Net zero’ basically means achieving a balance between the carbon emitted into the atmosphere, and the carbon removed from it. So we will need to cut emissions from homes, transport, farming and industry. And unavoidable emissions will have to be removed, either by allowing trees and other plants to absorb them or by using carbon capture and storage. The majority of our household emissions come from heating. In 2017, the average household generated 2745 kg of carbon dioxide emissions from heating. To reach the 2050 net zero target, we will need to cut heating emissions to 138 kg CO2 per household: a reduction of 95%. So how can we do it? Making the shift to renewables We will only reach net zero emissions if we stop heating our homes with fossil fuels like natural gas and oil, which emit carbon dioxide when burned. So we need to make the shift towards renewable energy. There are many options available, including: Heat pumps Air source heat pumps absorb heat from the outside air and use it to heat radiators, underfloor or warm air heating systems, as well as hot water. Ground source heat pumps work in a similar way, using underground pipes to absorb heat from the ground itself. Heat pumps run on electricity, making them an even greener option when you consider that an increasing amount of our electricity comes from low carbon sources. There are two main challenges with heat pumps. Firstly, homes have to be well insulated to make the best use of this technology – and a high proportion of British homes aren’t. Also, if we switch huge numbers of homes over to heat pumps it will lead to massive additional demand on the electricity grid. That issue is compounded by the fact that many homes are also expected to start powering their car from their electricity grid in the coming decades. On the other hand, decarbonising the grid further means building more renewable generation, and heat pumps and electric cars could give us just the sort of controllable demand we need to soak up surplus renewable electricity when we’re over-generating. District heating District heating will also help with decarbonisation. In a district heating scheme, homes are connected to a network of highly insulated pipes. The scheme has an energy source, from which heat is distributed through the pipes into the homes. District heating schemes help with decarbonisation in two ways. Firstly it’s often more efficient to have one large heating system delivering heat to multiple homes, offices schools and factories, rather than each building having its own boiler. Secondly, district heating schemes are often powered from green energy – large heat pumps or biomass plants. They may even use waste heat, produced by factories or rubbish incinerators. There are already over 17,000 district heating schemes in the UK that uses excess heat from the underground to warm homes. Another option to decarbonise heating is incorporating higher levels of biogas or hydrogen into the gas that runs through the national gas network. Unsurprisingly, the gas industry favours this option. But it will require a huge development of new infrastructure if we are to supply sustainable gas to most of our homes. Biogas and hydrogen are currently produced in relatively small amounts, and hydrogen is usually made from fossil fuels. Large scale, low carbon production is possible – but it will take time to develop. Beyond these three main options, there are other technologies that can be used to heat homes, though at this stage they’re perhaps more suitable for green enthusiasts or homes with specific situations and heating requirements, rather than being a mass solution for the UK’s housing stock. For example: Solar water heating systems use energy from the sun to heat up water for your home may be an option for some – particularly larger – homes. But at the moment it’s a technology that’s more cost-effective in countries that are hotter and sunnier than the UK. Water source heat pumps work for homes near a lake, river or even the sea. Like a ground or air source heat pump, they extract latent heat from the water and use it to heat the building. This specialist equipment tends to be installed as a bespoke solution on larger properties. Around 900,000 UK homes have solar panels to generate electricity. For these homes, products are available to route any unused home-generated electricity to power an immersion heater, in this way “storing” unwanted electricity in the form of hot water. Raising awareness is essential How is our heating going to look in 2050? There will probably be a range of different systems across the UK, depending on your location and the size of your home. But one thing is certain: we have to move away from heating systems that use fossil fuels. At the moment, people just aren’t aware of why or how to make the move. In a 2019 study, 69% of heating installers surveyed said that their customers either rarely or never asked about low carbon heating. So there must be a major effort to raise public awareness of decarbonisation: why it is needed, how it can be done and what benefits it will bring. We can see an example of best practice with Home Energy Scotland, a Scottish Government service, where in addition to telephone advice; people interested in fitting renewable heating systems receive a free, in home, expert, government-funded assessment. In Wales and Northern Ireland services are not so advanced but telephone advice provision is available there. But in England, home to 84% of the UK’s population, there’s no service which provides advice to the public about energy and the environment. This has to change. In the coming years, there will be many low-carbon heating options to choose from and many complicated decisions to be made. Impartial trusted energy advice will become increasingly important for UK householders – and for our chances of reaching net zero by 2050.