Producing Power: Combined heat and power generation in the UK
16th December 2021
Combined Heat and Power (CHP), also referred to as Co-Generation, is an established technology and one which has an important role on the journey to achieving net zero.
CHP can act to decarbonise on two fronts: power generation as well as the heat that’s produced as a product of electricity generation. Rather than allowing it to escape, as is usual, it can be captured and the thermal energy used to heat/cool buildings or simply provide hot water. Tying together heat and electricity in this way acts to lift the efficiency of the conversion process too.
More efficient energy generation
CHP plants typically demonstrate an average conversion efficiency of up to 80% as against that of around 45-50% for a typical combined cycle gas turbine plant. The improved efficiency of delivery in turn flows through to energy bills. Evidence shows that organisations that use CHP may typically expect to lower their energy expenditure by around 20%.
Through the use of less fuel overall, CHP confers emission-reduction benefits. The resultant saving in carbon emissions is assessed by the UK government at up to 30% when compared to the more traditional approach of drawing on a separate boiler, for heat, and a grid-connected power station, for electricity. The use of CHP in 2020 alone was responsible for lowering UK emissions by 3.5 million tonnes carbon dioxide equivalent (MtCO2e).
At the same time as reducing emissions, generation and consumption of electricity and heat locally through CHP serves to avoid losses inherent to energy being transported across networks. There’s also scope to limit the amounts of power drawn from the grid when prices are high through prioritising self-generation.
Powering the future
In 2020, there were 2,659 CHP sites across the UK, with “qualifying” CHP output amounting to 7.7% of overall electricity generation. The word “qualifying” refers to those CHP installations whose input and output are certified under the UK government’s CHP Quality Assurance programme (CHPQA).
A CHP scheme may use a range of fuels for its operation. These include natural gas, petroleum-based products, and, increasingly, more renewable fuel types such as biomass, biogas, and waste.
Natural gas is, however, the most common and in 2020 accounted for 72% of the UK CHP fuel mix. The use of renewables in CHP reached 15% in the same year having registered only 2% as recently as 2008.
Typical locations for CHP deployment include hospitals, residential homes and universities. These reflect for the bulk of CHP use and amounted to 70% of qualifying UK output in 2020.
Community and district heating
CHP is often an attractive solution when evaluating the provision of heat to multiple buildings, or a wider network of sites, from one centralised location. The scale will naturally vary between schemes more geared to community heating at one end of the scale, that serve a smaller number of buildings in close proximity, to the other extreme of district heating projects that potentially cover a wide area, maybe whole towns or cities.
There are in fact around 14,000 such heat networks in the UK that collectively provide the energy needs of just under half a million customers. However, it’s estimated that a realistic potential exists for heat networks to deliver ten times that amount by 2050, around 20% of the UK’s heat requirement.
Turning generators into vendors
As CHP can serve both a single building and a network of sites, it represents an option that smaller and larger businesses alike could choose to adopt. The UK government offers a range of financial CHP incentives for which projects certified as fully or partly “good quality” under the CHPQA programme may be eligible for.
Looking for a partner?
Drax supports 61 CHP power generators whose total generating capacity exceeds 140 MW. We therefore hold the experience and expertise to support your business on its CHP journey.
Get in touch today to discover how we can help you optimise your CHP operations in the market.