Solar energy is a clean, affordable, and secure energy. By using solar thermal in industries, GHG emissions would be significantly reduced and therefore the air quality would be improved.

It is directly linked to Flat Plate Collectors (FPC), Evacuated Tube Collectors (ETC), on-site and nearby renewable energy generation (heat/cold).

Deployment levels are mainly determined by the economic competitiveness of solar thermal systems. The majority of industrial heat demand (75%) takes place in large complex industrial sites. Although solar thermal energy could save costs in the long run, the complexities of integrating new heat sources into existing processes creates possible risks that the bulk producing industries try to avoid. One opportunity is to integrate solar thermal heating plants during the construction of new industrial plants.

For small- and medium-size industrial plants, solar process heat could reduce the dependence on volatile fossil fuel prices. The key challenge is to maximise the share of heat provided by solar heating. This means that solar heating needs to be accompanied by storage to allow process heating during non-sun hours, storage for non-production hours, or more advanced control systems to optimise the usage of solar heating.

For small- and medium-size enterprises, rooftop space and finance opportunities for the upfront costs are the key barriers

Key challenges for solar thermal heat in industrial applications are:

• Short pay-back times that are expected (< 3 years),
• Relatively low fossil fuel prices charged in the industrial sector
• Integration into existing industrial processes

The main barriers to increased deployment of solar industrial process heat and cooling systems are as follows:

• High investment costs and lack of finance options
• Fossil fuel pricing
• Public awareness
• Scaling issues
• Lack of suitable design guidelines and tools

There is a mismatch between the supply of solar irradiation and the demand for heat. For domestic hot water applications, during summer the discrepancy can be compensated with relatively small water storage to store the heat demand for about two days; however, if a seasonal mismatch must be offset, a very large storage volume will be required. Although technical solutions are available, such seasonal storage is currently only installed in pilot plants, since it increases the level of investment required and, consequently, the price of solar thermal heat rises significantly.

Solar thermal energy is often still not yet cost-competitive with fossil fuels at today’s prices. The correct economic way to compare solar heat prices with those from fossil fuels is to calculate these over the lifetime of the solar thermal system. Then, competitiveness is strongly dependent on the assumed growth rate of fossil fuel prices.

In addition, a significant increase in public support programmes and budgets for research and development is needed, to stimulate the development of solar thermal technology with higher solar fractions, lower costs, and improved efficiency and reliability. In the long run, the combination of both, increased market stimulation and increased R&D will help solar thermal to become cost-competitive and an attractive heat source in Europe, without subsidies.

• Renewable Power Generation Costs in 2020 (IRENA: International Renewable Energy Agency)
• Cost trends of solar energy for heat in industry (Solar Payback)
• Solar Heat for Industrial Processes - Technology Brief (IRENA: International Renewable Energy Agency)

There are different factors that influence the environmental profile, including location, size, applied technology and materials (used for construction), water use, land use, operation and maintenance needs, etc.

Solar thermal is likely to be replacing gas, or possibly oil in rural areas, while solar PV will replace electricity.

The government figures for kilograms of carbon per kWh for each fuel type in 2021 can be seen below.

So, if we’re replacing oil, solar thermal would lead to greater emissions reductions than solar PV but slightly lower if gas. However, it’s a bit more complicated than that because of the continuing decarbonisation of the electricity grid as more renewables replace other forms of electricity generation. By 2030 electricity is likely to have emissions of only 0.09kgCO2e/kWh (according to government predictions) while the carbon emissions from oil and gas will remain fairly constant. Additionally, in the summer when the solar panels will be generating the most, the national grid has a lower carbon intensity anyway because of all the other solar PV that is plugged into it.

DNSH:

• Climate change adaptation
• Transition to a circular economy
• Protection and restoration of biodiversity and ecosystems

Despite the technical potential, as well as the potential economic benefits of using solar heat in industry, actual deployment levels remain quite low. To achieve higher market penetration, policy options are: create more awareness of the benefits of solar process heating, especially in industrial clusters of small- and medium-size enterprises; provide financing mechanisms to cover upfront costs; and consider whether support for solar thermal could be an alternative to fossil fuel price subsidies to national industries.

Furthermore, solar process heat technologies can be supported by local manufacturing, as showcased in India, thus providing a mutually reinforcing strategy to support a healthy national industry.

SEIA Case studies

Matias, João & Saraiva, S. & Melicio, Rui & Catalão, João & Matias, J.C.O. & Cabrita, Carlos. (2011). Solar thermal system: practical case study. Link