Recent news that the Dutch city of Amsterdam plans to massively extend its district heating network – from supplying 10% of the city with heat generated by burning refuse to 40% – serves well to illustrate the growing role for waste and biomass waste fuels for CHP/cogeneration installations.
The last few weeks have seen a flurry of new waste-to-energy heat and power generation schemes being announced or opened around the world, whether the fuel derives from domestic or industrial refuse, or solid or gaseous organic wastes from farming, food production or wastewater treatment plants.
For example, the Fiji Sugar Corporation is commissioning a new 10 MW CHP plant at a sugar mill in the north of the island country, fuelled with bagasse, a by-product of sugar processing. The company has two further plants, totalling 45 MW in size, in construction. Meanwhile, a poultry facility in South Carolina, US, is using methane produced in an on-site digester to fuel its new CHP plant.
At a much larger scale in Poland, Fortum is building a 220 MW multi-fuel CHP plant – to operate mainly with locally sourced refuse-derived fuel and coal, but also with biomass – to provide heat for the district heating network serving 70,000 households in Zabrze. Last, the coal-fired Unit 1 at the CHP plant at Avedøre, Denmark, is to be converted to run on wood pellets to end the use of coal and gas fuels for district heating in the Greater Copenhagen area.
Given that the primary efficiency benefits of CHP arise from its making use of what would otherwise be ‘waste’ heat to massively improve the efficiency of electricity generation, the use of various ‘waste’ products as fuel is entirely appropriate. And, of course, adds considerably to the environmental benefits of the technology.
The widespread growth of renewable technologies around the world is mainly responsible for the apparent stalling of the growth of global emissions of carbon dioxide to the atmosphere in 2014, as reported last month by the International Energy Agency (IEA). Global emissions from the energy sector stalled at 32 billion tonnes, said the IEA – the first time emissions have failed to increase in 40 years, except for the three occasions when falls coincided with global economic downturns.
Waste as fuel; waste heat made use of – CHP/cogeneration is playing its part in the essential greening of energy production.