Austin's solar rebate program is out of money again.

The program, which pays for up to about half of the cost of installing a home's solar array, will likely not have any money again until October, when the city's new fiscal year starts. The city will still accept new rebate applications, said Karl Rabágo, a vice president with Austin Energy, on Monday. But they will not be processed until the program has funding again. The qualifying applications that have already been submitted will be granted rebates, he said.

It's the second time this fiscal year that the rebate program has been effectively shut down as city officials wrestle with how much the city should pay to entice homeowners to install solar arrays.

Austin has made a priority of pushing solar and other renewable sources of power, and has put millions of dollars annually behind that commitment. But in late September, before the current fiscal year had even begun, the city abruptly announced that it had received more applications than the program's $4 million 2009-10 budget could support. The city accepted about $3 million worth of applications from homes and businesses. It then decreased the rebate available for homes by a third and decided to spend no more than $100,000 more this fiscal year on rebates for businesses.

The change drew some angry reactions — a group of homeowners in the Mueller subdivision sued, contending they are entitled to the higher rebate — and some solar advocates said Austin risked blunting solar's potential. Others said demand was high enough and prices low enough that homeowners could be enticed to buy panels with smaller rebates.

This time, the angry e-mail strings have not surfaced, as city leaders have reported each week how much money remained in the program.

Rabágo said the city is analyzing whether the rebates should be further reduced. But he said Austin Energy, the city-owned electricity provider, will probably not recommend eliminating them.

I don't think the market is self-sustaining without rebates yet, Rabágo said.