What is green energy?
Green energy is produced from clean, renewable sources that don't harm the environment. It's more expensive than energy from fossil fuel alternatives, but fossil fuel energy doesn't take into account such hidden costs as resource depletion, pollution and the impact on climate change. While you don't pay for these now, nature does — and future generations will.
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How is ActewAGL committed to green energy?
ActewAGL has a number of programs to help people use more renewable energy. These include our solar and mini-hydro initiatives.
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How can I purchase green energy?
You can help us purchase green energy with our Greenchoice programs for home and business. Through Greenchoice ActewAGL buys green energy from sources like mini-hydro, wind energy and biomass.
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Does ActewAGL have a mini-hydro?
Yes. Most hydro–electric developments require the building of dams and lakes. This affects the flora and fauna in the valley, and the changes to the downstream flow can be environmentally damaging.
ActewAGL's mini-hydro, located at Mt Stromlo Water Treatment Plant, uses an existing water supply — in this case, the gravity main from Bendora Dam to Mount Stromlo. Corin and Bendora dams were already in existence to supply Canberra with clean water, so there are no additional environmental impacts involved. The clean, green energy from the Stromlo mini-hydro will save over 3,600 tonnes of greenhouse gas emissions each year, by supplying electricity that would otherwise come from fossil–fuel power stations.
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How does the mini-hydro work?
The mini-hydro is designed to operate whenever the flow in the gravity main is within the turbine operating range. This is dependent on water demand from the Stromlo storage tank, which feeds our suburban reservoirs. Most of the time, the flow is sufficient.
The generator starts to rotate when the bypass valve is closed and the turbine inlet valve opened, diverting water through the turbine. Water flows into the turbine spiral case surrounding the runner chamber. The spiral shape ensures that the water enters the chamber evenly.
Wicket gates around the runner chamber are used to adjust the flow. The flow inside the runner chamber spins the runner, which is connected to the generator. To start generating electricity, the wicket gates are slowly opened, increasing the flow until the generator is spinning at 750 revolutions per minute. At this speed the circuit breaker — a very big switch inside the electrical cubicle — can be closed, connecting the Stromlo mini-hydro to the electrical network.
The wicket gates automatically adjust whenever more or less water is required from the gravity main, in turn affecting the amount of energy generated — so the more water we use, the more energy the mini-hydro produces.
The electricity is fed into the network via the substation, where a transformer converts the power from 415 volts to 11,000 volts for efficient transmission. A programmable logic controller inside the control cubicle automatically controls operations.
Auxiliary equipment in the power station includes:
- a backup battery and charger, which provide power for essential equipment so that the mini-hydro can be safely shut down in the event of a power failure
- a hydraulic power pack, which provides high pressure oil to operate the valves and gates
- an oil containment system that detects, separates and prevents the release of any spilled or leaked oils
- surge relief valves, to prevent the pipeline from being over-pressurised in the unlikely circumstance that a malfunction causes the flow to stop too quickly.
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How does ActewAGL support solar?
Canberra households can now use renewable energy to help reduce the emission of greenhouse gases, usually released through the conventional electricity production methods.
Australia is a country that mostly enjoys abundant sunlight year round. By using solar or photovoltaic (PV) cells we can capture this sunlight and turn it into solar energy without emitting any harmful substances into the environment. This is a practical way to reduce our dependence on traditional electricity sources such as coal, oil and gas, which can be harmful.
ActewAGL is working to encourage the use of renewable energy sources, offering support and advice to those interested in installing solar generation systems to their homes.
Through the ActewAGL Solar scheme you can install a solar system to your home, utilising the non-polluting energy that it generates and at the same time reduce the amount of electricity you draw from the grid for your household needs.
For more information call us on 13 14 93.
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How can I learn more about ActewAGL's Greenchoice program?
Environmental issues need practical solutions. That's why we developed the Greenchoice program — so everyone, whether or not they're our customer, can help the environment by supporting renewable-energy generation.
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Want to find out more about green energy?
Visit these websites to learn more about renewable energy and other related environmental issues:
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