It takes a lot of energy to deliver safe water, remove and treat sewage, and manage drainage and waterways across Melbourne. We’re always looking for opportunities to improve our energy efficiency and generate more renewable energy from our operations.
In 2015/16, Melbourne Water’s water supply network has generated more electricity than it used for the third year in a row. We generate most of this energy from hydro-electricity and biogas – a by-product of sewage treatment.
We have nine hydro-electricity plants at our reservoirs which generate up to 61,000 megawatt hours of electricity each year. . The plants generate energy from the flow and pressure of moving water, and feed it back into the electricity grid.
By using hydro-electricity, we can offset the equivalent of 69,000 tonnes of carbon dioxide emissions each year – equivalent to the emissions of over 8,000 households.
As part of our commitment to renewable energy initiatives, we are constructing five new mini hydro-electricity plants during the 2016/17 financial year.
These new plants will be constructed in Melbourne’s south east - Wantirna, Boronia, Dandenong and Mount Waverley Reservoirs and at the Cardinia Creek environmental release. In addition we have another 8 hydro-electric power stations in planning.
To find out more about these upcoming works, see our mini-hydro electricity plant project.
Biogas – converting sewage into energy
Biogas fired power plant at the Western Treatment Plant
Sewage is much more than a waste product. We can generate electricity by combusting biogas, which is captured under covers that are placed over our sewage treatment lagoons.
The Western Treatment Plant uses biogas to meet nearly all of its electricity needs. It generates 71,500 megawatt hours of renewable electricity every year, which prevents 87,000 tonnes of carbon dioxide from being emitted through the burning of fossil fuels. Sometimes the plant produces more energy than it uses, so this excess electricity is exported to the electricity grid to offset usage at our other sites.
The Eastern Treatment Plant uses biogas to power a substantial part of its electricity usage, and most of its heating and cooling. The plant’s seven generators can run solely on biogas or be supplemented by natural gas as needed.
Read more about renewable energy at our sewage treatment plants:
Energy use is one of our biggest sources of greenhouse gas emissions. Finding opportunities to improve energy efficiency will reduce our energy consumption.
We’ve already made many improvements, with:
- over 95% of our electricity use audited
- plant energy baselines established via improved monitoring
- over 100 energy efficiency opportunities identified
- annual energy savings of over $1.4 million identified, with more than $700,000 in total potential savings implemented.
In 2013 we developed an Energy Productivity Plan, which has a number of focus areas to improve energy efficiency. These include:
- resourcing, governance and alternate funding sources
- Energy Efficiency Opportunities program participation
- energy performance auditing, monitoring, measuring and analysis
- benchmarking energy performance internally and externally against others
- optimising processes and assets via mathematical modelling
- efficient design of processes and assets
- renewable energy generation
- training, awareness and communications.
Energy Efficiency Opportunities program
The Australian Government’s Energy Efficiency Opportunities program encourages large energy-using businesses to improve their energy efficiency.
We are required to participate in the program as we use more than 0.5 petajoules of energy each year – equal to 139 gigawatt hours, 21,500 tonnes of black coal or 15 million litres of petrol. This requires us to identify, evaluate and publicly report on cost-effective energy saving opportunities.