Release Date: July 2012
The solar heating and cooling (SHC) roadmap outlines a pathway for solar energy to supply almost one sixth (16.5 EJ) of the world’s total energy use for both heating and cooling by 2050. This would save some 800 megatonnes of carbon dioxide (CO2) emissions per year; more than the total CO2 emissions in Germany in 2009.
While solar heating and cooling today makes a modest contribution to world energy demand, the roadmap envisages that if concerted action is taken by governments and industry, solar energy could annually produce more than 16% of total final energy use for low temperature heat and nearly 17% for cooling. Given that global energy demand for heat represents almost half of the world’s final energy use – more than the combined global demand for electricity and transport – solar heat can make a significant contribution in both tackling climate change and strengthening energy security.
- Solar collectors for hot water and space heating could reach an installed capacity of nearly 3 500 GWth, satisfying annually around 8.9 EJ of energy demand for hot water and space heating in the building sector by 2050. Solar hot water and space heating accounts for 14% of space and water heating energy use by that time.
- Solar collectors for low-temperature process heat in industry (< 120oC) could reach an installed capacity of 3 200 GWth, producing around 7.2 EJ solar heat per year by 2050. Solar process heat accounts for 20% of energy use for low temperature industrial heat by that time.
- Solar heat for cooling could reach a contribution of 1.5 EJ per year from an installed capacity of more than 1 000 GWth for cooling, accounting for nearly 17% of energy use for cooling in 2050.
- Swimming pool heating could reach an installed capacity of 200 GWth, producing annually around 400 PJ solar heat by 2050.
- By achieving the above mentioned deployment levels, solar heating and cooling can avoid some 800 megatonnes (Mt) of CO2 emissions per year by 2050.
- Achieving this roadmap’s vision requires a rapid expansion of solar hot water heating in the building sector, including in solar supported district heating, as well as in industrial applications. Dedicated policy support should overcome barriers related to information failures, split incentives and high up-front investments.
- While a number of industrial and agricultural processes can use low-temperature flat-plate collectors, advanced flat-plate collectors and concentrating technology should be further developed to produce medium-temperature heat. Industrial process heat offers enormous potential in sectors that use low- and medium-temperature heat for processes such as washing, leaching (mining industry), drying of agricultural products, pre-heating of boiler feed water, pasteurisation and cooking.
- The development of compact storage will allow heat to be transferred so that it can be used when the load is required, aiding the deployment of solar space heating in individual buildings. Dedicated research, development and demonstration (RD&D) resources could make compact storage commercially viable between 2020 and 2030.
- Solar cooling could avoid the need for additional electricity transmission capacity caused by higher average peak loads from the rapidly increasing cooling demand in many parts of the world. With substantially higher RD&D resources, standardised, cost competitive and reliable solar cooling systems could enter the market between 2015 and 2020.