Among renewable technologies, some are better known than others. Solar heat has received (too) little attention so far, despite many advantages. Systems are manufactured in Europe. They offer a resilient, affordable and reliable source of hot water and heat supply for many users from the sun’s free energy. With climate change progressing at a worrying speed and geopolitical tensions calling for greater energy security, technologies such as solar heat definitely have a role to play and should gain much more support from policy makers.

What is the installed base of solar thermal in Europe? 
When I joined the Solar Heat Europe trade association in March 2023, I was really impressed by the potential of this sector and the passion of its people. Solar heat has so much to offer. We already have 11 million rooftops equipped with solar thermal collectors in Europe, delivering 41 GWth (thermal) of clean energy harnessed from the sun’s free energy. Around 90% of this applies essentially to residential buildings. But solar heat can also be used for commercial and tertiary buildings, as well as district heating and industry.

This is a fantastic source of energy which deserves to be further harnessed and promoted. Heat represents half of our total energy needs and up to 80% in buildings. Using resilient, ready-to-deploy and carbon neutral sources such as solar heat should be a no-brainer.

And if, traditionally, solar heat has been very present in countries such as Greece and Cyprus – where it is by default a solution in most houses – it is actually Germany which has the largest installed solar thermal generating capacity in Europe by volume (13 MWth). Denmark leads the world as the country with the largest number of solar heat district heating networks installed (124). This demonstrates that solar heat is working in all regions, from south to north.

What are recent developments in solar thermal? 
Solar Heat Europe released its 2023 market report, Solar Heat Market Outlook 2023/2024, in June. It shows that the momentum which we saw in the market in 2022 towards more energy security, whilst progressing towards our Paris Agreement objectives, seems to have been lost over 2023. Like other renewable heat technologies, we are observing insufficient growth of the total installed capacity of solar thermal in Europe over the year.

Comparing 2023 with 2022, we saw very different dynamics with, for example, a 70% market growth in the (still very small) UK, to an 8% growth in France and a 43% decline in Germany (the largest market in volume for solar heat) – due to an unfortunate counter effect of the Heat Law there. In total,1.8mn m² of thermal solar collectors were installed.

This growth was accompanied by projects commissioned in the large-scale markets. These include several solar district heating networks in Germany and Austria, as well as several projects for industry decarbonisation in different European countries, the largest one in France at 11 MWth and the biggest one in Spain at 30 MWth.

However, while we have seen different market dynamics across countries and market segments, the pace of heat decarbonisation is a far cry from what Europe needs in order to reach its climate and energy security targets, particularly when many companies manufacturing such technologies are European Union (EU) based SMEs (small and medium-sized enterprises).

Germany has the largest installed solar thermal generating capacity in Europe by volume, at 13 MWth, while Denmark leads the world as the country with the largest number (124) of solar heat district heating networks installed.

What energy policy provisions does solar heat need? 
Looking ahead, the solar thermal sector looks forward to the swift and ambitious national implementation of the EU’s ‘Fit for 55’ package for climate neutrality by 2050 and a 55% reduction in greenhouse gas emissions by 2030. This offers a clear opportunity to the 27 member states for a decisive step forward towards the faster uptake of renewable solutions.

There are many examples of measures that can unleash at national levels an unprecedented commitment to the energy transition and to climate change mitigation. These include provisions such as the ones in the Renewable Energy Directive (RED) for renewable heat, for the use of renewable energy sources (RES) in buildings and industry, the provisions for clean and efficient district heating by 2050, including targets for RES in district heating, the requirements for municipalities to provide heating and cooling plans, the solar mandate in the Energy Performance of Buildings Directive, and the enlargement of the Emissions Trading Scheme to buildings.

All these measures must be implemented, rapidly, to give to heat the visibility it needs and to give to solar thermal the support it deserves, through constant, predictable market signals to enable our companies to grow and help Europe meet its 2050 ambitions.

We urge policy makers at national level to give it clear support, as all renewables are needed in the race towards climate neutrality. We also look forward to working with the incoming Members of the European Parliament and the new Commissioners towards these goals, in line with our Solar Heat is SMART manifesto calls.

The views and opinions expressed in this article are strictly those of the author only and are not necessarily given or endorsed by or on behalf of the Energy Institute.

• Further reading: ‘In the swim – a perfect fit for solar thermal’. Heated swimming pools, many of which are publicly owned, use lots of energy. With fossil fuel prices going ever higher, it could be time to replace gas and oil with solar thermal technology, which is well-suited to the application. 
• Tackling heat is a priority to tackle net zero, according to Christophe Williams, CEO and co-founder of solar design and engineering company Naked Energy, who discusses the UK’s neglect of solar thermal compared to European neighbours.