One of the few parts of the UK economy to have a good April was solar power.

The Met Office says it has probably been the sunniest April on record and the solar power industry reported its highest ever production of electricity (9.68GW) in the UK at 12:30 on Monday 20 April.

With 16 solar panels on his roof Brian McCallion, from Northern Ireland, has been one of those benefitting from the good weather.

"We have had them for about five years, and we save about £1,000 per year," says Mr McCallion, who lives in Strabane, just by the border.

"If they were more efficient we could save more," he says, "and maybe invest in batteries to store it."

That efficiency might be coming. There is a worldwide race, from San Francisco to Shenzhen, to make a more efficient solar cell.

Today's average commercial solar panel converts 17-19% of the light energy hitting it to electricity. This is up from 12% just 10 years ago. But what if we could boost this to 30%?

More efficient solar cells mean we could get much more than today's 2.4% of global electricity supply from the sun.

Solar is already the world's fastest growing energy technology. Ten years ago, there were only 20 gigawatts of installed solar capacity globally - one gigawatt being roughly the output of a single large power station.

By the end of last year, the world's installed solar power had jumped to about 600 gigawatts.

Even with the disruption caused by Covid-19, we will probably add 105 gigawatts of solar capacity worldwide this year, forecasts London-based research company, IHS Markit.

Most solar cells are made from wafer-thin slices of silicon crystals, 70% of which are made in China and Taiwan.