Bioenergy at a small scale: Impacts on nature and people
21 May 2012 | Fact sheet
Are you planning to fund, build or manage a bioenergy project? Have you considered the environmental, social and economic issues this can raise? Are you prepared to manage these issues?
Pacific Energy Projects: Impacts on nature and people
TYPICAL BIOENERGY PROJECTS
Natural materials can be used to produce energy, providing an alternative to fossil fuels. Targeted approaches to bioenergy can be divided amongst:
Biomass – solid material used directly, such as burning, or indirectly in a boiler, to produce electricity, steam, heat or a combination.
Biofuels – where materials are processed to make liquids such as alcohols and oils which can be used in vehicles or generators.
Biogas - where decomposition releases methane or other gases, which then can be used directly for cooking and lighting, or substitute for products like LPG.
Bioenergy crops are often described as:
First generation: energy sources derived from typical food growing practices, such as edible oils, corn starch, and sugar cane products, or simple processes such as biogas from sewage.
Second generation: energy sources derived from inedible crops, woody or agricultural residues, such as cellulose, lignin, Jatropha oil, often with more complex processing.
Basic, unprocessed, fuels such as wood or charcoal for cooking are not always discussed as formal bioenergy projects, however are important for many peoples’ livelihoods.
BIOENERGY PROJECT DEVELOPMENT
Bioenergy projects have complicated interactions with the environment. From choosing the crop, selecting the site, to transport and processing, each stage of the lifecycle may have different, site-specific issues and stakeholders. Growing, harvesting and transporting bioenergy crops can be similar to other large-scale or commercial agriculture, while processing and uses such as electricity generation may be similar to industrial activities.
Decision-making needs to be integrated with policies such as land, water, soils, food security and biodiversity.
The demand for bioenergy can encourage conversion of ecosystems to cropland, introduce species – deliberately or accidentally – and promote irrigation and chemical use. The lower energy density of bioenergy compared to fossil fuels means increased material inputs: a little over 3 rugby fields of coconut plantations are needed for enough coconut oil to provide the same energy as a typical fuel truck. Processing the biomass by direct combustion, sulphuric acid, methanol or other chemicals, can create solid waste and pollute air and water. All these can affect the ecosystems that provide bioenergy and other services.
Bioenergy builds on existing agricultural skills to build a self-sufficient energy supply, particularly in remote areas. Unlike solar or wind power, bioenergy usually needs a business or community approach and can involve many people. Where these crops use productive land, this can affect food production. Producing fuels such as coconut oil may be labour intensive, so the benefits of a local fuel may not meet the expectation of an easier life.
Continually removing biological material from an ecosystem is unlikely to be sustainable as energy and nutrients are lost. As with other agricultural systems, pesticides and fertilisers may be used for productivity. Across a catchment or area, this can impact soil fertility, erosion and waterways. Bioenergy often replaces fossil fuels and so avoids greenhouse gas emissions. Using a lifecycle approach compares these savings with other emissions such as land use change or fuel for harvesting.
Further information on additional resources can be found on the PDF available for download.