As of 1 July 2017, the World Ports Climate Initiative (WPCI)’s Environmental Ship Index (ESI) commenced evaluating performance of CO2 in the field. Previously, only the environmental performance of ships on emissions of air pollution (NOx and SOx) was assessed. SEA\LNG, says utilising best practices and appropriate technologies to minimise methane leakage, realistic reductions of GHG by 10-20% are achievable, with a potential for up to 25% compared with conventional oil-based fuels.
The change makes the index the first sustainable quality mark in international shipping that includes the reduction in CO2 in its assessment. It does this based on historical data already included in the index. The ESI compares the fuel consumption and the nautical miles travelled in the past three years (e.g. 2013, 2014, 2015) to that of the following year (2016). If relatively less fuel has been consumed – in other words, if sailing was more efficient – then less CO2 has been emitted. ESI has selected this method because it is actually very difficult to measure CO2 emissions.
Environmental Ship Index
The ESI is a score that is issued at the request of ship owners as of 1 January 2011. Ships that score high on the ESI receive a premium from the participating ports and other organisations that reward sustainable shipping. As of 1 April 2017, the index comprised 5497 ships and 50 bonus providers.
Vessels that perform better than the legal norm are rewarded with a 10% discount on the gross tonnage part of port dues. Since 01-01-2015, the discount is doubled when vessels also have low NOx emissions. Low NOx emissions are achieved by using LNG as fuel, or large catalysts.
LNG-Powered Ship Emissions Study
A European Commission DG Environment News Alert Service (Issue 444 January 2016) cites a 2015 study environmental impact study entitled Particle- and Gaseous Emissions from an LNG Powered Ship.(1) “This study clearly shows that emissions of particles and some gases are lower when using LNG as the primary energy source as compared to marine fuel oils. However, it also shows that there are issues with LNG requiring further investigation, most clearly emissions of methane and thus the overall impact on the climate compared to conventional fuels. These issues are being addressed by expert forums, including the IMO, the European Sustainable Shipping Forum and the Society for Gas as a Marine Fuel. Already some options to minimise methane slip have been identified, such as methane emissions mitigation plans, optimisation of transport efficiency of LNG-fuelled ships and adequate design of the LNG supply chain.”
According to DNV GL, “While different technologies can be used to comply with air emission limits, LNG technology is the only option that can meet existing and upcoming requirements for the main types of emissions (SOx, NOx, PM, CO2).”
SEA\LNG is a multi-sector industry coalition, created to accelerate the widespread adoption of liquefied natural gas (LNG) as a marine fuel.
Source: Adapted from Port of Rotterdam press release
Source for Study: Anderson, M., Salo, K. and Fridell, E. (2015). Particle- and Gaseous Emissions from an LNG Powered Ship. Environmental Science & Technology, 49(20), pp.12568-12575. DOI: 10.1021/acs.est.5b02678
Source for EC Science for Environment Policy: Newsletter: http://ec.europa.eu/environment/integration/research/newsalert/pdf/methane_emissions_from_lng_powered_ships_higher_than_current_marine_fuel_oils_444na4_en.pdf