Located in Northern Finland just inside the Arctic Circle lies the village of Kempele; a small community of ten families living completely off-grid. However, their lifestyle may be somewhat different from what is considered the “conventional off-gridder”. The homes have fully equipped kitchens, an abundance of low energy lighting – some have Jacuzzis! So how do they provide enough electricity and heat to sustain them throughout the year which can include a very cold Finnish winter (-30°C kind of cold)?
The answer is a Volter Gasifier plant. Using wood chips from the local area, the gasifier burns this fuel incompletely to produce wood gas, which is then burned to provide electricity. The thermal energy produced is used to heat a huge water tank, which then pumps the warm water through a series of pipes making up an underfloor heating system for the houses. By using the thermal energy to heat water the community is reducing its electricity usage. Any excess electricity is stored in three large battery packs for later use. The Volter is able to power and heat the ten homes for the whole year, even through the cold winter. Each family pays €1,500 ($1580) per year for both their heating and electric.
The Volter system starts at €150,000 ($158,000) which the community paid for collectively, by pooling their resources. Although a steep initial investment, it’s taken only seven years for the community to see returns. In locations where the cost of electricity and heating is higher than Finland, returns on the initial investment could be seen in as little as three years.
After the success of Volter’s initial pilot project in Kempele, the product design has been adapted and streamlined to look more aesthetically pleasing and is being rolled out across a wide range of countries, including Canada, Australia and the UK.
But what exactly is a gasifier and how does it work?
Gasification is the process of using heat to transform a solid fuel, like wood, into a flammable fuel, normally gas. Initially the solid fuel is burned without enough oxygen, a process called incomplete combustion. The output gases produced (including carbon monoxide and hydrogen) are still combustible and so can be burned as a fuel. This is basically a process which involves controlling the stages of combustion. You can find out more details on the staged combustion process here.
Gasifiers are not new technology, in fact far from it. During the Second World War over a million vehicles in Europe had on board gasifiers due to a rationing of fuel such as diesel. They have also been used in agricultural machinery such as tractors.
In more recent times however, gasifiers can be used to power whole communities, such as in the example above or can be more small scale.
For example, the BioGen Woodlog Power and Heat Unit produced by Microgen. This on or off-grid unit is a combination of wood gasification and Microgen free piston power generation, providing both a power and heating solution. Wood is placed in the primary fire box which produces wood gas by being heated in low oxygen conditions. The wood gas is then sucked into a second fire box with higher oxygen conditions where it is fully combusted. It is in this second firebox that the head of the Microgen biomass stirling power unit is located. When this reaches a certain temperature the unit starts to produce power which can be in either AC or DC. The heat of the fire boxes is absorbed by a coolant through heat exchangers on the walls of the boxes.
The thermal output is a maximum 20KW, with a water capacity for 100 litres and temperatures reaching up to 90°C. The 180cm x 60cm x 85cm unit weighs in at 450kg and has 80% efficiency.
There is also the option to build your own gasifier and there are many instructions available online for various models. However, working with flammable materials and toxic gases can be very dangerous and should you decide to go down this route, it is very important to do lots of research and take all necessary precautions to keep yourself and those around you safe.