Study shines light on how to pay off solar in 7 years

Residential solar systems in Queensland can pay for themselves within seven years if households are smart about their electricity usage, research by Queensland University of Technology has found.

As part of an economic study into residential grid-connected photovoltaic systems, engineering expert Dr Kame Khouzam said solar power had the potential to make money in the long-term.

"Government incentives have been enough to bring solar technology within the means of many households," said Dr Khouzam, from QUT's Faculty of Built Environment and Engineering.

"Economic analysis shows that under the right conditions solar systems provide significant savings with payback time reasonably as quick as seven years."

But he said the key to achieving a return was adopting smart energy-use practices.

"There are things that you can do that will give you the best financial benefit from installing solar systems," Dr Khouzam said. "The most important thing to remember when using a solar system is that if you are able to export electricity you are able to make money."

Dr Khouzam said the best way to achieve this was to shift your load (or energy use) to non-daylight hours when the system was not generating electricity.

He said electricity companies paid a premium fee for power fed into the electricity grid which presented an opportunity for households to recover expenses at a fast rate making solar a more attractive investment.

"Utility companies charge about 18 cents per kilowatt-hour for energy used, however they purchase excess household energy generated at a rate of 44 cents in Queensland, with some electricity companies even paying higher," he said.

"So reducing energy consumption during the day and shifting the load to after the generation time which is between 6am and 6pm, means you will make the most from your solar. All that is needed is a change in behaviour.

"For example during the day don't iron, don't cook unnecessarily, and don't wash. All these things can be done at night, so this way you can export as much electricity as you can."

Dr Khouzam said installing a minimum of a 1.5kW solar system was essential to making the most of securing the premium electricity rate.

"A 1.5kW system generates excess energy to sell electricity back into the grid. A 1kW system will save on your bill but it may not generate a reasonable return on your money."

He said installing a solar hot water system would also go a long way to reducing energy use, which was crucial given household electricity consumption had nearly doubled in the last 14 years.

"Solar hot water will save about 25 to 30 per cent on your electricity bill."

Media contact - Niki Widdowson, QUT media officer 3138 1841 or n.widdowson@qut.edu.au
** A high-res photo available for media use