Can energy from under a park in London's Hackney help tackle climate change?

The heat beneath the ground offers a reliable source of low carbon energy that could be crucial in the battle to mitigate climate change. Anna Turns investigates…

Deep below a park in Hackney, in London’s east end, plans are afoot to tap into this underground source as part of a bid to switch to renewable energy.

Welcome to the stage an innovative new project in London that will generate a new source of low carbon heat which could potentially help fight climate change. Installing heat pumps below some of Hackney’s parks could allow for low temperature heat to be collected from the ground and concentrated, then pumped into the buildings above for heating. 

Surrounding schools, hospitals, council offices and public buildings, even lidos and homes, could potentially one day benefit from this renewable energy.

Hackney Council is working in partnership with energy consultants at Scene and the charity 10:10 Climate Action for the Powering Parks Project, ‘a real-life solution’ that will see heat pumps providing power and heat for nearby buildings. Max Wakefield, director of campaigns at 10:10 says: “Parks have a particular social currency because everyone loves parks. People understand that local budgets are under threat so this project is a great opportunity to introduce people to a technology that is going to need to be far more commonplace in all of our lives if we are going to fix climate change.”

Installing heat pumps in parks is far more cost-effective than digging up the roads to install pipes, and there are other financial benefits when compared directly to energy sourced from fossil fuels. Wakefield estimates that one proposed site in Hackney could save the council £4,000 per year once the heat pump is installed. But the government’s Renewable Heat Incentive that pays councils for every unit of heat that is generated from ground- and water-source heat pumps to help them meet the costs, is set to expire in April 2021. So, watch this - urban green - space.

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Getting all pumped up

In the UK, a third of emissions come from heating indoor spaces and if this system rolls out nationally, parks could be part of the solution. Heat pumps are being installed at Edinburgh’s Saughton Park, Bristol’s Owen Square Co-op project, and a tower block project in Enfield. The National Trust installs heat pumps to move its historic buildings away from relying on fossil fuels, and Wakefield hopes that this could one day provide a renewable energy source to millions of homes too. “In order to fully exploit this untapped resource, we’d absolutely need to go beyond local public estate buildings. Councils are sitting on low carbon heat that they could be exploiting and selling to private third parties,” says Wakefield.

While heat pumps are not yet widely used in the UK, they are more mainstream elsewhere. This market has grown for the fourth consecutive year, according to the European Heat Pump Market and Statistics Report 2018. Installation rates in France and Italy are much higher than in the UK, and in Germany heat pumps were installed in 43 per cent of homes in 2017, moving ahead of gas heaters for the first time. “Scandinavian countries are way ahead of the game and countries like the Netherlands, Austria and Switzerland have ambitious industrial or municipality-scale heat pump schemes,” explains Louise Waters, senior energy consultant at Scene.

She explains how this technology works: “Ground- or water-source heat pumps extract energy from the ground or water, and transfer it to a building’s heating system so that radiators get warm and the taps run hot. They use electricity to do this, but are so efficient that for every unit of electricity used, between three and five units of heat are delivered to the building. The heat that’s extracted from the ground or water is naturally replenished over time, meaning that the heat resource is truly renewable.”

London Fields

Park pilots

After much mapping and number crunching, three suitable sites from across Hackney will soon be chosen as the pilots for the Powering Parks Project which is funded by Nesta’s Rethinking Parks programme. Councillor Jon Burke, cabinet member for energy, sustainability and community services is pleased that Hackney Council is taking the lead: “It’s important that we proactively reduce our reliance on fossil fuels, so I’m proud to be joining forces with experts in the field to investigate such an exciting initiative. The Powering Parks project has the potential to help us unlock sustainable energy and save – or even generate – money for important council services.”

The heat pumps are due to be installed in 2020 and the team is currently estimating the national potential of this model, as Wakefield explains: “We’re using GIS [geographic information system] data of the UK’s green spaces, ground temperatures and certain assumptions to create some reasonably robust estimates about how much of the UK’s heat demand could in theory be met by projects like this that feed back into local economies.”

Clissold Park

Full of hot air?

Engaging local people through community outreach is crucial. “We want to increase awareness of the need to cut gas use for heating, and show how heat pumps in parks can be part of the solution, while bringing local benefits,” adds Wakefield.  

Waters agrees that ground-source heat is a massively untapped resource: “There are about 100 times more gas boilers sold in the UK per year than heat pumps. Ground heat is not a limitless resource, but we could use much, much more than we do at the moment.”

She believes that it’s an obvious option for houses and non-domestic buildings that have gardens or are near to open spaces, or for new buildings that can have heat collectors installed underneath them. “Ground heat could also be used to power heat networks that deliver heat to multiple buildings instead of them all having their own gas boilers or electric heaters.”

While Waters warns that heat pumps are not the only solution – “they are one of a handful of technologies that will be heating our homes in a low-carbon future world” – she’s excited by the scale of the impact from community schemes like this one, with carbon savings being equivalent to perhaps 20 or 30 domestic installations. “Local authorities are huge consumers of energy, and as they become more knowledgeable and comfortable with choosing heat pumps for the buildings in their portfolios there is great potential for replication,” she says. “Hackney Council is particularly driven by sustainability considerations, so it’s a good place to pilot a park-based ground heat scheme but from a technical point of view, similar installations would be possible in any UK town or city.”

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