2023 was a busy year on Phase II of the Lesotho Highlands Water Project with the start of the water transfer main works and final steps on advance infrastructure, bringing the promise of increased water supply to South Africa one step closer.
The first signs of site establishment activity at the Polihali dam and transfer tunnel sites early in the year following the awarding of the construction tenders at the end of 2022, were a welcome sight and confirmation that the Phase II water transfer main works had moved into the final and most critical construction stage. Simultaneously, procurement for the hydropower component is underway while several advance infrastructure construction programmes like bulk power and telecommunications infrastructure, housing, diversion tunnels, roads, Katse Lodge upgrade, operations centre and commercial centre have been completed or are nearing completion.
This was reaffirmed in May at the formal sod-turning ceremony at Malingoaneng, Mokhotlong for the water transfer main works and the Senqu Bridge. Officiated by His Majesty King Letsie III and the President of South Africa, His Excellency Cyril Ramaphosa, and attended by cabinet ministers and senior officials from both countries, it demonstrated the warm relations between the two countries and their commitment to a project that delivers much-needed water to the Gauteng region and simultaneously provides hydropower to Lesotho and is considered to be one of the most successful cross-border water collaboration schemes between two sovereign states in the world.
Early milestones in the dam and tunnel construction include the diversion of the Senqu River by the pre-cofferdam, and the subsequent diversion of the river into and through the diversion tunnels ahead of the construction of the cofferdam upstream of the Polihali Dam wall in early August. Both the upstream and downstream cofferdams are expected to be completed by January 2024.
Diverting the river through the transfer tunnels which were constructed as part of the advance infrastructure creates a dry working area for the construction of the Polihali Dam. Excavations of the main dam and intake structure have commenced.
A transfer tunnel milestone was the first blast making way for excavation works at the tunnel boring machine access adit in September 2023.
The Polihali Reservoir will inundate a large area which includes existing roads and bridges. Three major bridges are being built along the Maseru to Mokhotlong A1 road at the Mabunyane, Khubelu and Senqu rivers.
Construction of the Senqu bridge commenced in late 2022 and is expected to be completed in 2026. Construction of the other two bridges commenced in August 2023 following the construction tender award to the Concor-Nthane Brothers M&K Bridges Joint Venture.
The three major bridges will provide access to Mokhotlong town across the reservoir even at full supply and retain connectivity to the national road network along the A1, the main road between the Mokhotlong district in the mountainous north-east of the country and Maseru.
The major bridges programme is complemented by the construction of four pedestrian bridges and six vehicle bridges under the feeder roads and bridges programme to maintain access and ensure mobility for communities across and around the reservoir area. The feeder roads and bridges programme is currently under procurement, the tender having been launched in November 2023.
The access roads programme consisting of the Polihali North East Access Road (PNEAR), the Polihali Western Access Road (PWAR) and the Northern Access Road (NAR) is nearing completion.
Construction of the Polihali village is complete as is that of the operations centre, while the commercial centre and upgrades to Katse Lodge are underway.
The operations centre is a multifaceted building comprising an office building, exhibition hall, conference facilities and Visitors Information Centre. The building will be used by LHDA and dam consultants during the construction phase, and LHDA Polihali Operations will take it over post-construction.
The commercial centre – the only one of its kind in the area, the nearest village convenience store being approximately 15 to 20 kilometres away in the Mapholaneng area, will accommodate retail outlets to meet the day-to-day needs of consumers at Polihali village and the immediate neighbouring villages. Anchored by a small supermarket, it will include speciality shops, and has space to accommodate a police post with the option to extend the centre to include a filling station at a later stage. The construction tender was awarded to Unik Construction Engineering in mid-January 2023.
Procurement for the hydropower engineering, Environmental and Social Impact Assessment (ESIA) and the Resettlement Action Planning (RAP) studies for the Oxbow Hydropower Scheme is underway. Although physically separate from the ‘Muela hydropower plant, the two schemes are complementary and Oxbow’s 80MW capacity will add to ‘Muela’s installed capacity of 72MW. Power generation at the Oxbow Hydropower Scheme, the hydropower component of Phase II, is expected to start in 2029.
With much more construction activity on the ground, the physical progress of the Project in 2023 is clear. This is under the stewardship of a newly appointed Pula Nala Joint Venture Phase II Project Management Unit, confirmed by the LHDA to manage the final lap of Phase II construction. The joint venture combines South African, Basotho and international companies, in keeping with the tenets of the Phase II Agreement.
“We are confident that the Project will continue to progress steadily as we move into the final construction phase,” confirmed Tente Tente, LHDA CE.
In late December it was announed that The Lesotho Highlands Development Authority (LHDA) has appointed the Pula Nala Joint Venture as the Programme Management Unit (PMU) to manage the final lap of Phase II of the Lesotho Highlands Water Project (LHWP) construction. After a transition period spanning several months during which the Pula Nala team worked alongside the outgoing PMU (CDM Smith), Pula Nala Joint Venture took the helm on 01 June 2023.
The Pula Nala Joint Venture combines South African, Basotho and international companies, in keeping with the tenets of the Phase II Agreement. Main JV partners are Mariswe (Pty) Ltd (South Africa), JB Barry and Partners Ltd (Ireland) and Royal HaskoningDHV (South Africa). Sub-consultants are ARQ Dams (Pty) Ltd (South Africa), Mafube Consulting (Pty) Ltd (Lesotho), NHA Group (Lesotho) and ABK Consulting Engineering (Lesotho) and CAPIC (South Africa).
“The PMU is a specialist unit within the LHDA. It is a multidisciplinary JV with extensive expertise in the management of large water transfer and hydropower schemes appointed to oversee Phase II through to completion,” confirmed Mr Nt’soli Maiketso the, Divisional Manager on Phase II. “Many of the key engineering, environmental and social, and project management discipline leads within the PMU have been retained to ensure seamless transition under the new structure. We are confident that the Project will continue to progress steadily as we move into the final construction phase.”
The Pula Nala Joint Venture was appointed following an open tender process. The contract duration is seven years. This contract is intended to remain in place until construction is completed and the Polihali Dam, the Polihali Transfer Tunnel and the Oxbow Hydropower Scheme are commissioned and the handover to LHDA is complete.
Progress on Snowy 2.0
Another major construction project underway is Snowy 2.0, Australia’s largest renewable energy project currently in development, which is set to play a central role in the country’s transition to renewable energy sources. Upon completion, it will provide 2200MW of dispatchable electricity. The target date for the commercial operation of all units is December 2028, with the first power expected in the second half of 2027.
In December’s Snowy 2.0 update, Snowy Hydro CEO Dennis Barnes recapped progress and key events throughout the last 12 months. The review and reset of the pumped-hydro Snowy Scheme expansion project has been a major milestone in 2023. The reset has put Snowy 2.0 on a robust and sustainable footing, with new contract arrangements in place and a revised cost of $12 billion.
The focus of the project is prioritising safety and environmental outcomes while achieving construction program targets.
Meanwhile tunnel boring machine (TBM) Florence is underway again at Tantangara after a significant period paused in soft ground conditions after a surface depression formed above the cutter head. Following an extensive process of ground stabilisation, the project has recently received NSW government approval for a planning modification, enabling the machine to restart tunnelling the headrace adit.
Progress highlights for 2023 include TBM Lady Eileen Hudson being relaunched in July to excavate her second tunnel for the project – she’s now one kilometre into the tailrace tunnel.
There are more than 2700 people employed on Snowy 2.0 and a total of 20 million hours have been worked to date.
Drill and blast excavation of the power station cavern crowns is well underway from both ends of the machine and transformer halls and we’re seeing large power station components manufactured by Voith Hydro delivered to site.
Senior electrical quality engineer Victor Teo went to Shanghai, China, where Voith is fabricating some of the key electrical components for Snowy 2.0, including stator bars, rotor bars and poles.
468 stator bars are needed for each of the six pump-turbine generator units, so over 3,000 of them including spares will be produced.
There is always a member from the Snowy Hydro team in China to conduct quality assurance activities, monitor progress, act as a conduit to close out technical issues and to conduct Factory Acceptance Tests
Snowy 2.0 project manager and environmental engineer Emily Martin was at Tantangara, where TBM Florence is tunnelling in slurry, or closed, mode. This mode utilises the onsite slurry treatment plant and allows the team to pressurise the ground around the TBM to provide additional stability.
The intake excavation works at Tantangara are progressing well, with stage 2 well underway.
This involves another 78,000 cubic metres of drilling and blasting earthworks, along with rockbolt installation and shotcreting.
The intake excavation, which is where water will enter the headrace tunnel, is currently about 35m deep and it will be extended to a total depth of 55m.
Tunnelling has resumed at the Snowy 2.0 project’s Tantangara site following the approval of a planning modification by the New South Wales (NSW) government. The project faced a temporary halt due to soft ground conditions and the emergence of a sinkhole above the tunnel boring machine (TBM) Florence.
The restart saw TBM Florence making its initial advance in mid-December, utilizing closed (slurry) mode for slow and steady progress. The project has deployed specialized and experienced personnel to oversee the tunnelling process.
Dennis Barnes, CEO of Snowy Hydro, expressed satisfaction at reaching this milestone and emphasized the importance of the green light for the Tantangara tunnelling to recommence.
“The conditions of approval were developed through the extensive review, public consultation and determination process, and will be strictly adhered to as we get back underway with excavation of the tunnel,” Barnes said. “The Snowy 2.0 delivery team is acutely aware of its responsibilities working in the sensitive environment of Kosciuszko National Park. We are focused on achieving excellent environmental outcomes throughout construction of this pumped-hydro expansion of the Snowy Scheme and critical infrastructure for Australia’s transition to renewable energy.”
The modification approval extends the project’s western boundary above the TBM at Tantangara, allowing for close monitoring of surface conditions as TBM Florence advances. Surface monitoring will persist until there is at least 100m of overburden between the TBM and the surface.
Preparations for the restart included comprehensive geotechnical investigations along the headrace adit alignment and ground improvement works.
In parallel developments: At Talbingo, the Snowy 2.0 project is making strides with the excavation of the tailrace tunnel. TBM Lady Eileen Hudson has covered approximately 1000m since its relaunch in July.
Manufacturing of the project’s six pumped-hydro units, set to generate up to 2200MW of power for Australia’s electricity grid, is in full swing. Notably, five of the six 153-tonne spiral cases have been manufactured, along with other major power station components, including the first turbine runner. One of the 13m-long, 7.5m-wide spiral cases recently completed a 442km night-time journey from Port Kembla to Lobs Hole in the Snowy Mountains.
Kidston celebrates milestone
In a significant development for the 250MW Kidston Pumped Storage Hydro Project (K2-Hydro) in Queensland, Australia, Genex Power Limited announced the successful completion of the Main Access Tunnel (MAT) for the underground works back in November 2023. This crucial milestone was achieved by the Engineering, Procurement, and Construction (EPC) Contractor – a McConnell Dowell and John Holland Group joint venture – marking a major step forward in the project’s construction.
The MAT, serving as the permanent access point to the power station cavern, was excavated in high-quality rock conditions, meeting the required standards. This achievement ensures unimpeded access for lower bench excavation works and subsequent fit-out activities in the power station cavern, all accomplished within the established timeframe of the overall construction program.
Following an incident of water ingress in September 2022, Genex made the strategic decision to realign the MAT away from the zone of fractured material encountered in the original heading. Despite the additional length of 436m for the realigned MAT, this adjustment significantly reduced the overall risk associated with the underground works. Tunnelling works on the realigned MAT commenced in December 2022.
The completion of the MAT marks a major turning point in the underground works, effectively contributing to the de-risking of the entire Kidston Pumped Storage Hydro Project. The company affirms that the project remains on schedule for energization in the second half of 2024.
“The completion of the realigned Main Access Tunnel represents a major milestone for Genex and the Kidston Pumped Storage Hydro Project. We are extremely pleased with the way in which the Genex and EPC Contractor teams responded to the water ingress event last year, completing the redesign and recommencing production with minimal delay. This has limited the time and cost impacts of the water ingress event on the overall Project,” said Genex CEO Craig Francis. “[The] milestone is extremely significant, as it enables Genex and its stakeholders to draw a line under one of the material outstanding risk items for the underground works. Importantly it moves us one step closer toward commencing the power station fit-out works ahead of energisation later in 2024.”
Recently, Andritz Hydro, who is supplying the electro-mechanical equipment for the project, said that the last pieces of equipment arrived on site in October, paving the way for the installation of the project’s components.
Site C moves on
BC Hydro has confirmed that the commencement of reservoir filling for the Site C dam project in Canada is slated to stay on schedule, with the process set to kick off in 2024 as originally planned.
Despite initial considerations to accelerate reservoir filling by a year and commence this fall, BC Hydro faced critical tasks that demanded completion prior to initiating the process. Crucial work areas, such as the approach channel, spillway gates, and powerhouse intake gates, still require attention. The onset of winter weather and colder conditions presented a narrowing window of opportunity for the safe initiation of reservoir filling. Consequently, BC Hydro has made the decision to adhere to the existing project timeline.
Work on the Site C project will continue to advance on schedule and be ready for filling to begin next fall. The project remains on track to achieve first power in 2024, have all six generating units in service by 2025, and be completed within the approved budget.
Commencing construction in July 2015, the Site C project has made substantial progress, and is now over 80% complete. Key project components, including the earthfill dam, Highway 29 realignment, two 500kV, 75km transmission lines, and a new substation, have already been successfully executed.
SMEC continues involvement in Baleh
Sarawak Energy Berhad’s Baleh Hydroelectric Project (HEP), a cornerstone of the Sarawak Corridor of Renewable Energy (SCORE) initiative, remains on course for success, with SMEC playing a key role in its realization. Located in Sarawak, East Malaysia, this ambitious project is poised to transform the region’s energy landscape, offering economic growth and job opportunities.
With a history dating back to 2015, SMEC has had significant involvement in the Baleh HEP, contributing to the critical phases, including tender design and evaluation, providing a sturdy foundation for the project’s progress.
The Baleh HEP’s infrastructure includes a 188m-high concrete-faced rockfill dam, a surface power plant featuring five 257MW Francis turbines, a radial gated spillway, diversion tunnels, pressure steel pipes, an intake structure, and a double circuit 500kV power transmission line connecting the electricity to Sarawak Energy Berhad’s grid. Complementing these features are elements like a low-level outlet, jetty, bridges, and access roads linking Kapit town to the project site.
SMEC’s contributions have gone beyond design, as they now oversee the construction phase, reviewing the contractor’s design calculations and drawings. This scrutiny encompasses key project elements, including the two 12-meter diameter diversion tunnels, the towering concrete-faced rockfill dam, and a radial gated spillway capable of handling 16,500m3/sec.
The Baleh HEP is projected to reach completion in 2028 and is anticipated to generate 1285MW of renewable energy, marking a significant milestone in Sarawak’s energy journey.
Hydropower in Vietnam
A new hydropower project in Vietnam is now onstream thanks to three Volvo excavators that delivered the performance and reliability needed to meet the demanding construction timetable. Local dealer TCMP provided 24/7 support to keep the project on track, while Volvo’s advanced CareTrack program provided the insights and analytics to keep work optimised.
Three hardworking and versatile EC210D excavators from Volvo Construction Equipment (Volvo CE) played a central role in delivering the Nam Cum Hydropower Project in Lai Chau Province in Northwest Vietnam. The power plant entered operation earlier this year after a three-year construction period managed by contractor North-West No.1 Heavy Construction Company, which purchased the Volvo excavators from local dealer TCMP.
“This was a really important project for the local community because of long-running power outages in the area. The work was demanding, and the customer was looking for machines that could handle 14 to 16 hours a day, backed up with fast response from a local partner to keep uptime to a maximum. That’s why we recommended the EC210D models, and then installed a local service team to provide 24/7 support,” said Nguyen Huu Truong, Sales Manager TCMP.
Harnessing power from the local water supply meant the contractor was also seeking machines that would minimise any impact on the surrounding environment, again making the EC210D an ideal choice. Not only did the machines deliver lower emissions output, but fuel use was also reduced compared to alternatives, meaning greater efficiencies and cost savings.
For optimum uptime, North-West No.1 Heavy Construction Company also took advantage of Volvo CE’s CareTrack platform which is offered with all its machines. CareTrack is a telematics system that allows users to proactively manage service and maintenance to maximize uptime. It also offers the ability to monitor machine use to optimize operations, reduce fuel costs, and improve operator performance.
As part of its National Energy Masterplan, Vietnam is diversifying its energy mix and targeting 15%-20% from renewables by 2030, and 80%-85% from renewables by 2050. Part of this plan includes a network of small and medium-sized hydropower plants as these are faster and simpler to install than alternatives such as solar or wind, and they can also contribute to peak capacity requirements. The Volvo CE EC210D excavators played a critical role in ensuring that the project process stayed ahead of schedule, helping to provide precious energy to the country.
Captions
First Blast At TBM Access Adit
A transfer tunnel milestone was the first blast making way for excavation works at the tunnel boring machine access adit in September 2023 at LHWP.
Upstream Cofferdam
The LHWP upstream cofferdam is expected to be completed by January 2024.
Senqu Bridge Construction and SenquBridgeConstructionPier1Slide
Construction of the Senqu bridge as part of the LHWP commenced in late 2022 and is expected to be completed in 2026
Senqu River water flowing through diversion tunnels
The Senqu river was diverted into and through the diversion tunnels ahead of the construction of the cofferdam upstream of the Polihali Dam wall in early August as part of the LHWP
NorthernAccessRoad_AsphaltPaving
Asphalt paving of the northern access road as part of the construction work for Lesotho Highlands Water project
Polihali Lodge and Polihali Village
Construction of the Polihali village is complete as is that of the operations centre, while the commercial centre and upgrades to Katse Lodge are underway at LHWP
Snowy 2.0 spiral
Snowy 2.0 spiral cases and other components at the Voith Hydro Shanghai factory
Snowy 2.0 Tantangara
Snowy 2.0’s Tantangara adit with the TBM conveyor belt stacker in the foreground and the western boundary behind the adit face
Volvo 1 and Volvo 2
Three EC210D excavators from Volvo Construction Equipment played a central role in delivering the Nam Cum Hydropower Project in Lai Chau Province in Northwest Vietnam
This article first appeared in International Water Power magazine.
