As part of the Climate Change Act, the UK government are working towards an 80% reduction in greenhouse gas emissions by 2050. At present, however, only 4.2% of power used comes from renewable sources, which indicates that the UK generates the third lowest amount of renewable energy in the EU28. Therefore, developing new forms of renewable energy will play an essential role in meeting UK carbon management targets, with power generated from tidal lagoons potentially presenting a significant step towards this long term environmental objective.
Location, Location, Location
Holding the second highest tidal range in the world, it has been estimated that the Severn Estuary, situated between western England and Wales, could hold the capacity to generate up to 10% of the UK’s energy resources. Following a previously rejected proposal for a $30bn shore-to-shore barrage due to wide concerns from environmental groups, energy firm Tidal Lagoon Power are currently in the application process for the first of five potential lagoons.
In the event of a successful application, Tidal Lagoon Swansea Bay will be targeting the generation of power by the second half of 2018 through building a 320 MW tidal lagoon power project. Hydroelectric turbines are installed into a breakwater which is built around an area of the sea bed. The turbines then generate electricity during the entry and exit of the incoming and outgoing tides, which would be the daily equivalent of 100,000 Olympic swimming pools worth of water passing through the tidal lagoons turbines.
The reliability of energy being generated is consistently much higher with tidal power than other renewable sources due to the predictability of the tides rather than relying on weather patterns. Furthermore, economic studies have found that once the first three UK tidal lagoons have been built, it would result in low carbon power at a significantly cheaper price than offshore wind by 2021. CEO of Tidal Lagoon Power, Mark Shorrock, highlights that tidal lagoons will become one of the cheapest sources of electricity, despite the expensive initial first years, as well as having an operating lifespan of 120 years that will offer future generations even lower costs of electricity.
The current world leaders in Tidal Power
The Sihwa Tidal Power Station, based in South Korea, is currently the largest tidal power project in the world. The power station came as a result of regenerating a seawall, originally built for flood mitigation in 1994, in the Sihwa Lake reservoir. The construction of the seawall initially resulted in polluting the water conditions and therefore making it no longer appropriate for agriculture work. Unlike the Tidal Lagoon Swansea Bay project, power is generated only from the tidal inflow and therefore resulting in a fairly inefficient approach for generating power. Despite this, the approach has led to significant improvements for Sihwa Lake’s agricultural potential, as by opening up the wall once again it’s allowed water to enter and leave the reservoir.
In a bid to reduce greenhouse gas emissions, five further tidal power stations are being planned in South Korea, where large tides off the western coast present an ideal opportunity to harness tidal power, but questions are being widely raised about the damaging effects this will have on natural habitats and communities. It is argued by Ko and Schubert (2011) that the present debate on tidal power creates a conflicting argument where both sides are claiming “green” credentials. It is also suggested that, while it’s possible to identify and solve an isolated issue, today’s energy decisions have a complexity whereby addressing one environmental aspect has the potential to create problems for many other aspects (Ko and Schubert, 2011). So while tidal power would reduce carbon emissions, there could be even greater problems as a result such as the threat to endangered species or damage to costal ecosystems.
Reaction to the Tidal Lagoon
The Tidal Lagoon Swansea Bay proposal has resulted in a variety of responses, with the main viewpoint being widely shared that lagoons are less damaging and will have a far less significant impact on the tidal flow of the Severn Estuary than the previous England to Wales barrage. Friends of the Earth Cymru representative, Gareth Clubb, stated “ Provided they meet strict environmental criteria, tidal lagoons can play a key role in building a low carbon future…With its huge coastlines, the UK has plenty of potential for developing schemes like this…along with other renewable forms of energy”. Furthermore, the RSPB welcomed the fact that the conversation has moved on from the damaging shore-to-shore Severn Barrage plans, and has moved onto the more environmentally concerned lagoon projects. However, local MP, and key supporter of the barrage, Peter Hain, argues “You’d need 50 of them for the whole of the estuary to get anywhere near what the power of the barrage could do. That’s why the barrage is the answer for the Severn Estuary”.
What happens next?
At this point in time, the Tidal Lagoon Swansea Bay is in the reviewing process, conducted by the Planning Inspectorate, with the final decision ultimately being made by the Secretary of State for Energy and Climate Change. The financial viability of the project, and its’ environmental benefits and concerns, will then determine whether or not this particular proposal will be the beginning of utilizing tidal power in UK.
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