A European official who helped launch, and now oversees, a 27-nation carbon dioxide emissions trading program advised senators Monday that they should keep any emissions plan for the United States simple.

Jos Delbeke, the European Commission’s climate change chief, told Sen. Jeff Bingaman, chairman of the Energy and Natural Resources Committee, that the United States should allow the market to determine the trading price of allowances and minimize interference with companies.

Delbeke and other European officials briefed Bingaman, D-N.M., and Sen. Pete V. Domenici, R-N.M., the panel’s ranking Republican, on what was done right and what went wrong in the 27-nation European Union Emission Trading Scheme (EUETS). The comments came during a roundtable the senators held as part of their investigation as Bingaman prepares a climate bill that has been more than two years in the making.

Bingaman and Sen. Arlen Specter, R-Pa., have circulated a “discussion draft” of climate legislation that aims to slow the growth of emissions, cap them and then reduce them.

Bingaman told reporters later he hopes to introduce a bill in April, when it will join a number of other climate measures already introduced.

The EU launched the world’s largest tradable permits system for carbon dioxide — the main greenhouse gas blamed for global warming — in January 2005.

After a three-year “learning period,” the plan enters a new phase next year as commitments under the 1997 Kyoto climate treaty take effect in 2008-2012. EU environment ministers have voiced support for a post-Kyoto emissions reduction of 20 percent by 2020.

Bingaman called the European plan “one of the most significant endeavors being undertaken on climate change today.”

But Domenici said he did not believe a majority of U.S. legislators thought the plan was “doing quite well.”

Delbeke said he now believes that emissions monitoring and verifying should precede establishment of a trading system.

He said the EU had insufficient historic emissions and other data when setting caps for the start-up period and the resulting inaccuracies led to too-modest levels for emissions reductions and a drop in market prices for allowances.

Bingaman told reporters later that setting up a greenhouse gas emissions registry would be an important early action in a U.S. climate plan.

“I think we should strengthen the current law regarding reporting and monitoring of emissions,” Bingaman said.

He said that trying to accomplish this at an early stage is “something we’re looking at.”

The Energy Department currently has a voluntary reporting plan launched under the 1992 Energy Policy Act.

Bingaman said he hopes for a U.S. CO2 reduction plan that would set targets over a longer period, avoiding some of the problems the Europeans encountered in the first phase of their program.

But he said, “How quickly we’ll be able to move any of those bills to the Senate floor for consideration, I just don’t know.”