The widespread use of energy crops for power generation will carry their own environmental implications. One of the most important of these is land use. There is a danger that the use of arable land for energy plantations will reduce that available for growing food. Currently this does not appear to be a problem in Europe and North America where sufficient land is available. In other parts of the world any significant shift in land usage could have a significant effect of food production. Under current circumstances this must be considered detrimental.
The effect of the energy plantations themselves on the environment could be beneficial, though this will depend to a large extent on how well they are managed. Most energy crops will remain in place for a number of years, improving the stability of the local environment. This can help stabilise soil conditions where erosion has become a problem and the raising of woody crops can improve groundwater retention and reduce damaging run-off of rainwater. Energy crops generally require less fertiliser than food crops, again a benefit to the environment.
The use of biomass waste for power generation can also be beneficial, with the caveat already expressed that sufficient organic material is returned to the soil to maintain fertility. In California, where a significant biomass power generation capacity has evolved since the 1970s, the industry has inadvertently become a major part of the US state's waste management system. The economic value of the removal and beneficial destruction of waste in this way is not usually recognised. Were it to be taken into account, it could make the argument for biomass power generation stronger still.
Biomass power generation is still a relatively small sector of the power generation industry at the beginning of the twenty-first century. Much of the existing capacity is relatively inefficient and the future success of biomass as a source of electricity will depend on the development of more efficient systems for exploiting the fuel.
Improvements to traditional direct-firing technologies together with the development of biomass gasification systems are underway. New direct-firing technologies offering higher efficiencies should be available by the end of the first decade of this century. These are based on well-understood coal-plant technologies and the economic risks associated with the introduction of such techniques should be minimal.
Co-firing is a new technique which may pose a slightly higher level of risk in the early stages of its introduction. However the addition of co-firing capability to a coal-fired power plant will normally be part of a sustainable or green energy policy and the economic benefits of this - or the penalties associated with failing to implement such policies - will normally outweigh the technological risk.
Biomass gasification is in the development and demonstration stage. As a new technology it can be expected to be less reliable in its early stages of use. However it can take advantage of parallel development of coal gasification technology and this should help reduce development costs and help improve reliability. Commercial biomass gasification plants should be available during the second decade of the century.
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Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.