Heating of space and water in buildings accounts for about 44% of all energy consumed globally according to the International Energy Agency. This heat is still overwhelmingly generated by burning fossil fuels, making it an enormous source of the carbon emissions driving climate change. But you might be surprised to learn just how much heat is wasted each day. Finding ways to recover and recycle it could drastically reduce emissions.
Consider a standard petrol or diesel car. The engine provides the momentum and produces excess heat that a radiator removes. This heat is largely wasted, except in winter when it warms the windscreen and passengers. Generators that supply electricity to the grid work in a similar way – their excess heat could be diverted to heat buildings instead. In the UK, there are many gas engines on standby to supply the power grid when needed. I was part of the team that linked the heat from a gas power generator to a building central heating system.
The idea of combined heat and power is nothing new. In Nottingham, the energy for the city’s district heating network and some electricity comes from a waste incinerator. This also reduces the amount of rubbish sent to landfill. But once you realise just how much heat is out there, waiting to be reused, the problem of decarbonising heating doesn’t seem so mighty. Here are seven examples.
