Issue link: https://fhpublishing.uberflip.com/i/1218318
COMBINED HEAT & POWER Combined heat & power offers a wide range of advantages including financial, ecological and legislative support, says Helec Ltd's Jonathan Passmore T he British government is committed to reduce greenhouse gas emissions to net zero by 2050. That's praiseworthy, but it's not clear yet how the country will achieve that goal while also serving the needs of both consumers and industry. Experts have long called for a switch of government support for gas, coal and oil, to investment in renewable energy, public transport and a nationwide energy efficiency programme. Divesting from fossil fuels and investing in renewables is, of course, one way to reduce greenhouse gas emissions. Wind is the lowest cost large-scale renewable NETWORK / 24 / MARCH 2020 Achieving the UK's zero carbon goals should include CHP energy source, while roo op solar PV panels are competitive with retail electricity price. But we shouldn't forget other opportunities, including technologies that help to keep up with the UK's heat demand while using energy more efficiently. This is where Combined Heat and Power (CHP), also known as cogeneration, comes in to play. CHP captures and utilises heat that is produced during the generation of electricity, thereby generating reliable on- site electricity and thermal heat energy at the same time. CHP systems o en aren't considered a 'true' sustainable energy source because they're predom - inately fuelled by natural gas. But they can be operated with a variety of fuels, including bio- mass woodchip, wood pellets and biogas (e.g. produced by anaerobic digestion), in which case they are essentially carbon neutral. Either way, CHP helps to reduce energy consumption and greenhouse gas emissions. It can reduce carbon emissions by up to 30% compared to the separate means of conventional generation via a boiler and power station. And a single appropriately-sized CHP system can lead to energy savings of up to 40%, offering a consistent ongoing reduction in energy costs to due to on-site electrical generation, thus removing the need for third party electrical procurement. So why aren't more businesses investing in a CHP system? A major drawback is that the initial capital expenditure (capex) for a commercial CHP system can be high. This tends to make it prohibitive for smaller scale (non-domestic) installations to be specified and delivered below 16kWe, due to long-term payback periods from the on-site generated electricity. The government has introduced a number of fiscal and financial support mecha - nisms designed to improve the economics of developing and operating CHP plants certified, either fully or partly, as "Good Quality" by the CHP Quality Assurance programme. Tax can also be claimed back on the procurement of large and small-scale CHP systems for use in commercial buildings or district heating schemes. Plus, biomass and other sustain - ably fuelled CHP systems may qualify for Renewable Obliga- tion Certificates (ROCs), which function in a similar fashion to the feed-in-tariff (FIT) in that they provide an income from the CHP system, depending on metered run hours. Some providers also offer Power Purchase Agreements (PPAs), which allow the user to install a CHP system with generally no up-front capex cost, as they will engage in an agreed fixed-term contract with a funder to purchase the elec - tricity generated on site (via the CHP installed), at generally a lower rate to the energy market costs. This route to market has several benefits as it can fix the energy rate for a known period to aide production costs, reduce the local DNO sub-station de - mand, and provide a capex-free solution to cogenerate thermal heat and electricity on site. New sources of heat The government's search for alternative renewable sources of heat has gained pace a er ministers pledged to ban gas-fired boilers from new- build homes from 2025. But that pledge applies only to the domestic sector. There is no such strategy for commercial