Tool calculates solar power savings
Whether you can save money with a solar power system depends on when you use power, where your house is and even the direction your roof faces, a researcher says.
Kiti Suomalainen, a research fellow at the University of Auckland’s business school, has developed an online tool to help Auckland households and businesses work out whether it makes financial sense to install solar panels.
The free calculator factors in the unique ‘‘solar rooftop potential’’ of half a million Auckland buildings down to 1 square metre.
This potential depends on such things as the roof’s slope and aspect, and shade from surrounding buildings and trees.
‘‘Solar generation is rapidly rising in New Zealand, with homes leading the trend. We wanted to offer an educational tool that is impartial and realistic to help people work out if solar is economic for their households or workplaces,’’ Suomalainen said.
New Zealand’s total installed solar capacity rose fivefold over the three years to 2017, and the Auckland Council has a goal of 970MW installed capacity of solar photovoltaics by 2040.
The calculator allows users to zoom in on their rooftop for a colour-coded view of its solar energy potential, which highlights the best spots to place panels.
They can also enter the size and quality of solar panel they prefer, how much power they would use and how much they would sell to the grid, and several other values.
Suomalainen said the way households used power would be a key factor in whether it made sense to install solar power.
‘‘If you’re at home all day you will probably use more power than someone who is at work or school most of the day. For every kilowatt-hour of solar power you use, you save about 27 cents. The buy-back rate at the moment is around 8 cents – so the more you use, the greater the overall value of your solar generation.’’
She said the tool was a conservative estimate.