Volter – Electricity from the woodgas

Pekka Hietala

Volter power plant produces electricity and thermal energy by gasifying the woodchips. New indoor –model electric power output is 40kW but plants can also be connected side by side, if more effeciency needed.

Wood gasification

The wood will gasify in the high temperature if there is oxygen minimally available. The product gas which forms in the pyrolysis can be used as fuel of the combustion engines.

Wood gas was familiar fuel of the vehicles of the formely times. The problem in the combustion engines was tar contained by the gas. Later the technique has been developed to improve the quality of the wood gas. The problematic tar can be broken to smaller particles during the gasification process.

Wood gas generator with combustion engine provides an interesting way to produce energy from renewable fuel. Electric energy can be obtained, when the wood gas engine is connected to a generator. Also the heat which is created in the process can be utilised.

Finnish power plant manufacturer Volter has examined the gasification of the wood and after few years of product development has built the power plant capable of produces electricity and heat. The fuel of the power plant is woodchips.

Product gas consist about 17% of hydrogen 25% of carbon monoxide and 2% of methane. In the cleaning device that has been connected to the gasification process a soot and coal can be separated furthermore. When burning, product gas emissions are only water vapour and carbon dioxide which has bound itself to the wood.

 Wood gas which is suitable for a motor

The Technical Research Centre of Finland (VTT) has studied the contents of Volter powerplant product gas. In the results it was mentioned that product gas is very clean so the gasifying process is idealised. The contents of tars were very small and there were really no compounds heavier than the naphthalene in gas. Output power level of plant or the fuel itself did not have an effect on the tar content on basis of the measurings either.

Volter CHP -power plant produces electricity 40kW and heat 100kW. According to managing director Jarno Haapakoski, the plant is suitable for example for an industrial establishment, to a farm or for the group of the residential buildings. When plant is connected to the country network it is possible to sell the electricity produced by the plant. The plant can be equipped, if necessary, also as an independent energy islet.

To create optimal power plant Volter was first concentrated especially on functional technique in the product development. The first model was packed in a container which can be landscaped to their environment on alternative covering materials.

The power plant container can be placed on a yard and connected to the electric and heat network of the buildings. The demand is that in all the buildings heating systems should based on water circulation. Heat produced by the power plant can be also utilised, for instance drying of the woodchips or, on the farms, for the drying of the corn.

According to Jarno Haapakoski, 80% of the plants is sold abroad. Container model produced considerable transportation costs so a new model which could be installed in a finished building was needed – Time was ripe to a new compact power plant model.

Indoor 40 – new covering but familiar effect and technique


New compact indoor model produces also 40kW electricity and 100kW heat –  The tested technigue is familiar of the container power plants but now installed the steel body frame which has been covered metal sheet.

The outside measures of the plant are length 4820mm, width 1270mm and height 2500mm, so it can be installed in a small state. Plant has been designed to be installed in the interior so a cover is sound-proofed and plant has an efficient heat recovery in it. The woodchip feeding takes place from the top of the device and the necessary interfaces are also ready. The ash removal has also been automated.

Indoor -model can serve as an individual unit or plants can be connected side by side. The wholeness can be use to produce heat for example to a district heating net and electricity can be produced for own purposes or to be sold.

At side by side connection model capacity of electricity and heat can be added or reduced fast and flexible according of needs. Also the maintenance of devices goes without interrupting production. In the side by side connection for example the production of the electricity can be adjusted between 30 kW – 500kW.

Volter the power plants can also be connected side by side

Volter has distribution channels in Europe, in North America and in Australia. The device deliveries have been made to the following targets:

  • 3 x 30kW Oulu district, Finland, 2009-2011
  • 40 kW Nurmes, Finland, 2012
  • 30 kW Ilomantsi, Finland, 2013
  • 40 kW, Alpua, Finland, 2013
  • 70 kW, Stamford, UK, 2013
  • 40 kW, Oulu, Finland 2014
  • 40 kW, Timmins, Ontario, Canada, 2014
  • 30kW, Leeds, UK, 2014
  • 80 kW, Sydney, Australia, 201480 kW, Grasheide, Belgium, 2015

Model:       Volter 40

Fuel:          Wood chips (birch, spruce, pine, aspen)

Fuel moisture: <18%

Particle size: 8mm ≤ P ≤ 50mm, fine particles (<3,15mm) <1%, all <63mm

Fuel supply: Spring agitator, auger, rotating feeder

Gasmotor: Agco Sisu Power 8,4L, 6-cyl.

Output:     Generator output 30kW (40kW), thermal 80kW (100kW)

Plant usage (e): ca. 1,5-2,5kW

Fuel consumption:      ca. 3,5 m3 (4,5 m3) of chips/24h at 100% power level

Automation: Schneider electric PLC, GSM –alarms, remote internet control

Connections: Electricity cable, Heat channel, water line, broadband, GSM-connection

Ash removal: Automatic ash removal

Maint. interval: once a week


The ecovillage shows the direction for the future

 ekokortteli 254

The energysociety of 10 detached houses served as the pilot target for Volter power plant product development. Ecovillage was not connected at all to the country network.

The development work of the Volter power plant was begun at 2009 by founding the ”energysociety” of 10 detached houses. This ecovillage was not connected to a country network so the electricity and heat needed by the houses had to be produced in all the situations with an own power plant. The development work that had been made in front of the compulsion led to the reliable technique.

The ecovillage was a totally self-sufficient energy islet during the development work so a reserve power machine was needed and the produced electricity was stored to a 200 V batteries which reservation capacity is 6200Ah. In the power plant building there is a boiler of 7000 litres from which the heat was divided into house-specific smaller boilers.

The power plant has produced electricity 70580 kW per year and heat 228,700 MWh. A five year pilot episode succeeded because all electricity and heat were independently produced.

Power plant with high standards

Omasähkövoimala voidaan maisemoida pihapiiriin sopivaksi.

The power plant can be landscaped to suit its environment.

The standard of the first container plant that has been delivered to the customer was extremely challenging.

The area of the buildings was altogether 400m² so the heat need was relatively minor with respect to the capacity of the power plant. The power plant produces electricity only a third compared to the heat but still the demands into an electricity produce were high. The electricity would be sold to the country network whenever possible.

To adjusting to different production situations was required of the power plant. Furthermore, the reliable operation of the power plant was an absolute precondition. Also the landscaping of a plant and woodchip warehouse to the yard required special arrangements. The unit is a energyislet and there are the intelligent mains supply, fully automation and follow-up of the energy consumption.

The logic control (PLC) of the unit is able to adjust electric power when necessary. The operation of the plant can be followed and can be adjusted with the help of the remote connection for example with a computer or telephone.

The plant unit is able to scale electricity production on the space 10–30 kW and it serve independently also in the interruptions in the distribution of electricity of the country network.

The unit will produce 129MWh of electricity in a year from which about 50 MWh is sold. The heat is produced 450 MWh in a year and the wearing of the woodchip is about 700 MWh.

Renewable energy at use on the contryside

Kun tarvittavat putkitukset ja kaapeloinnit olivat valmiina, voimala tuotiin tontille ja liitettiin verkkoon. Voimalan vierellä on erillinen hakesiilo, josta polttoaine otetaan jousipurkaimella ja ruuvikuljettimilla voimalalle.

Power plant and chip warehouse side by side. The electricity and the heat are produced to 300 cattle farm.

The first Volter power plant that has been delivered to a Finnish farm produces 40kW electricity and 100kW heat. On the farm there are 300 cattle and it produces a million litre of milk per year and corn also. The electricity consumption was 350000kWh in a year. Furthermore, there was an oil heating in the buildings.The power plant was delivered to the farm in the container and a woodchip warehouse was built next to it. The feeding of the woodchip to the plant from the warehouse has been automated. The power plant was connected as part of a country network so the surplus electricity is sold out and if necessary, is bought from there when needing electricity. The plant is able to produce all heat needed and it is possible to utilise the extraheat also in corn drying and drying of the woodchip. The woodchip which is dry enough (moisture <18%) is a precondition for the operation of the power plant.In the dryer warm air is directed to the woodchip pile with the duct fan from below. 50 cubic metres of chip will dry in three days.

fortel 100

Optimal product gas is created from an good quality and dry woochips

The plant has been run forexample in mild weather (<-10°C) directed with the heat need an about 45% effect in which case the plant will spend woodchip in about 2m³/a day. With this driving model the power plant has been able to produce the electricity which is half of the need 16000kWh/month. The heat is always sufficiently obtained.

The maintenance of the power plant can be made without the specialisation. The automatism manages the cleaning of filters independently. The forming coal is automatically carried to the container which is emptied twice per week. The oil change of the gas motor is performed at intervals of 500 hours.


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