From next year, Supermarket chain Sainsburys is to send all of its waste food to special plants where it will be converted to methane gas. This in turn will generate electricity to heat and light the chain’s eight hundred stores around the UK. Using the waste food in this way also reduces the need for landfill sites which otherwise are used to accommodate it.

The methane production will obviously need to be a highly controlled process as methane emissions threaten the fragile ozone layer.