Powergen’s electricity and gas prices will rise by 9.7% and 18.4% respectively for affected residential customers from August 21, 2006.

The company says that over 10% of Powergen customers are unaffected by this announcement as they are currently on capped or fixed price products, and it urges other customers to adopt its capped price tariff that limits price rises until 2010.

Nick Horler, managing director of Powergen Retail, said: We take today’s announcement very seriously and have fully considered its impact on our customers.

Despite this increase, for the average customer, we are still over 10% cheaper than British Gas and we remain fully committed to working with our customers to help them reduce their consumption and lessen their impact on the environment.

E.ON says that it plans to invest GBP3 billion over the next three years in power generation – including renewables, the distribution network, and gas storage. In addition, E.ON UK has also announced the submission of a scoping application to build an underground gas storage facility in East Yorkshire which would be able to store an amount of gas equivalent to that used by the whole of the UK on a cold winter’s day, it said in a statement.