Pump up the volume: Cornish village to pilot communal grid for green energy

The environmental evangelising of a retired mechanical engineer, Brian Piper, is bringing a renewable energy revolution to the streets of a small Cornish village.

Until now, Stithians, which sits halfway between Redruth and Falmouth, was best known for its annual show, said to be the largest agricultural spectacle in Cornwall. But Piper is determined that in future the village will become known for its role in tackling climate change.

For years Piper has been educating local parishes about the threat from global heating.

In 2017 he formed the Stithians Energy Group, producing pamphlets which circulated helpful information around the local parishes about how people could reduce their carbon footprint. “We talked about climate change, from the very basics right through to net zero Britain. One of the things that we featured was heat pumps,” he said.

“But the problem with ground source heat pumps is the cost. They come in at around £20,000 depending on the size of the property, and that has been a deterrent for people.”

One of the members of the energy group worked for the Cornish firm Kensa Utilities, whose factory three miles from the village is the only UK producer of ground-source heat pumps. So when the company applied for money from the EU’s European Regional Development Fund (ERDF) money to pursue the idea of spreading the use of ground-source heat pumps by providing a communal grid of underground pipes to source the energy, the villagers of Stithians wrote in support of its application.

Now Stithians is part of a multimillion-pound pilot project to link homes to the underground low-carbon energy system.

Known as Heat the Streets, the project has been given £6.2m from the ERDF. Hundreds of homes, both new-build and older houses and bungalows, in three areas of Cornwall will be linked up to the new system of underground heating.

The first boreholes were drilled this month in the streets to install a network of pipes to draw heat from the rock beneath, and feed into heat pumps in individual properties.

“It will be just like a gas network of pipes,” said Lisa Treseder, senior project manager for Kensa Utilities. “Rather than taking energy from the air, ground-source heat pumps take it from the ground. So these vertical boreholes are drilled, and plastic pipes are put into them that collect heat from the ground. What we are creating is a shared network of pipes to feed individual heat pumps in a community.”

The government has set a target of installing 600,000 heat pumps a year by 2028 but its own projects have so far fallen far short of what is required to transform the domestic energy system. Domestic heating accounts for around 14% of UK emissions, according to the Institute for Government, and decarbonising the way homes are heated will cost an estimated £200bn over the next 30 years. Government-funded green stimulus programmes have so far failed to tackle the scale of the challenge; the £1.5 bn green homes grant scheme closed early after disastrous administrative delays, and less ambitious £450m boiler upgrade scheme was launched.

In Cornwall the sinking of boreholes into the streets to create a communal low-carbon energy system, is a sign of what a combination of grassroots activism and an enlightened private business can do.

The network of boreholes, pipes and heat pumps which are part of the pilot scheme are being installed in two other areas of Cornwall: Carlyon Bay, near St Austell and Harlyn Bay, near Padstow, to connect 200 new-build homes to ground-source energy.

In Stithians all the linking to the network of energy pipes will involve retrofitting existing houses, from 120-year-old stone cottages, to 1970s bungalows.

Householders selected would be given their heat pump free and once connected they would pay £300 a year for their energy, said Treseder. “The idea of these networks is to make it easier for people to install a ground-source heat pump, and reduce the cost for individual households,” she said.

“The ground array of pipes will last for 100 years. It is a utility for the public, emulating the gas and electricity utility structure.”

The parish chair, Phil Blease, is one of many who have applied to have his 120-year-old four-bedroom, detached house connected under the pilot scheme. “There is a whole mix of houses,” he said. “We are trying to demonstrate that the technology can be applied to all these different properties. Brian has done brilliantly raising awareness of climate change and ways to tackle and mitigate it, and motivating others.”

The project has proved so popular it is oversubscribed, with more than 270 villagers expressing an interest in having their homes connected. Many will be disappointed because the funding is likely to cover around 120 properties. But Stithians’ residents and Kensa both hope the pilot will be just the start of the much-needed energy transition.

“Kensa intends to demonstrate a business model that can overcome some of the barriers to decarbonisation of heat in domestic properties, primarily through split ownership: retaining ownership of the ground array to reduce the upfront cost to households,” said Treseder. “Once established this business model will work without government incentives.”

“People are very excited,” said Piper. “Other villages are watching closely. It is our hope that what we are doing here will just keep spreading.”