Biomass is nationally and globally considered to be the greatest potential of renewable energy. It is composed of materials of plant and animal origin, suitable for energetical use. According to the source of creation there is:

• forest biomass - fuelwood, limbs, stumps, roots, bark, sawdust
• agricultural biomass - a cereal and rape straw, hemp, animal excrements, junk
• woodworking industry waste - shred, shavings, sawdust
• solid municipal waste - wooden matter in the SMW is about 1%, which forms approximately 1 kg / person / year

The most wide-spread biomass is wood. Plant remains, such as straw, or animal excrements are less used. For energetical purposes fast growing trees (willow, poplar) and plants (hemp) are intentionally grown. The energy production is similar as in thermal power stations by fossil fuels’ combustion (coal, gas), but with much lower rates of CO2 emission. Biomass is considered to be a neutral fuel according to the CO2 emissions, because during its combustion, same amount of CO2 is released, as a plant has accepted during its growth. Biomass energy has its origin in the sun radiation and photosynthesis.

Biomass was used for heating long time ago. Except ordinary heat production by direct combustion the biomass energy is nowadays used for electricity production, and as the so called biofuel for cars.

According to the used biofuel and a device for the conversion of bioenergy into electricity, there exist more basic conceptions of electricity producton. They are especially:

• Steam boiler (grate, fluid bed, etc.) for solid, respectively gaseous biofuel with a steam turbine and an electric generator (flash prezentacia). Electric energy is gained from biomass by combustion of biomass and production of steam, that moves the steam turbine. Similar to ordinary thermal power stations.
• Combustion turbine with an animal excrement biogas electric generator, respectively wood gas generator - for gasificated wood. It is a newer method, where the biomass gasification begins without air access, that means gasification or biogas production. The biogas is used in the gas combustion turbine that runs the electrical generator.
• A piston gas engine with a generator driven by biogas or wood gas. The produced biogas or wood gas is used in a gas engine, which runs the electrical generator.
• Piston engine with a generator, driven by biodiesel or ethanol
• Electrochemical fuel cell with biogas, respectively liquid biofuel.

For reaching the maximum use of energy in the fuel, all the sources mentioned above are realized mainly as a combined energy and heat production. They are labelled by KVET shortcut or by a word cogeneration.

One of the biomass-using energy sources in Slovakia is being built by our company in Hnúšťa. We produce electrical and thermal energy based on the wood gas combustion in the piston engine with a generator. We gain wood gas by thermochemical gasification of the biomass (wood chip) in the gasification reactor. The power plant is going to be in service from the beginning of 2015 and is going to produce 1 MW of electricity and simultaneously produce similar amount of heat, which will be delivered to flats and other industrial objects in the city.

It is a clean wooden ash, without chemical or dangerous additives, which is environmentally unharmful. The ash contain more than 95 % of carbon, which means it can be considered as the powdery charcoal. The amount of this ash produced is 150 tonnes / year. It is meant to be sold as an additive for energetical commodities, or it is possible to produce charcoal briquettes by self-processing of the ash.

The increase of the traffic congestion by trucks that will be transporting the wooden waste into the biomass power station in Hnúšťa, is minimal in comparison with the present state. The prediction is designed for 500 trucks per year.

The biomass is a neutral fuel. The amount of CO2 produced by its combustion is nearly equal to the amout of CO2 consumed during growth of the biomass by photosynthesis. Unlike fossil fuels, the combustion of biomass does not increase the concentration of organic hydrocarbons in the atmosphere.

The Earth’s fossil fuel resources are being reduced and switching on renewable sources such as water, wind, sun, thermal energy and biomass is more and more emphasized. A problem in the heat production is the dependence on the gas supply from the Russian federation, what was most seen during the gas supply interruption for more than 14 days in January 2009.

Production of heat in the biomass power plant brings energetical independence from gas supplies, which were used for production and supply of heat in Hnúšťa, too. By replacing the traditional fossil fuels (gas, coal) with a domestic ecological source - the biomass, respectively with other renewable energy sources, we achieve except lowering the greenhouse gases’ emissions the fact, that finances would stay in the region. Growing and preparation of biomass in local conditions ensures creation of new job positions including those, which are not attractive for foreign investors because of insufficiently built infrastructure.

• lowering the need for gas means the independence of the city from gas supplies, respectively other primary energetical sources, and smooth supplying with heat even during a “gas crysis”.
• use of wooden waste from production or from cleaning of forests,from an urban greenery; securing the wooden waste consumption for woodworking industry and forestry in the plant’s surroundings during the whole year.
• The new source of electrical energy secures an improvement in city’s electrical network. lowering the amount of potential outages of the power supply, increase the potential for the development of business entities in the city
• Increase of employment by creating 25 job opportunities in the power station and in parallel productions.
• indirect - secondary increase of employment in the cleaning of forest after the logging, preparation of the fuel, and logistics (about 30 people for every 10 000 t of wood mass)