Up to three tidal lagoons could be in operation in Britain by 2021 producing low carbon power at cheaper prices than wind. Initially the company proposes to construct the first of its kind at Swansea Bay in south Wales, They say that it could produce power for about £100 per megawatt hour (MWh). These plans were accepted for consideration by the Government's Planning Inspectorate. Tidal Lagoon hopes that construction will immense in 2015 and that power will be generated by 2018. "This study clearly demonstrates that tidal lagoons can rapidly become one of the cheapest sources of electricity in the UK. The more water we impound, the more power we produce, the less support we require," said Mark Shorrock, chief executive of Tidal Lagoon Power. The £100 per MWh cost compares with recent Government calculations for a offshore wind farm in 2021 of about £131 per MWh. The cheapest of the projects assessed Lagoon 3 has a cost of about £90 per MWh,  similar to onshore wind, solar Mark Shorrock said. Environmentalists who have protested against other tidal projects such as the Severn Barrage in the past, remain wary about the impact the scheme will have on wildlife.