The production of heat accounts for around one half of energy demand around the globe – the largest of all energy end uses. Heat demand is also significant in some of the hottest countries such as India where despite the climate it is still necessary for cooking, hot water and industry.
In fact in India, heat accounts for two-thirds of total final energy consumption. Currently, only 10% of this comes from ‘modern’ renewable heat, which excludes the traditional use of biomass which is generally very inefficient and often unsustainable.
Growth of modern renewable heat in India has been modest, seeing a 14% increase between 2007 and 2015. Solar thermal (mostly used for water heating) has seen the most rapid growth, albeit from a very low starting point, with the latest figures from the IEA Technology Collaboration Programme on Solar Heating and Cooling showing an increase in the number of systems installed in India by 26% in 2017. The country now has the sixth largest installed capacity for solar thermal globally, although it still lags behind other emerging economies such Brazil and Turkey while China remains the global leader in solar thermal capacity by a large margin.
Policy can be successful in encouraging the wider use of solar heat. For example, solar obligations require all or a certain share of hot water demand to be met by solar thermal installations. Such obligations were first pioneered by Israel in 1980 and have since been successfully adopted in many countries, either nationally or at city level.
India recently joined the revised Energy Conservation Building Code, published in March 2017. This code proposes that, depending on floor space, solar thermal meet 20-40% of the demand for hot water in new buildings located in India’s cold weather zones, as well as in new hotels and hospitals across the entire country. While the Indian national building code is not mandatory, some states and municipalities use it to regulate construction activity. For example, Telegana state has embedded it into its building approval system.
There is also scope for meeting a portion of industrial heat demand with solar heat, especially in industries such as food and drink, agriculture, chemicals and textiles. At present, industrial applications account for less than 1% of total solar thermal installations in India but significant potential has been identified. In 2017, India installed 36 new industrial solar process heat systems with a total collector area of 15,313 m2, the second largest outside of Oman.
In addition to conventional solar thermal installations, interest is growing in concentrating solar thermal technologies. India was the first country globally to introduce a support scheme for these technologies in 2010. The scheme has recently been extended to 2020 and aims to achieve the installation of 90,000 m2 of collectors between 2017 and 2020. It targets industrial process heat, as well as community cooking and space heating/cooling applications.
India’s efforts are part of a larger effort worldwide to shift away from fossil fuel for the production of heat. However, much more needs to be done. In order to realize the IEA’s Sustainable Development Scenario, the share of solar thermal heating would need to quadruple globally by 2030 and increase by a factor of 10 in India. Policy-makers everywhere will need to give more consideration to achieving these ambitious goals.