Lawmakers this week passed a bill aimed at boosting the development of renewable energy generation, but its proponents said the final measure was a “skinny” version of what they had hoped to pass.

The bill comes as several state officials warn that Illinois is falling behind on its clean energy goals. The state’s main funding mechanism for renewable energy projects also faces a potential $3 billion budget shortfall in the coming years.

The legislation gives state regulators more authority to balance the budget for a key renewable energy financing tool, partially by shifting financial risk to electric utility customers. It also sets up a study of energy storage technology that is intended to form the basis of a new bill later this year.

“We’ve seen the effects of climate change. We’ve seen the effects on storms, extreme storms, extreme heat, extreme cold,” Rep. Robyn Gabel, an Evanston Democrat, said during floor debate. “This is something we must do. We must move from fossil fuel, which emits carbon into the atmosphere, to renewable energy. This bill has a few small changes that will help us get renewable energy on the grid.”

The measure passed in the Senate 39-16 on Monday, with the House passing it the next day 74-39. It will next head to the governor’s desk for final approval before becoming law.

The bill makes several changes to how the state funds renewable energy developments. Sen. Bill Cunningham, a Chicago Democrat, described these as “highly technical.”

Existing law requires the state to purchase a certain amount of electricity from renewable sources. The Illinois Power Agency purchases this electricity using a system of financial instruments such as “renewable energy credits.” These are tracked and budgeted using the state’s renewable portfolio standard, or RPS.

But the IPA has struggled to find developers for some of these projects – particularly wind farms. One of the driving concerns that developers cite is whether the budget for the RPS, which is funded by a monthly charge to utility customers, is sufficient to fund renewable energy contracts approved by the agency.

The bill would guarantee that projects approved under the RPS will be funded in case of unexpected spikes in prices by allowing utility companies to charge consumers for the costs of any budget shortfall.

Gabel said during debate Tuesday that she doesn’t expect the policy to lead to rate increases and that even if utilities needed to recover money from customers, it would only be a temporary increase. But Republicans were skeptical of transferring risk to ratepayers.

“All we’re doing here to add security to these failing projects is to transfer, to put the burden on taxpayers, on ratepayers, one way or another to make sure the creditors are going to get paid,” Rep. Brad Halbrook, a Shelbyville Republican, said during debate last week.

The bill also requires the Illinois Commerce Commission to host a series of workshops exploring battery-based energy storage. Renewable energy advocates increasingly are looking to the nascent technology as a way to make wind and solar power more reliable.

The bill passed Tuesday is also notable for what it didn’t include. In addition to cutting out much of the battery storage policy, the final bill didn’t include a set of provisions dealing with energy efficiency programs.

That portion of the bill would have updated the state’s requirements for solar energy rebates and provided subsidies for consumers who buy efficient appliances.

Those provisions, which were backed by the Illinois Clean Jobs Coalition, were cut after the governor’s office “raised some concerns,” according to Cunningham.