Other ways of producing bioenergy
Apart from producing an alternative fuel for the transport sector, biomass can also be used in other types of processes to provide energy with higher efficiencies as for example through biogas plants, CHP (combined heat and power), cofiring (combustion of two different materials at the same time, as for example biomass with coal in existing coal plants), gasification (process that converts materials such as coal, biomass or waste into carbon monoxide and hydrogen) or heating. These tend to have higher efficiency results than converting biomass into biofuel.
Biogas is what results after the anaerobic digestion (Bacterial processes carried out in the absence of oxygen) process of organic waste materials, slurries or animal manure in a biogas plant. The combustion of a digester gas provides a source of renewable energy that substitute for natural gas or propane, while providing environmentally sound means of waste disposal. Different applications include for direct use on cooking stoves and lightening, for combined heat and power, injection into natural gas grids or used as fuel in vehicles. The ideal system are small scale units where waste is treated and used near the source minimizing transport emissions and costs.
This process reduces methane emissions which are 23-fold stronger as a driver on global warming, and nitrous oxide (300 fold). Nevertheless only waste that has not been diverted from other uses (such as animal feed, paper production or compost), that is to say products that would otherwise be discarded, or that have no implications on land-use should be used. Using for example maize crops as done in many plants in Germany (ADAS 2009) can lead to displacement of food production and to significant emmissions from the use of nitrogen fertiliser or ploughing up of permanent grasslands.
The production of biogas from waste depends directly on the waste management policy implemented and therefore on the quality of waste collected. In some Member States, especially in Eastern Europe, only a small part of agricultural by-products and agricultural waste is collected and sorted from the total waste stream.
Combined heat and power generation (CHP or cogeneration) is the process of generating both electricity and heat in a power station. In a conventional power plant the heat originated as a by-product is released without being used, whereas by CHP it is recovered, usually in a heat recovery boiler and supplied to number of industrial processes to provide for example hot water or even cooling. Fossils fuels which were most commonly used before are now increasingly being substituted by biomass.
A clear support to cogeneration could avoid the emission of 127 million tones of CO2 in the EU in 2010 and 258 million tones in 2020. However, the European Commission acknowledges in its report on the status of CHP (EC Communication 2008), several barriers that are hindering the right development of the Cogeneration Directive such as complex administrative procedures, complex legal frameworks and difficulty and high costs on upgrading the grid connections to accomodate CHP.
Currently CHP contributes only in a 2% towards the 20% European objective of annual primary energy saving, but its potential is much higher. A consistent policy and strong governmental support are needed to overcome the slow progress made so far.
Policies encouraging the production of bioenergy through any system must include a robust system of full sustainability certification, as the use of any biomass can lead to new pressure on land and natural resources (and hence to new environmental and social pressure). A certification system must be implemented including biomass and waste. If waste were completely excluded from the certification system, vast amounts of unsustainable raw material would be simply declared to be waste.
In the case of harvest residues from agriculture or forestry, it is conceivable that the same “waste” co-product that is currently not influencing production choices would start influencing them, and hence land management choices, once it has acquired sufficient market value. For example, this is conceivable with straw, which is currently usually just a by-product of cereal production. However, the emergence of a lucrative market for straw for co-fired CHP plants could give it enough economic value to fundamentally alter the profitability of cereal cultivation in certain areas, leading to the expansion of such cultivation at the expense of valuable habitats and carbon stocks such as grasslands. Any such co-product which begins to drive market value for a commodity should therefore be re-classified as a biomass source that requires certification.
In the case of forestry residues harvesting and stump extraction their collection could cause other negative impacts on the ecosystems not necessarily connected with land-use change but harmful for water cycle, erosion, nutrient availability etc. Such harvesting should hence be subjected to specific standards, even if the material collected would currently be considered as waste (in the sense of not having any economic value).
Finally, it should be noted that in terms of how we choose to use our biomass resource, the material use of a waste product (e.g. as a soil improver, construction material, or as a material in the chemical industry) should be placed higher in the waste hierarchy and locks in carbon as opposed to burning the biomass for energy.
The European Commission will, by the end of 2009, report on whether they propose any sustainability criteria standards for solid biomass. For details, please see BirdLife's response to the European Commission consultation on a sustainability scheme for energy uses of biomass. (Sep 2008)
ADAS (2009). RMP/5142 Analysis of Policy Instruments for Reducing Greenhouse Gas Emissions from Agriculture, Forestry and Land Management.
Biogas for Eastern Europe (2008). The Biogas Handbook.
European Commission Communication 2008: Europe can save more energy by combined heat and power generation.