This article first appeared in our COP27 special issue of My Green Pod Magazine, published on 10 November 2022. Click here to subscribe to our digital edition and get each issue delivered straight to your inbox
Home heating is responsible for up to 14% of the UK’s total carbon emissions.
That’s a staggering amount of carbon, but it’s also a contribution that people like you and I now have the power to change, without having to sacrifice comfort or convenience.
Climate-friendly heating is finally becoming an accessible alternative to gas and oil boilers for thousands of households across the UK, reducing people’s need to rely on extremely pricey gas and paving the way for a decarbonised future.
In April 2022, the government launched its Boiler Upgrade Scheme, offering homeowners up to £6,000 if they choose to replace their old gas heating system with a heat pump or biomass boiler.
Since then, Octopus Energy has set out to change the record on heating for good, by installing air-source heat pumps for roughly the same price as a gas boiler.
So has the time finally come for climate-friendly heating to kick gas to the curb? And if so, are heat pumps the winning solution – or could the beacon be handed to one of their competitors?
Heat pumps are a tried and tested technology – in fact, 97% of us already have something similar in our homes. Fridges work just like a heat pump – so do air conditioners.
The only difference is that fridges take energy from your home and use it to cool the air inside them.
Heat pumps, on the other hand, syphon energy from cooler air outside and use it to heat our homes (they’re what’s known as ‘active heat exchangers’).
Like most home appliances, a heat pump runs on electricity. This means that they reap the rewards of the increasingly clean, green electricity in the electrical grid (in 2021, 40% of the UK’s electricity was generated by renewables).
Heat pumps don’t just use electricity to produce heating, they also use it to harness extra energy from the atmosphere, and then use that to help warm your home.
With this in mind, you actually get more heat energy out of a heat pump than the electrical energy you put in; compared with a traditional combi boiler (with a 75-90% efficiency), heat pumps generally achieve a 300-400% efficiency, making them four times more efficient.
This gives customers way more bang for their buck, and gives heat pumps a green edge over their competitors.
Of course, heat pumps aren’t the only heating solution on the market. Another low-carbon alternative – hydrogen heating – has been getting a lot of attention lately for its potential to replace methane as our gas of choice.
Burning hydrogen (or using it to power a ‘hydrogen fuel cell’) is a lot cleaner than burning gas.
It doesn’t produce any carbon emissions – in fact, the only byproduct is water. This has led some to argue that we should use hydrogen, rather than gas, to power our home heating.
But unlike fossil fuels, burning hydrogen isn’t the issue – producing it is. There are various ways to make hydrogen and each method is colour-coded grey, blue or green.
Unfortunately ‘grey hydrogen’, which is extracted from natural gas, is not only the dirtiest method (studies suggest it’s dirtier than burning coal), but also the most common – 98% of the world’s hydrogen is produced this way.
Green hydrogen, on the other hand, is far more sustainable. It’s produced by splitting water molecules through electrolysis which, as the name suggests, can be done with electricity.
This means it can be powered by climate-friendly renewables, making it much greener.
Green hydrogen could be incredibly useful for decarbonising tricky-to-reach sectors, like heavy industry, aviation and heavy transport.
Octopus Hydrogen, founded by the Octopus Energy Group in 2021, is investing £3bn in green hydrogen production with the intention of tackling carbon emissions in hard-to -reach sectors.
But for the time being, green hydrogen is hard to come by, relatively expensive to make and requires a tonne of electricity, so we’ve got to be careful how we use it – and use good alternatives where possible.
Until we have the infrastructure in place to support green hydrogen generation at scale, hydrogen heating would mean piping dirty grey hydrogen to homes, which would extend our reliance on fossil fuels – damaging the climate further rather than protecting it.
Even if we did have enough green hydrogen, a recent review of 32 hydrogen studies in the scientific journal Joule found that hydrogen boilers are actually far less efficient, and more expensive, than heat pumps.
This sentiment was echoed by David Cebon of the Hydrogen Science Coalition who, speaking to the BBC, recently explained that: ‘In the UK, heating homes with green hydrogen would use approximately six times more renewable electricity than heat pumps.’
On a wider, societal scale, the ‘repurposing’ of the polluting gas network for hydrogen would be a huge job, which unfortunately wouldn’t be a case of simply switching
methane for hydrogen.
It would involve changing millions of boilers, as well as ‘relaxing’ 15% of the pipes in the network.
This is also expected to be extremely expensive; in 2020 the UK’s gas networks estimated the cost to be an eye-watering £900m.
If money needs to be spent to change home heating, it may as well be on the most efficient option – an option that uses less green electricity to make more heat.
Having weighed up the evidence in the race for green heating, heat pumps continue to come out tops.
For starters, they’re a tried and tested technology. In fact, a recent poll found that Octopus heat pump customers were 20% more satisfied with their heating overall than those with traditional heating.
They’re also far more efficient, safer and – given the lack of truly green hydrogen – greener, too.
Heat pumps are also getting cheaper to buy, and run at a much faster rate than their competitors.
According to the International Council on Clean Transportation, ‘By 2050, a heat pump will cost an average £496 a year including energy bills, compared with £1,090 for a hydrogen boiler.’
Given that heat pumps run on electricity alone, they have the ability to give customers some protection as gas prices skyrocket, and pave the way to leaving gas behind all together.
In fact, these days if you’ve got solar panels and a home battery, you can essentially make your home self-sufficient, removing the need to connect to the grid entirely (but we’ll save that for another article).
For a long time, heat pumps were a cottage industry with only a few plucky specialist installers, unable to deliver an affordable heat pump solution to the masses.
Now Octopus is applying its resources and expertise to do just that, helping to build a greener future for everyone.
By investing £10m in building the UK’s first heat pump research, development and training centre, Octopus Energy will soon double the number of green heating engineers in the UK, employing a mighty 1,000 of them. And that’s not all.
These eco-engineers are backed by an all-new crack squad of green-heating geeks, working hard to make heat pumps more efficient than ever before and helping to integrate them with intelligent tech and ‘smart tariffs’.
Where heat pumps already cost around the same to run as a gas boiler, these boffins have enabled smart-tariff customers to save up to 30% on their bills without sacrificing comfort by running their heat pumps at the greenest, cheapest times.
We’re excited to finally see heat pumps, green and great as they are, delivered – and run – for a fraction of the price.
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