UPDATE 1-Latest Northeast U.S. carbon permit sales net $94 million

(Adds details of results, reaction from RGGI official, background on new EPA rules)

WASHINGTON, March 7 (Reuters) - The price for power plants to emit 1 ton of carbon dioxide in nine northeastern U.S. states cleared at a record $4 per short ton at the Regional Greenhouse Gas Initiative's (RGGI) 23rd permit auction, the market's administrator said Friday.

The electronic auction, held on Wednesday, raised a total of $93.96 million that can be used by the participating states to invest in clean energy and other consumer benefit programs.

All of the 18.5 million emissions allowances offered at the auction were sold.

Another 5 million so-called "cost containment reserve (CCR) allowances" were also sold. Those are extra allowances only available for sale if CO2 prices exceed certain benchmarks.

Electricity generators and their corporate affiliates bought 45 percent of allowances. The rest were bought by speculators or other groups that may want to "retire" the credits.

Wednesday's auction was the first after members recently made the program more stringent by lowering the collective carbon emission cap by 45 percent to 91 million short tons for 2014. This would then decline by 2.5 percent each year from 2015 to 2020.

"Our first auction under the new cap demonstrates how market-based programs cost-effectively reduce carbon pollution while driving investments in a clean energy economy," said Collin O'Mara, vice-chair of the RGGI and secretary of Delaware's Department of Natural Resources.

The RGGI targets emissions from power plants in Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New York, Rhode Island and Vermont.

Officials in those states are making a strong push for the U.S. Environmental Protection Agency to recognize the RGGI program as a model for other states to help them meet forthcoming regulations that will curb carbon emissions from the country's more than 1,000 power plants.

The EPA has not yet released details of the proposal, which is expected in June, but has been seeking input from states, which will be responsible for designing plans for their power plants to comply with future federal rules.

The RGGI states have submitted comments to the EPA describing why regional cap-and-trade programs like RGGI should be allowed as a way for states to achieve greenhouse gas standards and asking it to get credit for the early action taken by RGGI's members.

RGGI held its first quarterly allowance auction in 2008.

A report released in February by RGGI's program administrator, RGGI Inc, found that auction proceeds to date are projected to return more than $2 billion in lifetime energy bill savings to more than 3 million households and 12,000 businesses in the region.

The report said 73 percent of the state-invested RGGI funds have gone to energy efficiency programs in the region.

(Reporting by Valerie Volcovici; Editing by Ros Krasny, Bill Trott and Susan Heavey)