29 May 20

Combined Heat and Power – An energy efficient solution for the UK

Triple Point’s Mike Pelmore reveals how Combined Heat and Power is central to the UK’s energy efficient roadmap.

One of the positive stories that has emerged from this crisis is the record fall in global carbon emissions. Daily emissions of carbon dioxide dropped 17% by early April compared with 2019 levels. Whilst this is a good news story, we should remember that this unprecedented fall is unlikely to have a significant impact on the climate. When the world opens again for business, energy efficient solutions will be required if we intend to address climate change in the long-term.

To effectively fight climate change, we first must understand energy efficiency: the ratio of a system’s useful output to its energy (read: carbon) input. In its simplest form, an increase in energy efficiency (or in energy productivity) is achieved through either an increase in useful output from the same energy input, or by maintaining the level of useful output from a lower energy input. So, if we want to improve our quality of life in the UK and fight climate change whilst lowering our carbon footprint, we need to significantly increase the UK’s energy efficiency.

One way to enact this is to think more holistically about our various energy systems and their interfaces with each other. Rather than improving the efficiency of individual system components (e.g. cars, fridges and computers) we need to ramp up our thinking on where seemingly separate systems can work together to generate mass energy efficiencies. We need to ask ourselves, ‘Where can one system’s waste product form another system’s useful input?’ Really, this is just plain old recycling, but it’s more complex, because you can’t just pick up your waste energy and put it out for collection on Monday morning.

One solution that integrates two systems together in this way is known as combined heat and power (or CHP). Gas-fired CHPs pump heat; a waste output from electricity generating gas engines, to where it becomes a useful input, avoiding the need for that system to burn its own fossil fuels. This could be for heating people’s homes, public swimming pools or hospitals in what’s known as a district heating network. However, we can even go further and add some natural carbon capture. Plants need CO2 for photosynthesis and growth, so if a commercial greenhouse is connected to a power plant, the system can become even more energy efficient by also including the waste CO2 in the list of useful inputs required to grow plants and food.

But it’s not just the heating side of things that adds to CHP’s energy efficiency story. These gas engines are connected to the same local electricity networks as renewables like solar and wind, and in contrast to large conventional gas power plants, they can be started up exceptionally quickly (5 minutes vs. 2 hours) to balance the fluctuations in electrical generation caused by the highly variable nature of renewables. This reduces the need for grid operators to maintain the grid’s balance by turning off renewable sources when they could be generating at their fullest. If you’ve ever been frustrated at the sight of a wind farm not spinning on a windy day you’ll be glad to know that the addition of energy efficient, quickly dispatchable generating solutions like CHP can keep those blades turning, increasing the UK’s energy efficiency even further. Since 2015 Triple Point has been investing in the UK’s energy efficiency through the provision and arrangement of circa £60m funding for highly efficient gas-fired CHP projects.

There’s still a long way to go to reduce the UK’s carbon emissions to meet net zero by 2050, and the electricity network is only one part of it. However, when we start thinking not just about the efficiency of systems themselves, but how they interact with each other, we can unlock even further efficiency gains on a higher level, helping keep our quality of life for future generations by reducing our dependency on carbon.