2022 – Prefeasibility Study of Hydropower Potential at Seqwater Dams

Peyman Andaroodi – Senior Dam Planning Engineer, Seqwater, Jeremy Kent-Johnston – Technical Principal – Dams & Hydropower, SMEC, Dr Nayim Kabir – Team Lead OT Architecture and Energy, Seqwater, Anna West – Technical Principal – Water Infrastructure, SMEC

With the retirement of coal-fired power stations being expedited by the emergence of economical renewable energy sources, energy storage is becoming critical, with Pumped Hydro Energy Storage (PHES) a key piece of the puzzle. A prefeasibility study was undertaken for Seqwater with the objective of determining whether pumped storage as well as conventional hydropower schemes would be viable at existing dam sites across South East Queensland.

The study initially undertook a background review, gathering, collating and reviewing existing reports, documents, drawings and other data for each of the sites to be assessed. Design criteria were determined to allow sites to be screened, with a shortlist of fourteen PHES options and nine conventional hydropower options taken into further options development and basic design for Seqwater dams.

Options development was undertaken on the shortlisted sites and basic designs prepared including general layouts and longitudinal profiles. In some cases, multiple options and designs were prepared for the same dam site. Designs considered options for upper and lower storages, site topography, penstock alignment, underground and surface options, connection to existing transmission infrastructure, road access, environmental constraints, geology and geotechnical features. Following options development, it was recommended that all shortlisted sites be taken into the economic analysis phase to ensure any potentially viable sites were identified.

Economic analysis was based on incremental costs in dollar ($) per kilowatt (kW) to rank options for PHES projects considered suitable as the energy grid is seeking the most cost-effective way to add energy and capacity. For conventional hydropower, financial modelling was undertaken with a discounted cashflow method used to determine an indication of project viability.

In terms of PHES, the options development and economic analysis recommended that development be prioritised for five options with incremental costs under $2000 / kW. These options were identified for Borumba, Somerset, Maroon and Hinze Dams. If resources allowed, Options at Little Nerang and Wappa-Cooloolabin Dams were also recommended to be studied.

For conventional hydropower, a scheme at Cooloolabin Dam was the only option deemed as economically viable; however, schemes at Borumba, Hinze and Moogerah Dams had marginal options which were recommended to be kept on the table for future development.

Additional opportunities to increase the viability of proposed hydropower schemes were also identified as part of the economic assessment by considering individual schemes in conjunction with other Seqwater programs of work such as dam safety, flood mitigation, water security and water quality upgrades.

Buy this resource