Client: Australian Gas Light (AGL Southern Hydro)
The 140 MW Bogong power scheme completes a cascade of four hydro-electric power stations in the Kiewa Valley in the Australian state of Victoria.
The scheme is built in a popular Alpine National Park so the project concepts were developed on strategies of low environmental and recreational impact - a prime factor in gaining the support of all stakeholders and progressing project consenting and approvals.
The scheme develops a head of 420 m via a 5 m diameter, 6,500 m long machine bored pressure tunnel conveying water from the tailrace of the existing McKay Creek power station to two 70 MW Francis turbine-generators in a new subsurface power station on the shores of Lake Guy near Bogong village. The power station output connects to the Mt Beauty Terminal Sub-station via unitised indoor generator step-up transformers, indoor switchgear and a 250 m long single-circuit 220 kV underground cable to the existing transmission line.
SKM initially examined the project pre-feasibility in 2001, including preliminary geotechnical appraisals, the development of conceptual tunnel designs, preliminary power station design, energy modelling and cost estimates. The preliminary tunnel design included an evaluation of both mechanised drill and blast construction and tunnel boring machine methods.
SKM continued to develop the scheme concepts with the client to the stage of the main construction contracts for the civil works and the generating sets being signed in September 2006. As part of a consultant team, SKM prepared the concept design and technical specifications for the EPC design-build contracts, including the headpond, headrace tunnel, steel liner and penstocks, powerhouse and plant, tailrace and transmission system connection. Technical assistance extended through the construction period, with commissioning scheduled for the end of 2009.