By David Appleyard
In May this year the International Hydropower Association (IHA) released its 2015 Key Trends in Hydropower report, showing that 1.46 GW of new pumped storage capacity was put into operation in 2014.
It is clear that the advantages of pumped hydro in terms of voltage and frequency regulation of the grid and reserve capacity capabilities make the technology increasingly attractive, particularly in the face of the increasing influence of variable output renewables such as wind and solar.
The IHA says in Europe, pumped storage continues to be a focus, with new facilities totalling 8,600 MW in the planning and construction stages.
Developments in variable-speed technology are expected to be a key component of this new capacity, the IHA adds.
Europe is pushing forward with a swathe of new pumped storage projects with new build and refurbishment and replacement of electromechanicals and uprating civils.
For example, global technology manufacturer Alstom recently received an order from Vattenfall Europe Generation AG for the overhaul of a synchronous generator at the 1,050 MW Markersbach pumped-storage plant on Germany’s Mittweida River.
A contractual option covers the overhaul of Markersbach’s four remaining generators at a rate of one unit per year.
Markersbach was commissioned in 1979 and is the second-largest pumped-storage project in Germany.
Vattenfall Europe Generation, the German unit of Sweden-based Vattenfall AB, has performed numerous modifications to Markersbach since it was put into operation. In 2013, it took bids to expand the upper and lower reservoirs of the project. In 2012, the utility took bids for concrete work at 11 hydro projects including Markersbach. Most recently, Vattenfall sought bids to upgrade and repair pump-turbines and other equipment in March 2014.
|A swathe of new pumped storage development is underway. Source: Vattenfall.|
Elsewhere in Germany, March saw a unit of European utility Statkraft invite applications to expand the water storage capacity of the 200 MW Erzhausen Pumped-Storage project in Germany, built in 1964.
Work would involve the crest of the ring dam and intake structure of the upper reservoir, the overflow threshold at the pumping station and the water side embankment slope of the lower reservoir’s main dam.
In 2014, Voith announced that it had been awarded a contract by E.ON Kraftwerke GmbH involving the replacement, assembly and commissioning of the stator and rotor of the generator in unit 6 at the Waldeck 2 pumped storage power plant, in North Hesse, Germany. The contract includes an option for the modernization of a further machine. Construction of the original power plant took place in 1970.
The project should ensure an increase of about 10% in efficiency of the machine unit.
This year Voith has also been commissioned to modernize four motor-generators at the 1,290 MW Vianden pumped storage plant in Luxemburg. The project includes design, construction and installation of four rotors.
Vianden is located close to the border between with Germany and feeds directly into the German power network. The plant is owned by Societé Electrique de l’Our S.A. and is marketed and used by RWE Generation. The plant was first set into operation in 1964. After expansions in 1976 and 2014, the total installed pump capacity is 1045 MW.
Germany’s pumped-storage power plants have a combined capacity of about 7 GW, but a recent study by the Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University and Voith indicates there is potential to add to nearly 24 GW of new pumped-storage capacity in the states of Baden-Wà¼rttemberg and Thuringia.
Dr. Andreas Schäfer, chief engineer at the Institute for Electric Plants and Energy at RWTH Aachen, commented: “Pumped-storage plants would offer important systems services, especially for control reserves, but also for the provision of secured outputs. In this way, pumped-storage systems can make a contribution to the success of the energy transition.”
The study shows that with a 60% share of renewables, about 2 TWh of renewable electricity can be additionally utilized if pump storage capacity in Germany is increased to a total capacity of 15 GW.
Stephan Kohler, Chairman of the Board of Deutsche Energie-Agentur (dena), argues that more should be done to recognise the ancillary services potential of pumped hydro: “Pumped storage power plants should be given first priority, because they are the only existing industrial-scale power storage systems and, beyond that, also make many valuable contributions to the power grid. We have to adapt the framework conditions in such a way, that this added value is also adequately remunerated.”
In neighbouring Austria, this year saw the civil engineering contract for a new 940 MW pumped-storage plant.
|Refurbishment of pumped storage can significantly increase capacity. Source: Vattenfall.|
Pumpspeicherkraftwerk Koralm GmbH has selected ILF Consulting Engineers and AF-Consult to provide engineering services for the Koralm project in Austria.
The Koralm plant will include an upper and lower reservoir, headrace, penstock and tailrace, surge tank, cavern powerhouse and access tunnel, transmission line and switchyard. The plant is expected to have a head of about 650 m and will the largest hydroelectric plant in Austria upon its completion.
Austria is also home to the new Ober-vermuntwerk II and Rellswerk pumped storage projects, which are located in Montafon, Vorarlberg. Voith will supply the energy provider Vorarlberger Ill-werke AG with two pumps and a pump turbine for the two projects under the terms of a contract announced in December 2014. The Obervermuntwerk II pumped-storage power plant is being constructed between the Silvretta and Vermunt reservoirs at an altitude of around 1700 m.
For the Obervermuntwerk II, Voith is to supply, assemble and commission two 170 MW storage pumps. For the new Rellswerk project, Voith Hydro will supply a 13 MW, 3-stage pump turbine.
Over in Portugal EDP – Gestà£o da Produçà£o de Energia, S.A., awarded an ANDRITZ HYDRO-led consortium an order for the supply and erection of the complete electromechanical equipment for the pumped storage project Foz Tua.
The contract includes two reversible pump turbines of 120 MW each and the station will be erected on the river Tua, a tributary of the Douro River in the north of Portugal.
Portuguese pumped storage also got a boost in 2015 with the delivery of a spherical valve to be installed at the 383 MW Frades 2 pumped-storage hydro plant. The 170 tonne component is one of two that will control flows through the Frades 2 plant’s pair of reversible pump turbines on the left bank of the Cavado River.
Although only Argentina is the only South American country to have installed significant pump storage capacity to date, the technology is certainly under consideration. In a novel application, for example, proposals have been put forward that would see a 600 MW solar plant coupled with a 300 MW pump-storage facility in Chile. According to the proposals from developer Valhalla Energy and submitted to Chile’s environmental regulatory authorities (Servicio de Evaluación Ambiental, SEIA), the hydroelectric pumped-storage plant set for the northern Tarapaca region will use seawater.
The so-called ‘Mirror of Tarapaca’ project is expected to require an investment of some US$1 billion.
While South America has seen very limited pumped-storage development to date, North America is on a roll, with a raft of announcements suggestive of a buoyant market for additional pumped storage capacity.
In September, for example, GB Energy Park LLC and Alstom announced an agreement for equipment supply for the 400 MW Gordon Butte project.
A closed-loop pumped storage facility in south central Montana, it will consist of upper and lower reservoirs connected by an underground concrete and steel-lined hydraulic shaft. The head between the two reservoirs if 1,025 feet. The powerhouse will contain four pump-turbine units with total installed capacity of 400 MW and expected annual energy generation of 1,300 GWh.
This followed news that San Diego is to pursue a two-year, $900,000 study of the proposed San Vicente pumped-storage hydropower project that would involve the construction of a 240 to 500 MW hydroelectric plant using the existing San Vicente Dam and reservoir.
This year also saw United Power Corp. file an application to study development of the 30 MW South Maui Pumped-Storage project on the south coast of Maui Island, Hawaii. This project would also use seawater from the Pacific Ocean.
The proposed project includes an upper reservoir composed of four concrete storage tanks and a powerhouse containing three 10 MW variable-speed pumps and two 15 MW variable-speed Pelton turbine-generators. Estimated annual generation is 5.2 GWh.
And, in a recent development, an affiliate of Eagle Crest Energy has agreed to buy the Kaiser Eagle Mountain mine near Desert Center, California, as part of a plan to create a new pumped storage hydropower plant from two of the iron ore mine’s vacant pits.
The project is expected to have a capacity of up to 1,300 MW.
Africa’s pumped hydro ambitions
Although a vast tranche of Africa’s conventional hydropower potential has yet to be developed, pumped storage projects are nonetheless underway.
In South Africa, incumbent utility Eskom is increasing its pumped storage capacity with a new project set to be commissioned this year. Eskom’s operational pumped-storage schemes include the 1,000 MW Drakensberg in the mountains of the Northern Drakensberg of KwaZulu Natal and the 400 MW Palmiet, 2 km upstream of Kogelberg Dam on the Palmiet River near Cape Town.
A third pumped-storage site, the 1,332 MW Ingula project, is being constructed 55 km from Ladysmith, within the Drakensberg range, on the border between the Free State and KwaZulu-Natal provinces. The scheme is being built on a 9,000 ha site at a cost of RND8.9 billion.
Development of the pumped storage scheme was first proposed in 2002. Construction encompasses two dams for the upper and lower reservoirs; a powerhouse, two tunnels, access roads and transmission lines. The underground powerhouse contains four 333 MW pump turbines.
And, in July this year, the Lesotho Highlands Development Authority (LHDA) issued a tender call for economic studies and development arrangements for the 1200 MW Kobong Pumped-Storage project.
South Africa’s Cabinet agreed in 2008 to invest US$712 million in the Lesotho Highlands Water Project (LHWP) Phase 2, which includes construction of Kobong Pumped-Storage project, Polihali Dam as upper reservoir for Kobong, a Polihali-Katse transfer tunnel, roads and associated environmental and social programs.
A contract was recently awarded to Maleka, Ntshihlele, Putsoa Joint Venture for 8 million maloti (US$648,397) for demarcation of Polihali Reservoir.
Asia expands PS projects
Asia, too, is seeing its share of development. Recently, a consortium led by South Korean builder Daelim Industrial Co., was selected to build the 1040 MW Upper Cisokan pumped storage hydropower plant in Indonesia’s West Java province.
The consortium also includes Italian construction firm Astaldi SpA and Indonesia’s Wijaya Karya (WIKA). Being developed on behalf of Indonesian utility PLN, the deal is worth about US$323 million.
Financing for the project is coming in large part from the World Bank.
In July, Nepal advanced the development of its first pumped storage hydro project, as Tanahu Hydropower Ltd awarded contracts to engineering firm Lahmeyer International GmbH and sub-consultant Manitoba Hydro International. The contracts relate to the development of the 140 MW Tanahu pumped-storage project.
Tanahu will be located on the Seti River about 100 km from Kathmandu. The project’s upper reservoir will be impounded by a 140-meter-tall gravity dam.
More recently, in September, Voith was awarded a new contract to supply electromechanical equipment for a pumped storage plant in Thailand. The order is for the extension of the Lam Ta Khong plant and includes the supply of two motor-generators and two 255 MW vertical pump turbines.
Located on the Lam Ta Khong River 200 km northeast of Bangkok, the extension project will double the capacity to a total of 1000 MW.
Australia, too, is looking to expand its pumped storage capacity as Genex Power has appointed consulting firm Entura to provide a feasibility study for the 330 MW Kidston pumped-storage hydropower plant, proposed for construction in North Queensland, Australia, at the site of the Kidston Gold Mine. The project includes two large adjacent pits that would act as the plant’s upper and lower reservoirs [see box panel].
In a nod to further development in the eastern hemisphere, August saw Russia’s PJSC RusHydro and the Korean Water Resources Corp. jointly look to develop a pumped-storage hydroelectric plant in Russia’s Far East.
RusHydro and K-Water will create a working group to study the feasibility of the Primorsky Energy and Water Resources Complex (PEWC), including the Primorskaya pumped storage plant.
Of course, China cannot be ignored when it comes to pumped storage. Last year Hainan Pumped Storage Power Generation Co. Ltd. awarded a US$71.14 million contract to Alstom to equip the 600 MW Hainan Qiongzhong pumped-storage plant.
Hainan Province’s first pumped-storage project operations are due in December 2017.
Under the terms of the deal, Alstom will provide three 200 MW turbine units, including pump turbines, motor generators and other equipment.
Outlook for pumped storage hydro
According to the IHA, the world’s total pumped storage capacity now stands at some 142 GW, increasing by something north of 10% during 2014 alone. Clearly, there is a strong appetite not just for new build pumped storage, but also refurbishment and rehabilitation. This push for additional pumped storage capacity has a number of drivers, but chief among them is the headlong rush for more solar and wind power, renewable energy technologies that require back-up if security of energy supply is to be maintained. Pumped storage is an ideal solution, if not the only realistically economical one. As such, demand for its ample utility in service is likely to grow in the coming decades as the global economy inexorably shifts toward a clean energy system.
David Appleyard is Chief Editor of HRW – Hydro Review Worldwide magazine
Glyn Rhonwy quarry pumped storage
Although the nearby 1800 MW pumped storage plant Dinorwig has been operating since the 1980s, development of pumped storage capacity is still being actively pursued in Snowdonia, the mountainous region of north Wales, in the UK.
If plans proceed to construction, two abandoned slate quarries, Glyn Rhonwy and Chwarel Fawr, are set to be the basis of the UK’s first new pumped storage capacity for several decades.
First mooted in 2012, in April this year, the UK’s Crown Estate agreed to lease 13 Ha of land to Snowdonia Pumped Hydro for its £100 million (US$155 million) project. This followed the granting of planning permission in September 2013.
The project includes the construction of a 20-metre-high dam on the upper reservoir at Chwarel Fawr and a 15-metre-high dam on the lower reservoir at Glyn Rhonwy.
Originally, the Glyn Rhonwy plant had been planned as a 49.9 MW capacity installation, that proposal was increased by a further 50 MW in December last year, pushing the application to the UK Planning Inspectorate.
The proposed change in output, involves installing larger turbines and associated equipment within the powerhouse, now expected to be operational by 2019.
Snowdonia Pumped Hydro is a subsidiary of Quarry Battery Company, which together with AECOM developed a preferred design, including the dams and a cut and fill pen stock.
Construction is anticipated to take 3 to 5 years with the upper reservoir holding some 1.1 billion litres.
The developers see a strong business case for a multitude of such brownfield sites, with their relatively low additional infrastructure costs and minimal visual and environmental impact.
“By continuing to utilize unconventional sites such as the abandoned quarry on The Crown Estate’s land, Britain can realize an additional 15 GW of grid-scale storage using pumped hydro technology alone,” said Peter Taylor, chairman of Quarry Battery.
The company is proposing a new generation of small-scale pumped storage facilities, arguing that they are economically viable and environmentally more acceptable.
Last year it secured a further £3 million (US$4.8 million) in private funding for initial work at the site, near Llanberis and it is in negotiations to secure five further sites from a short list of 30 identified potentials.