Misplaced Pages

#253746

71-661: Tidal Lagoon Swansea Bay was a proposed tidal lagoon power plant that was to be constructed in Swansea Bay off the south coast of Wales , United Kingdom. Development consent was granted by the UK government in June 2015, and in June 2018 the Welsh Government approved the plan and offered to invest £200 million; however, later that month the UK government withdrew its support on value-for-money grounds. Other options to enable

142-560: A bridge. Calmer waters may also allow better recreation in the bay or estuary. In August 2004, a humpback whale swam through the open sluice gate of the Annapolis Royal Generating Station at slack tide, ending up trapped for several days before eventually finding its way out to the Annapolis Basin . Environmentally, the main concerns are blade strike on fish attempting to enter the lagoon ,

213-451: A brittle structure that was most likely created in a "hot-mixing" technique with quicklime rather than traditional slaked lime , causing cracks to preferentially move through the lime clasts, thus potentially playing a critical role in the self-healing mechanism. Concrete and, in particular, the hydraulic mortar responsible for its cohesion, was a type of structural ceramic whose utility derived largely from its rheological plasticity in

284-454: 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. In January 2017 a government-commissioned review, published by Charles Hendry , gave backing to

355-491: A later period of time. Geographically dispersed tidal lagoons with a time delay between peak production would also flatten out peak production providing near baseload production at a higher cost than other alternatives such as district heating renewable energy storage. The cancelled Tidal Lagoon Swansea Bay in Wales, United Kingdom would have been the first tidal power station of this type once built. Dynamic tidal power (or DTP)

426-476: A median value of 23.8 gCO 2 -eq/kWhe. This is in line with the impact of other renewables like wind and solar power, and significantly better than fossil-based technologies. The Tethys database provides access to scientific literature and general information on the potential environmental effects of tidal energy. The main environmental concern with tidal energy is associated with blade strike and entanglement of marine organisms as high-speed water increases

497-557: A proper debate. (Charles Hendry, 26 June 2018) It would be constructed to withstand 500-year-storms and to function as a 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

568-451: A result, the production period of each generating unit is reduced, lower metal consumption is needed and technical efficiency is greater. A possible risk is rising sea levels due to climate change, which may alter the characteristics of the local tides reducing future power generation. The high load factors resulting from the fact that water is around 800 times denser than air, and the predictable and reliable nature of tides compared with

639-440: 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

710-426: 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. A House of Commons Briefing Paper has tried to provide some context for MPs following the conflicting statements and views regarding

781-508: A tidal energy project in 2007. In April 2009 the PUD selected OpenHydro, a company based in Ireland, to develop turbines and equipment for eventual installation. The project as initially designed was to place generation equipment in areas of high tidal flow and operate that equipment for four to five years. After the trial period the equipment would be removed. The project was initially budgeted at

SECTION 10

#1732765531254

852-454: A total cost of $ 10 million, with half of that funding provided by the PUD out of utility reserve funds, and half from grants, primarily from the US federal government. The PUD paid for part of this project from reserves and received a $ 900,000 grant in 2009 and a $ 3.5 million grant in 2010 in addition to using reserves to pay an estimated $ 4 million of costs. In 2010 the budget estimate

923-465: A variety of causes, they continue to stand to this day. Another technology used to improve the strength and stability of concrete was its gradation in domes. One example is the Pantheon , where the aggregate of the upper dome region consists of alternating layers of light tuff and pumice , giving the concrete a density of 1,350 kilograms per cubic metre (84 lb/cu ft). The foundation of

994-737: A worldwide first, the project could start within 18 months but would take more than a decade to complete. Tidal lagoon Although not yet widely used, tidal energy has the potential for future electricity generation . Tides are more predictable than the wind and the sun . Among sources of renewable energy , tidal energy has traditionally suffered from relatively high cost and limited availability of sites with sufficiently high tidal ranges or flow velocities, thus constricting its total availability. However many recent technological developments and improvements, both in design (e.g. dynamic tidal power , tidal lagoons ) and turbine technology (e.g. new axial turbines , cross flow turbines ), indicate that

1065-477: Is a theoretical technology that would exploit an interaction between potential and kinetic energies in tidal flows. It proposes that very long dams (for example: 30–50 km length) be built from coasts straight out into the sea or ocean, without enclosing an area. Tidal phase differences are introduced across the dam, leading to a significant water-level differential in shallow coastal seas – featuring strong coast-parallel oscillating tidal currents such as found in

1136-399: Is very close to that of modern cement to which blast furnace slag , fly ash , or silica fume have been added. The strength and longevity of Roman 'marine' concrete is understood to benefit from a reaction of seawater with a mixture of volcanic ash and quicklime to create a rare crystal called tobermorite , which may resist fracturing. As seawater percolated within the tiny cracks in

1207-521: The Italian peninsula , interruptions and internal constructions within walls and domes created discontinuities in the concrete mass. Portions of the building could then shift slightly when there was movement of the earth to accommodate such stresses, enhancing the overall strength of the structure. It was in this sense that bricks and concrete were flexible. It may have been precisely for this reason that, although many buildings sustained serious cracking from

1278-515: The Middle Ages , or even from Roman times . The process of using falling water and spinning turbines to create electricity was introduced in the U.S. and Europe in the 19th century. Electricity generation from marine technologies increased an estimated 16% in 2018, and an estimated 13% in 2019. Policies promoting R&D are needed to achieve further cost reductions and large-scale development. The world's first large-scale tidal power plant

1349-534: The seabed and in turbulence . This loss of energy has caused the rotation of the Earth to slow in the 4.5 billion years since its formation. During the last 620 million years the period of rotation of the Earth (length of a day) has increased from 21.9 hours to 24 hours; in this period the Earth-Moon system has lost 17% of its rotational energy. While tidal power will take additional energy from

1420-509: The Atlantic Ocean and North Sea. This area has a very strong tidal current, which can travel up to 4 m/s (8.9 mph; 7.8 kn; 14 km/h) in spring tides. Tidal energy developers that have tested at the site include: Alstom (formerly Tidal Generation Ltd); ANDRITZ HYDRO Hammerfest; Atlantis Resources Corporation; Nautricity; OpenHydro; Scotrenewables Tidal Power; Voith. The resource could be 4 TJ per year. Elsewhere in

1491-498: The Earth's internal heat , which comes from a combination of residual heat from planetary accretion (about 20%) and heat produced through radioactive decay (80%). A tidal generator converts the energy of tidal flows into electricity. Greater tidal variation and higher tidal current velocities can dramatically increase the potential of a site for tidal electricity generation. On the other hand, tidal energy has high reliability, excellent energy density, and high durability. Because

SECTION 20

#1732765531254

1562-466: The Earth's tides are ultimately due to gravitational interaction with the Moon and Sun and the Earth's rotation, tidal power is practically inexhaustible, and is thus classified as a renewable energy resource. Movement of tides causes a loss of mechanical energy in the Earth-Moon system: this results from pumping of water through natural restrictions around coastlines and consequent viscous dissipation at

1633-618: 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

1704-669: The Roman concrete, it reacted with phillipsite naturally found in the volcanic rock and created aluminous tobermorite crystals. The result is a candidate for "the most durable building material in human history". In contrast, modern concrete exposed to saltwater deteriorates within decades. The Roman concrete at the Tomb of Caecilia Metella is another variation higher in potassium that triggered changes that "reinforce interfacial zones and potentially contribute to improved mechanical performance". For an environment as prone to earthquakes as

1775-636: The UK, China, and Korea. The first study of large scale tidal power plants was by the US Federal Power Commission in 1924. If built, power plants would have been located in the northern border area of the US state of Maine and the southeastern border area of the Canadian province of New Brunswick, with various dams, powerhouses, and ship locks enclosing the Bay of Fundy and Passamaquoddy Bay (note: see map in reference). Nothing came of

1846-469: The UK, annual energy of 50 TWh can be extracted if 25 GW capacity is installed with pivotable blades. Tidal power can affect marine life. The turbines' rotating blades can accidentally kill swimming sea life. Projects such as the one in Strangford include a safety mechanism that turns off the turbine when marine animals approach. However, this feature causes a major loss in energy because of

1917-602: The UK. Based in Orkney, Scotland, the European Marine Energy Centre (EMEC) has supported the deployment of more wave and tidal energy devices than at any other single site in the world. EMEC provides a variety of test sites in real sea conditions. Its grid connected tidal test site is located at the Fall of Warness , off the island of Eday , in a narrow channel which concentrates the tide as it flows between

1988-508: The University of California Berkeley published an article that described for the first time the mechanism by which the suprastable calcium-aluminium-silicate-hydrate compound binds the material together. During its production, less carbon dioxide is released into the atmosphere than any modern concrete production process. It is no coincidence that the walls of Roman buildings are thicker than those of modern buildings. However, Roman concrete

2059-577: The acoustic output from turbines, and changes in sedimentation processes. However, all these effects are localized and do not affect the entire estuary or bay. Saltwater causes corrosion in metal parts. It can be difficult to maintain tidal stream generators due to their size and depth in the water. The use of corrosion-resistant materials such as stainless steels, high-nickel alloys, copper-nickel alloys, nickel-copper alloys and titanium can greatly reduce, or eliminate corrosion damage. Mechanical fluids, such as lubricants, can leak out, which may be harmful to

2130-530: The aggregates often included larger components; hence, it was laid rather than poured. Roman concretes, like any hydraulic concrete, were usually able to set underwater, which was useful for bridges and other waterside construction. Vitruvius , writing around 25 BC in his Ten Books on Architecture , distinguished types of materials appropriate for the preparation of lime mortars . For structural mortars, he recommended pozzolana ( pulvis puteolanus in Latin),

2201-483: The amount of marine life that passes through the turbines. Some fish may avoid the area if threatened by a constantly rotating or noisy object. Marine life is a huge factor when siting tidal power energy generators , and precautions are taken to ensure that as few marine animals as possible are affected by it. In terms of global warming potential (i.e. carbon footprint), the impact of tidal power generation technologies ranges between 15 and 37 gCO 2 -eq/kWhe, with

Tidal Lagoon Swansea Bay - Misplaced Pages Continue

2272-409: The concrete more resistant to salt water than modern-day concrete. Pozzolanic mortar had a high content of alumina and silica . Research in 2023 found that lime clasts, previously considered a sign of poor aggregation technique, react with water seeping into any cracks. This produces reactive calcium, which allows new calcium carbonate crystals to form and reseal the cracks. These lime clasts have

2343-429: The death of fish that act as a vital food source to birds and mammals. Migrating fish may also be unable to access breeding streams, and may attempt to pass through the turbines. The same acoustic concerns apply to tidal barrages. Decreasing shipping accessibility can become a socio-economic issue, though locks can be added to allow slow passage. However, the barrage may improve the local economy by increasing land access as

2414-590: The development of the brick and concrete industries. Roman concrete, like any concrete , consists of an aggregate and hydraulic mortar , a binder mixed with water that hardens over time. The composition of the aggregate varied, and included pieces of rock, ceramic tile, lime clasts, and brick rubble from the remains of previously demolished buildings. In Rome, readily available tuff was often used as an aggregate. Gypsum and quicklime were used as binders. Volcanic dusts, called pozzolana or "pit sand", were favoured where they could be obtained. Pozzolana makes

2485-409: The difference in height (or hydraulic head ) between high and low tides. When using tidal barrages to generate power, the potential energy from a tide is seized through the strategic placement of specialized dams. When the sea level rises and the tide begins to come in, the temporary increase in tidal power is channeled into a large basin behind the dam, holding a large amount of potential energy. With

2556-436: The economic impact of two additional tidal lagoons: "Cardiff could support five times more total direct FTEs than [Swansea Bay] (11,482); Colwyn Bay could support six times more (13,918)". ...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

2627-419: The end of the 2nd century BC. The harbour of Caesarea is an example (22-15 BC) of the use of underwater Roman concrete technology on a large scale, for which enormous quantities of pozzolana were imported from Puteoli . For rebuilding Rome after the fire in 64 AD which destroyed large portions of the city, Nero 's new building code largely called for brick-faced concrete. This appears to have encouraged

2698-604: The facts around tidal lagoons, the Swansea Bay proposal, and its rejection by the UK Government. 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

2769-604: The federal government refused to pay this, the PUD cancelled the project after spending nearly $ 10 million from reserves and grants. The PUD abandoned all tidal energy exploration after this project was cancelled and does not own or operate any tidal energy sources. In 1966, Électricité de France opened the Rance Tidal Power Station , located on the estuary of the Rance River in Brittany . It

2840-422: The location is artificial and does not contain a pre-existing ecosystem. The lagoons can also be in double (or triple) format without pumping or with pumping that will flatten out the power output. The pumping power could be provided by excess to grid demand renewable energy from for example wind turbines or solar photovoltaic arrays. Excess renewable energy rather than being curtailed could be used and stored for

2911-425: The low-carbon electricity generated by the tide flowing through turbines in a concrete wall along Swansea Bay. Property company Land Securities , Cardiff Airport and property developer Berkeley Group are among those to have expressed an interest in signing a power purchase agreement (PPA) with the lagoon company. In January 2023, plans of a new Swansea tidal lagoon project called "Blue Eden" emerged but this time

Tidal Lagoon Swansea Bay - Misplaced Pages Continue

2982-443: 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. Roman concrete

3053-416: The marine life nearby. Proper maintenance can minimize the number of harmful chemicals that may enter the environment. The biological events that happen when placing any structure in an area of high tidal currents and high biological productivity in the ocean will ensure that the structure becomes an ideal substrate for the growth of marine organisms. Tidal energy has a high initial cost, which may be one of

3124-407: The multi-billion pound project would be fully funded by the private sector. Phase SA1 of the project is said to include an electric battery manufacturing plant, battery storage facility, a tidal lagoon in Swansea Bay with a floating solar farm, data storage centre, a green hydrogen production facility, an oceanic and climate change research centre, and hundreds of waterfront homes. Claimed it would be

3195-570: The paste state. The setting and hardening of hydraulic cements derived from hydration of materials and the subsequent chemical and physical interaction of these hydration products. This differed from the setting of slaked lime mortars , the most common cements of the pre-Roman world. Once set, Roman concrete exhibited little plasticity, although it retained some resistance to tensile stresses. The setting of pozzolanic cements has much in common with setting of their modern counterpart, Portland cement . The high silica composition of Roman pozzolana cements

3266-564: The potential for tidal barrages at Chignecto Bay and Minas Basin – at the end of the Fundy Bay estuary. There were three sites determined to be financially feasible: Shepody Bay (1550 MW), Cumberland Basin (1085 MW), and Cobequid Bay (3800 MW). These were never built despite their apparent feasibility in 1977. The Snohomish PUD , a public utility district located primarily in Snohomish County, Washington State, began

3337-522: The proposal to go ahead were reportedly still being explored. If built, the project would have become the world's first tidal lagoon power plant; other types of tidal power plants do exist. 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

3408-442: The reasons why it is not a popular source of renewable energy , although research has shown that the public is willing to pay for and support research and development of tidal energy devices. The methods of generating electricity from tidal energy are relatively new technology. Tidal energy is however still very early in the research process and it may be possible to reduce costs in future. The cost-effectiveness varies according to

3479-479: The receding tide, this energy is then converted into mechanical energy as the water is released through large turbines that create electrical power through the use of generators. Barrages are essentially dams across the full width of a tidal estuary. A new tidal energy design option is to construct circular retaining walls embedded with turbines that can capture the potential energy of tides. The created reservoirs are similar to those of tidal barrages, except that

3550-423: The risk of organisms being pushed near or through these devices. As with all offshore renewable energies, there is also a concern about how the creation of electromagnetic fields and acoustic outputs may affect marine organisms. Because these devices are in the water, the acoustic output can be greater than those created with offshore wind energy . Depending on the frequency and amplitude of sound generated by

3621-672: The seafloor and coastlines . Tidal power is the only technology that draws on energy inherent in the orbital characteristics of the Earth–Moon system, and to a lesser extent in the Earth–Sun system. Other natural energies exploited by human technology originate directly or indirectly from the Sun, including fossil fuel , conventional hydroelectric , wind , biofuel , wave and solar energy . Nuclear energy makes use of Earth's mineral deposits of fissionable elements, while geothermal power utilizes

SECTION 50

#1732765531254

3692-501: The site of the tidal generators. One indication of cost-effectiveness is the Gibrat ratio, which is the length of the barrage in metres divided by the annual energy production in kilowatt hours . As tidal energy is reliable, it can reasonably be predicted how long it will take to pay off the high up-front cost of these generators. Due to the success of a greatly simplified design, the orthogonal turbine offers considerable cost savings. As

3763-518: The structure used travertine as an aggregate, having a much higher density of 2,200 kilograms per cubic metre (140 lb/cu ft). Scientific studies of Roman concrete since 2010 have attracted both media and industry attention. Because of its unusual durability, longevity, and lessened environmental footprint, corporations and municipalities are starting to explore the use of Roman-style concrete in North America. This involves replacing

3834-774: The study, and it is unknown whether Canada had been approached about the study by the US Federal Power Commission. In 1956, utility Nova Scotia Light and Power of Halifax commissioned a pair of studies into commercial tidal power development feasibility on the Nova Scotia side of the Bay of Fundy. The two studies, by Stone & Webster of Boston and by Montreal Engineering Company of Montreal , independently concluded that millions of horsepower (i.e. gigawatts) could be harnessed from Fundy but that development costs would be commercially prohibitive. There

3905-713: The system, the effect is negligible and would not be noticeable in the foreseeable future. Tidal power can be classified into four generating methods: Tidal stream generators make use of the kinetic energy of moving water to power turbines, in a similar way to wind turbines that use the wind to power turbines. Some tidal generators can be built into the structures of existing bridges or are entirely submersed, thus avoiding concerns over aesthetics or visual impact. Land constrictions such as straits or inlets can create high velocities at specific sites, which can be captured using turbines. These turbines can be horizontal, vertical, open, or ducted. Tidal barrages use potential energy in

3976-541: The technology's viability and the concept of tidal generation, but not specifically to this company's commercial proposal. The economics of the Swansea Bay proposal have been criticised. The effects on fish and wildlife were reportedly being assessed. In February 2019, the Guardian reported that a Swansea tidal lagoon plan had been revived without the need for government funding. It is reported that Swansea-based Tidal Power plc has several major companies interested in buying

4047-412: The tidal device to severely affecting nearshore ecosystems and processes. Installing a barrage may change the shoreline within the bay or estuary , affecting a large ecosystem that depends on tidal flats . Inhibiting the flow of water in and out of the bay, there may also be less flushing of the bay or estuary, causing additional turbidity (suspended solids) and less saltwater, which may result in

4118-466: The tidal energy devices, this acoustic output can have varying effects on marine mammals (particularly those who echolocate to communicate and navigate in the marine environment, such as dolphins and whales ). Tidal energy removal can also cause environmental concerns such as degrading far-field water quality and disrupting sediment processes. Depending on the size of the project, these effects can range from small traces of sediment building up near

4189-596: The tides and that the Tidal Lagoon Swansea Bay would have had a load factor of 19% compared to around 50% for offshore wind power . However, as the monthly variation is predictable, tidal lagoon energy could allow reduction in the amount of energy generated by gas-fired power plants. During the construction period the project would have sustained over 2,200 construction and manufacturing jobs, but in operation would only require 28 workers. The 2016 Hendry Review (the source of these figures) also considered

4260-561: The total availability of tidal power may be much higher than previously assumed and that economic and environmental costs may be brought down to competitive levels. Historically, tide mills have been used both in Europe and on the Atlantic coast of North America. Incoming water was contained in large storage ponds, and as the tide goes out, it turns waterwheels that use the mechanical power to mill grain. The earliest occurrences date from

4331-423: The volcanic ash with coal fly ash that has similar properties. Proponents say that concrete made with fly ash can cost up to 60% less, because it requires less cement. It also has a reduced environmental footprint, due to its lower cooking temperature and much longer lifespan. Usable examples of Roman concrete exposed to harsh marine environments have been found to be 2000 years old with little or no wear. In 2013,

SECTION 60

#1732765531254

4402-400: The volcanic sand from the beds of Pozzuoli , which are brownish-yellow-gray in colour in that area around Naples, and reddish-brown near Rome. Vitruvius specifies a ratio of 1 part lime to 3 parts pozzolana for mortar used in buildings and a 1:2 ratio for underwater work. The Romans first used hydraulic concrete in coastal underwater structures, probably in the harbours around Baiae before

4473-589: The wind, make tidal energy particularly attractive for electric power generation. Condition monitoring is the key for exploiting it cost-efficiently. Roman concrete Roman concrete , also called opus caementicium , was used in construction in ancient Rome . Like its modern equivalent , Roman concrete was based on a hydraulic-setting cement added to an aggregate . Many buildings and structures still standing today, such as bridges, reservoirs and aqueducts, were built with this material, which attests to both its versatility and its durability. Its strength

4544-419: The world's oceans. This results in periodic changes in sea levels, varying as the Earth rotates. These changes are highly regular and predictable, due to the consistent pattern of the Earth's rotation and the Moon's orbit around the Earth. The magnitude and variations of this motion reflect the changing positions of the Moon and Sun relative to the Earth, the effects of Earth's rotation , and local geography of

4615-642: Was France's Rance Tidal Power Station , which became operational in 1966. It was the largest tidal power station in terms of output until Sihwa Lake Tidal Power Station opened in South Korea in August 2011. The Sihwa station uses sea wall defense barriers complete with 10 turbines generating 254 MW. Tidal energy is taken from the Earth's oceanic tides . Tidal forces result from periodic variations in gravitational attraction exerted by celestial bodies. These forces create corresponding motions or currents in

4686-597: Was also a report on the international commission in April 1961 entitled "Investigation of the International Passamaquoddy Tidal Power Project" produced by both the US and Canadian Federal Governments. According to benefit to costs ratios, the project was beneficial to the US but not to Canada. A study was commissioned by the Canadian & Nova Scotian and New Brunswick governments (Reassessment of Fundy Tidal Power) to determine

4757-511: Was developed a century before that. It was often used in combination with facings and other supports, and interiors were further decorated by stucco , fresco paintings, or coloured marble. Further innovative developments in the material, part of the so-called concrete revolution , contributed to structurally complicated forms. The most prominent example of these is the Pantheon dome, the world's largest and oldest unreinforced concrete dome. Roman concrete differs from modern concrete in that

4828-430: Was increased to $ 20 million, half to be paid by the utility, half by the federal government. The utility was unable to control costs on this project, and by October 2014, the costs had ballooned to an estimated $ 38 million and were projected to continue to increase. The PUD proposed that the federal government provide an additional $ 10 million towards this increased cost, citing a gentlemen's agreement . When

4899-428: Was proposed as a suitable material for constructing the sea walls. 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

4970-419: Was sometimes enhanced by the incorporation of pozzolanic ash where available (particularly in the Bay of Naples ). The addition of ash prevented cracks from spreading. Recent research has shown that the incorporation of mixtures of different types of lime, forming conglomerate "clasts" allowed the concrete to self-repair cracks. Roman concrete was in widespread use from about 150 BC; some scholars believe it

5041-402: Was the world's first tidal power station. The plant was for 45 years the largest tidal power station in the world by installed capacity: Its 24 turbines reach peak output at 240 megawatts (MW) and average 57 MW, a capacity factor of approximately 24%. The world's first marine energy test facility was established in 2003 to start the development of the wave and tidal energy industry in

#253746