The Drax power plant consists of six power units, four of which have a combined capacity of 2.58 GW and use agricultural solid waste and wood byproducts as a fuel. The other two power units, which have a combined capacity of 64 megawatts (MW), are powered by natural gas, which plays a supporting role in electricity generation. The power plant used to have six more coal-fired power units, four of which were closed between 2013 and 2018, and the last two in 2023.
The large amount of emissions is related to the fact that the operating principles of biomass power plants are similar those of coal- and gas-fired power plants: feedstock combustion is used to generate thermal energy, which helps generate electricity. The advantage of this type of electricity generation is the reliability of power supply: for instance, the average utilization rate of U.S. biomass plants in 2023 was 59.6%, whereas that of wind and solar power plants, which depend on weather conditions, stood at 33.5% and 23.3%, respectively, according to the U.S. Energy Information Administration (EIA). Its disadvantages include high capital intensity: bringing into operation 1 kilowatt (kW) of biomass power plant capacity costs an average of $2,590 in the U.S., which is significantly more expensive compared to wind generators ($1,430 per kW) and solar panels ($1,560 per kW).
Another disadvantage is the relatively high level of emissions. The International Panel on Climate Change (IPCC) estimates that the volume of greenhouse gas emissions throughout the entire operating cycle of biomass plants ranges from 130 to 890 grams of CO2 equivalent per kilowatt-hour (kWh) of electricity, depending on the type of feedstock and the use of cogeneration technologies. As a point of comparison: the range for gas power plants is 410 to 650 grams of CO2 equivalent per kWh. This is why biomass plants can have a bigger carbon footprint than fossil fuel power plants.
Emissions can be minimized through the use of CO2 capture, storage and utilization (CCUS) technologies. The Drax power plant is no exception, since, starting from 2027, it will intercept carbon dioxide using two industrial columns lined from the inside with metal-organic frameworks (MOFs) – crystalline porous materials made of metal ions that are linked together by organic molecules. Molecules of foreign compounds can be placed inside MOFs and later extracted when the temperature changes. The two columns will alternately absorb CO2 from the flue gas and will subsequently be heated to desorb it, also alternately.
