<p>Supply licence conditions, enforced by the independent regulator Ofgem, state that differences in price between payment methods for energy must reflect the cost to the supplier of that payment method. The costs of managing prepayment meters are higher than those for standard meters due to the different metering requirements and payment systems.</p><p> </p><p>Ofgem has said that it will be looking at all energy payment methods to see whether there is a case for levelling them, taking account of the trade-offs and other issues that would involve.</p>