The Huizhou Pumped Storage Power Plant is a pumped storage hydroelectric power station near Huizhou in Guangdong province, China. It contains 8 pump-generators that are all expected to be commercially online in 2011, totaling a 2,400 MW installed capacity. Initial units went online between 2007 and 2008.

Huizhou Pumped-storage Power Station
Country	China
Locale	Huizhou, Guangdong
Status	Partially operational
Commission date	2007
Pumped-storage station information
Pump-generators	8
Power generation information
Maximum capacity	2,400 MW
Annual generation	4,200 GWh

Garorim Bay Tidal Power Plant Project is located between Seosan City and Taean County of Chungnam Province, South Korea, at the western seashore of South Korea. The electric power generation capacity of the plant will be 520 megawatt-hours per day (26 MW·h * 20 sets). This is more than twice the capacity of the Rance Power Plant in France, which is the biggest tidal power plant in the world as of 2007.

Environmental impact

Garorim Bay Tidal Power Plant Project is regarded as one of the important tidal flats in South Korea. The Korean government included this bay in the National Wetland Inventory. The Yellow Sea Large Marine Ecosystem (YSLME) Project, managed by the United Nations Development Programme and the Global Environment Facility, also surveyed the ecology of this bay.

According to a survey on fishery resources in 1981, supported by the Korean Ocean Research and Development Institute, this bay is an important spawning ground for many species of fish. The study predicted that the plant's construction would cause critical damage to the bay's ecology.

The bay is one of the most important fish farming sites in Korea, composed of about 2000 fishery households.

Response of local fishermen

On 20 August 2007, the power company tried to hold a Hearing from Residents, an official proceeding required by the Environmental Impact Assessment (EIA). But about 1000 fishermen, demanding cancellation of the entire project, prevented the hearing from being held so the EIA requirement would not be met.

Relation to renewable energy strategy

Garorim Bay Tidal Power Plant Project is now being included in the South Korean government's renewable energy strategy. The Korean government classifies tidal power as renewable, and the Garorim Bay Project is included in the renewable energy plan which the government announced in September 2008.

The Korean Federation for Environmental Movement (Friends of the Earth Korea) has criticized the project, arguing that the power plant is contrary to the purpose of renewable energy, because it would destroy the valuable tidal flats in the area, thus accelerating global warming.

A list of ten proposed Severn Barrage Tidal Energy projects was published in July 2008. The feasibility study looked in further detail at the ten schemes and the consultation document published in January 2009 proposed that a short-list of 5 schemes should be the subject of more extensive research in phase two of the study. The 5 schemes are:

• Shoots Barrage (1.05GW scheme located downstream of the new Severn road crossing with an estimated construction cost of £3.2bn)
• Beachley Barrage (625MW scheme located further upstream of the first Severn road bridge with an estimated cost of construction of £2.3bn)
• Bridgwater Bay Lagoon (1.36GW impoundment on the English side of the Estuary with an estimated construction cost of £3.8bn)
• Fleming Lagoon (1.36GW impoundment on the Welsh bank of the Estuary with an estimated construction cost of £4.0bn)
• Cardiff-Weston (Lavernock Point to Brean Down) Barrage (8.46GW scheme, commonly known as the ‘Severn Barrage’, with an estimated cost of construction of £20.9bn).

The Government response to consultation was published in July 2009. This confirmed detailed study in phase 2 would be carried out on the 5 schemes that were recommended in the consultation document. It also announced work to bring forward 3 further schemes that are currently in the very early stages of development.

Power generation potential

The Severn Barrage plans would provide a predictable source of green energy during lifetime of the scheme, 5% of the UK's output from the 10-mile version. This could reduce the cost of meeting UK’s renewable energy targets, and help the UK to meet such targets, including those to tackle climate change. This is because of the few carbon emissions associated with the plan, because unlike conventional power generation, the Severn Barrage plans do not involve the combustion of fossil fuels. A consequence of this plan is that the carbon payback time—the time it takes for saved carbon emissions (those produced by generating the same amount of power in other ways) to outstrip those produced during construction— could be as little as four-and-a-half months, although likely to be around six.

It could continue to operate for around 120 years, compared with 30–40 years for nuclear power plants. An additional benefit would be to improve energy security.

However, although power supply is predictable, peaks in generation from the barrage do not necessarily coincide with peaks in demand. There are two major tidal cycles affecting power output:

• semi-diurnal cycle: the familiar daily rise and fall of the sea with a full cycle every 24 hours and 50 minutes, with two high and low tides, giving maximum power generation opportunities a few hours after each of the two high tides;
• spring-neap cycle: a 29.5 day tidal range cycle with the lowest power days producing about 25% of the power of the highest power days.

Just under eight hours per day of generation time is expected.

Construction costs

Estimated costs for existing plans could be as low as £10bn and as high as £34bn. Recent studies have suggested that the smaller short-listed options could be privately financed, and so in effect the matter of cost and risk becomes a private one between the building consortium and their banks. Schemes of the scale of Cardiff-Weston are likely to require significant Government involvement. If the banks feel that a smaller project is viable and decide to lend the money at an acceptable cost of finance then the projects will go ahead (subject to planning and other approvals). None of this cost would directly fall on the tax-payer but any support mechanism for the tidal power would be likely to fall on consumers. There would though be secondary knock-on costs from the tidal power project that might be met by the tax-payer, such as modifying existing ports, provision of compensatory habitat and dealing with environmental change. However, these would be offset by the positive knock-on effects, such as flood protection - which would have otherwise also cost tax-payer money. Whether the parties actually decided to exchange money for these knock-on effects would be a matter for Government negotiation.

Local impact

Any large-scale barrage would create leisure-friendly water conditions behind it. Flood protection would be provided by the barrage, covering the vulnerable Severn estuary from storm surges from the sea. New road and/or rail transport links could be built across a barrage if demand rises in the future, as outlined below. Any barrage could provide a boost to the local economy — construction industry in the short term, tourism and infrastructure in the long term.

However, shipping would have to navigate locks, and existing estuary industries, including fisheries, would be damaged and jobs lost. All industrial discharges into the River Severn (e.g. from Avonmouth) would have to be reassessed.

The Penzhin Tidal Power Plant Project is a set of proposals for construction of tidal power plant in the Penzhin Bay, which is an upper right arm of Shelikhov Bay in the north-east corner of the Sea of Okhotsk. Because Penzhin Bay has one of the strongest tides, several projects of power station was suggested. One of proposed variants presumes installed capacity 87 GW and annual production 200 TWh of electricity.

Geographically, the dam of the power station would extend through the administrative border of Magadan Oblast and Kamchatka Krai of Russia.

The altitude of tides in Penzhin Bay constitutes 9 metres (30 ft) and reaches 12.9 metres (42 ft) in the case of syzygian tides, that is the highest magnitude for Pacific ocean. As the area of the bay basin is 20,530 km² (7,930 mi²), it corresponds to diurnal discharge of 360−530 km³ (86−130 cu mi). This water rate is 20-30 times higher, than it is for the Amazon River, the biggest river of the Earth. Two projects were developed for tidal power stations. First of them is earliest in time and proposes use of entire basin of the bay. The second one suggests smaller scale plant, which must use northern part of basin with higher tides:

Due to the lack of local consumers and power lines, there are suggestions of a discrete work of the station to supply power-consuming productions. One of such regulators, for example, would be the production of liquid hydrogen.

Hydrological potential of the bay

The tides in the Penzhin Bay of the Sea of Okhotsk is highest one for Pacific ocean reaching the height 13.4 metres (44 ft). The tides in Shelikhov Bay is a duirnal type, the area of Penzhin Bay basin is 20 530 km². Hence, the assumption, that the average magnitude of tide is equal to 10 metres (33 ft), gives the diurnal flow of water in the bay equal to 410.6 cubic kilometres (98.5 cu mi) or average discharge 4.75×10⁶ m³•sec^-1.

The passing stream has its own potential energy, which in the gravity field of Earth is above zero only in the case of non-zero head of water (H_Head) and can be expressed as follows:

, (1)

where E denotes potential anergy; ρ_sw — density of sea water, equal to 1,027 kg/m³; S_Basin — area of basin; H_Tide — height of the tide and g — gravitational acceleration, set to 9.81 m/sec². The part of expression in brackets denotes terms defining the mass of water passing through the basin daily.

As it can be seen in formula (1), the potential energy becomes zero in the case of zero head of water and in the case of equal heights of head and tide. Regarding this formula as function of head (H_Head), it is a parabolic function, which has the maximum at H_Tide = 2•H_Head or at H_Head = 5 m. This value of H_Head gives two times lower height of tide in the bay and twice smaller average discharge of water — 5 m and 2.38×10⁶ m³•sec^-1 (205.3 km³/day), correspondingly.

The substitution of obtained parameters into (1) and dividing it by the day length in seconds gives the average capacity 120 GW. The latter one allows to obtain 1,054 TW•h or 3.79×10¹⁸ Joules of energy annually. Depending on the efficiency of conversion of potential energy into electricity, the total quantity of electricity and electric capacity will have somewhat lower values. The assumption, that the efficiency of conversion is equal to 96%, gives an average electric capacity 115 GW and available amount of electricity 1,012 TW•h or 3.64×10¹⁸ J per year.

Sihwa Lake Tidal Power Plant is a large tidal power station currently under construction. Due to be completed in December 2010 and it will operate with a total power output capacity of 254 MW, surpassing the 240 MW Rance Tidal Power Station to become the world's largest tidal power installation.

The tidal barrage makes use of a seawall constructed in 1994 for flood mitigation and agricultural purposes. Ten 25.4 MW submerged bulb turbines are driven in an unpumped flood generation scheme; power is generated on tidal inflows only and the outflow is sluiced away. This slightly unconventional and relatively inefficient approach has been chosen to balance a complex mix of existing land use, water use, conservation, environmental and power generation considerations.

The Sihwa Lake Tidal Power Plant should provide indirect environmental benefits as well as renewable energy generation. After the seawall was built, pollution built up in the newly created Sihwa Lake reservoir, making its water useless for agriculture. In 2004, seawater was reintroduced in the hope of flushing out contamination; future inflows from the tidal barrage are envisaged as a complementary permanent solution.

Cost of the Sihwa Lake Tidal Power Plant project is being met by the South Korean Government and at present totals 313.5 billion won. Mean operating tidal range is 5.6 m (18 ft), with a spring tidal range of 7.8 m (26 ft). The working basin area is 43 km² (17 sq mi).

Sihwa Lake Tidal Power Plant
Country	South Korea
Locale	Sihwa Lake, Gyeonggi Province
Status	Under construction
Opening date	December 2010
Construction cost	₩313.5 billion
Owner(s)	Korean Water Resource Corporation
Power station
Type	Tidal barrage
Turbines	10 × 25.4 MW
Installed capacity	254 MW

Uldolmok Tidal Power Plant is a tidal power station in Uldolmok, Jindo County, South Korea. The plant was commissioned in May 14, 2009 (2009-05-14) by the South Korean government. The plant cost US$10 million and has an installed capacity of 1,000 KW (1 MW), generating 2.4 GWh annually, sufficient to meet the demand of 430 households.

The South Korean government plans to increase this capacity of 1 MW to 90 MW by the end of the year 2013, increasing the demand cover to 46,000 households, while simultaneously working on the 254 MW Sihwa Lake Tidal Power Station. Part of the goal of generating 5,260 GWh through tidal power by 2020.

Strangford Lough SeaGen is the world's first large scale commercial tidal stream generator located in Strangford Lough. It is more powerful than any other tidal stream generator in the world. In 2007 Strangford Lough SeaGen became home to the world's first commercial tidal stream power station. The 1.2 megawatt underwater tidal electricity generator, part of Northern Ireland's Environment and Renewable Energy Fund scheme, takes advantage of the fast tidal flow in the lough which can be up to 4 m/s. Although the generator is powerful enough to power up to a thousand homes, the turbine has a minimal environmental impact, as it is almost entirely submerged, and the rotors turn slowly enough that they pose no danger to wildlife.

The first SeaGen generator was installed in Strangford Narrows between Strangford and Portaferry in Northern Ireland in April 2008 and was connected to the grid in July 2008. It generates 1.2 MW for between 18 and 20 hours a day while the tides are forced in and out of Strangford Lough through the Narrows. Interestingly, Strangford Lough was also the site of the very first known tide mill in the world, the Nendrum Monastery mill where remains dating from 787 have been excavated.

Since June 2008 a tidal energy device called Evopod has been tested in Strangford Lough near the Portaferry Ferry landing. The device is a 1/10 scale prototype and is being monitored by Queens University Belfast. The device is a semi submerged floating tidal turbine and is moored to the seabed via a buoy mounted swivel so that it always maintains optimum heading into the direction of the tidal flow. The scale device is not grid connected and dissipates the small amount of power it generates as heat into the sea.

Technology

SeaGen generator weights 300 tonnes. It consists of twin axial-flow rotors of 16 metres (52 ft) in diameter, each driving a generator through a gearbox like a hydro-electric or wind turbine. These turbines have a patented feature by which the rotor blades can be pitched through 180 degrees allowing them to operate in both flow directions – on ebb and flood tides. The power units of each system are mounted on arm-like extensions either side of a tubular steel monopile some 3 metres (9.8 ft) in diameter and the arms with the power units can be raised above the surface for safe and easy maintenance access. The SeaGen was built at Belfast's Harland and Wolff's shipyards.^[9]

Environmental impact

SeaGen has been licensed to operate over a period of 5 years, during which there will be a comprehensive environmental monitoring programme to determine the precise impact on the marine environment.

The Kislaya Guba Tidal Power Plant is an experimental project in Kislaya Guba, Russia.

Kislaya Guba Tidal Power Station
Country	Russia
Locale	Kislaya Guba
Status	Operational
Commission date	1968
Owner(s)	RusHydro
Power station information
Primary fuel	Tide
Generation units	1 × 0.2 MW 1 × 1.5 MW
Power generation information
Installed capacity	1.7 MW

The Jiangxia Tidal Power Plant located in Wuyantou, Wenling City, Zhejiang Province, China. It is the third largest tidal power station in the world. Although the proposed design for the facility was 3,000 KW, the current installed capacity is 3,200 KW, generated from one unit of 500 KW, one unit of 600 KW, and three units of 700 KW, totalling the installed capacity to 3,200 KW. Proposals were made to install a sixth 700 KW unit, but this has not yet been installed.^[2][3] The facility generates up to 6.5 GWh of power annually.

Jiangxia Tidal Power Plant
Country	China
Locale	Wuyantou, Wenling, Zhejiang
Status	Operational
Dam and spillways
Type of dam	Barrage
Reservoir
Tidal range	8.39 m (27.5 ft)
Power station
Commission date	April 1980
Type	Tidal barrage
Turbines	1 × 500 KW 1 × 600 KW 3 × 700 KW
Installed capacity	3.2 MW
Maximum capacity	3.9 MW
Annual generation	6,500 MWh

The project has had mixed results. While effectively generating electricity, the blocking of water flow by the dam (to allow the tidal difference to accumulate every six hours) has resulted in increased river bank erosion on both the upstream and downstream ends. The dam is also known as a trap for marine life. Two notable cases occurred in:

• August 2004: a mature Humpback whale (nicknamed Sluice) swam through the open sluice gate at slack tide, ending up trapped for several days in the upper part of the river before eventually finding its way out to the Annapolis Basin.
• Spring 2007: When a body of an immature Humpback whale was discovered near the head of tide in the river at Bridgetown. A post-mortem was inconclusive but suggested the whale had become trapped in the river after following fish through the sluice gates.

In spite of the high development cost of the project, the costs have now been recovered, and electricity production costs are lower than that of nuclear power generation (1.8c per kWh, versus 2.5c per kWh for nuclear).

Rance Tidal Power Plant Environmental impact

The barrage has caused progressive silting of the Rance ecosystem. Sand-eels and plaice have disappeared, though sea bass and cuttlefish have returned to the river. By definition, tides still flow in the estuary and the operators, EDF endeavours to adjust their level to minimize the biological impact.

Tourist attraction

The Rance Tidal Power Plant facility attracts approximately 200,000 visitors per year. A canal lock in the west end of the dam permits the passage of 16,000 vessels between the English Channel and the Rance. Departmental highway 168 crosses the dam and allows vehicles to travel between Dinard and Saint-Malo. There is a drawbridge where the road crosses the lock which may be raised to allow larger vessels to pass.

Rance Tidal Power Plant
Country	France
Locale	Brittany
Status	Operational
Construction began	26 July 1963
Opening date	26 November 1966
Construction cost	₣620 million
Owner(s)	Électricité de France
Dam and spillways
Type of dam	Barrage
Length	700 m (2,300 ft)
Reservoir
Tidal range	8 m (26 ft)
Power station
Type	Tidal barrage
Turbines	24
Installed capacity	240 MW
Annual generation	600 GWh

The following page lists most Largest tidal power plant. Since tidal stream generators are an immature technology, no technology has yet emerged as the clear standard. Although, a large variety of designs are being experimented with, some very close to large scale deployment. Hence, the following page lists stations of different technologies.

Largest Tidal power plant

Operational

The following table lists tidal power stations that are in operation as of August 2010.

Tidal Power Station	Capacity (MW)	Country	Comm
La Rance Tidal Power Plant	240	France	1966
Annapolis Royal Tidal Power Plant	20	Canada	1984
Jiangxia Tidal Power Plant	3.2	China	1980
Kislaya Guba Tidal Power Plant	1.7	Russia	1968
Strangford Lough SeaGen	1.2	United Kingdom	2008
Uldolmok	1.0	South Korea	2009

Under construction

The following table lists tidal power stations that are currently under construction as of the date in each cited source.

Tidal Power Station	Capacity (MW)	Country	Comp
Sihwa Lake	254	South Korea	2010

Proposed

The following table lists tidal power stations that are only at a proposal stage.

Tidal Power Station	Capacity (MW)	Country
Penzhin Tidal Power Plant Project	87,100	Russia
Mesen - Mezenskaya Tidal Power Plant	12,000-8,000	Russia
Severn Barrage Tidal Energy	8,640	England Wales
Tugurskaya Tidal Power Plant	3,640	Russia
Dalupiri Blue Energy Project	2,200	Philippines
Incheon Tidal Power Plant Project	1,320	South Korea
Garorim Bay Tidal Power Plant Project	520	South Korea
Gulf of Kutch Project	50	India
Skerries Tidal Farm	10.5	United Kingdom

The following page lists the Largest run of the river hydroelectric power plants. This list includes most power stations that are larger than 100 MW in maximum net capacity, which are currently operational or under construction. Those run of the river hydroelectric power stations that are smaller than 100 MW, and those that are only at a planning/proposal stage may be found in regional lists.

Station	Country	Capacity (MW)
Jinping-II Hydroelectric Plant	China	4,800
Chief Joseph Dam	United States	2,620
John Day Dam Hydroelectric Power	United States	2,160
Beauharnois Hydroelectric Power Plant	Canada	1,903
The Dalles Hydroelectric Dam	United States	1,779
Ghazi-Barotha Hydropower Project	Pakistan	1,450
La Grande-1 Hydroelectric Plant	Canada	1,436
Tianshengqiao-II Hydropower Plant	China	1,320
Jean-Lesage Hydroelectric Plant	Canada	1,145
Bonneville Lock and Dam	United States	1,092
Outardes-3 Hydroelectric Plant	Canada	1,026
McNary Hydroelectric Dam	United States	980
Little Goose Lock and Dam	United States	932
Lower Granite Lock and Dam	United States	932
Lower Monumental Lock and Dam	United States	932
Bersimis 2 Generating Station	Canada	869
Carillon Generating Station	Canada	753
Birecik Dam	Turkey	672
Outardes-2 Hydroelectric Plant	Canada	523
Baglihar Dam-Hydroelectric Power Project	India	450
Gilgel Gibe II Power Station	Ethiopia	420
Ranganadi Dam	India	405