There is a massive problem with photo-voltaic solar power. Modern cities and industries require power 24/7 but solar panels can only deliver significant energy from 9am to 3pm on a clear day - a maximum of 25% of the time. Even within this time, energy production peaks at midday and falls off steeply on either side.

Science has yet to develop a solar storage battery suitable for grid power. It must be sufficiently large, cheap and efficient to hold the solar power generated during the short solar maximum so it can be used later, when peak demand usually occurs. This process requires that much of the solar energy produced in peak times would have to be devoted to recharging the massive battery.

But Planet Earth has already solved this problem. For millions of years Earth has used photosynthesis to store solar energy in wood and plant material then converted this to long-term storage in the form of coal.

Coal is nature's answer to solar energy storage and in a wonderful bit of synergy, the process of recovering the energy releases back to the atmosphere the building blocks of life - water vapour and carbon dioxide. These are again converted back by solar energy into more plants/wood/coal. And the whole process does a bit towards postponing the next ice age and returning Earth to that warm, moist, verdant, life-filled environment that existed when the coals were formed.

Coal is a gift from Gaia - the 100% natural, clean, green and sustainable answer to Solar Energy Storage!