Aemetis Inc., a renewable natural gas (RNG) and renewable fuels company focused on negative carbon intensity products, and the American Power Group (APG) demonstrated the patented “Turbocharged Natural Gas Dual-Fuel System” for truck engines to multiple truck fleet owners and operators who transport biofuels, animal feed, and other agricultural products for Aemetis and other businesses in the region. Earlier this week, the technology was demonstrated for regulatory agencies and policy makers in Sacramento.
The technology allows a turbo-diesel engine to operate on up to 65% natural gas and 35% diesel, including renewable diesel. The technology is already operating in more than 3000 stationary engines and 1000 trucks worldwide, complying with US Environmental Protection Agency (EPA) Clean Alternative Fuel Vehicle Conversion regulations.
APG, founded in 2009, developed the patented dual-fuel technology to simultaneously combust two fuels, natural gas and diesel fuel, to power a diesel engine. A truck operated using Aemetis locally produced dairy RNG and renewable diesel or biodiesel would be carbon negative, low emissions, and lower cost than diesel. The system maintains the power of a 100% diesel engine while using less than half as much diesel fuel, leading to significantly fewer emissions.
Annual fuel savings from using RNG to replace up to 65% of diesel fuel have been shown to exceed US$30,000 per truck per year, depending on respective cost of the fuel sources. Dairy RNG is usually US$2 to US$3 per diesel gallon equivalent (DGE) less expensive than petroleum diesel. Retrofit costs about US$10,000 plus the cost of an on-board natural gas tank. The system adds natural gas tanks to a Class 8 diesel tractor and uses software to manage the two fuels, saving money at the pump while reducing emissions. The dual-fuel system is fully automated, eliminating the need for operator intervention.
“These dual-fuel systems represent an important transition step in California’s evolution to cleaner air and ultimately net-zero carbon emissions,” stated Eric McAfee, chair and CEO of Aemetis. “Currently, the heavy-duty vehicle fleet in California is still more than 98% diesel-powered. The low-cost conversion of existing diesel trucks will drive the adoption of reduced cost, lower-emission fuels such as dairy-generated RNG.”
“This patented technology replaces up to 65% of the fuel used by a turbodiesel truck with RNG at only about a US$25,000 cost of conversion that takes less than one day to complete,” said Chuck Coppa, CEO of APG. “By using Aemetis dairy RNG, a waste material is powering the replacement of diesel which significantly reduces emissions.”
APG created a digital design to safely introduce natural gas into the air induction system before the turbocharger spins up — in essence turbocharging air already going to the engine. The spinning air reaches the compression chamber to create higher energy at the point of combustion.
Aemetis is focused on producing below-zero carbon intensity renewable fuels, including negative carbon intensity RNG sustainable aviation fuel, renewable diesel, and bioethanol. Aemetis is also in the process of permitting two carbon capture and sequestration wells near its biofuel facilities in central California. Its goal is to maximize the use of agricultural waste or byproducts as feedstocks to produce renewable fuels, while leveraging the value of federal and state carbon reduction programs.
