Sinking prices at the electricity exchange in Leipzig, where prices are arranged, are passed on to industrial customers but not to households, said Gunnar Harms, an energy expert, in a report commissioned for the Green Party.
Deputy leader of the Green parliamentary party Bärbel Höhn told the Tagesspiegel newspaper this was evidence that the government was pushing through the change in energy generation from nuclear and coal to more renewable sources, "at the expense of consumers."
And prices are only set to increase this autumn, according to Environment Minister Peter Altmaier, the paper said. Altmaier has warned that the additional burden due to a fixed price being set for 20 years in order to pay for the change to renewable energy, would rise by around five percent next year.
Currently domestic and commercial customers pay a 2.6 cent per kilowatt hour contribution for renewable energy. A further 3.2 cent is levied in taxes.
Industrial customers pay around 10 cent per kilowatt-hour, while domestic customers pay more than 26 cents, said Harms.
A major factor in the difference is that companies with high consumption have been let off a large part, and in some cases, all the renewables subsidy.
An average household which uses 3,500kilowatt hours a year pays €125 a year for renewables, of which €31 is due to the exclusion of industrial customers from paying a share, he said.