Whilst we're amid an energy fuel bill crisis and trying to adjust to electric heating sources predominantly being used to heat our buildings; we need to be inventive about designing heating systems that are low carbon, low energy and have low fuel bills.
We know that self-generation of electricity is important when electricity is the primary heat source. The default method we reach for when achieving this is PV panels, and for good reason, however not all buildings have the roof space required and PV could be difficult to install as a retrofit.
A misunderstood method of generating both heat and electricity is via Combined Heat and Power units or CHP. A CHP is effectively an engine that uses fuel to produce electricity and, as a by-product, provides hot water. The most common mistake made when selecting a CHP was to base its size on the thermal output required. A CHP shouldn't run until it has a constant base electrical load and therefore should be sized on its electrical output and not on its thermal output.
CHP works best when there is a reliable heat demand and electrical load. They should ideally be selected so that they run as often as possible. However, allowing them to switch on and off shouldn't be discounted and in the current climate, using a CHP as a method of generating heat and electricity shouldn't be excluded.
CHP can be combined with battery storage to allow scenarios where batteries can be charged during the daytime to allow the stored power to be drawn off during the evening or where the batteries are charged during the week and the power is drawn off over the weekend. This helps to reduce a buildings reliance on the electricity grid.
CHPs don't need to be natural gas. They can be hydrogen or hydrogen blend, methane, or methane blend. They can also be biofuel, making use of recycled oils from fats and greases.
Whilst they are not suitable for every building type they shouldn't be cast aside when the right conditions exist. Any scenario where you can create your own electricity for the same price it costs to buy gas, hydrogen, methane, or biofuel would help to keep energy costs low.
The technology is used on a larger scale in district heating networks where a network owner can create electricity for the price it costs to use a cheaper fuel source. This approach can reduce payback periods for capital costs and generate income for a network operator of heat networks that serve multiple buildings.
