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GAS MARK 2 COULD RAISE GHG EMISSIONS

Friday, July 10, 2020 

Shipping is facing a power revolution with the demand for a reduction in greenhouse gas (GHG) emissions by 50% of 2008 levels and 40% by 2030 the race is on to develop fuels that can achieve the required cuts in emissions.

Current thinking by some industry experts suggest that LNG could be used as a transition fuel for the industry reducing carbon by around 20%, others claim that this is a fallacy and that certain factors could mean that LNG will in fact increase the amount of carbon emissions, rather than reduce them.

Dr Elizabeth Lindstad - chief scientist at the Norwegian research institute SINTEF Ocean AS, told an audience of shipowners at last autumn’s Clean Shipping Alliance conference in Brussels that the use of low-pressure LNG power in dual fuel engines would mean that the emissions on a well-to-wake basis would be higher than emissions from HFO operating with scrubber technology.

In an eight-year research project SINTEF compared the use of low and high-pressure LNG technology in both two and four stroke engines and used the emissions for MGO as a baseline, 100% emission level.

Two stroke engines using low pressure LNG as a fuel were rated at 137% of the MGO emissions, while low pressure four stroke dual fuel engines fared better at 106% of the MGO emissions, but low pressure LNG only four-stroke engines produced similar carbon emission levels to MGO compared to 97% for HFO with a scrubber.

Lindstad said with the Energy Efficiency Design Index (EEDI) only measuring CO2, and the low-pressure LNG system being the cheapest option in terms of capital expenses to satisfy EEDI phase III this could lead to an increase in GHG emissions if owners were to take up the cheapest LNG option.

Looking at this scenario Lindstad asked, “What do you think will happen? The business for these manufacturers is booming, but we are not achieving our climate targets, we are on the totally wrong track.”

High pressure systems on two-stroke units were more efficient in burning the LNG and so suffered little from methane slip. That efficiency was reflected in the emission levels for those engines at 93% of the MGO carbon emission levels of MGO, compared to HFO with a scrubber at 97%, according to Lindstad.

SINTEF’s research lays bare the belief that LNG can be used as a transition fuel that would help the maritime industry meet its decarbonisation targets and Lindstad was strident in her criticism of some organisations that promote LNG as a transitional fuel.

In a comparison of studies on the well-to-tank carbon emissions for LNG Lindstad pointed to Concave’s 2013 study, which calculated that LNG emissions totalled 21.1 grams of CO2 equivalent emissions per megajoule; while Veerbeek made the same calculation two years later and recorded a figure of 19.0; however in 2018 class society DNV GL made a similar calculation and it recorded well-to-tank emissions of just 10.7 grams of CO2 equivalent emissions per megajoule.

The DNV GL figure comes from an earlier Veerbeek study, in 2013, which was subsequently corrected after Veerbeek had recognised errors in the calculations, according to Lindstad.

It’s not a surprise that LNG looks good in the DNV GL study, according to Lindstad, but, the low figure  makes a big impact on the conclusions because when uses the low well to tank figure it means that, even after including quite significant methane slip, LNG is at 90% of the greenhouse impact of MGO, explained Lindstad.

High pressure LNG systems can achieve up to 35% CO2 reductions with a slender ship design and improved efficiency gains, while HFO with a scrubber and exhaust gas recirculation unit can achieve up to 20% reductions in GHG emissions, but the low-pressure LNG solution would “boost global warming,” explained Lindstad.

In response to Lindstad’s criticisms Christos Chryssakis, Business Development Manager
DNV GL – Maritime, told CSI that the class society’s 2013 study and 2014 Position Paper showed three scenarios, with well-to-tank emissions ranging from 9.7 gCO2eq/MJ (called LNG from Qatar), 15.1 gCO2eq/MJ (called FLNG) and 22.3 gCO2eq/MJ (called CNG).

According to Chryssakis technology has developed a lot since 2013, and the two-stroke engines available today solve, to a large extent, the methane slip problem. “The next generation of engines will actually be even better,” he said.

Chryssakis added, “In my opinion, and given the fact that there are technical solutions for methane slip available, this becomes really a question of cost and not technology. The MAN engines are currently more expensive. However, they offer significant reductions in GHG emissions. The same should be expected by the new generation of low-pressure engines, which will most likely come with an increased price tag.”

In a recent report UMAS, the partnership between the University College London (UCL) Energy Institute and consultancy MATRANS Ltd, warned that shipping’s transition to zero carbon could cost more than US$1.4 trillion.

UMAS warned of the high cost of the transition to a low or no carbon future for the industry, with some 87% of the cost being borne by shore-based industries and a smaller, but still significant portion, of 13% expected to be paid via the ship operators.

The UMAS report went on to say that the scale of the cumulative investment needed between 2030 and 2050 to achieve the IMO carbon targets is approximately USD1-1.4 trillion, or on average between USD50- 70 billion annually for 20 years. This estimate should be seen in the context of annual global investments in energy, which in 2018 amounted to US$1.85 trillion.

The report was based on the assumption that ammonia, (NH3) would be the carbon free fuel of choice for the industry, but the report also states that, should hydrogen or other synthetic fuels be developed it would substantially alter the costs for shipping.

Dr Tristan Smith, a reader in energy and shipping at University College London and one of the authors of the UMAS report, told CSI, that wind and other renewable energy in the UK had been financed by adding a small charge to everyone’s bill and that infrastructure cost was reducing fast, while nobody asked governments to pay to build refineries as part of the carbon based infrastructure.

Smith added, “The independent proposal [to add a few dollars to the price of fuel] by the International Chamber of Shipping and the World Shipping Council will not achieve change.”

According to Smith, the carbon price is closer to US$300/tonne and that could bring about new developments in an industry that burns in excess of 300 million tonnes of fuel a year.

The most likely method of funding would be through a kind of hybrid, using public funds and a carbon charge of between US$100-200/tonne of fuel.

Alternative maritime fuels will be developed in the future, whether that transition will include the use of LNG will rely substantially on the price of alternative fuels compared to the demand and price for the gas. And that will depend on the economic map at the time, and that is a wait and see scenario.

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