CHP Plants: Potential emissions and policies

Combined Heat and Power (CHP) plants are well-established in Denmark, Finland, Sweden and other parts of Northern Europe owing to the presence of vast amounts of forestry which serve as ready bio-feedstock for cogenerating electricity and heat. Efficiencies of these plants are dependent on biomass quality as well as plant size, and when used to generate solely electricity, efficiencies have been observed to improve. Today's post briefly explores the potential emissions from such plants, and highlights the benefits of feed-in-tariff policies. 

 Most CHP plants can utilize waste matter from forestry and agricultural operations, thus reducing the amount of waste going to the environment. However, biofuel utilization in these plants are not 100% carbon dioxide emission-free, as some fossil fuel is often required to facilitate the pre-treatment of bio-feedstock as some may require size reduction, screening and pre-drying, while others may have compounds that need to be removed to prevent material corrosion in the combustion chamber. Electrostatic precipitators and cyclones are also needed to collect dust particles which are inevitably produced during the combustion process.Fortunately, some life cycle assessments have shown that total emissions during the conversion process are about 10% less than fossil fuels, and hydrochloric acid, sulphur oxides, dioxins, heavy metals as well as dust generated during this process are often sent to appropriate landfills.

 To encourage the use of biofuels in CHP plants, governments actively need to create incentives for both power distributors/generators as well as end-users. Up to 50 countries such as Sweden have successfully incorporated green energy feed-in-tariff systems in order to facilitate affordable biofuel utilization especially in developing nations by encouraging investments. This renewable energy payment system is different from previous policies which focused on increasing fossil fuel prices in a bid to make biofuels and other renewables more attractive. In the feed-in tariff scheme, residential end-users are paid for every kilowatt of electricity they generate from renewable energy systems. The feed-in tariff scheme also facilitates the UN Framework Convention on Climate Change (UNFCCC) agreement by developed nations to assist developing nations meet their energy demands and also provides much-needed funds for installations.

More information available here and here.