Enhancing the safety of dams and securing reliable water supplies are top priorities of the Queensland Government’s 2019-20 Natural Resources, Mines and Energy budget. With electricity the biggest cost of drinking water production, bulk water provider Seqwater is harnessing the power of its dams to generate renewable energy and reduce operational expenses.
Seqwater is the Queensland Government statutory authority responsible for providing safe, affordable and reliable bulk drinking water supply for more than 3.2 million people across South East Queensland (SEQ).
It is one of Australia’s largest water businesses with the most geographically spread and diverse asset base of any capital city water authority. Seqwater operations extend from the New South Wales border to the base of the Toowoomba ranges and north to Gympie.
Seqwater manages water supply assets including the SEQ Water Grid and the natural catchments that make up the region’s major water supply sources. Seqwater owns and operates 26 dams, 51 weirs, 37 water treatment plants, one desalination plant and 646km of supply pipelines across SEQ.
With electricity the highest single cost to the production of drinking water, identifying ways to reduce energy expenses is critical to managing operational costs and Seqwater’s overall environmental footprint.
To make sure Seqwater sustainably meets the region’s long-term water supply demands, the organisation produced an Energy Strategy in April 2018 which focused on four outcome areas: sustainable energy culture, energy efficiency, energy generation and optimised commercial energy arrangements.
As part of the Energy Strategy, Seqwater completed the refurbishment of the Somerset Dam Hydroelectric Plant in May 2019. The plant is a key asset to the strategy which originally commenced operation when the dam was built in 1954, but had been offline for more than seven years after it was inundated by flood waters in January 2011.
Optimising energy consumption to reduce water supply costs
Hydro plants capture the energy of falling water to generate electricity. A turbine converts the kinetic energy of falling water into mechanical energy, and a generator then converts the mechanical energy from the turbine into electrical energy.
A comprehensive study of the Somerset Dam Hydroelectric Plant was undertaken post-flood which identified a rebuild of the plant as the best option for its future.
The $12 million refurbishment has restored the plant to virtually as-new condition and included a redesign of the original turbine to increase capacity from 3.2 to 4.3 megawatts. Refurbishment works have increased output and efficiency, while a new generator and control system have allowed for remote operation.
The plant is able to operate up to 24 hours a day and has increased Seqwater’s capacity to produce renewable energy for the state’s electricity grid as part of regular dam operation.
The water used to generate green energy is also used to provide drinking water for the region. Somerset is unique in the way water releases can be retained for water supply as flows leave Somerset Dam and are captured downstream at Wivenhoe Dam which provides up to 50 per cent of SEQ’s water supply.
Seqwater estimates up to 30-40 per cent of its annual energy consumption could be provided by renewable energy over the next decade. Seqwater’s energy initiatives will contribute to the Powering Queensland Plan initiative of the Queensland Government and achieving its target of 50 per cent renewable energy by 2030.
Seqwater Chief Executive Officer, Neil Brennan, said there were significant opportunities available to offset electricity costs by increasing Seqwater’s renewable energy generation and optimising energy consumption.
“In turn this can help reduce the cost of water treatment and the supply of drinking water to businesses and households,’’ Mr Brennan said.
“Seqwater now produces hydro energy at Wivenhoe, Somerset and the Landers Shute Water Treatment Plant, while the possibility of more hydropower being produced by state dams is being examined.”
More hydropower prospects on the horizon
Seqwater is currently undertaking a pre-feasibility study to understand the technical and economic feasibility of hydropower generation across its other dams. The study will examine sites for traditional hydroelectric plants at existing dams as well as the pre-feasibility of larger pumped hydro storage.
The pre-feasibility study is expected to be completed by the end of 2019. Mr Brennan said Seqwater was continuously looking for opportunities to improve energy usage which was a challenge shared across the industry.
“Seqwater will continue to collaborate with government and industry peers to align and deliver improved energy outcomes while continuing to supply safe, affordable and reliable drinking water to the community,” he said.
To assist with the tracking of its strategic energy objectives, Seqwater is developing an Energy Management System and Plan based on ISO 50001 – an International Standard that enables organisations to establish systems and processes necessary to continually improve energy performance, including energy efficiency, energy use and energy consumption. Seqwater is the first organisation in Queensland to align its energy management practices to ISO 50001 and the second water body in Australia to exercise such practice.