In 2014 the Renewable Energy Target achieved the objective of ensuring ecologically sustainable renewable energy sources:
- 36.8 million renewable energy certificates were validated–these must meet several criteria including ecologically sustainable sources, and
- accredited power stations used 12 different types of renewable energy sources including ecologically sustainable solar energy, wind, hydro, biomass (such as wood waste, agricultural waste and sugar cane waste, known as bagasse) and biogas (landfill gas, sewage gas and biomass-based components of sewage).
Commonwealth, state and territory environmental regulation provides a framework for ensuring the Renewable Energy Target promotes the use of ecologically sustainable renewable energy sources.14
For an energy source to be eligible for renewable energy certificates it must meet several criteria, including that it is 'ecologically sustainable'.
Section 17 of the Renewable Energy (Electricity) Act 2000 lists 19 renewable energy sources considered to be ecologically sustainable, and therefore eligible for the creation of renewable energy certificates.
The main types are:
- biomass sources that use vegetable and animal-derived organic material such as wood waste, agricultural waste, food processing waste or bagasse (a residue from sugar cane milling) to fuel engines or biomass boilers, excluding fossilised biomass
- landfill gas sources that harness methane emitted from landfills (mainly solid wastes and industrial wastes) to fuel engines or steam turbines
- solar power sources that use sunlight to heat air, water or other fluids to drive turbines or convert solar radiation into electricity through photovoltaic cells
- wind sources that harness wind currents to drive turbines, and
- hydroelectric sources that harness kinetic energy from reservoirs, rivers, streams or waterfalls to drive turbines.
In addition, the Renewable Energy (Electricity) Regulations 2001 set out specific eligibility requirements for other energy sources, such as waste coal mine gas, which are considered ecologically sustainable under certain conditions.