Concentrated Solar Thermal for Industrial Heat: IDAE Guide

Decarbonizing industry represents one of the greatest challenges of the energy transition. Heat is central to this challenge: two-thirds of annual energy consumption in European Union industries is used for process heat. Currently, the vast majority of this demand is met by fossil fuels, with natural gas playing a central role.

Figure 1: Final energy consumption in the EU in 2021. Source: World Energy Balance 2022, IEA

To promote the deployment of technologies capable of changing this situation, Spain’s Institute for Energy Diversification and Saving (IDAE) has published the “Guide to Concentrated Solar Thermal Energy for Industrial Processes.” This document provides detailed and relevant information on concentrated solar thermal technology, particularly for industrial users seeking sustainable and efficient alternatives for processes with high thermal energy demand at medium and high temperatures (100–400°C). In this blog, we summarize the most important information from the Guide.

What Role Does Concentrated Solar Thermal Energy Play in Industrial Decarbonization?

Concentrated solar thermal (CST) energy is emerging as one of the most attractive solutions for meeting industrial heat demand. It is a proven technology capable of supplying renewable heat reliably and competitively. Through the use of thermal energy storage, CST can be integrated into industrial processes, ensuring operational continuity and reducing dependence on fossil fuels.

Which Industrial Sectors and Processes Can Benefit from CST?

CST is particularly well suited to industries requiring heat in the medium-temperature range (100–400°C).

• In the food and beverage sector, for example, CST can be integrated into processes such as drying, pasteurization, sterilization, and industrial frying.
• In the chemical and plastics industries, CST can supply heat for synthesis, distillation, extrusion, and polymer molding.
• The textile sector, which relies heavily on heat for dyeing, drying, and fabric setting, also finds CST a realistic and scalable alternative.
• Mining and construction materials industries, with processes such as mineral drying and gypsum kilns, represent sectors with high thermal demand and available space for solar installations.

Industrial processes of greatest interest for CST include steam and hot water production, drying operations, and separation processes. A key advantage is thermal energy storage, which makes CST a competitive option compared with alternatives such as photovoltaics, as it ensures heat supply at night or during cloudy periods. This is particularly valuable for factories operating continuously or with stable thermal loads.

How Does CST Compare with Other Industrial Heat Decarbonization Technologies?

When comparing the available decarbonization options for industrial processes in the 100–400°C range, the conclusion is clear. Biomass can supply heat, but it raises significant environmental concerns: it competes with biodiversity, generates air pollution, and releases greenhouse gases today that must be reabsorbed through the growth of new forests in the future. Industrial heat pumps, although highly promising, do not yet have commercial solutions capable of reaching these temperatures and currently supply heat only up to 150°C.

Electric boilers powered by on-site solar photovoltaics represent the only real alternative that can compete with concentrated solar thermal energy on price, thanks to the low cost of PV modules and the possibility of participating in ancillary service markets for the electricity grid. However, CST also has advantages, most notably its lower land requirements.

What Institutional Support Programs Are Available for CST in Spain?

Thanks to these advantages, institutional support for CST is growing significantly in Spain. Some of the most important programs and mechanisms include:

• The Energy Savings Certificate (CAE) system, which allows energy consumption reductions achieved through solar thermal installations to be monetized, creating an additional revenue stream that improves project profitability. A technology-specific standardized measure is currently being developed and is expected to be published.
• The Recovery, Transformation and Resilience Plan includes dedicated funding for renewable industrial heat projects, with an emphasis on integrating solutions such as CST.
• The European Regional Development Fund (ERDF) 2021–2027 also supports renewable energy investments in regions with high potential, creating opportunities for scalable projects beyond the pilot stage.
• The LIFE program finances innovation and demonstration projects, which are essential for validating new applications in specific industrial sectors.

Alongside institutional support, business models have also evolved. Heat as a Service (HaaS) is emerging as a transformative model because it removes the barrier of upfront investment for industrial customers. Under this model, the customer does not purchase the plant but pays only for the heat consumed. The service provider assumes the technological and operational risks, while the industrial customer benefits from renewable heat at stable and predictable prices.

This approach is particularly attractive in a context of high gas and electricity price volatility, as it provides greater cost certainty and competitiveness. It also enables small and medium-sized industrial companies, which might otherwise be unable to invest in CST, to access the benefits of this technology.

Why Is CST an Alternative for Decarbonizing Industrial Heat?

In conclusion, decarbonizing industrial heat in the 100–400°C range is a major challenge in the energy transition. The options are limited: biomass, with its environmental impacts; electrification through electric boilers, which can be competitive but depend on electricity prices and require more land for photovoltaic installations; and, finally, concentrated solar thermal energy.

Among these options, CST stands out as the most mature, competitive, and scalable solution. It provides continuous renewable heat thanks to thermal energy storage, can be adapted to multiple industrial sectors, benefits from growing institutional support, and offers innovative business models such as Heat as a Service, which reduce entry barriers and facilitate widespread adoption.

Spain, with its exceptional solar resources and favorable institutional framework, has the opportunity to position itself at the forefront of this transformation and lead the decarbonization of industrial heat in Europe.