NYC’s 'Renewable Diesel' Linked to Amazon Deforestation, Other Environmental Concerns
New York City Has Leaned Into Renewable Diesel as a Climate Solution, But Experts Warn It’s Not so Green
Over the last few years, New York City has aggressively expanded the use of renewable diesel by the municipal vehicle fleet, and officials have described it as “extraordinarily important” for the city’s green ambitions. However, experts warn that the controversial fuel is not as environmentally friendly as the city says.
In 2015, the Mayor’s Office and the NYC Department of Citywide Administrative Services launched the NYC Clean Fleet plan, aimed at cutting 50 percent of the fleet’s greenhouse gas emissions by 2025, and 80 percent by 2035. One of the key ways that the city has stayed on pace with those goals is swapping out petroleum diesel for renewable diesel. Renewable diesel is a type of biofuel made by chemically treating a mix of animal fats, soybean oil, corn oil, and used cooking oil.
In 2024, the city’s entire heavy-duty and off-road vehicle fleet started using renewable diesel, and in 2025 the Staten Island Ferry switched over too.
According to the city, renewable diesel offers substantial benefits over petroleum diesel including fewer greenhouse gas emissions and a less harmful impact on local air quality.
In 2024, the city claimed that using renewable diesel to power its 12,500 heavy-duty and off-road vehicles will prevent “162 million pounds of global carbon dioxide emissions from entering the air every year.”
However, experts say that renewable diesel causes significant, harmful environmental impacts, and it remains unclear if the switch from petroleum diesel is beneficial overall.
“There’s no basis for claiming any kind of benefit whatsoever. Just because they call it something doesn’t make it clean or renewable,” said Mark Jacobson, a professor of engineering at Stanford University who studies climate change and air pollution. “It’s bad in terms of both air pollution and in terms of greenhouse gas emissions.”
Michael Hamersky, the Executive Director of the Pace Energy and Climate Center at Pace University’s law school, said renewable diesel can offer some limited benefits as a short-term “bridge” to electric vehicles, but warned that NYC could end up delaying electrification by adopting it.
Hamersky said renewable diesel can be made from a wide variety of sources, and the environmental impacts vary depending on what those sources are.
New York City buys its renewable diesel from a company called Approved Oil, which gets it from a Louisiana-based manufacturer called Diamond Green Diesel.
According to Diamond Green Diesel, their renewable diesel is made from a combination of “recycled animal fats,” “inedible corn oil,” and “used cooking oil.”
Hamersky said the inclusion of corn oil is a “red flag.”
“The opportunity cost of taking otherwise productive agricultural land out of the food chain process, where it could be used to grow high-nutrition fruits and vegetables for human consumption, and to utilize that land to grow corn for fuel, is just inefficient,” Hamersky said.
The “recycled animal fats” and “used cooking oil” may also warrant environmental concerns.
In 2025, Grist reported that Diamond Green Diesel sources animal fat from cattle raised on illegally cleared lands in the Amazon rainforest. Experts told Grist and Reuters that rising demand for Diamond Green Diesel’s products could drive further deforestation in the Amazon.
Hamersky said used cooking oil is the most sustainable of the three sources. But according to Jacobson, it can introduce additional air pollutants that may go under the radar because they aren’t included in standard emissions testing.
“Once you have random peoples’ kitchen junk” going into the fuel, “compositions are all over the place and they contain all sorts of things you don’t even know about,” according to Jacobson.
Jacobson said industry marketing is driving governments like NYC’s to adopt and incentivize renewable diesel in spite of the facts.
“They just look at what the industry claims and buy into it hook, line and sinker,” Jacobson said.
“The message around biofuels and the biofuel lobby, particularly in this country, is effectively greenwashing,” Hamersky said.
According to public records, Approved Oil has spent $432,500 on lobbying the city government since 2021.
Approved Oil’s CEO and other executives have also made campaign contributions to key decision-makers including former mayor Eric Adams and James Gennaro, the chair of the City Council’s Committee on Environmental Protection & Waterfronts.
In 2024, The City reported that Approved Oil won a $90 million contract with NYC after their CEO made multiple donations to Eric Adams’ campaign and hired a lobbyist linked to Adams.
Gennaro, who has received campaign contributions from Approved Oil’s CEO and their Wholesale Manager, recently sponsored two new pro-renewable diesel bills in the city council: one that would require all City-owned-or-operated diesel fuel-powered motor vehicles to be powered by renewable diesel beginning July 1, 2026, and another that would require the city to study the feasibility of using renewable diesel to heat buildings, both publicly and privately owned.
Gennaro’s office did not respond to requests for comment.
Jacobson and Hamersky say the city council should avoid supporting any legislation that could be used as justification for delaying electrification.