The former Tory party chairman Grant Shapps is promoting renewable energy in his new role as minister for Africa. Launching a bid to exploit British prowess in the booming solar sector and aid the poor, he insisted governments should be attracted by an energy source that is “so much cleaner” than traditional supplies, and more “attractive”. “Lots of people think that it doesn’t compare favourably with other forms of electricity,” he said. “They haven’t put it all together and it’s hard to know why.”

Quite right. The world is moving away from fossil fuels towards increased reliance on cleaner energies, which account for almost a quarter of global electricity generation. Fast-developing nations such as China, India, Ghana and Kenya are investing heavily in renewables, with Beijing predicting they will provide almost two-thirds of energy by 2050 and Singapore revealing plans for a giant floating solar farm. In the United States, Barack Obama recently announced a $1bn drive to boost the number of homes with solar panels, while firms such as Apple and Google are ramping up investments to reduce greenhouse gases.

Britain has not been left behind, with a thriving green energy industry and rapidly rising reliance on renewables under a prime minister who once famously put a wind turbine on his home. Our islands have the finest clean energy resources in Europe. The climate may not be perfect for harnessing the sun’s power, but even the solar sector is soaring: cells stuck on roofs and in fields now generate twice the electricity of the biggest power station.

So, given this admirable desire for low-carbon energy on both a domestic and global scale, what on earth is the government doing savaging a successful sector? The Tory manifesto promised to boost renewables and hold down bills. Yet instead came plans to withdraw subsidies for new onshore wind farms earlier than planned and give local nimbys power to stop such projects. Since new figures reveal this to be the cheapest source of British energy, it seems bizarre to make such regressive moves: major investments worth billions have already been scrapped.

And it gets worse. Sums paid to homeowners who install solar panels have been slashed more than two-thirds since the Conservatives regained office five years ago as part of the coalition’s self-proclaimed “greenest government ever”. Despite this, the panels rose in popularity with more installed by homeowners in Britain than anywhere else in the EU last year. Solar energy generation is rising faster than other forms of renewables. But now subsidies are to be shredded by another 87%, making them almost meaningless.

This has been driven by a panicked Treasury, applauded by climate-change deniers on the right and defended by an energy secretary telling the sector to “stand on its own two feet”. Yet for all the fuss over recent steel cutbacks, there seems minimal concern over the solar industry, although it employs more people and was expanding. Already four major players are going out of business, with about 1,000 jobs lost; the trade body warns 25,000 more could go, pouring down the drain public money spent on new technologies.

This is daft, even if you put aside the disconcerting politics of a prime minister who sold himself as a green crusader and once pushed the concept of feed-in tariffs. The cost of such subsidies is minimal, adding just £7 to average annual household bills – especially when compared with huge sums being staked on building a Chinese-backed nuclear plant.

Those involved in solar power say they could deliver the same amount of power for half the price and none of the risk. And that they’re only three years from avoiding the need for any subsidies, with new batteries arriving that can store energy generated while the sun shines for use at night when people want power.

Wind and solar power was once the domain of hippies, but renewable energy is now a cutting-edge industry, so these moves cause as much concern in City circles as among Greenpeace activists. One report found the green economy employed 357,000 people in 2012, while £40bn has gone into green investment in the past four years.

“The government’s attack on renewables is like the White House deciding in 1995 that it wanted to restrict and badmouth Silicon Valley,” says James Murray, of the website BusinessGreen. “Clean tech entrepreneurs have built a thriving industry and are now seeing it torpedoed.”

The shame of this short-sighted stance is that, for all the talk of “green crap”, David Cameron often stood firm on environmental issues, introducing tough targets to halve carbon emissions by 2025. Sometimes it was by stealth, yet on the global stage he resisted sceptics to push climate change causes. Next month’s key Paris summit presents another test of his commitment.

Ministers talk of clean energy having a bright future. Certainly, while costs of new nuclear and gas-fired power stations rise, solar and wind costs fall. Energy firms still make over-inflated profits. So why cripple a thriving renewables sector, especially amid a global boom? There is nothing Conservative about undermining entrepreneurs and homeowners, especially those seeking to preserve the planet’s resources.