You have to appreciate the serendipity: On the heels of Duke Energy’s announcement that it will cost $3 billionnot $2 billion, as originally projectedto build its two proposed coal-fired power plants, the state is unveiling its renewable energy study.

Under direction from the state Environmental Review Commission, the N.C. Utilities Commission sponsored a study to analyze the costs and benefits of a Renewable Portfolio Standard. If adopted by the legislature, an RPS would require the state’s three investor-owned utilities to generate a portion of their electricity from renewable sources by a given date.

The Utilities Commission paid $150,000 to Boston-based contractor La Capra to conduct the study, which is due out this week.

State Rep. Pricey Harrison (D-Greensboro) is an ERC member and a vocal proponent of renewable energy. In previous legislative sessions, Harrison tried to push through a 10 percent Renewable Portfolio Standard, but “it was clear that it didn’t have the momentum or foundation” to pass, she said.

According to the Pew Center on Global Climate Change, 23 states and the District of Columbia have a Renewable Portfolio Standard, although if North Carolina adopted one, it would be the first southeastern state to do so.

Among the most ambitious states are California, which has committed to generating 20 percent of its energy from renewables by 2020, and Maryland, which is scheduled to use 7.5 percent by 2008. States can achieve their goals by generating the energy through sources such as wind or biomass (organic material such as hog waste), or by trading renewable energy credits.

States adopt these standards for environmental and economic reasons. The Pew Center reports that because of Texas’ RPS, the state has avoided emitting 3.3 million tons of carbon dioxide, the main component in greenhouse gases, which cause global warming.

Economically, the N.C. State Energy Office estimates renewables could create 3,000 jobs, while decreasing the $15 billion the state spends to import energy.

Several state environmental groups, including the N.C. Sustainable Energy Coalition, are urging the state to adopt a renewable standard. The N.C. Commission on Global Climate Change, which includes Harrison and state Rep. Joe Hackney (D-Chapel Hill) as members, is also interested in the issue.

Yet, even if the study recommends the state adopt an RPS, the utilities are expected to oppose it. “It’s clear we have to overcome resistance from the utilities, which are very influential at the legislature,” Harrison said.

Duke Energy has made few inroads into renewable energy, and its efforts pale in comparison to many utilities. CPS Energy, a municipally owned utility in San Antonio with 640,000 customers, provides more than 260 megawatts of renewable energy, primarily wind. (However, CPS is also building a 750-megawatt coal-fired power plant.)

Duke Energy, with more than 2 million customers in North Carolina, buys biomass-generated and hydroelectric power. Total megawatts: 19.

ERC will release the study results at a public meeting Dec. 13 at 9:30 a.m. in Room 1228 of the Legislative Office Building, 300 N. Salisbury St., Raleigh.