is not possible to produce yourself and should be considered critically. We posses most appliances and gear that are considered normal in today’s world (well, we don’t have a home theater or even a TV) so in that respect we are not “better” than anyone else. Decrease consumption and dependence, increase product lifespan, recycle, fix, simplify.
Minimise wasteAll organic / biological waste is kept on the property except solids from the septic tank (even those could be kept and composted). Newspapers are mostly used for lighting the fires. Other paper, cardboard, glass and plastic is cycled. We try to minimise “Mixed waste” and should work more on minimising plastic. The amount of cardboard and plastic correlates strongly with food bought from shops so food self sufficiency is a way to decrease waste.
Create a healthy and inspiring living environment for ourselvesI think we have done it.
Enable social life and living according to our valuesWe have had more friends and new acquantacies visit us at Iso-orvokkiniitty than in our lifetime before this. Covid19 changed that temporarily but we are getting back to normal.
Share our experiencesOur blog, this Diploma work, workshops etc at our place.
We need space for workshops and accommodation.
Being self-sufficient is fair to others who also need the resources.
HospitalitySee above. We need more space for accommodation.

Integration with other designs

In the last stage of writing this design I narrowed it down to the energy aspect. Likewise I narrowed Design 1 down to the Ponds instead of the whole water system. So a spinoff of both designs (1 & 2) would be “Household water system at Iso-orvokkiniitty”.

A big part of our vision has been to increase our self-sufficiency in food and if possible other materials. So “Food” should be a design. One of the other materials is fire wood which would link to a “Forest management” design.

Also a “social design” would be in place covering the other needs (environmental, cognitive, emotional, psychological, alignment, connection).

What Design Tools did I use?

  • VOBREDIMET framework where Design is Tweak.
    • I used VOBREDIMET also in Design 1. It works well for me but in future designs I should experiment also with the other frameworks.
  • Vision linked to Permaculture Ethics
    • To me this is the best way to get the vision right.
  • Needs analysed with Maslow and Sosteric and Ratkovic mapped in a table with Vision
  • Site analysis including Zones and Sectors in linked articles
  • Functions-Elements of House and Energy System in linked article
  • SWOC to analyse alternative solutions
    • a quick way to see positives and negatives of any solution
  • Illustrations
  • Evaluations
    • Holmgren design principles
      • they are an effective way to look at a design from different perspectives that one might not otherwise think about
    • Functions – elements analysis
      • good way to visualise connections or lack thereof
    • Planetary Boundaries
      • in this case Planetary boundaries was not that useful other than showing that energy mainly links only to one aspect of planetary boundaries
    • Permaculture Ethics
      • evaluate how vision was realised using the same tool as for formulating it

All the tools were useful for the design and there was not much overlap.

The learning pathway

This design has been in the works for quite some time. I started writing the design in January 2022 but it links to articles written much earlier and of course the house and energy system were designed during 2015. The design is also quite big and was originally even bigger comprising all aspects of the buildings at Iso-orvokkiniitty. I finally focused in the energy aspect only but you can still see traces of the other aspects in the design. In fact if you design a new house you do need to take all aspects into account and the design becomes extremely complex. That is why there are standard solutions for building houses and no design actually starts from scratch. That can become a problem if you are designing for a permaculture lifestyle. Then you should start from your needs and how you are planning to satisfy them and how that affects your lifestyle and what you will need in your house.

The Design category is “Built Environment” and “Tools & Technology”. The Design Framework is VOBREDIMET so the same as in Design 1. Several tools are used, many of which the same as in Design 1. In this design I am heavily using SWOC analysis to evaluate different alternative tweaks. I also illustrated a Functions – Elements analysis which seemed appropriate in a relatively complex situation like this. I did not use Scale of Permanence as the Yeoman framework did not seem useful in this case and also the Planetary Boundaries only showed that when focusing on Energy we are focusing on Climate.

(1) Sosteric, M., & Ratkovic, G. (2020, December 19). Eupsychian Theory: Reclaiming Maslow and Rejecting The Pyramid – The Seven Essential Needs. See also “The Heroes Journey, The Myth of Heroic Independence, and the Circle of Seven Essential Needs

(2) Paul Jennings. 26.8.2018. What might buildings, settlements and even regions look like through the lens of Permaculture design?

(3) https://www.openco2.net/fi/co2-muunnin

(4) https://www.openco2.net/fi/co2-muunnin

(5) https://weatherguardwind.com/how-much-does-wind-turbine-cost-worth-it/

(6) https://www.halkoliiteri.com/polttopuuinfo/energialaskuri

(7) https://julkaisut.valtioneuvosto.fi/bitstream/handle/10024/162032/TEM_2020_3_Biokaasuohjelmaa%20valmistelevan%20tyoryhman%20loppur%20.pdf?sequence=1&isAllowed=y&fbclid=IwAR03jYkdaU4odL_F7vlQcTeW7LxZ76atlIyRrhYdEpMfgcrANt6gariTR8o

(8) https://liikennefakta.fi/fi/ymparisto/liikenteen-kasvihuonekaasupaastot-ja-energiankulutus?fbclid=IwAR1yd6-9o_gdR0VEqL-hxRYDsVp86f5L4KHMahQuHC8iabXYeLCPk24fxFM

(9) https://www.marketwatch.com/guides/solar/how-long-do-solar-panels-last/

(10) https://www.hs.fi/talous/art-2000009741275.html