Electricity is expected to be free in Norway's two biggest cities Monday, experts said, the silver lining of a wet summer.

With power almost exclusively produced from hydro in Norway, the more it rains or snows the more the reservoirs fill up and the lower the electricity price.

A particularly violent summer storm dubbed "Hans" that swept across Scandinavia in August has filled dams in parts of Norway.

As a result, the spot price of electricity, before taxes and grid fees, was expected to hover between 0 and -0.3 kroner (-0.03 US cents) on Monday in the capital Oslo and the second-biggest city Bergen, according to specialised news site Europower.

A negative price means electricity companies pay consumers to use their production.

"(Electricity) producers have explained in the past that it is better to produce when prices are a little bit negative rather than take measures to stop production," the site said.

Even though the spot price is slightly in the red in some parts of the country -- which is divided into various price zones -- companies are still able to make money from green electricity certificates.

According to Europower, this is the second time electricity prices have gone negative in parts of Norway. The first time was on August 8 in the wake of the storm "Hans".