Abstract

The lignite power industry produces low cost electricity but the associated pollutant emissions are higher than from other fossil fuels. Tighter environmental legislation requires older facilities to either upgrade or face closure. The rising contribution of renewable energy sources obliges plants to operate more flexibly, responding to variable demands.
This report provides a comprehensive review of suitable technologies for the retrofitting of lignite pulverised coal power plants to lower emissions while raising plant performance. Adaptations based upon the existing plant technology include: combustor modification, advanced instruments and controls, anti-fouling systems and steam turbine upgrades. Alternatives to mainstream effluent treatments are discussed, including hybrid and multi-component technologies to lower emission of NOx, SOx, particulates and mercury. Unique to lignite, the drying and pre-treatment of the fuel is explored as one route to improved heat rate. Flexible plant options reviewed include energy storage, indirect firing and natural gas integrated co-generation. Latest developments on the introduction of CCUS techniques applied to lignite plants are discussed together with other means to lower plant carbon footprint.