Starting in 2007, Google committed significant resources to tackle the world’s climate and energy problems. A few of these efforts proved very successful: Google deployed some of the most energy-efficient data centers in the world, purchased large amounts of renewable energy, and offset what remained of its carbon footprint.

Google’s boldest energy move was an effort known as RE<C, which aimed to develop renewable energy sources that would generate electricity more cheaply than coal-fired power plants do. The company announced that Google would help promising technologies mature by investing in start-ups and conducting its own internal R&D. Its aspirational goal: to produce a gigawatt of renewable power more cheaply than a coal-fired plant could, and to achieve this in years, not decades.

Unfortunately, not every Google moon shot leaves Earth orbit. In 2011, the company decided that RE<C was not on track to meet its target and shut down the initiative. The two of us, who worked as engineers on the internal RE<C projects, were then forced to reexamine our assumptions.

At the start of RE<C, we had shared the attitude of many stalwart environmentalists: We felt that with steady improvements to today’s renewable energy technologies, our society could stave off catastrophic climate change. We now know that to be a false hope—but that doesn’t mean the planet is doomed.......

Whenever somebody with a decent grasp of maths and physics looks into the idea of a fully renewables-powered civilised future for the human race with a reasonably open mind, they normally come to the conclusion that it simply isn't feasible. Merely generating the relatively small proportion of our energy that we consume today in the form of electricity is already an insuperably difficult task for renewables: generating huge amounts more on top to carry out the tasks we do today using fossil-fuelled heat isn't even vaguely plausible.

Even if one were to electrify all of transport, industry, heating and so on, so much renewable generation and balancing/storage equipment would be needed to power it that astronomical new requirements for steel, concrete, copper, glass, carbon fibre, neodymium, shipping and haulage etc etc would appear. All these things are made using mammoth amounts of energy: far from achieving massive energy savings, which most plans for a renewables future rely on implicitly, we would wind up needing far more energy, which would mean even more vast renewables farms - and even more materials and energy to make and maintain them and so on. The scale of the building would be like nothing ever attempted by the human race.

In reality, well before any such stage was reached, energy would become horrifyingly expensive - which means that everything would become horrifyingly expensive (even the present well-under-one-per-cent renewables level in the UK has pushed up utility bills very considerably). This in turn means that everyone would become miserably poor and economic growth would cease (the more honest hardline greens admit this openly). That, however, means that such expensive luxuries as welfare states and pensioners, proper healthcare (watch out for that pandemic), reasonable public services, affordable manufactured goods and transport, decent personal hygiene, space programmes (watch out for the meteor!) etc etc would all have to go - none of those things are sustainable without economic growth.