SA Water aims for $0 net electricity costs by 2020

SA Water plans to reduce its demand on the grid and increase its renewable energy generation and storage capacity, in an ambitious plan to achieve zero net electricity costs within the next three years.

SA Water Chief Executive Roch Cheroux said 2020 target will be progressed through a range of complementary initiatives that will see mature technologies embraced for immediate impact. “A range of innovative emerging technologies will also be tested in partnership with local and international providers,” Cheroux said.

The utility will initially invest $10 million on up to 6 MW of solar photovoltaic panels to be installed across some of its large metropolitan sites, with the first installations expected to begin in the first half of next year.

A $500,000 pilot 100 kW solar photovoltaic and 50 kWh battery storage system is also currently being installed at SA Water’s Crystal Brook workshop, chosen for the size and orientation of its roof, and potential for high-quality solar irradiance.

The other pilot projects being funded by technology partners that will move into testing phases in 2018 include:

• Floating solar photovoltaic arrays on reservoirs — The arrays will be trialled on SA Water’s Happy Valley Reservoir, with the installation of a 100 kW pilot system. As well as producing electricity to power the nearby Happy Valley Water Treatment Plant, the floating solar panels may also help reduce evaporation and the incidence of algal blooms. French company Akuo Energy will be provided access to Happy Valley Reservoir to implement the test program, which will initially use technology from Ciel et Terre. Should the pilot program be a success, Akuo Energy will investigate options to have floats manufactured in South Australia.
• Silicon thermal storage to complement existing biogas generation — SA Water will trial new silicon thermal energy storage technology at its Glenelg Wastewater Treatment Plant. Glenelg Wastewater Treatment Plant is already 80% self-sufficient, burning the natural biogas created through sewage treatment processes to generate electricity through reciprocating gas engines that is then used in the facility. Adelaide-based company 1414 Degrees recently received a $1.6 million grant from the State Government’s Renewable Technology Fund to progress the pilot program.The technology will store latent heat in molten silicon at 1414 degrees Celsius to form a 10 MWh thermal storage device. This will release approximately 250 kW for six hours as well as heat which is returned to the plant’s digesters.
• Flywheel mechanical battery storage systems — The 128 kW flywheel energy storage system will be trialled to capture energy generated by solar arrays at Hope Valley Reservoir. The flywheel technology forms a mechanical battery by converting and storing electrical energy in a rotating mass, and is fast to charge, has unlimited cycling capability and can discharge for up to four hours. In comparison to chemical batteries, flywheels may also have other benefits such as low energy losses, zero capacity degradation, no chemical reactions or fire hazards, and no end-of-life disposal challenges. Should the trial prove successful, South Australian, Aboriginal-owned company Greenfields Energy will investigate options to manufacture them within the state.

Further capital investment will be guided by the outcomes of the pilot projects and be considered on a case-by-case basis to ensure the best return on investment and outcome for SA Water’s customers.

“We’ve already been reducing our electricity costs by more than $3 million a year since 2013, so we know that with a concerted push, our goal is ambitious, but within reach,” Cheroux said.

SA Water’s existing and successful energy management portfolio includes biogas power generation (a by-product of the sewage treatment process) and hydroelectric systems (harnessing the force of moving water within the network to generate electricity).

Through renewable energy generation, the utility’s Bolivar and Glenelg Wastewater Treatment Plants are now 92 and 80% energy self-sufficient respectively.

Hydroelectric systems at Hope Valley, Seacliff Park and the Adelaide Desalination Plant (ADP) supply approximately 7000 MWh per year, equating to 14% of the total electricity produced by SA Water.

SA Water serves 1.6 million people across South Australia and is one of the largest electricity users in the state, with energy-intensive pumping and treatment operations consuming 220 GWh in 2016/17 at a cost of around $55 million.

Image caption: Happy Valley Reservoir and Water Treatment Plant.