Along with this literary endorsement, solar power also has a growing number of advocates in the scientific and environmental communities. Strictly speaking, almost all our energy is solar. Carbon fuels are the product of photosynthesis millions of years ago and so are stored up sunlight; wind power comes from pressure differences caused by heating from the sun. Indeed, apart from nuclear, tidal and geothermal energy, all our major energy sources are somehow conversions of sunlight.

But more prosaically, there are two mainstream types of solar power. One is solar thermal. This can take the form of both the collectors on the roofs of houses which heat up water, and the giant parabolic mirrors in the desert which follow the sun. They absorb heat in a central container which is cooled with water to make steam. This then drives a turbine and produces electricity.

Photovoltaics - which can also be the shiny black panels you see on roofs - is the other serious solar energy conversion technology. This uses the photo-electric effect - discovered by Einstein in 1905 - to turn photons (subatomic particles which transmit light) into usable current. When a photon hits a semiconductor material like silicon, it can nudge an electron to hop to another atom; this can destabilise the precarious equilibrium in the semiconductor and lead to the next electron being bumped along. By carefully engineering the materials to encourage and channel these cascades of electrons, sunlight is converted into usable direct current.

So this is a method which is green and feasible. But is it practical?