Why connecting to windfarms could supply heat networks

Prof Pearson, Group Sustainable Development Director at Star Refrigeration, the company that manufactured the river heat pump that supplies the Queens Quay district heating scheme with "near zero carbon heat", knows full well the barriers to rolling out this technology.

Whilst the Queens Quay heat network was a remarkable feat, four years after its launch, it remains the only such high temperature heat network to have even secured planning permission in Scotland.

This is despite the fact that Star Refrigeration is a world leader and installed what was in 2011, and still is, the largest high temperature ammonia heat pump, in Drammen, Norway.

The company's most recent giant heat pump was shipped from its Glasgow factory earlier this month, destined for the Mersey Heat Network. "The best thing to head to Liverpool from Glasgow since Kenny Dalglish," he joked.

Star Refrigeration's latest heat pump about to head to the River Mersey (Image: Star Refrigeration)

The key factor, said Prof Pearson, affecting the viability of large heat pumps is the cost of electricity. “At current grid prices this makes heat from big heat pumps about double that of gas.”

That is so, he pointed out, despite the fact that electricity from renewables is now cheap at the site of production. "Electricity, whilst sold for over 30p/kWh now costs as little as 7.5p/kWh to generate at wind farms. These generate most in windy periods when heat demand is high.”

“The high electricity price is partly because every single kWh bought pays a huge levy to the grid /government (UK). About half of the sold price even if just a few miles from the user at a time when supply exceeds demand.”

“A huge rebalancing effort is underway called REMA; Review of Electricity Market Arrangement. This proposes various rebalancing efforts but it won’t deliver the structural change to make electrified heat competitive with gas.”

For a heat pump to be viable, without subsidy, the price of electricity would need, he said, to be “considerably less than 10p/kWh”.

Electricity legislation is reserved to Westminster, but Prof Pearson's private wire idea could be, he said, a pragmatic way through which the Scottish Government could do something about the problem regardless.

“It is legally and technically possible to run a cable from anywhere to anywhere in Scotland and such a private wire would allow this power to be bought and sold for close to that 7.5p/kWh level.”

Every large wind farm, old and new, he advocated, should be compelled to offer a side tapping of power to a private wire network running into the big heat demand areas. This helps the wind farms which make more when operating than when idle.

“Private wire is a well-understood technique. However, like all investments, it needs surety of utilisation. Given that the only entity that can guarantee that public sector buildings will become the anchor loads of heat networks within LHEES zones is the Scottish Government then it's simple enough to reason the Scottish Government should underwrite these cables to create the affordable power for big heat pumps for cities."

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The Scottish Government, he advocated, would not need to fund these private power supplies. That, as well as deployment, he said, should be done by the private sector.

“If after five years, the Government hasn’t delivered the policies to create enough demand for the deployment of heat networks from clean sources (which I’m confident they will) like big river source heat pumps, they would step in and support the developers.

“In the meantime, developers of district heating and big heat pumps could be offering heat at prices far closer to gas and gain a march on the European cities still struggling to find enough sources of clean heat at the right price.”

Prof Pearson noted that the investment potential is huge. “It has been conservatively estimated that with the right policies each Scottish city could welcome over a billion pounds of private investment to deliver clean heat. That’s a lot of employment and resulting tax revenue not to mention secondary local economy spending.”

He believes they can be an element of a Just Transition. “Achieving that,” he said, “relies not just on fairly priced heat which would be possible with sensibly priced electricity, but economic activity (local jobs) to offer a higher quality of employment to anyone wanting to retrain."

Minister for Climate Action Gillian Martin said: “Responsibility for energy infrastructure is reserved to the UK Government. While there is potential for private wires to offer cost savings on the wholesale cost of electricity, a clear approach to rebalancing gas and electricity prices – as recommended by the Independent Review of Net Zero and called for by the Climate Change Committee – would negate the need for these proposals.

“Our consultation for a Heat in Buildings Bill included proposals to legislate to encourage certain buildings to connect to heat networks, where appropriate.  We are also exploring the potential for new duties for public sector buildings in relation to heat networks.  These potential changes will unlock investment in large-scale district heating by providing far more certainty over the revenue that the heat network can expect to raise over time.”