Why heat networks are the answer, Simon Kerr

IT is a welcome move, indeed, the Scottish Government’s request of every local authority in the land, that they submit plans (by the end of this year) for how they intend to roll out heat networks across their patch – as noted, here.

Sometimes described as ‘central heating for cities’, heat networks (also known as district heating) supply heat from a central source to consumers, via a network of underground pipes carrying hot water.

They can be large or small – citywide or a small cluster of individual properties – but one thing is for sure: they avoid the need for individual boilers or electric heaters in every building.

They are not a new technology, either here in Scotland or abroad, and it is to Denmark that many of us look for inspiration, its investment in heat networks sparked by the dramatic oil price hike during the 1970s. Heat networks, harnessing the waste heat from the country’s industry, was Denmark’s way of becoming less dependent on external sources of energy.

There was also a price element, with waste heat-powered heat networks seen as a way of reducing people’s energy bills.

When any of us are considering energy, there are three considerations that need to be addressed: carbon emissions, affordability and security. In industry-speak, what’s known as the ‘energy trilemma’ (as explained here).

Here in Edinburgh, there are over 100 small seat networks, including Harvesters Way in Wester Hailes and the recently-built St James Quarter. The challenge is how we might connect all these relatively small developments into a large, citywide heat network.

In drawing up their heat network plans, local authorities will be turning to a Scottish Government-produced interactive heat map (here), to help identify where to house energy centres and where to run the pipes.

For individual households, that will mean a certain amount of disruption – as road are dug up, for pipe laying – but also an invitation to connect (using what’s known as a Heat Interface Unit) to a heating and hot water source that is less expensive, and with lower carbon emissions too, than their existing boilers and heaters.

The raw material for a heat network can be pretty much anything, which is its one of its beauties, because the wind doesn’t blow and the sun doesn’t shine all of the time. The facility to use a variety of sources allows for easy switching, should one source become scarce or too expensive. It is also future-proofed, should a new energy source be discovered or developed.

And one possible source stands out, head and shoulders: waste heat. Every industrial process produces it and much of it is simply pumped into the atmosphere, up chimneys.

If, somehow, that waste heat could be captured, it promises to be a game-changer.

It is being claimed – here – that almost all of the EU’s energy needs could be satisfied by all the waste heat produced within the EU.

There is no reason to believe that it would be any different in Scotland: in other words, that all of Scotland’s heating needs could be met by the waste heat produced by our whisky distillers, oil refineries, bakeries, etc.

It’s an intriguing possibility that demands careful consideration.

Simon Kerr is an account manager at Edinburgh-based SAV Systems, which provides “low-carbon, energy-efficient, heating and ventilation solutions”. He is also an active participant in Transition Edinburgh, that seeks to support community groups and projects that strive for a “greener, fairer, healthier and more resilient Edinburgh”.

Picture credit: SAV Systems

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