::: nBlog :::
For the past 12 years, we’ve lived in the countryside seafront aroud 50km from Helsinki. Our property, or a fishing farm as it was called in the early 1900s, is technically on an island of the Finnish Gulf, with a road isthmus built somehwere in the middle of 1800s.
Water pumps (both for drinking water and heating) and sewage treatment require constant electricity, so in order to cope with intermittent grid outages we decided to build a 5kW wind turbine, 2.5kW of photovoltaic panels and a 50kWh battery bank to overcome a missing grid for up to two weeks. In addition, there’s a 75kW Diesel generator with a tank allowing for two months total self-sufficiency. The biggest energy drain, heating for 400m2 house, is a triple system employing geothermal, biomass furnace and lastly an oil burner utilizing the generator Diesel reservoir.
After the system was built up, our biggest surprise was the variability of wind and solar power available at any given moment. Furthermore, I had not realized that heating was actually around 80% of all our energy consumption. With the help of accurate measurements with our platform, however, we were able to attain around 30% efficiency gains by adjusting the geothermal system and burning own wood and suitable household waste.
In addition to direct investment costs, there are also maintenance costs and work which are very different for different energy sources. The wind turbine requires yearly gearbox inspection and lubrication and needs a large crane for it. The Diesel generator must be test-run every month and wants an oil change every two years. The solar panels (both photovoltaic and heating) must be washed a couple of times in the spring. And, last but definitively not least the 1200kg lead-acid battery bank needs watering and corrosion inspection around four times a year. Even with careful care, these 100 year old technology batteries only last a maximum of 9 years; meaning that we’ve recently replaced them all.
A long story short, being energy efficient and self-sufficient is not an easy endeavor. The semi-omnipresent grid and cheap gas has made our societies wasteful and careless, by introducing electric-only heating systems and abominations like open-air balcony heaters.
To reach a sustainable society also what comes to energy, the first step is to enable accurate measurement and control of these precious resources. This requires a sea change in thinking, but luckily we’re seeing promising, albeit slow progress with our utilities and other service providers.