Work

Development of a Hydrogen Portable Emissions Measurement System to Quantify Exhaust H2 Emissions from Fuel Cell Electric Vehicles

Year: 2026

Type: article

Abstract: Portable emissions measurement systems (PEMS) have been key in determining real-world driving emissions from both light- and heavy-duty vehicles. PEMS enable the operator to quantify mass emissions and correlate those emissions to the fuel consumed or vehicle miles traveled. Mass-based emissions quantifications are enabled by the concurrent use of concentration sensors for species of concern along with methods to quantify the total exhaust flow rate. We developed a hydrogen (H2) PEMS system based on a review of the literature on fuel cell electric vehicles, expected gas concentrations, available H2 sensors, and flow measurement options. Our target accuracy was within ±15% over multiple orders of magnitude in mass-specific emissions rates. Early results from multiple trips of a single transit bus showed exhaust hydrogen emissions ranged from about 2.4 to 4.5 g/km or around 2.0–3.8% of their fuel. It is important to understand these and other emissions-associated fueling stations because H2 emissions can impact atmospheric chemistry and act as an indirect climate forcer. Furthermore, at current hydrogen prices, excessive losses discourage adoption of this transportation technology.

Source: ACS ES&T Air

DOI: 10.1021/acsestair.6c00180