Biomass (organic matter) can be used to provide solid, gaseous and liquid biofuels (wood logs, pellets, biomethane, bioethanol). The different types of fuels can be used to produce electricity, heat or fuels for transportation purpose. The market for biomass based heat is dominated by small scale units for providing thermal energy for cooking and for space heating from mainly solid wood fuels in developing countries. In industrialized countries, the heat market is determined by small and large scale devices mainly for room heating purpose based on woody solid biofuels; the latter is partly realized in CHP.

The markets for solid biofuels needed to operate especially small scale ovens are often characterized by informal market structures, particularly in rural areas; this is true in less developed countries as well as in industrialized nations. Therefore, the available data about the biomass-based heat provision is fragmentary and varies considerably. One estimate indicates globally a heat provision of 23.7 EJ (2014) originating from solid biofuels with a fuel energy of 59.3 EJ (2014).

By the end of 2014 the worldwide installed electrical capacity of the biomass fired power and CHP-plants have been between 75 and 93 GW. During 2014, the electrical power operated by biomass increased by estimated 5 GW.
On a global scale, electricity generation from biomass is clearly increasing. In recent years, the US, Germany, China, Brazil and Japan have had a significant power production from biomass. Within the US an installed electrical power of 16.1 GW has been under operation by the end of 2014. Due to limited policy incentives for new installations, growth has slowed down in recent years and only 0.3 GW has been newly installed in 2014.
In China, the capacity installed in biomass fired systems increased by 1.5 GW by the end of 2014 compared to the year before. Altogether 10 GW has been under operation. These installed power plants realized an estimated electricity generation between 35 and 70 TWh (2014).

Japan added close to 0.9 GW of new capacity installed in biomass fired systems to the available power plant park. This leads to an overall available electrical power of around 4.7 GW with an electricity production of 16 to 33 TWh (2014).

In India, a total of around 5 GW is installed in power plants operated by biomass. These plants produced between 16 and 35 TWh (2014). Because of uncertainties in biomass supply the growth has slowed down in 2014; only 0.5 GW of new electrical power have been added during the year 2014.

In Europe, close to 36.5 GW of electrical capacity have been in operation at the end of 2014 providing between 128 and 256 TWh (2014). Countries that added significant new capacities have been for example the UK (0.5 GW) and Germany (0.4 GW).

Solid biomass

From a technological point of view, a share of 70 % electricity production from solid biomass is dominated by "classical" grate or fluidized bed fired power plants operated for a pure electricity generation as well as in cogeneration (i.e. CHP); grate fired systems are most widely used on a global scale due to their robustness and cost-efficiency as well as the well-known and relatively simple resp. robust technology.

Additionally, co-firing in coal fired power plants is also widely used especially in some European countries (the UK, Netherlands, Belgium, and Finland) where significant amounts of biomass are used for electricity generation with high electricity generation efficiencies. By the end of 2014, only very few gasification projects for electricity generation are under operation or construction worldwide (Güssing and Oberwart in Austria, Ulm in Germany, Gothenburg in Sweden).

The solid biofuels used globally for electricity generation are mainly provided from wood or wood waste from forestry as well as the subsequent processing industries (especially the wood processing industry); biofuels for electricity generation are also provided from solid residues from the sugar cane processing industry (e.g. for sugar, for bioethanol) (i.e. bagasse) as well as from liquid residues from the pulp and paper production (i.e. black liquor). The wood pellets used, especially in co-combustion facilities, are typically produced from wood waste from the wood processing industry to allow an easy transport to power plants using coal and biomass in one unit.

In summary, the installed capacity in conversion units to provide electricity using solid biomass is between 46 and 64 GW by the end of 2014. Assuming a capacity factor of 0.4 to 0.8 this installed power represents an electricity generation between 161 and 445 TWh (2014) globally.

For example, in Brazil around 1.7 GW of electrical capacity have been newly installed in 2014. This newly available capacity allows for a theoretical electricity generation between 6.0 and 11.9 TWh (2014). In contrast, in the US the growth slowed down because of political insecurities and the fact that shale gas is still available at very low prices; thus, electricity generation based on woody biomass increased in 2014 only by 6 %; in 2014, between 55 and 110 TWh has been produced from solid biomass in the US with an overall installed electrical capacity of approximately 15 GW.

In Europe solid biofuels based electricity capacity is estimated to be around 29 GW by the end of 2014. These power plants are able to provide an electricity generation between 101 and 203 TWh (2014). The electricity generation is dominated by cogeneration plants. The top five bio power producers are Germany, Finland, the UK, Sweden and Poland.

Beside this electricity generation, these plants provide heat distributed by a district heating system, used by industry as well as by household customers. Globally, between 388 and 450 PJ (2014) of heat are provided in parallel to the electricity generation outlined above from solid biomass throughout 2014.

Biogas

During an anaerobic decomposition of organic matter within an aqueous environment an energy rich gas is produced by microorganism. This gas is released from the biomass and can be used as an energy carrier. Depending on the substrate, this gas is called landfill gas using organic waste tipped on landfills, sewage gas using sewage sludge or biogas using other organic material (organic household waste, animal manure, energy crops). This gas can be used for electricity generation in cogeneration facilities. 

In 2014, the globally installed biogas operated electrical capacity has been almost 16.1 GW realizing an electricity generation between 56 and 112 TWh (2014); this includes facilities using landfill and sewage gas. In recent years, the annual growth rate of the worldwide installed capacity in biogas-based electricity has been close to 7.5 %. The biggest share of the global biogas-based power is installed in Europe. In comparison, in all other countries the biogas-based electricity is still at a low level. Nevertheless, this might not be true for biogas production for providing heat for cooking and heating purpose realized in rural areas in countries like India and China.

The biogas based electricity generation within the EU is estimated with 55 TWh (2014) realized with an installed electrical capacity of 8.8 GW. Germany has the highest biogas provision in Europe. Here an biogas-based power close to 3.9 GW has been installed realizing an electricity generation of 27 TWh. A rapid increase in biogas production is expected for the UK, Italy, Poland, France and the Czech Republic, where these biogas-driven systems are mainly operated in CHP.

Renewable municipal solid waste

Municipal solid waste (MSW) needs to be collected and depolluted. Depending on the legal frames, MSW is often used as an energy carrier as one of the most promising disposal route. Because solid waste from municipalities contains roughly 50% organic material, this share is considered as biomass.

MSW can be incinerated by providing electricity and heat in thermal waste treatment facilities. In 2014, approximately 270 Mio. t of MSW has been used globally in such thermal treatment facilities. Based on the estimated overall installed capacity of waste-to-energy facilities of 11.1 GW, an electricity generation between 39 and 78 TWh (2014) has been realized. Last year, electricity generation by MSW incineration grew worldwide with roughly 5.5% compared to 2013. Some of these MSW plants are operated within a CHP mode. Beside the electricity outlined above, ca. 80 PJ (2014) of heat produced in coupled production has been provided and sold on the local heat market.

China and the US are still the biggest nations using MSW to provide energy. For example, close to 2.3 GW of electrical power installed in power plants using MSW is under operation in China, realizing an electricity generation between 8 and 16 TWh (2014). In Europe MSW-based electricity is around 19.9 TWh, with an installed capacity of ca. 2.8 GW. The biggest producer within Europe for MSW based electricity is Germany, followed by Italy, France and the Netherlands.

Liquid biofuels

Liquid biofuels can be produced from plants containing starch (e.g. corn for bioethanol), sugar (e.g. sugar cane for bioethanol) or oil (e.g. fruits of the oil palms for vegetable oil or FAME). However, for liquid biofuels the transport sector is the main market. Thus, the use of liquid biofuels for electricity generation in 2014 within power and/or cogeneration facilities continues to play a negligible role within the global energy system.
Additionally, due to the economic environment, electricity generation based on liquid biofuels has stagnated or even decreased. It is expected that the worldwide annual electricity generation remains at the low level of the last three years (7 to 14 TWh). There is a certain electricity production from liquid biofuels e.g. in Italy, Germany, Brazil and Argentina. Most of these units are operated in CHP; i.e. beside the electricity generation indicated above heat is also produced and sold on the local heat market.

Figure 1. Global electricity generation from biomass in 2014.
 

Outlook still on a growth pathway

Biomass-based electricity provision reflects a significant market, contributing on a low level to cover the global electricity demand. Altogether, between 263 and 651 TWh (2014) have been provided from solid, liquid and gaseous biofuels. Related to the globally generated electricity of 23,536 TWh (2014) this represents a share of 1.1 to 2.8%. As in the past this electricity generation is dominated by the use of solid biofuels especially provided and used within the wood processing industry and used mainly in grate fired system.
The market of electricity from solid biomass will grow steadily in the years to come. The same is true for the electricity markets for MSW and biogas – but still on a lower level compared to solid biofuels during the near future. The driving force behind the electricity market for biomass is not necessarily only electricity generation. Other aspects like waste management and a combined generation of heat and electricity (efficient heat provision) also play an important role during the development phase of such plants, improving the economic performance of such conversion units. Thus it can be expected that due to an increasing environmental awareness and growing markets for electricity especially in emerging markets such plants, based especially on organic waste, will gain more market share in the future.

ABOUT THE AUTHORS

Prof. Dr. Martin Kaltschmitt is Managing Director of Deutsches Bio-masseforschungszentrum in Leipzig and Head of Institute of Energy and Process Engi-neering at TU Hamburg-Harburg.

Dr.-Ing. Sebastian Janczik is Geothermal Expert at Institute of Environmental Technolo-gy and Energy Economics (IUE), Hamburg University of Technology (TUHH)