Implement solar thermal to decarbonize industry

Industry accounts for 25% of total CO2 emissions from energy systems, with process heat making up nearly two-thirds of industrial energy demand. Today, more than 80% of this heat still comes from fossil fuels, making its decarbonization essential for achieving net-zero emissions. Fortunately, various renewable heating solutions, such as heat pumps, solar thermal, and thermal energy storage, are already commercially available

Currently, there are just under 1 GW of solar thermal solutions for industrial processes installed globally. Currently, there are just under 1 GW of solar thermal solutions for industrial processes installed globally. (1) However, the potential of the technology is much greater. Estimates forecast it can supply up to 12% of the global final energy demand (2) and feature it as an important piece in the portfolio of renewable heating solutions needed to reach net-zero GHG emissions. According to the International Energy Agency (IEA), the deployment of solar thermal solutions in industry needs to accelerate rapidly and be up to 20 times faster during 2022-2028 than currently projected to have a chance at limiting global warming to 1.5°C. (3)

Solar thermal solutions use solar collectors to absorb sunlight and generate heat. They efficiently expose water or another fluid inside the collectors to the sun, heating it up to the desired temperature. The generated heat can then be used for residential and commercial heating, for district heating networks and industrial processes requiring hot water or steam at temperatures up to 400°C.

Figure 1: Types of solar thermal solutions and example industrial processes where they can supply heat

Solar thermal solutions encompass a variety of technologies that can be roughly split into two categories – non-concentrated and concentrated solar thermal solutions.

• Non-concentrated solar thermal solutions are mostly suitable for lower temperature uses – such as preheating water – but are more cost and space efficient. They include flat plate collectors, evacuated tube collectors, and compound parabolic concentrator collectors.

• Concentrated solar thermal solutions concentrate direct sunlight into a specific point to generate heat at higher temperatures than their non-concentrated counterparts and can produce high pressure steam. They include parabolic trough and linear Fresnel solutions.

Additionally, solar thermal solutions can be paired with absorption chillers and other technologies to provide cooling to buildings and industrial processes. Finally, there are photovoltaic thermal (PVT) hybrid collectors producing both heat and electricity available on the market.

More use cases available in the WBCSD’s Renewable industrial heat navigator brief: Solar thermal solutions.

Sustainability impact

Climate

Solar thermal solutions generate fully renewable energy without any emissions. They therefore save 200-400kg of CO2-eq per MWh of heat supplied depending on the fossil fuel technology they are displacing.

The lifecycle emissions of solar thermal solutions are only about 9-35 kg CO2-eq per MWh (1) coming primarily from the manufacturing process and steel production.

Nature

Solar thermal solutions have large land footprint (1.6-4.2 m2/kW) which can cause negative side-effect on nature. However, larger ground installations can be combined with other land uses such as animal grazing.

Social

Solar thermal eliminates local air pollution (NOx and other harmful emissions) associated with conventional combustion of fossil fuels.

Business impact

Benefits

Solar thermal solutions come with several inherent advantages which make them attractive for some industrial applications. These are:

• They provide fully decarbonized and renewable heat.

• They do not use any fuel to generate heat, practically eliminating operational costs and avoiding fossil fuel, electricity, and biomass price fluctuations as well as supply shortages.

• Under favorable conditions, they offer short payback periods of 3-5 years.

• They do not require costly upgrades to local grid or other infrastructure and can be deployed in fully off-grid remote locations.

• They can supply low, medium, or high-pressure steam at temperatures up to 400°C.

Costs

Typical business profile

The solar thermal technology is best suited for industries using heat below 200°C, such as food and beverage, paper and pulp, fast-moving consumer goods, and pharmaceuticals. Moreover, it reaches highest efficiencies in low latitude regions with high solar radiation and small seasonal differences. Finally, solar thermal does not require almost any local infrastructure. Therefore, it is suitable for off-grid applications such as mining and material processing.

Solar thermal solutions have high upfront capital costs but minimal operational costs and long lifetime. They are therefore ideal for novel financing models such as Heat-as-a-Service which allow companies to avoid the capital expenditure and rather just pay for the supply of heat (such as in the case of the Heineken plant in Seville, Spain).

Approach

1. Assess Heat Demand and Temperature Requirements

2. Evaluate site Conditions

3. Select Suitable Technology

4. Explore financing Options

5. Engage stakeholders Early

6. Conduct Feasibility and Permitting Studies

7. Design and Engineer the System

8. Procure and Construct

9. Commission and Optimize

10. Monitor and Maintain

Stakeholders involved

• Manufacturing plant director: Solar thermal supplies hot water or steam which are instrumental to the manufacturing processes. The implementation project therefore requires strong buy-in from the plant leadership.

• Operations: In addition to the plant leadership, company-level operations professionals should bring in specialized expertise and experience from similar projects.

• Finance: Solar thermal represents a large capital investment which in most companies requires approval of an investment committee including finance professionals.

• Sustainability: Implementation of solar thermal significantly reduces Scope 1 emissions and should be included in long-term emissions reduction plans.

Key parameters to consider

Generally, three main parameters are seen as crucial for assessing the commercial viability of solar thermal solutions:

• Required temperature: lower required temperature improves efficiency and lowers capital costs

• Project size: larger systems benefit from economies of scale

• Location: high solar irradiance increases amount of heat generated and easy availability of land close to the industrial facility reduces the required investment

Ideal locations with high solar irradiance include for example southwest of the United States, northern Africa, southern Europe and Australia. Other viable locations with medium and low irradiance are east coast of the United States, central and northern Europe, and northern China. However, operational projects are spread across the whole world. You can find their locations and specifications in this database published by AEE Intec.

You can find approximate irradiation levels for your location on this map provided by the World Bank Group, Esmap, and Solargis.

Implementation and operations tips

Common implementation success factors reported by companies are:

• Availability of land close to the facility

• Availability of capital subsidies and/or Heat-as-a-Service financing models

• A clear commitment to decarbonization by the industrial company