US Drive to Cut Methane Emissions

State agency Advanced Research Projects-Energy (ARPA-E) has awarded a US$3.2m grant to a MAHLE-led team to develop an exhaust gas aftertreatment solution for large, LNG-fuelled lean-burn engines used in power generation, marine propulsion and industrial applications.

The scheme forms part of a three-year, US$35m national endeavour entitled ‘Reducing Emissions of Methane Every Day of the Year’ (REMEDY). While the programme is referenced to a broad industrial swath, encompassing the oil, gas and coal sectors, the growing uptake of LNG-fuelled power in US shipping is pertinent to REMEDY’s drive to curb methane slip.

The research undertaking is a further expression of rising international concern over the deleterious effect of methane release into the atmosphere, reckoned to be 25 times more potent as a greenhouse gas than CO₂.

With main technical centres in the UK and Germany, MAHLE Powertrain’s participation in the US-sponsored project is through the company’s Plymouth, Michigan-based operation, which has a particular track record in R&D work for the US automotive industry. It is partnered in REMEDY by the Buffalo-located State University of New York (SUNY) and the Oak Ridge National Laboratory (ORNL) in Tennessee.

The collaborators are tasked with devising a catalytic system to oxidise methane in the exhaust gas of lean-burn, natural gas engines, and to implement the results by 2025. MAHLE also plans to tackle the associated issue of NOx emissions.

Lean-burn gas engines, widely used in the USA to generate electricity, drive compressors, and increasingly to re-power and power ships, were designed to minimise emissions of nitrogen oxides (NOx) and carbon monoxide (CO), which have been regulated for many years. However, such engines may produce relatively high methane emissions.

Addressing the USA and its industrial make-up, REMEDY is focused on three specific, and difficult to abate sources of methane emissions. Besides LNG-fired engines, an estimated 300,000 flares throughout the country, required for providing safe operations in oil and gas facilities, are collectively a significant contributor to methane release. Although most are designed to achieve a 98% methane reduction, ARPA-E’s goal is to increase performance to 99.5%, which would realise a 75% cut in emissions. Another source is coal mine ventilation air methane exhaust from approximately 250 underground mines.

Among the stipulations laid down for the raft of projects covered by REMEDY, systems must incorporate technology that are effective at lean and ultra-lean methane concentrations, integrated with measurement sensors and ensuring consistent operation.

In other areas of the programme, a team fronted by INNIO’s Waukesha Gas Engines is aiming to develop a new line of pistons fabricated using friction welding and designed to reduce the space for methane to ‘slip’ past the engine’s combustion zone.