The essence of combined heat and power technology, over recent decades, is to provide continuous supplies of electricity and heat. This is done at the highest levels of fuel efficiency – typically reaching around 90% – meaning that this has lower carbon emissions than grid-supplied electricity. Historically thermal power plants supplying the grid rarely had heat recovery. Compared to the separate purchase of electricity from the local grid and heat; often from a gas fuelled boiler CHP also delivers significant carbon savings.
With the move away from a centralized system and towards decentralized intermittent sources of power – such as wind and solar – does CHP technology still have a place?
The answer most definitely is yes.
Providing flexible supplies of electricity and heat is not new. The greenhouse sector has been using CHP plants that operate in a flexible manner for many years, with many hundreds of megawatts being delivered globally. These units not only generate heat to warm greenhouses in colder climates, electricity to power lighting and for export, but also recover carbon dioxide as enriched air to encourage the growth of plants – a partial capturing of carbon emissions.
This very same logic and technology can be deployed for industrial and commercial facilities that have opted to install a microgrid. Solar photovoltaics, wind turbines or energy storage can be married with a flexible base load source of power such as a CHP plant potentially with a thermal store. A flexible CHP plant can also deliver resilience in the event of local power supply outage and in parallel support the intermittent nature of other energy sources.
In addition, there is sometimes a misconception that CHP is always a carbon emitter. It is true that often CHP plants are fuelled by natural gas – a fossil fuel. It is likely that even with increasing renewable energy CHP plants will deliver carbon savings until the early 2030s compared to grid supplied electricity. However, they are also able to be readily fuelled by renewable gases – such as renewable natural gas (RNG) or alternatively hydrogen when it is available.
Both RNG and hydrogen are relatively more expensive to produce than natural gas, therefore it is even more essential that these valuable fuels must be used as efficiently and when most needed. Flexible CHP plants therefore have strong potential in the future to support a wholly renewable power supply network.
If you’d like to learn more about how Clarke Energy can provide flexible CHP plants, microgrid solutions, renewable natural gas upgrading plants or energy storage systems – contact us to learn more.