RWE npower considers biomass conversion

By Lisa Gibson | December 21, 2010

U.K.-based RWE npower is exploring the conversion of its 1,100-megawatt (MW) coal-fired Tilbury, England, Power Station to 100 percent biomass, sourcing the majority of its feedstock from the pellet plant its parent company is developing in the U.S.

The Tilbury station currently cofires 10 percent biomass as per U.K. Renewables Obligation regulations and has for a number of years, but a 100 percent biomass feedstock will decrease electricity generation at the station to 750 MW. The company has yet to make a final decision on the conversion and is awaiting consents and licenses from regulators, according to Dan Meredith, public relations manager for RWE npower.

“If we do go ahead with the fuel switch from coal to biomass, our recent trials indicate there will be significant environmental benefits due to reductions in emissions compared to coal,” Meredith said, citing a 70 percent to 80 percent reduction in sulfur dioxide, about half the nitrogen oxide emission concentration, and ash production of around a tenth the level associated with coal. The plant is opted out of the U.K.’s Large Combustion Plant Directive (LCPD) and therefore has run under a restricted operational regime of a maximum of 20,000 hours between 2008 and the station’s closure date in 2015.

“It is currently unknown whether a switch to biomass will alter the station’s LCPD status, but even with closure in 2015, RWE npower considers such a switch to have useful benefits: the impact on current air emissions including the avoidance of over two megatons of [carbon dioxide] from burning coal,” Meredith said. “In addition, the use of 100 percent biomass on this project will allow us to explore the sustainable sourcing of such fuel and support the establishment of supply chain infrastructure in the U.K.”

RWE npower is the U.K. unit of Germany-based RWE Group, which is constructing a 750,000-ton pellet plant in Waycross, Ga., slated for operation in 2011. The company chose the location because of the vast wood resources and availability of skilled workers in the forest industry, it said.

“If successful, the [Tilbury] plant will burn its last coal in the spring of next year and start to burn 100 percent biomass before the end of 2011,” Meredith said.