Heat networks are not new. In fact, the first known heat network dates to Roman Times; the Aquae Sulis, in Bath, used natural hot springs to heat public baths and private residences by distributing hot water through a network of pipes.
The UK’s first modern network was established in Sheffield in the 1870s. The Sheffield District Heating Supply Company used steam generated from a power station to provide heat to buildings in the city centre.
The technology behind heat networks has obviously developed since Roman times but the concept has remained simple, and their application has never been more important. Heat networks enable us to harness waste and recoverable heat sources and distribute this low and zero carbon heat to customers affordably. Clearly, as we build towards a net zero future, heat networks have a central role to play.
Our Heat Networks business started life in London over 15 years ago with supplies to a residential site in Woolwich. We now have a team of over 80 people working on all aspects of heat networks, from project development, through construction and into asset operations. We have a really exciting portfolio of projects (including decarbonising our first network in Woolwich!), that are going to be taking waste heat sources and distributing that waste heat to customers in towns and cities across the country.
As we move away from natural gas and towards electrified heat networks, how do those networks play into our Whole Systems Thinking (WST) approach?
There are a couple of great examples in practice. Often, we will use heat pumps to boost the temperature of a heat source so that its suitable for space heating and hot water. Heat pumps require electricity, and the goal is to source that from low carbon sources such as wind and solar. This raises the prospect of green supply arrangements or “sleeved” power purchase agreements from designated solar or wind farms. Then we need to consider whether there is a business case to install batteries in tandem with our heat pumps and, potentially to service customer loads. We already install large thermal stores which represent a very low-cost energy storage option but our teams’ expertise in battery storage enables us to assess whether a battery could be a viable solution in tandem.
Moving beyond the energy centre and thinking about our customer’s buildings, we know that heat pumps work most efficiently when they are supplying heat at slightly lower temperatures than the gas boilers that they are replacing. In some cases, that will mean looking at the building’s existing heating and cooling systems and looking at ways that we can supply lower temperature heat whilst minimising the impact of cost and change to that system.
Again, we have the expertise within the business to carry out these surveys, make recommendations and complete the associated works to enable a “low carbon, lower temperature ready” building.
Hopefully, this helps demonstrate that our expertise at both ends of the pipe means we can provide optimised solutions which offer low carbon heat and cooling at lowest cost. Whole System Thinking in action! So what projects are our teams working on now? We have several heat network projects under development. Among them is the “Aire Valley” project, in Leeds, where we’re working with Enfinium which operates an Energy-from-Waste Plant. Processes at such plants produce significant amounts of heat which we want to capture. We’re going to build a heat network to serve the local area and , we hope, in time connect our network with the existing one run by Leeds City Council. The result will be a city-wide heat network for Leeds, much as they have in cities in Europe, including Copenhagen, for example. The capital city of Denmark has one of the most developed heat networks in the world (it extends over 2,000 kms) and the city’s authorities have set a target of being carbon neutral by 2025, one of the most ambitious goals set by any city anywhere in the world.
When it comes to decarbonisation there is no ‘one size fits all’ solution but in towns and cities where you've got density of demand, with big anchor loads such as hospitals and universities, then heat networks are an excellent solution. These are exciting times for our sector with Ofgem becoming the regulator in England and Wales from 2025 and the introduction of heat zones, helping to support city scale heat network deployment.
It's a huge amount of work to do, but we cannot waste any time on the journey to net zero and I’m looking forward to a very interesting few years for my side of the business.