Researchers from the University of Copenhagen have for the “first time” quantified what the conversion of 10 Danish cogeneration plants from coal or natural gas to biomass have meant for the environment.
According to the report, issued yesterday, converting to biomass, either as woodchips or pellets, “benefited the climate” and were a “more climate-friendly option compared to coal and natural gas”.
The research was funded by Danish Energy, an association for Danish electricity producers and fellow trade body the Danish District Heating Association.
Among other things, researchers calculated the so-called carbon payback period for each plant. A coal-to-biomass conversion had a positive effect on CO2 emissions after an average of just six years, according to the report.
However, when it came to converting from natural gas, in most cases the payback took between 9 and 22 years, and in one case 37 years before CO2 emissions were reduced.
According to the report, ditching coal for biomass resulted in between a 15% and 71% reduction in CO2 emissions, while the move away from natural gas resulted in emissions reductions between -4 and 19%.
In the one case emissions were -4% after 30 years as a result of the conversion because burning natural gas emits less CO2 than burning wood, and that this particular plant had notable changes in its product portfolio, according to the report.
However, while the report does list the 10 plants used for the study, it does not link the finding to the individual facilities. The plants covered in the report are:
Of the 10 facilities, 32% processed biomass from Danish forests, while 41% sourced it from the Baltic states, 7% from Russia and Belarus, and 7% from the US. Those sourcing from furthest away fared worse environmentally, according to the report.
Only last month the Danish government brought in new sustainability rules around the types of biomass that could be used in power and heating plants.