Most industry-grade process heating systems are based on steam or hot water from boilers that today mainly burn fossil fuels like oil, gas and coal, or electricity generated by different sources.

Solar process heating systems can supply up to 20-30 % of the heating demands of an average plant. This is called the ‘solar fraction’. As a renewable energy source, low-temperature solar thermal technology has huge untapped potential. Solar thermal can be backed up by other heat sources and combined with storage systems for guaranteed supply.

Integration of solar thermal systems into industrial process heat can be done in the following ways:

• Direct heating of a circulating fluid (e.g. feed-water, return of closed circuits, air preheating)
• In processes with low-temperature requirements
• As an additional source for preheating supply water for steam boilers
• Direct integration of solar heating into fossil-fuelled industrial steam boilers

There are three groups of solar thermal technologies: solar air collectors (suitable for the food-processing industry to replace gas- and oil-based drying); solar water systems (installed on rooftops of any industrial building); and solar concentrators.

With advanced solar heating technologies, temperatures of around 400 degrees can be produced. Systems such as flat plate collectors (FPC) and evacuate tube collectors (ETC) can produce heat of up to 120 degrees. Ultra-high FPCs and ETCs can produce temperatures up to 200 degrees.

Most industrial processes require both the heating of a fluid stream (e.g. hot air streams, hot water, replenishment of water in baths) and heating of a reservoir (e.g. ovens, liquid baths).

Using solar energy for heating needs can go hand in hand with improvements in energy efficiency in buildings and heat-consuming processes, which generates additional cost-savings.

Solar thermal costs are largely predictable, with the biggest outlay expected during installation and set up, and typically pay for themselves quickly. Upfront investment is higher than conventional heating systems, but they are cheaper over the full life cycle.

The cost of energy generated through solar heat technologies is envisaged to continue declining over coming years (e.g. from 5-16 euro cents per KWh in 2006 to 2-6 euro cents in 2030 across the EU), according to ESTTP.