Asian advance16 March 2016
Hydro projects of all stages continue to make Asia a growth sector. Report by Patrick Reynolds
Among the many hydropower projects in development in Asia, expansions are underway at the Baglihar scheme in India, the Tarbela dam in Pakistan, and Lamtakong Jolabha Vadhana pumped storage plant in Thailand.
Also in Pakistan, milestone progress has been achieved recently at Neelum Jhelum, and studies are advancing plans for Thakot and other projects in the Indus basin.
A range of further supporting studies for hydro projects are underway in Nepal and Bhutan, respectively, and also Vietnam - including Lai Chai where were works are advanced. A refurbishment projects is in preparation for a key hydro scheme in Tajikistan.
Nepal also has a focus on irrigation needs, including a wider examination of flood hazard risk.
The 450MW Baglihar-II project in Jammu & Kashmir, India, was inaugurated recently by Prime Minister Narendra Modi.
Developed on the Chenab River, the project (3 x 150MW) is the second stage of the Baglihar scheme and doubles the installed capacity at the site to 900MW. The Stage I plant was built over 2000-2008. Their joint output is expected to be approximately 4180GWh of electricity per year.
Project developer is the Jammu & Kashmir State Power Development Corporation. Lahmeyer International (part of Tractebel Engineering, a division of ENGIE (previously GDF Suez) is the Engineer-in-Charge of the Baglihar site, and since 1999 has had engineering responsibilities on both stages of the development.
Contractor on both stages is Jaiprakash Associates. E&M supplier on Stage II are Voith Hydro and Andritz Hydro, and for Stage I were Voith Siemens and VATECH, respectively.
Both stages are served by a 144.5m high concrete gravity dam with an integrated overflow spillway. Each stage also features significant underground infrastructure. The intakes to both are located in the bank, immediately upstream of the dam.
The stages have parallel diversion tunnels at the dam. The headrace tunnels also run together for most of their distance, and each has a 77m high surge shaft.
The underground powerhouses of the two stages (each with 3 x 150MW Francis units) are close together - Stage II complex is located immediately upstream of the Stage I caverns. The cavern complexes are approximately 180m apart.
Each powerhouse cavern is 50m high x 24m wide x 121m long; and, the transformer caverns are 24m high x 15m wide x 112m long. The caverns were excavated over 2011-2013.
Downstream of each powerhouse complex are further underground works, located before the tailrace tunnels: the underground structures are "Collection Galleries". For Stage I, the collection gallery is a single cavern; for Stage II, the system includes a lower gallery (20.6m high x 14m wide x 95m long), three 14m wide riser shafts and a gate operating top gallery 9m high x 16m wide x 57m long).
The tailrace tunnels are different, too - Stage I is short (130m), high (29m) and flow is free-flowing; Stage II is a 350m long, 10m diameter pressurised tunnel.
Earlier work at the dam serving both stages saw challenges during construction. In 2005, during Stage I works, a large flood triggered slops failure and also consequent abutment scour damage. A combination of a temporary bottom outlet and sluices, mass concrete fill, and an extended spillway chute enabled seasonal flows to be managed and construction to advance, including completion of the plunge pool.
Other projects on the Chenab that Lahmeyer has worked on include Sawalkote, Ratle and Pakal Dul.
Separately, in Himachal Pradesh, Lahmeyer recently provided consultancy services for the Thana Plaun project being developed on the Beas River by Himachal Pradesh Power Corporation. The 187MW scheme involves dam works and an underground powerhouse, and is expected to generate about 530GWh per year.
Investigations are underway to prepare a feasibility study for the Thakot hydro scheme being developed on the Indus River by Pakistan's Water & Power Development Authority (WAPDA).
Thakot is being developed as a project of at least 2GW, and is located immediately upstream of the existing Tarbela reservoir. It is part of a cascade of large hydro schemes planned to be built on the river, and upstream projects include 2.4GW Patan and 4.5GW Daimer-Basha.
Lahmeyer is working with local partners on studies for the three WAPDA projects - Thakot, Patan and Daimer-Basha, respectively.
The next project upstream from Thakot in the Indus cascade is Patan, and others being planned include Dasu and Daimler-Basha, which is 315km upstream of Tarbela dam.
For the Thakot project, WAPDA is seeking to exploit a head of approximately 180m between Patan and Tarbela. Planning studies for Thakot are investigating options for either a single project or a few created as a small, intermediate cascade, says Lahmeyer. Thakot dam site is at a narrow section of the river, just downstream of Besham.
At Tarbela itself, WAPDA is currently constructing the 4th Extension Project at the site to add 1410MW (3 x 470MW) by June 2017 - an earlier deadline to an accelerated programme, announced in January. The extension will increase the installed capacity at Tarbela to 4888MW.
Civils works on the 4th Extension Project are being executed by SinoHydro, and the E&M package is being supplied by Voith Hydro. Consultants working on the project are Mott MacDonald and Coyne et Bellier (part of Tractebel Engineering (France), a division of ENGIE) with subconsultants MM Pakistan and ACE Pakistan. The consulting team has also undertaken studies for the 5th Extension project.
Tarbela was completed in the 1970s, and generating units have been added in phases up to the early 1990s.
An earlier project for Lahmeyer was a feasibility study review for the high-head, 34MW Harpo scheme, on a tributary on the Indus.
Separately from Indus developments, WAPDA last month noted the milestone progress achieved in underground works with a key tunnel breakthrough on the 969MW Neelum Jhelum scheme. The project is to be commissioned over the second half of 2017. Contractor is Chinese consortium CGGC-CMEC. Consultants are Neelum Jhelum Consultants, which is a joint venture of MWH, Norplan, Nespak, ACE and NDC.
Tajikistan: Qairokkum rehab
ILF is providing consultancy services to national utility Barqi Tojik for the rehabilitation, uprating and safety improvements at Qairokkum hydro plant, in Tajikistan.
The 66-year old plant on the Syr-Darya River is to have its capacity increased from 126MW to 174MW, and various E&M and civil engineering packages of works undertaken for the rehabilitation.
The project is also to deliver dam safety improvements, the quality of electricity supply, and climate change resilience.
ILF will provide services during procurement and construction phases, and commissioning.
Funding support for the scheme has been given by the European Bank for Reconstruction and Development (EBRD).
The bank also - along with the World Bank and European Investment Bank (EIB) - has given funding support to the related CASA-1000 transmission line project, which will help Tajikistan export hydropower to the Kyrgyz Republic, Pakistan and Afghanistan.
Mott MacDonald has also carried out climate resilience studies on Tajikistan's water sector for the Asian Development Bank (ADB).
Consultants Lahmeyer, Total Management Services (TMS), Entura and Manitoba Hydro International (MHI) are working across a number of water studies and projects in Nepal. The different contracts range from flood hazard studies and providing consultancy services to the Nagmati irrigation scheme and development of Tanahu hydro project, respectively.
Lahmeyer is working with local partner TMS on flood hazard studies in 25 key river basins - including a focus of mitigation measures in six catchments - for the Ministry of Irrigation. The studies are due for completion in the first quarter of this year.
The client division managing the task is the ministry's Water Resources Project Preparation Facility (WRPPF), which has ADB funding support to focus on urgent projects to mitigate both climate change impacts and ensure sustainability of food supply.
Separately, the ministry and ADB have commissioned Entura as lead consultant for the initial services of investigations and updating the feasibility study of the Nagmati dam, near Kathmandu.
Following consultancy services will include detailed design of the dam and reservoir operation regime, and assistance with procurement for the construction stage of the project to be built in the Bagmati river basin.
In hydropower, development services for the 140MW (2 x 70MW) Tanahu hydro project - the country's first large storage reservoir - are being provided by Lahmeyer with the support of MHI.
The consultants were appointed to the project last year by the developer, Tanahu Power Ltd, a special project company established by the Nepal Electricity Authority (NEA) to build and operate the scheme.
Tanahu is located on the Upper Seti River, and key infrastructure includes a 140m high gravity dam, chute spillway, underground powerhouse and associated tunnels. The reservoir will have a sediment flushing capability to help maintain the active storage volume.
The World Bank has appointed ÅF to undertake an environmental and sustainability study of the 720MW Mangdechhu hydro project, currently under construction in Bhutan.
ÅF is more than half way through the assignment on the Mangdechhu project being built in Trongsa Dzongkhag district in the centre of Bhutan.
The run-of-river scheme is designed to operate under a minimum gross head of 344m, and includes significant dam and underground works: a 101.5m high concrete gravity dam; diversion tunnel; 13.5km long headrace; and, powerhouse caverns.
The consultant is due to report its findings to the bank and Bhutanese authorities before the middle of this year. The work is being conducted in accordance with the Hydropower Sustainability Assessment Protocol, which covers a wide range of areas, including climate change and human rights.
The Mangdechhu scheme is being developed by Mangdechhu Hydroelectric Project Authority - a joint venture of the governments of Bhutan and India, the latter providing most of the finance. The project (4 x 180MW Peltons) is due for completion in 2018, generating more than 2900GWh/year, and supplying power domestically and to India.
In FY 2006-7, India's NHPC entered into an agreement with the Government of Bhutan to prepare a detailed project report of the proposed scheme, then envisaged with a capacity of 672MW. Feasibilities studies for the scheme were supported by Japan and Norway.
Thailand: Lamtakong Jolabha Vadhana PS, Phase 2
ÅF is supporting the Electricity Generating Authority of Thailand (EGAT) on the extension project to double the capacity of the 500MW Lamtakong Jolabha Vadhana pumped storage plant.
The underground plant has two pump-turbines (2 x 250MW) in operation, and was initially commissioned in 2002. The 500MW expansion project at Lamtakong Jolabha Vadhana is due for completion in late 2018.
Lamtakong Jolabha Vadhana is located in Nakhon Ratchasima province, was the first underground plant hydro facility in Thailand and remains the principal plant supplying power in the northeast provinces, says EGAT. Its upper reservoir is on Yai Tieng Mountain, and the powerhouse in 350m underground.
Phase 2 of the project will add two further 250MW units, taking the total capacity of the PS plant to 1GW. Work at the plant is also to include installation of 2 circuits of 95km long high voltage transmission lines to connect with the Tha Lan 3 substation, in Saraburi province.
ÅF signed a contract with EGAT to provide a range of services while the extension project is executed under by an engineering, procurement and construction (EPC) contractor.
The consultant's services include design review, project management, engineering and field services through all stages of execution, including commissioning.
Vietnam: Lai Chau HEP
ÅF is also active in neighbouring Vietnam, where the consultant most recent began work on the supporting the implementation of the environmental and social action plan for the Lai Chau hydro project.
The 1200MW Lai Chau project is under development on the Da River, in Lai Chau province, in the northwest of the country close to the border with China. Construction of the 131m high roller compacted concrete (RCC) dam at Lai Chau was completed in mid-2015.
Lai Chau is being development by Electricity of Viet Nam (EVN). ÅF has already been working on the project as sub-consultant to Power Engineering Consulting JSC No1 (PECC1), a former subsidiary of EVN, and the assignment continues to 2017.
Key areas of focus for the project's environmental and social action plan are:
- Community Engagement;
- Resettlement Services to Communities;
- Reservoir Vegetation Management and Erosion Control; and,
- Community Health and Safety
ÅF was awarded the environmental and social action plan contract by Son La Hydropower Management Board (SLaMB). The board - and ÅF - worked together previously on the 2400MW Son La project, on the same river and also featuring a major, 138m high RCC dam. Son La was completed in early 2011.
The environmental and social action plan contract for Lai Chau is funded by KfW, and ÅF is already working on another contract in Vietnam funded by the German development bank - gap analysis on environmental aspects of a smart grid transmission project. ÅF says the contract is similar to the objectives at Lai Chau by checking environmental and social due diligence, in this case for 6 x 220kV transmission lines.