They have always been the pride of the Dear Green Place. Now scientists reckons they could be its power too.

Engineers have calculated that heat pumps under the city’s parks and playing fields could warm up to 49,000 homes.

In fact, Glasgow, which is greener than most cities, has been identified as the local authority area in Scotland with the highest untapped capacity for ground source energy.

The Herald can reveal that the city, which is gunning to be Scotland’s first to achieve zero net carbon, is actively considering such technology.

Saughton Park in Edinburgh already has heat pump technology, which works like a fridge in reverse to generate warmth from the difference in two temperatures.

Now a study by a charity called Possible reckons Glasgow, North Lanarkshire and the capital all have substantial ground source heat potential.

Possible said Glasgow alone could use its parks and other green spaces to meet 297 megawatts of peak heat demand, cutting UK carbon emissions by 83,000 tonnes each year.

For the whole of the UK, the report revealed that the equivalent of five million homes could be warmed with clean heat by putting heat pumps under parks and public green spaces.

If this potential was harnessed, 30 gigawatts – equivalent to about 10 per cent of the country’s peak heat demand – could be generated, cutting UK carbon emissions by eight million tonnes a year, more than 2% of UK emissions.

The report was written for the Powering Parks project by climate charity Possible and Hackney Council’s social enterprise body, Scene. It also argues that heat pumps could generate income for councils and park authorities to reinvest locally.

Neil Jones, project manager at Possible, said: “Heating is a carbon bomb in the UK. One-third of all UK greenhouse gas emissions comes from heating and yet it’s often overlooked.

“But, in order to effectively tackle the climate crisis, finding ways to warm our homes and buildings with low carbon heat must be a priority.

“What’s so exciting about this report is that it not only offers a way to kick-start a society built on clean heat, it offers both economic and health benefits at the same time. It’s a win-win-win.”

Scotland has among the highest proportion of renewables in its electricity supply in the EU while also having the continent’s least renewable heating, which remains reliant on gas, usually in individual boilers.

Louise Waters, senior consultant at Scene, said: “Parks are unique in their ability to cultivate a space where all sections of society mix. So it’s incredibly exciting to be able to demonstrate their role in creating climate solutions.

“We’ve shown how previously untapped heat, stored in the ground below lawns and playing fields and replenished by nature, provides a huge part of the solution for low-carbon heat for our buildings, made possible through the wonder of heat pumps.”

A spokesman for Glasgow City Council said: “De-carbonising Glasgow’s heating systems has to be an essential part of the city’s efforts to become carbon neutral by 2030.

“We are currently investigating a wide range of options that will have the potential to minimise the carbon emissions produced by heating the city.

“Glasgow has thousands of hectares of parks and open spaces and ground-source heating networks are currently part of our considerations.”

Saughton Park is going green after installing a £500,000 turbine on a weir on the Water of Leith. It also has two ground-source heat pumps.

Shona Nelson, chairwoman of the Friends of Saughton Park, said: “The micro-hydro is the last piece of the jigsaw in the re-development of Saughton Park and we think it will really put the park on the map.”

The scheme was part of a ParkPower project being developed by GreenSpace Scotland, a charitable social enterprise.

The hydro power plant lights the park while its buildings get their heat from the ground.

Ground, air and water sourced heat pumps are all being seen as a safe and carbon-free alternative to Scotland’s gas central heating systems.

Engineers usually prefer water-sourced systems. A major heat pump district heating system is being built in Clydebank, at the old John Brown shipyard.

Another scheme in Orkney is heating public buildings using the sea. The heat pumps used for the Warehouse buildings in Stromness cost half the price of conventional fossil fuel boilers and have half the carbon footprint.