Our team has published hundreds of technical reports on low- and zero-emission fuels and technologies. You can read the executive summaries and download a sample of them here.
Game Changer: Next Generation Heavy-Duty Natural Gas Engines Fueled by Renewable Natural Gas
- An on-road heavy-duty vehicle powered by a near-zero-emission engine (certified to 0.02 g/bhp-hr) has tailpipe NOx emissions that are comparable to – or possibly lower than – the amount of NOx emitted to produce electricity used to charge a similar heavy-duty battery-electric vehicle (HD BEV).
- RNG has the lowest carbon intensity rating of key transportation fuels and can reduce greenhouse gas emissions by 40 to 125% or more. Studies from a range of reputable sources estimate that sufficient feedstock exists in the U.S. today to produce enough RNG to displace tens of billions of diesel gallons.
- There are three types of fuel-technology HDV platforms that can achieve zero or near-zero emissions. Dollar-for-dollar, Ultra-Low NOx HD NGVs fueled by RNG deliver the most cost-effective NOx and GHG reductions.
Renewable Diesel as a Major Transportation Fuel in California: Opportunities, Benefits & Challenges
- Renewable Diesel (RD) used in California’s transportation sector achieves a volume-weighted carbon intensity rating that is about 66 percent lower than petroleum diesel (mostly ultra-low sulfur diesel, or ULSD)
- RD is substantially similar to ULSD in its physical and chemical characteristics and can be directly used in existing diesel-powered vehicles and ULSD infrastructure.
- RD can be produced from a wide array of renewable, low-carbon-intensity feedstocks using existing oil refinery capacity.
- RD appears to significantly improve performance and reduce life-cycle costs of diesel particulate filters (DPFs), which are widely used to control PM emissions on post-2006 on-road HDVs (and some off-road HDVs).
Ultra-Low NOx Near-Zero Natural Gas Vehicle Evaluation ISX12N 400
- The ISX12N NG engine showed NOx emissions below the CARB optional low NOx standard (0.02 g/bhp-hr), averaging between 0.0012 and 0.02 g/bhp-hr for the various hot start tests.
- The NOx emissions were well controlled at low loads (i.e., Creep and Near Dock cycles) and during cruise conditions (i.e., Regional and HHDDT Cruise). This suggests stoichiometric NG engines are a good choice for regional NOx mitigation strategies where light loads are common.
- In contrast, recent studies by UCR suggest that 99% of the diesel trucks that operate within 10 miles of the ports (certified to 2010 EPA emissions standards) have in-use emissions of up to 1 g/bhp-hr NOx—largely attributed to poor performance of aftertreatment systems during low duty cycle operation.