The case of co-firing: The market level effects of subsidizing biomass co-combustion

Biomass combustion in co-firing power plants has been treated differently in renewable electricity promoting policy schemes. Some policy schemes subsidize biomass co-combustion while some do not. In this study, we analyze the impacts of a policy choice on the fuel uses, investment decisions, CO2 emissions, and on the values of renewable electricity promoting policy instruments. In particular, we look at the impacts of feed-in tariff and a subsidy to renewable energy, both together with CO2 emissions price. We present an electricity and heat market model, where all the solid fossil fuel power plants are able to co-fire biomass and fossil fuel. In the numerical application, the model is used to analyze the differences caused by the policy instruments. The results show that subsidizing biomass combustion in a co-firing power plant decreases the investments in pure renewable technology. However, the use of solid fossil fuels is not increased significantly. Also, the CO2 intensity levels of electricity production are nearly equal whether biomass co-combustion is subsidized or not.