CHP
T
he UK’s infrastructure is already constrained, making it challenging to deliver green electricity where it’s needed. System upgrades are in the pipeline, but even without planning objections or funding restrictions, they will take years to complete. So, how can we simply electrify our economy to meet net zero? The answer is, we can’t, at least not for many years to come. Even on the UK’s windiest and sunniest day, when all renewables and the nuclear fleet are at full throttle, they make up only 80% of our generation stack. Even though the average carbon content drops to 80 gCO2/kWhr, we continue to burn gas in our centralised Combined Cycle Gas Turbines (CCGTs), which make up around 15% of the generation stack. While CCGTs are efficient at producing electricity, they don’t recover waste heat. By the time the electrons reach their destination, many are lost due to system losses. So, any efficiency gained, compared to a locally installed generator, is wasted. Add waste heat recovery to the local generator, whether from the engine’s cooling system or its exhaust gas, and you can push efficiencies above 90% – this is called Combined Heat & Power (CHP). When evaluating carbon savings compared to average of 193 gCO2/kWhr in 2022, it’s evident that every hour we continue to burn gas without CHP is a missed opportunity to significantly increase efficiency, the cornerstone of sustainability. Until we can eliminate burning gas at central power stations, CHP should be running, delivering optimum efficiency and reducing global CO2 emissions. It would be madness not to! CHP and conventional gas boilers are not the only sources of heat. Heat pumps offer a potential solution, but challenges such as ensuring the electricity used is truly green and addressing potential
CHP – HERE TO STAY Alan Beech – Clarke Energy environmental impacts from sourcing water need to be considered. In ideal conditions, heat pumps can achieve excellent coefficients of performance (COP), but they still require electricity to operate. In a constrained UK electrical network, the question arises: can we secure the necessary grid connections for these, as well as other forms of electrification infrastructure such as electric vehicle (EV) charging stations? The answer may be CHP working in tandem with heat pumps and EV charging stations, providing a dependable source of heat and electricity while supporting the constrained grid, for those who do not have the benefit of a gas supply. I’m sure you are challenged with achieving net zero and have company targets to meet, almost certainly using Scope 1 to measure your direct energy use, which includes any mains gas brought to site. The problem is thus – to benefit from the carbon and financial savings of CHP, you need extra mains gas to generate electricity. Heat will effectively be free, offsetting gas used in your conventional boiler. However, this extra gas increases your Scope 1 reporting, even though the CHP is actually reducing global emissions of CO2. In a responsible society, we should prioritise doing what’s right over mere appearances. We must carefully consider the genuine benefits and wider implications of everything we do.
Reducing energy use wherever possible (simply switching it off), decreasing consumption (installing LED-style lighting), employing renewable energy where practical (setting up solar panels), and being efficient with essential energy consumption (when you need heat and electricity, choosing CHP should be an easy decision) are crucial steps. Additionally, it’s worth noting that mains gas is on its own path toward decarbonisation, with increasing injections of green renewable biomethane and plans for hydrogen blending, sourced from excess wind and solar power. INNIO Jenbacher gas engines can already run on 100% hydrogen, with the capability to be converted during their operational lifetime. Therefore, CHP will not become a stranded asset, it will be a critical part of your energy infrastructure and transition into the net zero world. In conclusion, we now know that quality CHP not only reduces CO2 emissions but also enhances site resilience (through black start and island mode capability), with payback periods often below two years. These substantial savings could and should be reinvested in green hybrid technologies that complement CHP. Can we afford to wait for 100% renewable electricity to be available 24/7? Can we wait for the planning approval and construction of upgraded electrical infrastructure to distribute electricity from point of generation to point of use? Can we afford to wait for commercially available hydrogen? As a responsible citizen or organization, your next action should be to make a meaningful contribution to the fight against global warming – whatever that may be. And remember, don’t be greenwashed! www.clarke-energy.com
ENERGY MANAGER MAGAZINE • NOVEMBER/DECEMBER 2023
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