Mayor Kenney will not sign a controversial moratorium on electric-vehicle permits passed by City Council earlier this month, saying a ban "sends the wrong message" about the benefits of electric vehicles. The law will still go into effect without his signature.

Returning the bill to Council without signing it, Kenney acknowledged that the city's current electric vehicle regulations are outdated and asked Council to take a fresh look at reforms.

"I will dedicate the resources of my administration to working with City Council to develop a comprehensive solution that encourages the growth of electronic vehicle usage, safeguards the needs of other residents, and promotes mass transit as well as active transportation," Kenney said in a letter to Council sent Thursday.

The legislation, passed by Council in an 11-6 vote, halts the issuance of new electric-vehicle parking permits, which allow car owners to use charging stations that they purchase and install outside their homes. It also changes the rules for the city's approximately 60 current permit holders, giving them 24/7 access to the spots but allowing empty spots to be used by the public for two-hour parking between 6 a.m. and 6 p.m.

Electric vehicle owners said it was unfair to change the rules on those who invested in the technology and argued that the ban, without a replacement plan, undermined the city's commitment to environmental efforts. Councilmen David Oh and Mark Squilla, the bill's sponsors, argued the moratorium was needed to curb the influx of permits and to allow the city to find a more equitable solution for charging stations citywide.

Kenney originally said he intended to sign the bill into law. His spokesman, Mike Dunn, said Kenney did not realize Council's vote was not unanimous and given the disagreement among Council members "opted to conduct an additional review of the measure."

On the day the moratorium passed, Squilla introduced a bill that would limit the moratorium to two years, a move he said would encourage Council to find a new solution quickly.

Kenney, in his letter to Council, said a moratorium is appropriate but for no longer than one year. The mayor was the sponsor of the city's existing electric vehicle legislation, passed in 2007. He wrote that in the decade since then, the electric vehicle industry has grown, and Philadelphia's policy "needs to mature with it."

He specifically asked Council to explore the behaviors of electric vehicle drivers, technological advancements in the industry, potential incentives to encourage electric vehicle usage, and best practices from around the country.

The mayor suggested creating a joint working group with Council and the administration to work on the issue.

Squilla said a year is a reasonable timeline for passing new regulations. Oh said Council plans to hold a hearing May 18 to start the process.

"When we ask the public to make concessions on public resources, we have to ensure that we have done our due diligence to use the most state-of-the-art technology and the most intelligent plan possible," Oh said. "We have not done that up to now."

The law will go into effect Thursday, though it will likely take some time for the city to change the signage on the existing electric vehicle spots.