Developers are already required to think green when erecting new buildings in San Francisco, but now they may have to think gold.

Mayor Ed Lee is planning to make the country’s already strictest environmental standards for buildings even stricter. Currently, new buildings need to meet a set of development standards called Leadership in Energy and Environmental Design, or LEED.

The LEED certification comes with different levels, silver, gold and platinum, based on the number of environmentally conscious aspects to the building’s design. At an Earth Day breakfast this week, Lee said he wants to introduce legislation that would require gold certification, not just silver.

“As a City, we are showing the nation that you can help your local economy recover by acting responsibly and promoting a clean energy economy,” Lee said in a statement.

bbegin@sfexaminer.com