New independent research published by Greenspace Scotland reveals how the rivers flowing through our towns and cities and the greenspaces between our buildings can act as vital low carbon heat sources to help Scotland achieve its climate targets.
The Green Heat in Greenspace study shows that through the use of heat pump technologies our urban rivers and greenspaces can act as major low carbon heat generators with the potential to supply nearly 80% (41 TWh) of the heat demand from Scotland’s towns and cities, saving 4.7 million tonnes CO2e. That is the carbon saving equivalent of taking 1.7 million cars (or 60% of Scotland’s car fleet) off the road for a year.
River catchment areas act as giant solar heat collectors concentrating water-borne thermal energy into river channels. As these ‘heat highways’ pass through urban areas where demand for heat is highest, some of the heat can be extracted by submerged pipes and boosted in temperature by large scale water source heat pumps. The heat can then be distributed to surrounding buildings through sub-surface pipes known as district heat networks. This technology is tried-and-tested and in widespread use in countries like Sweden, Norway and Austria. Indeed you only have to go as far as Queens Quay in West Dunbartonshire to find an example of heat being extracted from the River Clyde and delivered to new buildings on the site of what was once the John Brown Shipyard.
Speaking on the publication of the Green Heat in Greenspaces national findings report, Julie Procter, Chief Executive of greenspace scotland said:
“Wind turbines are now a familiar sight producing clean, green electricity. Scotland has an enviable track record in shifting to renewable sources of electricity. However, we remain bottom of the European league table for renewable heat with just 7% of our heat demand being met from low carbon sources. The Green Heat in Greenspaces study shows that Scotland has huge natural reserves of heat locked up in its water bodies and under its greenspaces yet we have barely scratched the surface in terms of their utilisation.”
Around half the energy we use is for heating buildings, creating a fifth (21%) of Scotland’s greenhouse gas emissions, in most cases from burning natural gas supplied by the mains grid. The International Energy Agency (IEA) recommend that to meet our climate goals no new fossil fuel boilers should be sold from 2025. The Scottish Government’s recent draft Heat in Buildings Strategy indicates we will need to move one million homes off the mains gas grid, together with 50,000 non-domestic buildings, and convert 167,000 buildings that are currently off the mains gas grid to greener sources of heat.
National findings indicate that up to 50% of current heat demand from Scotland’s 516 urban settlements could potentially be delivered from rivers, with significantly higher percentages for some towns and cities. While cities like Perth, Aberdeen, Stirling and Inverness are all ideal candidates for major river based heat schemes, it is Glasgow that, in absolute terms, offers the greatest capacity to offset its carbon footprint. The heat demand of Greater Glasgow is one fifth of the total demand from all of Scotland’s settlements. As the host city for the 2021 UN Climate Conference, COP26, it has major potential to lead the way in generating river source heat for Scotland and the UK.