Waste heat from a data centre at the University of Edinburgh is at the heart of a pioneering project, funded by the Scottish Government, pointing the way to how Scotland might decarbonise its public buildings, but also homes and offices. 

On the roof of the James Clerk Maxwell building at Kings Buildings campus, boxes connected to a data centre far below in its basement pump warmth out into the air of a bright day. A new £2 million  project, plans to ensure that heat, now lost, will replace gas as the source of a heating network on the site.

The plan is one of seven public sector projects across Scotland set to receive shares of a £20 million fund, and shows the potential of using waste heat to warm homes. 

“These are the chillers,” said Robert MacGregor, energy engineering manager at the University of Edinburgh. “Data centres use a lot of electricity and that gets turned into heat, so then you have to get rid of a lot of that heat, with something like this which sends the heat up until the air.”

“It’s not being used for anything, so it just is lost. What we’ll do is put that into a heat pump so we can use that to heat the buildings. You’re using all that heat that has been generated for a useful purpose rather than throwing it away.

Data centres, like these, in other parts of the University and other locations across the City of Edinburgh, are being seen as a prospective source of heat for the capital, as are other sites of lost heat like sewage treatment centres and waste plants.

Patrick Harvie, Minister for zero carbon buildings, visited the site of the new project to announce the first seven projects set, between them, to receive £11 million grant funding from a £20 million Public Sector Heat Decarbonisation Fund.

“It is remarkable,” he said, “the number of these data centres around the country, and currently they are having to use energy to extract heat out of them. You walk into one of these rows of racks and computers and you feel the heat – and all of that heat is lost.”

READ MORE: Insane to leave Bute House Agreement, says Patrick Harvie

READ MORE: Alba submits Harvie confidence motion following Cass Review response

READ MORE: Edinburgh City Council's plans for heat pumps and heat networks 

This tranche of projects will show how leisure centres, schools and university campuses will be transformed by a government fund designed to accelerate the decarbonisation of public sector properties.

That £20 million is part of £200 million already committed to the public sector for energy efficiency and renewable heating over the next five years - part of the wider plan to spend £1.8 billion during the current parliamentary session on decarbonising Scotland’s buildings.

Even with the cooling system on, it is warm inside the data centre. Temperatures range from around 20C to 40C. “Compare that temperature,” said Mr MacGregor, “to the outside air, which can, in winter-time, be below freezing, and think about using it for an air-source heat pump. It’s much more efficient to use the data centre as it’s producing a temperature higher than the air.”

The University, he explained, had been looking at how to move away from gas for heating its buildings for several years. “We had thought that probably hat was going to involve heat pumps and that if you’re using heat pumps you want to make them as efficient as you possibly can, and this heat source seemed obvious.”

The energy used to run this site gives an insight into the scale of energy consumption involved in data storage. Enough electricity is currently used in its one room, to power around 2-300 houses worth of heating. Each bank, according to data centre manager, Paul Hutton, uses about 14 houses worth of energy.

“Without the cooling system,” he added, “we would not be able to stand here. At the moment it’s generating in about 200 KW and we know that in a couple of months we’ll be generating about 400KW, because we’re bringing in some new equipment.”

Around £400,000 of the university's  £2 million grant will be used for the heat network and data centre conversion and the rest for other mesaures like insulation.

There are hopes, said Grant Ferguson, director of net zero and carbon leadership at the University of Edinburgh,  that the university, which has five gas-fired district heat networks, will be able to replicate this pilot project in other areas at a different, larger scale.

Currently, he said, the university is also working with City of Edinburgh Council to “map heat opportunities - not just from data centres, but sewage and other waste systems".

The Herald: Patrick Harvie inside the data centre with Grant FergusonPatrick Harvie inside the data centre with Grant Ferguson

“One of the principal things we want to do,” said Mr Harvie, “is decarbonise existing networks, many of which have used gas. We’re keen to use facilities like data centres, where heat is being wasted at the moment and put it into heat networks that have applications in urban areas like this, but many rural parts of Scotland as well.”

He noted:  “We don't know exactly what the heating potential from data centres across Scotland is. A current assessment wouldn’t even begin to give you the full picture, because we see technology proliferating, particularly with the growth in use of Artificial Intelligence.

“Data centres are going to continue to grow and we need to be using that energy efficiently. This represents a win-win because it reduces their operating costs. It reduces carbon emissions. And it gives a source of affordable heat to the users of those networks as well.”

The Herald: Patrick Harvie visits Edinburgh University district heating projectPatrick Harvie visits Edinburgh University district heating project

Countries which have already heavily invested in heat networks, include Denmark, which over fifty years has created a system in which around two-thirds of the country is served by networks. Half of these are currently fuelled by biomass. 

Mr Harvie admitted that there was a risk that “people may feel confused by that proliferation of different technologies” involved in decarbonisation heating. 

“But actually,” he said, “we need to recognise that this is a way of meeting people’s needs, affordably and low carbon. If we get this right we’ll not only get cheaper energy bills, we’ll not only get more secure energy, but also generate huge numbers of high quality careers.”

“For anyone looking for individual advice about their own home or building,” he said, "Home Energy Scotland is the way to go, Business Energy Scotland if it’s a small business."