THE WASTE HEAT KNOWLEDGE AND COMMUNICATIONS GAP

Waste heat, it’s a no-brainer, right? It’s already there, it’s low carbon, and it can be very cheap. BEIS (Department for Business, Energy & Industrial Strategy, UK) has identified 8 TWh/yr with economic potential (source). So why aren’t we using more of it? To answer this question, we need to look not at the heat networks industry but at industrial sectors that produce waste heat. Here, I’m going to explore how putting ourselves in the shoes of a prospective waste heat supplier might help reframe the way we think and communicate about waste heat.

Waste heat or a cooling need? Heat networks as a cooling service

Another way to look at industrial waste heat is as a cooling need. This is how it’s often looked at in Denmark, a country where around 28% of heat supplied to heat networks is surplus heat from energy from waste (EfW) or industrial processes.

Heat is a product of energy production, and it’s a by-product of industrial processes. In the heat networks industry, we call this waste heat, and we see it as a potential opportunity for a low-carbon, low-cost source of heat that contributes to a more efficient economy.

For those producing energy or managing industrial processes, this is generally not the main way they think about waste heat. They are not waste heat producers; waste heat is just part of their waste streams. It’s a waste stream because high-temperature heat cannot be released into the environment around us, according to environmental regulations in the UK. It must first be cooled to reduce the environmental impact of the heat and minimise thermal pollution. Thermal pollution occurs when human influence changes ambient water temperature. This can reduce the oxygen content in bodies of water and induce thermal shock in aquatic life, ultimately impacting our ecosystem. This creates a need for cooling.

Something interesting happens when we look at industrial waste heat as a cooling need. Instead of looking at waste heat as a resource, it becomes a cooling problem that we need to solve. This is the perspective of the prospective heat supplier. This fundamentally changes how we should approach discussions with high-temperature industries about waste heat.

Ultimately, waste heat is not the core business of an EfW, whose core business is managing waste. It’s not the core business of a power plant either, a distillery or a cement factory. There are not huge sums of money to be made in selling waste heat compared to selling power, whisky, or cement, even in a policy regime designed to incentivise its use. However, waste heat can be a way to cost-effectively manage an industrial cooling need or meet environmental ambitions associated with cooling. It can even create a small revenue stream.

An industrial facility with a cooling need might be considering installing a new mechanical draft cooling tower without a heat recovery system – this will, of course, have a cost associated with it that affects a company’s bottom line. Most cooling systems are a cost to the business. Another way to meet this cooling need might be to install a heat network supply connection. This is essentially a similar process, with heat taken from hot water, providing cool water. The heat is taken into the heat network, and the cool water is returned to the environment. The heat network supply connection brings with it an opportunity to recover part of the costs of the cooling investment through the sale of heat. In the right policy context, this should make for a more financially interesting proposition.

What does all this mean, then? Well, it means that heat networks are actually offering a cooling service to industrial facilities. This changes how we should discuss waste heat with prospective suppliers. It also provides an insight into how contracts might be structured. In Denmark, the cost of waste heat is often benchmarked against the alternative cost of cooling.

Intermittency, security of supply, and contracts

The framing of waste heat is not the only challenge. Misconceptions about waste heat are prevalent, and this is ultimately hampering how much we’re making use of waste heat.

In early 2022, the Danish Embassy and the Scottish Government held a joint workshop with key senior officials and representatives from the industry to discuss waste heat. Our roundtable focused on the whisky industry, as distilleries were identified to have up to 325,000MWh/annum waste heat potential in Scotland (a relatively big potential for a small country) (source). The Scotch Whisky Association raised a common challenge in the discussion on waste heat: intermittency of heat supply and the risk that this is penalised through contracts. The view that intermittent heat sources cannot work on heat networks in the UK is a common one, but it’s a misconception – a misconception which the heat networks industry in the UK could do more to combat.

Intermittent heat sources can be managed effectively on heat networks by diversifying generation and ensuring adequate capacity to supply the heat network in the event of a shutdown. Linked with this, thermal storage is a key enabler of intermittent heat sources, as it provides a buffer service day-to-day, and week-to-week, for both the network (ensuring stable heat supply) and the industry (ensuring stable cooling supply).

Intermittency is ultimately about the security of supply, and like any other network infrastructure, heat network operators will conduct risk assessments and make provisions to ensure the security of supply. Yet, there is a prevailing view in the UK that as a distillery, or a cement factory, you might end up as the sole supplier of a heat network. Concerns like ‘what happens to the heat when cement production shuts down for plant maintenance?’ are common. Businesses play a central role in their communities and do not want their community left without heat. Of course, they need not worry; the key point is that an intermittent heat source would never be the sole supplier to a heat network. Why, then, is this view so common?

Call to action: communication = confidence

Our roundtable concluded that more must be done to better communicate with high-temperature industries about how intermittency is managed and how risks are allocated in contracts. We must address this misconception that waste heat from industry would never be the sole heat source on a heat network. There is potential here for standardisation or providing some guidance, which could be explored jointly by industry and government. This could help provide greater confidence to the sectors. There is also a role for showcasing successful waste heat use examples to provide confidence to a market where this is still relatively new. A great example from Denmark is the Aalborg Portland cement factory, which annually recovers enough heat for 23,500 households equivalent for use in the district heat network. So, next time you’re talking about industrial waste heat, perhaps consider stepping into the shoes of a prospective heat supplier.

Just a fraction of heat networks in the UK uses waste heat from EfW or industrial processes, with 90% still running on gas (source). In the future, it’s estimated by BEIS that around 17% of heat supply to district heating could come from waste heat sources in an electrification, hydrogen, or gas scenario (source). How do we get there, though? We won’t if we can’t get waste heat suppliers on board. Cost remains a central barrier for waste heat in the UK, with the cost of a heat network connection still relatively high. Industry can start thinking more about how it communicates about waste heat, but it’s a government (alongside innovation) that helps play a role in reducing the cost of waste heat connections.