Solar technologies use the radiation from the sun to enable electrical, heating and cooling systems. Therefore, the produced energy can be used to power electrical appliances; produce heat for domestic hot water, district heating (residential and commercial), agriculture and industry; and produce cooling for air conditioning and industrial environment.
The electricity generated by solar energy can be either used in on-grid or off-grid systems, supporting the local energy supply and providing electricity to remote areas where this is scarce or non-existent. In small off-grid systems, the electricity is used to power electrical domestic appliances, while in the larger off-grid commercial and industrial premises, such as mines, telecom towers, agriculture equipment, hotels, hospitals and schools.
This concept has been also used to fill the electrification gap in some countries in Asia and sub-Saharan Africa, where 55% of the population still do not have access to electricity .
There are three main technologies used to harness energy from the sun that should be considered as complementary: photovoltaic (PV), solar thermal or solar heating and cooling (SHC) and concentrated solar power (CSP).
Photovoltaic (PV) Solar Energy
PV technology converts solar energy into electricity and can be used in on-grid and off-grid applications, being scalable from domestic to industrial power systems. Due to the evident cost reduction in the last 10 years, PV energy has become an attractive and affordable market, with an estimated capacity growth between 115GW and 130GW per year, reaching a total cumulative capacity of 1 TW by 2023 .
Solar Heating and Cooling (SHC) Energy
Solar heating and cooling technologies use solar collectors to absorb the thermal energy from the sun to generate heat. The portfolio includes highly efficient solutions at various temperatures for domestic and industrial applications, such as hot water, space heating and cooling.
Concentrated Solar Power (CSP)
Concentrated Solar Power technology converts sunlight into heat, generating steam that propels a turbine and, consequently, activates the electric power generators used in the CSP plants for the production of electricity. The most relevant advantage of CSP systems is its flexibility and stability when comparing to other systems, as the thermal energy can be stored in tanks and used during after sunset.
Sunlight is an abundant source of energy with tremendous potential. The global solar energy market has grown by approximately 50% per year over the last 10 years, accounting for around one percent of the world’s energy mix today. Moreover, the price of solar energy has halved in the last three years, and according to the IEA it will continue to halve in the next 3 years.
It is estimated that around 34% of the global electricity will be generated by renewable sources by 2040, of which solar energy will correspond to a third, and that 20% of all electricity will come from solar by 2050 .
 SDG7: Data and Projections Flagship report, IEA
 Solar Energy: Mapping the Road Ahead Technology report, IEA, October 2019
 New Energy Outlook 2019, Bloomberg