Households will be called on to boost their consumption of Great Britain’s record renewable energy this summer to help balance the power grid and lower energy bills. Under the new plans, people could be encouraged to run dishwashers and washing machines or charge up their electric vehicles when there is more wind and solar power than the electricity grid needs. The plan will be delivered with the help of energy suppliers, which may choose to offer heavily discounted or free electricity to their customers during specific periods when the energy system operator predicts there will be a surplus of electricity....