When a solar PV system is built, it produces electricity that displaces electricity from conventional generation (such as coal-fired power plants).
There are two schemes that provide financial support to solar PV. One is the large-scale renewable energy target that the Coalition government managed to reduce from 41,000 GWh to 33,000 GWh. Under this scheme each retailer has to buy enough renewable electricity to meet their share of the target.
However, if the solar PV system is less than 100kW then it goes under a different scheme, called the small-scall renewable energy scheme (SRES). All the renewable electricity that is produced under the SRES has to be bought by the electricity retailers, no matter what their obligations are under the large-scale target.
This means that all the electricity created by COREM projects (as long as they are under 100kW) are additional to the 33,000 GWh target, and so reduce emissions below what they otherwise would have been.
More information on the renewable energy targets can be found here.
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