"There are exciting green shoots in core solar markets where solar is taking off, but overall it is not growing fast enough," analyst for Ember Charles Moore said.

Total generation from solar panels lagged the electricity supply from coal, which stood at 14 per cent for the region in June and July of 2021, the report said.

As part of a package of climate policies, the European Commission has proposed an overhaul of renewable energy rules, which decide how quickly the bloc must increase the use of sources such as wind, solar and biomass energy produced from burning wood pellets or chips.

It has set an interim target for the EU to raise the share of such renewable energy to 40 per cent of final consumption by 2030, up from roughly 20 per cent in 2019.

The Ember data showed Germany maintained the largest share of solar power production in the region, going from 11.5 TWh to 13.4 TWh, which accounted for 17 per cent of overall electricity produced in the country during the summer period in 2021.

Spain had the largest growth for the summer period over four years, more than doubling from 3.1 TWh in 2018 to 6.4 TWh in 2021, which accounted for 16 per cent of total electricity produced in the country in 2021, the data showed.

The Netherlands showed the second largest growth over four years, nearly tripling production from solar panels to 3.2 TWh from 1.1 TWh in 2018, expanding the country's total power share by 10 per cent to 17 per cent.

The substantial increase in power production in both countries was a "reflection" of ambitious legislation, Charles said.

Italy was the third largest producer of energy from solar panels in 2021 but did not see substantial growth over the same period, going from 5.7 TWh to nearly 6 TWh, the data showed.

Solar supply in the EU-27 rose by an average 14 TWh per year in 2019 and 2020 and is expected to do the same in 2021, but will need to over double to 30 TWh per year to meet 2030 climate targets, the report said.

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