While environmental groups rallied at the state Capitol in support of a measure to prohibit building any new fossil-fuel power plants in Hawaii, at least one renewable-energy advocate urged lawmakers to proceed with caution.

Henry Curtis, executive director of preservation group Life of the Land, said his concerns focus mainly on the potential use of palm oil, a product that can be made from palm trees and used for cooking, cosmetics and as a biofuel.

Some environmental and climate groups have objected to widespread use of palm oil, because plantations can lead to tropical forest deforestation, endangering native species and contributing to climate-warming gases, according to the Worldwatch Institute.

“;My major concern is if we ban fossil fuels while we do not discuss tropical vegetable oils, like palm oil, then we will drive rain forest destruction, and that should not be the way we're going,”; Curtis said. “;There are some things that are far worse than petroleum.

“;Of course we believe in getting rid of petroleum, but it should not be done haphazardly, to the point where the solution we bring on is worse.”;

The measure being supported by environmental groups along with Gov. Linda Lingle is House Bill 1464, which prohibits power plants from increasing generating capacity using fossil fuels. It is among hundreds of bills being negotiated by House and Senate members in conference committees as the Legislature winds down the 2009 session.

Yesterday's rally was organized by the Blue Planet Foundation, based in Honolulu.

Lingle and others urged supporters to keep up the pressure on House and Senate members to approve HB 1464.

Opposition has come from a handful of utility companies, but Lingle noted that Hawaiian Electric Co.—the state's largest utility—already has agreed its new plant slated for Campbell Industrial Park will use renewable fuels.

“;They have gone on record as supporting this move,”; Lingle said of HECO. “;Rarely is there a time that the Legislature gets an issue handed to them with a ribbon around it all tied up and ready to go.”;

The conference committee on the measure is scheduled to resume tomorrow.