solar thermal


Solar Process Heat

From the regional breakdown, it is clear that most regions have the potential for the significant application of solar thermal systems for process heat production. Regional potentials are mainly dependent on the overall consumption of the selected sectors, on their demand for low temperature process heat and, importantly, on the amount of solar irradiation available. OECD countries have a large potential due to their large industrial energy demand. Niches exist in several sectors in which part of the low-temperature energy demand can be economically supplied by solar thermal systems.
In terms of the sectoral breakdown, the food and tobacco sector has almost half of the potential, with the balance well spread among other sectors. This is particularly important for developing and least developed countries, where the development and modernisation of the food industry has a critical role to play in terms of food security. Solar thermal systems can help developing countries to stabilise food prices by reducing their connection to the volatile prices of oil and other energy commodities.

Unlike biomass, where resource availability may limit the potential and raise sustainability concerns, solar has an almost unlimited resource potential. Estimates of the theoretical potential of different configuration and radiation levels, where good solar radiation is available, solar thermal technologies for industrial process heat are very close to break even. In many specific cases where the cost of the reference energy unit is higher or where locally manufactured solar thermal systems are cheaper, solar thermal technologies are already cost effective without any need for subsidies. In areas with lower solar radiation, such as in central Europe, solar thermal solar energy are in the range of millions of EJ/yr (e.g. 3.9 million EJ/yr). This is hundreds of thousands of times larger than the current world total primary energy supply of 503 EJ in 2007 (IEA statistics). The quality of the resource, i.e. the insolation rate, however, depends on latitude and climatological conditions.

An analysis of several sources suggests the current generation and investment costs for technologies need substantial cost reductions to become competitive. In some specific markets, taxes on fossil fuels or subsidies for renewable energy make solar thermal competitive already today even in areas of low solar radiation. Although solar cooling is still in an early demonstration stage, in countries with stable solar radiation and unstable, expensive electricity, solar cooling may become a viable alternative to electric chillers in the next ten years.

In industry, five sectors use a significant proportion of their process heat at temperatures lower than 400C, and are therefore likely to have a strong potential for solar thermal to meet their process heat needs. These are transport equipment, machinery, mining and quarrying, food and tobacco, and textiles and leather.


The chemical sector has also a high potential for solar thermal, but generally on a very large scale. Cost reductions in CSP technologies, combined with the growth in the production of chemicals in Africa and Middle East, suggest growing scope for the development of solar thermal applications in the chemical sector. The main barriers to the greater use of solar thermal in this sector are the scale of the area needed for solar collectors, (2.3 EJ/yr) below 100C. If half of this process heat demand were to be met in areas where direct natural insolation is sufficient to justify the use of CSP technologies, the potential for the use of solar thermal technologies in the chemical sector in 2050 would be around 2.4 EJ/yr. This would increase the total estimated potential for solar thermal in industrial applications in 2050 from 5.6 EJ/yr to around 8 EJ/yr.

Different solar technologies have different investment costs per unit of capacity, and different levels of capability in terms of thermal output. Flat plate collectors are the cheapest technology, but they can only be used to heat loads to around 70oC. Vacuum tubes or parabolic mirrors in combination with a suitable heat energy carrier can reach 120C to 400C. Successful tests have been carried out using solar energy to achieve temperatures sufficient to produce pure metals from ore. But the cost and technical challenges involved in upscaling these tests make the widespread application of solar heat at temperature levels above 400oC unlikely before 2050.

The Innovator

Gurmit Singh, New Delhi

Dr. Gurmit Singh is a research scientist and an environmentalist, his profound enthusiasm and passion for renewable energy technologies has been for 28 years now. He holds both his Bachelors and Masters degrees from 'Rheinisch-Westfalische Technische Hochschule Aachen.' In Germany and spent 14 years in Germany working as a research Scientist and then 8 years in Florida, USA in Solar Research. He is winner of 'Lockheed Martin Innovation Award 2008' in renewable energy, also won the '2010 BuildArch Award'and recently won the 'i3 India Innovates Award 2011'. His professional career started with a technology assessment of the carbon abatement potential of specific industrial technologies in the EU, and the evaluation of national and international policies and measures in the areas of climate change, energy efficiency and renewable energy. Currently he is a Visiting Faculty for 'Renewable Energy' at Amity University, Noida