The scheme is promoted by Tidal Lagoon (Swansea Bay) plc. According to the company, generation could operate 14 hours per day with a maximum output of 320 MW (
nameplate capacity), enough to power around 155,000 homes. There are different ways to evaluate tidal energy output. The UK government considered intermittency due to the tides, and concluded that the Tidal Lagoon Swansea Bay would have had a
load factor of 19% compared to around 50% for
offshore wind power. During the construction period, the project would have sustained over 2,200 construction and manufacturing jobs, but in operation it would only require 28 workers. ...just as gas plants and wind farms only create a small number of long-term jobs. The issue here was can we start a new global industry from the UK? Swansea would just be the start. Selective quotes from my Review do not enable us to have a proper debate. (Charles Hendry, 26 June 2018) The seawalls would be constructed to withstand 500-year-storms and to function as coastline protection against storms and floods. The project was named as part of the UK Government's 2014 National Infrastructure Plan and was granted development consent by the
Department for Energy and Climate Change in June 2015, although the department stated that decisions relating to affordability were a separate matter. In early June 2018, the
Welsh Government offered to invest £200 million to improve the project's difficult business case. On 25 June 2018, the
Department for Business, Energy and Industrial Strategy (BEIS) rejected a
contract for difference electricity purchasing agreement necessary to fund the £1.3 billion proposal. The main reason given was that there was little cost reduction potential for future lagoons, and a series of lagoons would cost the average electricity consumer an additional £700 by between 2031 and 2050 compared to a mix of
offshore wind and
nuclear power projects. The value-for-money calculation included the cost of all six of the proposed lagoons in the 35-year cost comparison. The calculations and assumptions made by BEIS which lie behind the rejection of the plan have been challenged by the company behind the proposal in an independently audited riposte which intimates that misleading statements were put to the Parliamentary Joint Select Committee. BEIS responded that the figures used are out of date. The first report by the National Infrastructure Commission published on 11 July 2018 appears to exclude the role of any form of tidal power in the UK's future green energy mix in favour of wind, solar and electric cars, based on a report by Aurora Energy Research looking at the market up to 2050. This states "Offshore wind becomes economical in the 2030s without subsidies, tidal never becomes competitive without government support". The Aurora Energy Research report also states "Amongst renewables, solar PV, onshore wind and offshore wind are the main sources of new renewables to enter economically under a carbon target. Building tidal power requires a subsidy, but the impact on total system cost is minimal". These contrasting perspectives all use different time periods for modelling costs and benefits but a common thread is that a shorter time-frame flatters alternatives to tidal power and a longer time-frame flatters tidal power compared to its alternatives.
Proposed design • 9.5 km of seawalls, impounding 11.5 km2 of the seabed • 16 bidirectional
turbines
Roman concrete was proposed as a suitable material for constructing the seawalls.
Finances Soon after the proposal was rejected by the UK Government, it was reported that the company behind the plan, owned by Mark Shorrock, was £23 million in debt and had spent £37 million on the proposal. One of the investors in Tidal Lagoon Swansea Bay was
Good Energy, a firm led at that time by Shorrock's wife
Juliet Davenport. In return, Good Energy took a comprehensive charge over the project's assets, giving it a uniquely privileged class of shares compared to the other ordinary investors. Further questions have arisen out of the web of Shorrock-owned companies involved in the project, such as Tidal Lagoon plc which reportedly gave a loan to Tidal Lagoon Swansea Bay plc at a 20 per cent interest rate. == Potential future plans ==