LNG utilisation in shipping is increasing and has direct effects namely benefits on air quality and human health. Moreover, CO2 emission is lower with gas use compared to diesel fuels, but ‘methane slip’ may form in gas combustion. The low-pressure dual fuel concept is the most popular LNG engine technology and unfortunately also the technology producing methane slip. Therefore, development of methane slip reduction technologies for these low-pressure dual fuel cases is the focus of this project.
Liquid natural gas (LNG) has the potential to make shipping more sustainable and also benefit human health. But while current technologies produce lower CO2 with gas, they may still emit methane. The EU-funded GREEN RAY project aims to reduce such "methane slip”by developing new add-on technologies for existing and new engines. New on-engine technologies will be developed both for four-stroke engines like those used in cruise ships and ferries, as well as for two-stroke engines used in tankers and container ships. In addition to on-engine technologies, an after treatment technology for methane oxidation is developed in GREEN RAY. The results will be demonstrated onboard two newly built vessels and one retrofitted ship.
To assess the methane emissions from shipping the GREEN RAY project will combine existing data collection with onboard measurements to address existing vessels and new builds, normal operation and varying loads, and further utilise these results in a model development to achieve LNG fleet level assessment.
To prevent the methane slip, the strong consortium of GREEN RAY will develop on-engine technologies for low pressure dual fuel engines and aftertreatment technologies for the existing vessels as well as newbuilds. First, the four stroke engine technology is developed further to enable methane slip reduction at all engine loads and to be applicable to the largest engines in the market involving cruise, ferry and gas carriers. Second, the on-engine technology development for the two stroke engine, around a patented LNG injection system, will aim to significantly reduce methane slip from e.g. tankers and container ships. Third, a unique approach of a sulphur resistant catalyst system to significant methane oxidation while also ensuring that the activity remains high over time. The achievements of these three technologies' development will be demonstrated onboard two new builds and one retrofit to existing vessel, all of them targeting TRL 7, and implementing the partnership on ZEWT. Dissemination and exploitation of GREEN RAY results towards acknowledged target groups will enable wide deployment of the new technologies maximising also the benefits for climate.