India, June 19 -- The European Union's rapid expansion of solar and wind power must be matched by investment in clean firm power and long-duration energy storage if the bloc is to deliver affordable, reliable and zero-carbon electricity, a new report says.

Clean firm power refers to zero- or low-carbon electricity that can be supplied on demand around the clock, independent of weather conditions.

The report by climate innovation think tank Future Cleantech Architects says variable renewable energy will dominate Europe's future power system because of falling costs and rapid deployment. But it warns that solar and wind alone cannot guarantee supply during prolonged periods of low generation, especially as electricity demand rises from el...