Key role for rooftop PV as world's cities embrace renewables: IRENA

Rooftop PV will be among the key technologies enabling the world's cities to embrace renewables thanks to the relative ease with which it can be installed and retrofitted, according to latest analysis by the International Renewable Energy Agency (IRENA).

Every city has a massive potential to cost-effectively boost renewable energy use at the local level, according to a new IRENA study of more than 3,500 conurbations. However, to achieve this transformation requires designing smart, integrated urban energy systems that can manage variable power produced by solar panels and wind turbines, the report, called Renewable Energy in Cities, concludes.

The analysis finds that established cities which have lower building turnover rates will largely rely on retrofits and technologies that can be added relatively easily to existing buildings, such as heat pumps and rooftop solar.

Low-density cities, with larger rooftop areas, could benefit from highly distributed renewable technologies like solar and the growth of electric cars.

"By 2050, urban populations are expected to double, making urbanisation one of this century's most transformative trends," said Adnan Amin, IRENA director-general. He added: "Renewable energy, combined with energy efficiency, will power the future growth of cities. We must ensure this transition happens as soon as possible."

Variable renewables account for 5% of global power generation today, but by 2030 this will reach 20%, IRENA states. As their share increases there is a need to synchronise supply and demand. Grids need to become smarter and more flexible and cities will play an important role in enabling this. For instance, as energy generation becomes more distributed and energy storage more prevalent, demand side management is becoming a major area of focus.

The latest analysis comes on the heels of the Unlocking Renewable Energy Investment report from IRENA in which the organisation argues that it is possible to double global investment in renewables by 2020 and more than triple it by 2030.