OptiFuel to test hybrid RNG locomotive

Hybrid-power product integrator OptiFuel Systems is receiving a $2.6m grant from the US Department of Energy to trial its renewable natural gas (RNG) hybrid 4,300 horsepower locomotive. As part of its plan to decarbonise the rail market, OptiFuel will operate a pre-production test service at the Association of American Railroads' Transportation Technology Center and a regional in-service pilot to demonstrate that commercially available engines can be transformed into near zero-emission RNG locomotives with 50% lower fuel costs. Adoption of RNG as a fuel would be a significant step for the freight line-haul sector, which has not yet seen much emissions-reducing developments.

OptiFuel Systems, a system integrator of Cummins and BAE Systems hybrid power products for decarbonizing the rail, marine, and microgrid power market, is in the process of finalizing a $2.6 million US Department of Energy (DOE) grant to demonstrate a pre-production Renewable Natural Gas (RNG) hybrid 4,300 hp line-haul locomotive.

The program will demonstrate that a suite of commercially available, EPA-rail-certified engines present a near-term, low-risk solution to create an affordable RNG hybrid line-haul locomotive with near zero emissions while simultaneously improving fuel cost by 50%.





This new program, partially funded with the DOE grant, will allow pre-production testing at AAR’s Transportation Technology Center, Inc. (TTCI) and will operate in-service with a regional railroad to validate that OptiFuel’s low-risk, affordable technology can also be applied in the higher horsepower freight and passenger locomotive market.

This program is integral to OptiFuel’s 5-year plan to disrupt and decarbonize the rail market with a full line of zero and near-zero NO x , PM and CO 2 emissions freight and passenger locomotives. In several weeks, OptiFuel will start taking orders, in 49 of the US states, for a new line of affordable 800 hp to 3,200 hp, 100% natural gas freight and transit locomotives. All will have zero NO x /PM emissions with carbon-neutral emissions by consuming an RNG/CNG mixture.

OptiFuel has already developed and tested a high volume CNG/RNG refueling system at the Indiana Harbor Belt CNG locomotive program, utilizing low-cost CNG. In the next 2 years, OptiFuel will be announcing additional refueling products, including an affordable 12,000 DGE (Diesel Gallon Equivalent) CNG/RNG tender; and a 9,000 CNG/RNG DGE, 1,600 hp zero emission, powered tender.

The rail sector is the only transportation modality without significant emissions related development that is feasible in the near-term to eliminate ozone, smog and GHG emissions, OptiFuel says. In comparison, the composite US freight line-haul fleet, which consumes 90% of the fuel in the rail industry, emits 8 g/bhp-hr of NO x while new CNG Class 8 trucks emit 0.02 g/bhp-hr of NOx, a reduction of 400 times.

Even if locomotives can carry 4 times amount of tonnage per horsepower as a new CNG Class 8 trucks, it still has emissions 100 times higher. Beside the US locomotive fleet average NNO x Ox emissions of 8 g/bhp-hr, the US rail fleet’s average fine Particulate Matter (PM) emissions is 0.22 g/bhp-hr. In comparison, OptiFuel’s 4,300 RNG hybrid line-haul locomotive is expected to emit 0.04 g/bhp-hr of NO x NOx, a reduction of 200 times, and emit 0.00 g/bhp-hr of PM.

Using RNG as the fuel, OptiFuel’s locomotive will significantly lower greenhouse gas (GHG) emissions resulting in a neutral or negative carbon footprint, in addition to far exceeding California’s Tier 5 locomotive petition standards to US EPA.

As of September 2016, there were more than 1,000 railyards in the US located in densely populated, urban areas classified as particulate matter and ozone EPA defined nonattainment areas. More than 122 million people (nearly 40% of the U.S. population) living in these nonattainment areas are having more acute and chronic adverse health outcomes, including exacerbation of respiratory and cardiovascular disease. In these US railyards, there are more than 28,000 technologically obsolete, diesel-powered locomotives operating which produce Pre-Tier 0 (non-regulated, pre-1973), Tier 0 or Tier 1 emissions. These pollutants create very high levels of ozone, air toxins, greenhouse gases, fine particulate matter, and other diesel exhaust compounds classified as carcinogenic to humans.

In 2018, Class I, II, and III railroads purchased 4.7 billion gallons of diesel fuel for the 39,000 locomotives used for freight operations in the US. Freight railroads emitted more than 1.6 million tons of NO x , 43,000 tons of PM, and 38 million metric tons of CO 2 , much of which occurs in Environmental Justice communities. OptiFuel’s EPA-rail-certified technology with a CNG/RNG fuel mixture would limit railroad emission throughout the US to 8,600 tons of NO x , zero tons of PM, and zero metric tons of CO 2 .

This demonstration will include a comprehensive natural gas hybrid propulsion package featuring four 100% natural gas engines–the OptiFuel KOFSG11.9400 (OFS12) and a single Cummins Tier 4, EPA-rail-certified, diesel-powered QSK60 in a hybrid configuration. The design also includes a 100% battery-electric mode for limited yard operations.

OptiFuel’s OFS12 engine is EPA-rail-certified with emissions of 0.00 g/bhp-hr for both NO x and PM, and is capable of operating on either CNG, RNG, LNG, or a CNG-RNG blend. The OFS12 engine, which is identical to the Cummins ISX12N for on-road applications, is the cleanest rail engine currently certified by EPA.

The pre-production locomotive will consume 83% natural gas with 20% improved efficiency versus Tier 4 diesel line-haul freight locomotives. OptiFuel will utilize one of its proprietary, Federal Railway Administration-approved onboard CNG/RNG storage systems holding 1,500 DGE to complete the locomotive design.

The production locomotive will be market-competitive in pricing and will have an industry-leading 5-year warranty on all engines along with comprehensive maintenance coverage. The propulsion system design is compact enough to fit on virtually any legacy EMD or GE line-haul locomotive with no structural modifications to the operator cab or frame.

The OptiFuel design will allow the railroads to repower existing Tier 3 and Tier 4 line-haul locomotives at half the cost of fully replacing older Pre-Tier 0 to Tier 2 locomotives. In production, OptiFuel will provide its proven locomotive CNG fueling station solution and expect the CNG to cost between 0.70 to $1.35 per DGE, depending on capitalization and implementation strategies of the locomotive operator. This is well below the 10-year average cost of $2.45 that the Class 1 railroads have paid for diesel, the company says.