Britain's offshore wind power has gone from zero to just under a fifth of its total electricity supply, in 25 years. The country's first offshore wind farm was built back in 2000. Since then, they've multiplied, and now supply 17 percent of total demand – that's around 16 million homes, according to global energy think tank Ember. Britain's electric power system has been transformed in that time – offshore wind has overtaken on-shore wind, as well as solar and nuclear, and is now second only to