Posted 10 May 2018
Hydroelectricity has been a well-circulated buzzword for the past decade, and one company on top of the trend is Melbourne Water, which installed 12 new hydroelectricity plants over the past 10 years.
Senior Project Manager Ian Royston said at Ozwater’18 that Melbourne Water had used hydroelectricity to harness the ongoing energy consumption issues faced by utility providers, and not only has it been a simple solution to the problem, but it’s one that is relatively quick to install.
“In three of the last five years, Melbourne Water’s water supply network generated more electricity than it used,” Royston said.
“This is due to the hydroelectricity generation up to 69,500 MWh of electricity each year or enough power for more than 14,100 homes.”
The move into hydroelectricity is aligned with Melbourne Water’s vision to “enhance life and liveability”, with the aim to create a sustainable region by reducing emissions and the innovative recovery of resources.
“Our commitment to renewable energy is a key component of our commitment to sustainability. By harnessing excessive hydraulic pressure with our hydro power plants, we are ‘utilising waste’,” he said.
In 2004, Melbourne Water reviewed its water supply network and identified sites that had potential for hydroelectric generation (mini-hydros).
Stage One sites (seven mini-hydros) were constructed between 2007 and 2011 and Stage Two sites saw the build of five mini-hydros between 2015 and 2017.
The process required an innovative approach, according to Royston, but said risks were eliminated through power station design, special valves and surge mitigation devices.
“All mini-hydros are fully remote controlled, adjustable offsite and seamlessly integrated into Melbourne Water’s supply system to ensure uninterrupted operation,” Royston said.
Each plant also includes a bypass system for easy changeover to the pressure-reducing valve network, if required.
Generation from the plants and associated revenue from electricity generation and renewable energy certificates now helps reduce Melbourne Water’s operating costs, delivering greater customer affordability.
The company is now working on a feasibility study for more mini-hydro plants using the learnings of its previous successes to fine-tune the process and deliverables.
Another company that has recently adopted an innovative energy management strategy is GHD.
The company’s Process Engineer Nikhil Khurana tabled to the Ozwater’18 conference the ways in which floating solar arrays were booming worldwide as a means of powering off-the-grid water treatment plants of the future.
According to Khurana, floating solar arrays consist of four components:
1. floating pontoon;
2. mooring system;
3. electricity-generating photovoltaic modules; and
4. cables and connectors.
“A power cost/benefit analysis shows floating solar is ripe for wide application in Australia, potentially turning water treatment plants into net energy producers,” Khurana said.
“Installation of floating solar arrays is now booming worldwide, including very recent mega-projects for large-scale energy production at Cirata Reservoir in West Java, Indonesia, and the world’s second largest project at Three Gorges Mine in China.”
So, what about us?
Western Water has conducted a study to assess the feasibility of a floating solar array on Lancefield Basin in Victoria, but as yet, there is no existing standard to work on for the design, material and craftsmanship of the floating solar arrays save for Australian Standard AS4020, Testing of products for use in contact with drinking water.
According to Khurana, the case for water authorities to consider floating solar is self-evident for water treatment facilities where there is no available land for a conventional ground-mounted PV system, or where the “available land is unsuitable due to planning, heritage or other constraints”.
“Floating solar is now a relatively established and proven technology, with potential to offer water authorities significant cost savings and reduction in energy consumption and should be considered in potable water supply systems,” he said.
10 May marks the last of the three Ozwater’18 conference days in Brisbane, at the Brisbane Convention and Exhibition Centre.