Smart controls
The traditional solution would be to build additional generating capacity to over-produce and then turn off when not needed. However, the stable source temperature of GSHPs makes them well suited to running when the grid can best support it. If properly synchronised, smart control of millions of devices such as GSHPs, electric vehicles and many others will allow the grid to function correctly without the need for over-generation. Combined with the low electricity consumption of GSHPs, this will save billions of pounds of capital investment in future generating capacity.
Consumers will also benefit as smart metering is giving suppliers the ability to charge consumers different prices at different times of day to reflect the availability of energy. Smart controls will allow householders to automatically take advantage of these dynamic tariffs to run their GSHPs when prices are lowest – our modelling shows savings of 25 to 40% are achievable right now. Better still, lower-priced times of day typically coincide with lower carbon grid electricity.
Cooling
Warmer summers, improved insulation, larger windows and urban heat islands are combining to increase the need for cooling, which is unhelpful in the fight against climate change. Traditional air conditioning makes the situation worse because all the heat taken out of the buildings is pumped into the air around the city.
A ground array with an ambient temperature district heating loop makes an excellent source of cooling – the by-product of extracting heat from the ground all winter is a large area of pre-chilled ground which is conveniently piped to each property (heat pump). Passive cooling can, therefore, be provided at the extremely low cost of running a small circulating pump. Even better, the heat that you take out of each property is reintroduced into the ground, which improves the heat pump heating efficiency the following winter.
For properties that need even more cooling, it is simple to reverse the heat pump hydraulic flows so that the heat pump actively cools the property and sends the waste heat into the ground.
PV-T panels
Solar panels that combine photovoltaic (PV) cells and thermal (T) water heat exchangers have been around for a while, yet their full potential can be realised by combining them with a ground array. In summer, the ground array cools the panels from 40 to 50ºC down to 15 to 25ºC, which increases the efficiency of the photovoltaic panels by 15 to 25%. The heat taken from the panels re-charges the ground array, which increases the efficiency of the heat pumps by 10 to 20%. Combining three renewable technologies in this way is a win-win-win, which improves the efficiency of each technology independently and results in a more efficient overall system, bill reductions and carbon reductions.
Timescales
These innovations all take advantage of existing technology but combine them in ways that bring huge benefits to the decarbonisation of heat. They are ready to go, and future-proofed, which means they can be deployed now with no regrets and their benefits will increase with time as the electricity grid evolves and decarbonises.
