Solar energy is a growing business in Austin, from smaller solar power panels at people's homes to the large commercial projects.

Austin Energy is hoping to build on that growth. The city tour of solar energy was still powerful enough to draw in a crowd on an overcast Monday.

"I think it's interesting to find out about the trend and find out where it's going," said Elizabeth Chapman.

It's going far in Austin.

Gary Vliet was one of Austin Energy's first test customers. The city put up his solar electric panels in 1999, but he installed his solar water heater up in the 1970s. Solar panels produce energy about 20 percent of the time. It’s considered to be only a marginally-effective source of energy. But Vliet says we need to think long-term.

“I guess you could ask, if our energy, if our cost of gas and oil is still pretty cheap, why do we use solar? Well, we're running out of those energy sources,” says Vliet.

The City of Austin does offer rebates. Between tax credits and rebates, you can save between $2,250 and $3,000 on the solar water heater. For solar energy panels, Austin Energy says a practical home system costs between $6000 and $10,000. The average rebate for that system is between 60 percent and 70 percent.

In Austin right now, there are 500 homes, 20 schools, 36 public buildings and 26 businesses are using solar energy.

"Right now we're selling energy back to the grid because most of our guests are away from the hotels," said Natalie Rose Marquis, general manager of Habitat Suites.

At Habitat Suites Hotel in North Austin, its solar system has 108 panels.

"On a day like today - it's more than 20 percent of our total electric consumption for our entire hotel property - so we're talking about a lot of green energy that we didn't have to buy from the grid," said Marquis.

The hotel went online with its new solar water heater in March. Marquis says its gas bill went down when prices shot up. She says this system is of the first things people should do when investing it solar energy – mainly because it’s much less expensive than solar panels.

And many people are listening to this call for solar energy.

Austin Energy says the time from September 2007 to 2008 was its biggest year for rebate applications and rebates paid out.