The Cornish hamlet exposing the flaws in the net zero oil boiler ban

Within the next three years, rural households who have relied on heating oil for decades could be forced to spend tens of thousands retrofitting their homes to accommodate a heat pump.

By 2026, replacing a broken oil boiler like for like is set to be banned, leaving homeowners not connected to the gas grid with no choice but to dig deep and buy an electric heating system. A similar proposed deadline for homes reliant on gas is not until 2035.

It is one of the policies put forward by the Government as it marches towards its goal of net zero carbon emissions by 2050. 

Heating oil, the Government argues, is an incredibly carbon-intensive fossil fuel and must be abandoned if Britain is to meet its green pledges.

But in a far-flung hamlet in Cornwall, an experiment to keep oil boilers – but using an alternative fuel – is showing that perhaps they can survive the green revolution – and could ultimately save Britain’s 1.7 million off-grid households millions of pounds in renovation costs.

For two years now, residents of Kehelland, a hamlet near Camborne, have been taking part in a landmark trial using cooking oil recycled from factories.

Hydrotreated vegetable oil is a form of renewable diesel, created by taking waste fat and feedstock and processing it using hydrogen. 

The chemical is already being used in transport. McDonald’s, for instance, already recycles its waste cooking oil for use in trucks. 

Official figures show that the vegetable oil produces 88pc fewer carbon emissions than kerosene, the typical choice for home heating oil. 

Boilers in Britain need only be fitted with a nozzle compatible with the recycled oil – a process which costs around £500 and takes an hour.

‘It’s a no-brainer’

There are 50 homeowners taking part in the Kehelland trial which has so far seen vegetable oil successfully substituted for kerosene in centuries’ old properties – including the local chapel. 

Andrew Geake, the Methodist church’s environment and climate change advocate, says the hamlet’s church has set itself a far more immediate net zero deadline of 2030. 

Two chapels are currently using vegetable oil, he adds, with another two lined up to join the scheme.

Old church buildings such as the one in Kehelland are typically restricted by their listed status, making heat pump-friendly renovations all but impossible.

“We’ve got about 150 churches in Cornwall and the majority of them are off-grid,” Mr Geake says. “Because these buildings use heat infrequently you need a system that will give you a rapid heat up, which you cannot get with heat pumps.

“Heat pumps are brilliant in the right place for the right thing, but a lot of church buildings are listed. You can’t go around putting in external insulation, that’s for sure, and you can’t really do internal insulation either.”

The existing pipework of church buildings such as the one in Kehelland would incur a “massive expenditure” for the chapel, which is “only just financially holding itself above water,” Mr Geake says.

A ban on oil boilers was first floated by Theresa May’s government, and later outlined in an Energy White Paper published under Boris Johnson in 2020. 

The now-infamous document outlined a “net zero future” in which electric heating systems would take the place of burning fossil fuels such as gas and oil. Mostly, this would be achieved by using heat pumps.

Britain’s approach stands in stark contrast to that of Europe, which has decided not to ban oil boilers provided they run on a renewable or non fossil fuel.

John Weedon, of Mitchell and Webber, the distributor supplying the Kehelland trial run by the UK and Ireland Fuel Distributors Association, said: “That means Southern Ireland will be allowed to keep the boilers and Northern Ireland won’t.”

Nonetheless, the Government has continued to throw its weight behind heat pumps, and still clings to its target of installing 600,000 of them every year by 2028. 

More than £81m in vouchers has been doled out in the form of £5,000 grants for air source heat pumps, and £6,000 for ground source heat pumps, a Government spokesman said.

But Britain has some of the oldest housing stock in Europe, and this has a direct consequence on their suitability for the green technology. 

Heat pumps work best in homes that are well insulated: for modern properties, this is less of an issue, as cavity wall insulation is cheap and easy to install. 

But older houses with solid walls, more common in rural areas, require internal or external insulation, which is both costly and unsightly. 

Installing a heat pump more often than not also requires the replacement of a home’s entire radiator system.

For homeowners, this translates into quoted costs of at least £45,000, sometimes higher if windows also need replacing. 

The estimated savings of a heat pump over time are minimal, according to the non-profit Energy Saving Trust, which calculates that a heat pump only saves £15 a year compared to an A-rated oil boiler, the most efficient available.

‘I hate throwing away something that’s working’

Stephen Thomas, 64, has lived in such a home for 27 years. His traditional detached house is one of the oldest in Kehelland, where the vegetable oil trial is taking place. 

Originally built in the 1860s, with two-foot granite walls, it would cost Mr Thomas untold thousands to externally insulate – and would undoubtedly spoil the look of the house.

The oil-fired boiler that heats the property is itself 17 years old, and Mr Thomas says it still works perfectly well. “I hate throwing away something that’s working,” he says. “That boiler could go on for another five or 10 years and it’s serviced every year.”

Dave Biggs, 74, whose bungalow was built in 1981, has also run into issues with planning regulations when faced with the prospect of parting with his oil boiler.

Planning laws dictated that his home had a low pitched roof when it was built, this would have to be entirely retiled to accommodate the loft insulation necessary for a heat pump.

“Building costs have gone up since Brexit – just the renovation alone would cost me £40,000 before you account for a new heating system,” he says.

Mr Biggs’s oil boiler is 27 years old, and if a ban would come into effect from 2026, he would be unable to replace it like for like. “In three years time the Government is saying ‘thou shalt not have an oil boiler, thou shalt only have an air source heat pump’,” he says.

“Really? I mean if it were a socialist government I would understand it, but I’m not expecting to hear that from a Conservative government.

“From a practical point of view, from a cost point of view, it’s just never going to happen.”

Mr Biggs, a pensioner, is also conscious that the payback time for such a large investment is unlikely to be within his lifetime. “Rural communities are a minority, but there are still 1.7 million of us and we are being unduly penalised and ignored.”

Andrew Waterhouse, was quoted £30,000 to install a heat pump in his 1960s detached house. His home is not as old as others in the area – and is equipped with cavity wall insulation and UPVC windows. 

But at the moment, he says, spending tens of thousands on renovating his home to accommodate a heat pump “isn’t palatable”, not least because burning vegetable oil has cut his emissions by 90pc, he claims.

“I’ve had to spend nothing to convert my boiler to become very, very green,” Mr Waterhouse says. “As heat pumps start to develop, I’m sure it’s something that I may consider. However, I don’t need to if I can have another viable option.”

The green heating oil is not without its drawbacks – there are concerns over how long it will last, and it is currently subject to the same excise duty rates as diesel, making it far more expensive for households than kerosene. 

There is little difference between the efficiency of vegetable oil and kerosene, but the former is more costly. 

Based on today’s prices, a household would expect to pay £750-£800 to fill up a 1,000l tank. The same tank would cost £1,500 to fill with vegetable oil due to higher excise duty. 

Added VAT is also higher for the latter, at 20pc compared to 5pc for kerosene.

George Eustice, former environment secretary and MP for Camborne and Redruth, is campaigning to change this, however, with suggested amendments to the Energy Bill tabled for its third reading in September that would bring the price more in line with kerosene.

Mr Eustice told the Telegraph: “It’s a no-brainer to allow households to use vegetable oil, provided you can get the cost of it on parity with kerosene.

“If you include VAT and excise duty, vegetable oil ends up being something like 50pc more expensive. This Energy Bill that’s coming up is the last chance that Parliament as a whole will have a chance to make a view on this.”

Mr Weedon said: “We want hydrotreated vegetable oil to have a parity with kerosene – and it may take a few years to get to that point.

“But you can’t compare kerosene and vegetable oil really because the latter is decarbonising your property and it stops you having to spend £30,000 or more upgrading your home.

“Rural communities are worried about the energy crisis like everyone else, but they have a realism that going green does cost something.”

Even if every home in Kehelland was a new build, a future in which every home has a heat pump is unlikely. Like many other remote areas of Britain, weak electricity infrastructure means too many households switching to electric heating would overload the grid.

Ofgem, the energy regulator, has previously said the expansion of supply into rural areas was “a massive project over the next decade” as the industry frantically tries to remove bottlenecks and accelerate grid connections.

A spokesman added that big policy promises were “empty words if communities can’t get connected to the grid wherever they live and when they need it – especially in the countryside.”

For now, a ban on oil boilers has not been confirmed. The Department of Energy Security and Net Zero said it would publish the results of the consultation in due course. 

It maintained that no household would be required to install a heating system that was unsuitable for their home or business.

This leaves homeowners like Mr Waterhouse in a bind: make renovations in anticipation of a ban, or wait until the last possible moment and replace the oil boiler with another. 

Switching to the greener fuel has made the households using it more conscious of their energy use – and all of the Kehelland residents spoken to by this newspaper said they have used less oil than they did before switching to HVO.

Andrew Griffith, economic secretary to the Treasury, visited Kehelland last week to see the trial for himself. He said: “Consumers are often fearful, they don’t feel that things are being done with them, but being done to them. 

“Hearing about their experience of vegetable oil – they felt quite empowered by the fact that they could switch fuels without having to incur all the upfront costs. Certainly that’s something that I will take back to fellow ministers across Whitehall, and see what more we can do to make sure that the benefits and the learnings from this trial are fully taken into account when we think about policy.”

A Government spokesman said: “We have always recognised that not all properties will be readily suitable for heat pumps and are investigating what role other solutions – including biofuels – could play in decarbonising these properties.”