The ACT's generous solar-rebate scheme that closed to new participants almost a decade ago still accounts for more than 98 per cent of government subsidies.
New figures shown that across the ACT government's three solar rebate schemes, used by almost 11,000 Canberra households, the total running cost to operate them comes in at $49.6 million.
The largest of the three schemes - the feed-in tariff scheme - has more than 10,000 households involved, at an estimated cost of $48.7 million.
That scheme was closed to new customers in 2011 after launching in 2009, such was the demand. Tariffs ranged between 30c and 50c per kilowatt hour. The scheme is run across three levels: small, medium and large scale feed-in tariffs.
The figures come as an Independent Competition and Regulatory Commission report found the cost of the tariff scheme for representative ACT homes for the 2017-18 financial year was $50 for small and medium feed-in tariffs and $111 for large-scale tariffs.
A spokeswoman for the Environment, Planning and Sustainable Development Directorate said a second scheme for low-income households, where subsidies of 50 per cent up to $2500 for solar panel installation apply, had more than 400 homes sign up since the program was launched in December 2017.
In the 2017-18 financial year, the scheme cost the government $657,000.
The most recent scheme for businesses and community groups launched in February and had a price tag of $293,000 last financial year.
That cost allows for 40 rebates as part of a 12-month trial. Two businesses are already signed up and a further eight are on the way.
"Over 60 businesses and community organisations are receiving tailored advice and support," the directorate spokeswoman said.
Businesses and community groups are subsidised up to $5000 under the scheme. The average rebate is estimated at $4840.
Under the low-income household scheme, the average amount of electricity generated per house was 5850 kilowatt hours over one year.
"Actual household generation will depend on the system size and other factors such as orientation and shading, with over 80 per cent of households estimated to generate over 5000 kilowatt hours per year," the directorate spokeswoman said.
The figures also showed a combined 47,000 megawatt hours of electricity was generated by Canberra homes on the small and medium feed-in tariff scheme.
For households under the small scheme, the average amount of electricity generated per year was 3.36 megawatt hours, while for medium scheme households it was 232 megawatt hours.
The directorate spokeswoman said a review of the feed-in tariff scheme was under way.
"The minister must review the operation of Electricity Feed-in Act 2008, which legislates the small and medium feed-in tariff scheme every five years," the spokeswoman said.
"The last review was completed in August 2015 and another review is currently under way.
"There is no legislative requirement to review the large scale feed-in tariff scheme."