Industrial heat decarbonisation: what low carbon technology options have we got?

Andrew McGhee

Principal Engineer at Reheat

5 minute read


The scale of heat decarbonisation required across Scottish industry to achieve net zero by 2045 is undoubtedly vast. The UK Government has stated its ambition to replace 50TWh of fossil fuels with low carbon alternatives by 2035 – primarily focusing on hydrogen, electrification, and bioenergy to achieve this goal. Scotland’s Energy Strategy outlines how it plans to improve industrial and commercial energy productivity by at least 30% by 2032, through a combination of fuel diversity, energy efficiency improvements and heat recovery.

This is particularly challenging when we consider industrial heat, which has a reputation as being ‘hard to decarbonise because of the high temperatures required and variety of applications. Drying, washing, baking, distilling and chemical reactions are just some of the ways industrial heat is used, further complicated by other factors such as industrial sites being dispersed or clustered, with the latter being responsible for around 8% of the UK’s carbon emissions.

In response, Government is putting its efforts into industrial decarbonisation by supporting low carbon energy generation – namely hydrogen, electrification, bioenergy, and efficiencies, including heat recovery and other approaches such as carbon capture and storage.

To benchmark how far along UK industry is on its journey to decarbonisation, a MakeUK survey stated that 96% of UK manufacturing businesses are either ‘already decarbonising their operations or have plans to do so’, with 31% saying decarbonising their business is a high priority right now and a further 49% said it is a medium priority. Comparing government policy and a snapshot of how companies are progressing gives an interesting perspective into the realities of industrial heat decarbonisation.

With applications such as process heat, steam, pressurised hot water, thermal oil, combined heat and power and space heating all traditionally generated using fossil fuels, Government has set out its stall for three primary low carbon energy generation and efficiency methods with which to reduce industrial CO2e emissions.

Here we offer up some insights around each approach to industrial energy generation and efficiency, and we also give an extended view on bioenergy:


Electrification and hydrogen

Direct electrification of heat is an option which can be highly efficient. Technology such as direct electric process heaters or eboilers can be used across various industrial processes to heat liquids and gases. However, how this kind of technology contributes to decarbonisation would very much depend on how ‘clean’ the electricity is that they draw on and the robustness of the local grid.

Renewable electrified heat technologies include heat pumps, which of themselves provide a range of options, be it air source, ground source or water source (including heat extracted from mine water which is location-specific but has big potential). Heat pumps have huge benefits in being a commercially ready technology and can offer a viable option for early fuel switching but are currently limited to relatively low temperature processes.

It is also worth taking into consideration the current difficulties with grid connection in order to generate heat from electricity. There are many reports of sites and business suffering from grid constraints, leading to prohibitively expensive upgrade work and extended timelines for connection, so if the ambition is to electrify, then onsite generation may be the most appropriate solution.

Hydrogen is a promising low carbon option for high temperature direct firing. High temperature hydrogen technologies are not yet commercially ready and require innovation and testing to bring them to maturity.


Heat recovery and efficiency

According to the MakeUK survey, for 74% of manufacturers, optimising energy efficiency is the main focus of decarbonisation. This makes complete sense as recovering energy that is being lost through industrial processes is a much smarter approach, especially when you consider that sectors such as steel and glass making reportedly waste over 50% of the heat they produce. As a result, there is scope to improve the efficiency of these heating processes. The use of heat recovery technologies can significantly reduce energy consumption, improve the efficiency of manufacturing processes and reduce waste.

It’s also worth noting industrial funds that support heat efficiency decarbonisation. Scotland’s Industrial Energy Transition Fund (SIETF) provides grant funding aimed at businesses with high energy use to reduce costs and emissions through increased energy efficiency. Despite the latest round (Call 3) of the SIETF having closed to new applications, Reheat understands that the policy team at Scottish Government is reengaging with representatives of key energy-intensive industrial sectors and will consider an extension to SIETF in 2024.



Last year, the UK Government published its latest Biomass Strategy, which supports its use across the UK economy, and reinforced its use in industrial decarbonisation. There is also renewed interest in biomass to be used in conjunction with Carbon Capture, Usage and Storage (CCUS) or Bioenergy with Carbon Capture and Storage (BECCS).

In Scotland, the last issued action on bioenergy was the Bioenergy Update in March 2021 that promised a subsequent Bioenergy Action Plan in 2023, which has been delayed but Reheat understands it will be available inside the first half of 2024. The tone of the Bioenergy Update was positive around bioenergy in industrial applications, saying ‘as a renewable energy source, it helps by directly displacing oil, coal and natural gas use or by decarbonising the fuel source for the production of materials such as steel and cement,’ so, we will hope for a similarly supportive Action Plan.

Bioenergy is indeed a big opportunity in decarbonising heavy industry, and options such as biomass, bio derived fuels (or synthetic fuels) and biogas all have industrial applications. This is in part due to its flexibility in switching from fossil fuels in order to meet industrial heat demands. Modern biomass systems and control systems can achieve the high temperatures and heat requirements for a range of industries, especially suitable for distilling processes that have notoriously high and variable demands for heat.

Reheat has designed and installed biomass systems for distilleries ranging from 850kW to 3MW which are required for round-the-clock process steam operation, coping with rapid peaks and intermittent heat demand. This has been a hugely successful for our clients, showing key metrics such as system availability at 99.4%, which is vital when unplanned production downtime is so costly. For one of our clients, Nc’nean Organic Whisky Distillery, both their production and space heating is provided by the company’s biomass system, and they have built their (now global) brand on the premise of being truly sustainability throughout every aspect of the whisky’s production.

Part of this includes the support we gave to Nc’nean about sourcing local, sustainable wood chip for their biomass boiler. This is a broader point in terms of biomass systems in Scotland, where there is large availability of sustainable wood fuel as a result of the country’s substantial forestry and timber processing supply chain. Biomass installations provide 70% of Scotland’s renewable heat, so utilising this for industrial decarbonisation makes sense when taking into account the local, rural economic impact of sustaining this domestic industry, as opposed to relying on carbon intensive imports. In fact, the value add of this industry is in the region of £1bn per year, with a workforce in excess of 25,000.

When we consider that bioenergy is widely available, a technically proven alternative to fossil fuels in industrial applications and supports Scotland’s rural economy, it becomes a very compelling option that is hard to ignore in the race to achieve net zero. If your business is interested in exploring solutions such as bioenergy, heat recovery, efficiencies and funds to help deliver your industrial heat decarbonisation efforts, then I would be happy to discuss this further with you.