Mayor Naheed Nenshi says the city will expand solar projects, if the payback makes sense.

Two new solar power initiatives launched by the city and its utility will help reduce carbon emissions, but it will take a long time before the capital costs are finally recovered through energy savings.

On Thursday, the city unveiled 150 evacuated tube-type solar panels on the roof of the Southland Leisure Centre, which will help heat the water in the building.

And Enmax Corp. is preparing a new program that will see the cityowned utility install solar panels on more than 8,000 homes in Alberta over five years, with owners paying a monthly fee.

The projects fall well into the green philosophy of the city and utility and are being greeted with enthusiasm by the mayor.

"If we don't do the innovation, no one will ever make the changes," Naheed Nenshi said Thursday.

Still, there are limitations.

The Enmax solar power plan, for instance, will appeal to the environmentally conscious, but not to those who want to save soon on their electrical bills.

"Through our program, we're trying to make it as affordable as we can right now," said Rob Harris, director of smart grid technologies with Enmax.

"Still, it has got a very long payback associated with it. You're going to be out more money than you're paying for the first part until it's paid off, that's for sure."

He said the average home with a solar panel will produce $15 worth of electricity a month, but the homeowner will have to pay nearly $60 a month over 15 years to lease the technology from the utility.

With a $1,500 down payment, that rate drops to $40, and $3,500 will bring it to $17 a month.

The solar panels will generate roughly 20 per cent of the energy needed by an average home. But if there are times when more power is being generated than consumed, it will go back into the grid, Harris said, and the homeowner will get a credit for it.

It will also take a long time -two decades if natural gas prices stay low -for the $640,000 Southland Leisure Centre project to pay back its initial costs, according to a city engineer. The three levels of government are helping to pay for the project.

The panels themselves will heat 15 and 20 per cent of the water in the building, with natural gas boilers continuing to produce the bulk of the energy.

But this will still reduce greenhouse gas emissions by roughly 90 tonnes of carbon dioxide a year, according to Muhammad Abbas, the city's senior energy engineer. The city says that's the equivalent of taking 15.5 cars off the road.

Twenty years (or less, if natural gas prices rise) until full payback is reasonable and sustainable, he said, given the panels are due to last longer than two decades.

"The bigger benefit is the environmental benefit, which you do not get from other projects directly," Abbas said.

Nenshi said this is an experiment and he expects the price of solar arrays to drop in the future.

One of the things the project will look at is how quickly the solar technology will pay back its initial costs.

"As we can improve the process, make it better here, we'll have the ability to expand this to other facilities," Nenshi said. "But we'll only do that if the payback makes sense."