An accurate tally of the world’s solar-power stations

REBUILDING AN ENTIRECOPAIW planet’s energy system is a big job. Just ask the delegates at the -26 climate conference scheduled to kick off in Britain on October 31st. The most basic problem is knowing what, exactly, you are trying to rebuild. Academic-research groups, think-tanks, charities and other concerned organisations try to keep track of the world’s wind turbines, solar-power plants, fossil-fuelled power stations, cement factories and so on. To this end, they rely heavily on data from national governments and big companies, but these are often incomplete. The most comprehensive database covering American solar-power installations, for instance, is thought to miss around a fifth of the photovoltaic panels actually installed on the ground.In a paper just published in , a team of researchers led by Lucas Kruitwagen, a climate scientist and researcher at Oxford University, demonstrate another way to keep tabs on the green-energy revolution. Dr Kruitwagen and his colleagues have put together an inventory of almost 69,000 big solar-power stations (defined as those with a rated capacity of 10k of electricity or more) all over the world—more than four times as many as were previously listed in public databases. This new inventory includes their locations, the date they entered service and a rough estimate of their generating capacity.