A major tax increase on alcohol, a plan to invest public money in start-ups to spur job growth and a measure to give undocumented immigrants tuition breaks at state colleges are among several issues left for lawmakers to decide Monday, on the last day of Maryland’s legislative session.

Five hours of debate Saturday on the proposed alcohol-tax increase suggested the proposal could eat up a considerable share of the final day, potentially leaving little time to pass hundreds of other bills awaiting approval from the House of Delegates, Senate or both.

While floor debate continues on those measures, frantic negotiations between lawmakers on final details of scores of others are poised to be worked out in hallways and conference rooms throughout the State House.

Expected to be among them is a measure that eluded much attention until recent days but now has environmentalists saying that it would undermine Maryland’s law to generate 20 percent of its energy from renewable resources within little more than a decade.

The measure would classify incineration of solid waste as a renewable source on par with solar and wind power. The state’s energy administration backs the plan, and Del. Dereck E. Davis (D-Prince George’s), chairman of a House committee that sets energy policy, said the state needs to classify incineration as a renewable resource to meet its 20-percent goal.

If Maryland doesn’t, he said during Saturday’s debate, ratepayers could see their bills increase because there are penalty charges built into the law if the state doesn’t meet its quota.

Del. Doyle L. Niemann (D-Prince George’s) blasted the plan, saying it amounted to abandoning the state’s pledge on clean energy, and he said loopholes would allow Maryland to count incineration in other states as its own clean-energy generation.

Brad Heavner, executive director of Environment Maryland, said equating trash incineration with solar or wind power to meet the state’s renewable energy goal amounted to “giving yourself a test, then cheating on it to make yourself look good.”

The House and Senate have passed versions of the legislation, but they have differences, including what clean-energy credit is assigned to out-of-state hydropower.

In preparation for the legislature’s final day, House leaders on Saturday muscled two bills needed to raise the alcohol tax through a first round of debate, rejecting repeated attempts by Republicans and conservative Democrats to weaken the bills.

The pair of bills would raise the sales tax on alcohol from 6 to 9 percent July 1, collapsing a three-year phase-in of the tax approved by the Senate.

Under the House plan, the roughly $85 million generated by the tax would be earmarked in the first year for programs benefiting people with disabilities, as well as school operating and construction costs.

During debate that stretched past 11 p.m. Saturday, House Minority Leader Anthony J. O’Donnell (R-Calvert) accused Democrats of trying to “jam a tax down the throats of Maryland citizens.”

The amendments that were rejected included attempts to delay the implementation of the tax increase — so that restaurants and merchants wouldn’t be scrambling to reprogram cash registers before the Fourth of July weekend — and to steer all of the proceeds to programs for the disabled, which have suffered from budget cuts in recent years. Advocates for the disabled have been among the biggest backers of the alcohol-tax increase.