A 10-mile barrage is on the shortlist of options being considered by the government to harness tidal power from the River Severn.

Ed Miliband, secretary for Energy and Climate Change, announced today five preferred options to generate green energy from the river, which also included two smaller barrages and two lagoon schemes.

However, other options such as a tidal fence and a reef were not included in the short list but Mr Miliband said £500,000 worth of funding would be made available to develop such new technologies.

Mr Miliband said: "The five schemes shortlisted today are what we believe can be feasible, but this doesn't mean we have lost sight of others.

"Half a million pounds of new funding will go some way to developing technologies still in their infancy, like tidal reefs and fences.

"We will consider the progress of this work before any final decisions are taken."

The River Severn has the second largest tidal range in the world and it is thought to have the capacity to generate up to five percent of the country’s energy needs.

The suggestion of a 10-mile Cardiff to Weston barrage has long been criticised by environmental groups, such Natural England and the Wildlife Trust, and local politicians who claim vital habitat for birds and fish could be destroyed.

Helen Phillips, Natural England's chief executive, said: "We cannot sacrifice an environment as sensitive as the Severn estuary without resolving, once and for all, whether there are better alternatives."

Steve Webb, MP for Northavon, said: "The Government has admitted that we won't be getting any tidal power from the Severn until well into the 2020s. In this case they should not be ruling out ideas such as a Tidal Reef which have the potential to reduce the environmental damage done by such a structure whilst still generating large amounts of renewable power."

A three-month public consultation will now be held on the shortlist.

The government plans to make a final decision in 2010 following a two-year feasibility study into the costs, benefits and impacts of a tidal scheme in the Severn.