Alex Dickson suggests we replace our fossil fuel supply with renewables. In industrialised countries we are used to the electricity being available round the clock. I can think of only one renewable that can meet such expectation and that is a very scarce resource: hydroelectricity. To meet 24/7 demand on each day of the year would mean falls like Niagara or high reservoirs topped up in summer by melting snow, as in Norway.

No continuous supply can depend on intermittent sources unless output can be stored. The main effect of renewables would appear to be to reduce demand for fossil fuel, as in renewable energy supplied to the grid reducing fuel consumption in the process. However, large numbers of renewable generators lying idle for much of the time can be an expensive redundancy.

Transport consumes large amounts of energy. Ships can be nuclear-powered. Rail can be electrified. The problem of lighter vehicles such as road vehicles and aircraft remains. These vehicles have a special relationship with oil, the only energy source sufficiently compact and light enough to be carried on board. There is no product of renewable energy that can replace oil as an energy source for light vehicles in the foreseeable future.

Chris Parton, 40 Bellshill Road, Uddingston.