Last week a massive 350-hectare open cast coal mine at Druridge Bay won planning permission. This got Chris Goodall wondering: what if the land was turned into a solar farm instead? His surprise discovery: solar power on England's south coast already costs no more than coal – and it's only getting cheaper.A week ago Northumberland council gave planning permission to a new open-cast coal mine at Druridge on the coastline just north of Newcastle.About 3 million tonnes of coal will be extracted over a five to seven-year period from an area of around 350 hectares, including storage space. (350 hectares is about 1.4 square miles)The environmental objections to the plan are striking. For example, the owners predict about 170 HGV movements a day along local roads during the whole lifetime of the project. The landscape impact is also severe although the developers say they will ensure that the local sandy beaches are unaffected.