In one hour, the sun casts upon the earth more energy than we, the whole of humankind, consume in a year.

It is a favourite of solar energy enthusiasts, as is the truism that all renewable energy sources - wind, falling water, ocean tides, biomass - are in fact converted sunshine.

Yet for all the abundance, solar energy, the light and heat that radiates from the sun, remains largely untapped.

Of all the energy consumed in Europe in 2010, according to Eurostat, only 0.2 percent came straight from the sun. Of all the electricity generated, it was 0.6 percent.

They are the EU’s latest figures, but, by mid-2012, are already outdated.

Over the course of last year, the amount of gigawatts (GW) installed almost doubled, from 30 GW to 52 GW, enough to power some 15 million households.

That increase is more than that of any other electricity source, and more than double the runner-up, wind. This year, another 14 GW to 19 GW are expected, according to Bloomberg New Energy Finance.

Today, solar is the world's third most important renewable energy source, according to European photovoltaic industry association Epia, after hydropower and wind.

It meets two percent of all electricity demand in Europe - and four percent of daytime demand, when people and the sun are up.

If that does not sound like a lot, compared to other parts of the world, it is.

Europe is the undisputed sun king of the world, with close to 75 percent of globally installed solar panels. It has more than 10 times as much as the number two, Japan. China and the US are following closely and growing fast.

But there are big differences between countries in Europe.

Germany leads the pack with almost half of all solar panels installed on the continent.

“On a sunny and windy day in the summer at lunchtime [when demand is low], in theory we can have 80 to 90 percent of electricity coming from solar and wind,” Sven Teske, renewable energy director at Greenpeace International, told EUobserver.

Other frontrunners are Italy, who last year added more than any other, Belgium and the Czech Republic - even though the latter is losing ground since it cut back on subsidies in 2011.

Scandinavia, eastern Europe, the Netherlands and the UK, by contrast, are all lagging behind.