From Derek Bolton, Sydney, Australia
Graham Lawton draws attention to some of the subtleties of meeting targets for net-zero carbon emissions (8 February, p 24). Another arises when a relatively small area – that of a district council, say – sets such a goal. Too often, this means exporting surplus solar electricity during the day to offset usage at night. If many neighbouring areas do that, it doesn’t scale: there is no one nearby to export to.
