What shipowners and operators need to do to comply with the new emissions regulations is one of the themes of a retrofit technology study by the Danish partnership "Green Ship of the Future" in which Lloyd's Register has participated

The project, named the ECA Retrofit Technology Study, compares technologies that meet the IMO's emission levels for ships sailing in Emission Control Areas (ECAs).

Jointly funded by the Danish Maritime Fund and the participating partner companies - Lloyd's Register, Alfa Laval Aalborg, D/S Norden, Danish Shipowners' Association, Elland Engineering, Maersk Maritime Technology, Maersk Tankers, MAN Diesel & Turbo and Schmidt Maritime. The study looks at three fuel options:

• Low sulphur fuel oil/marine gas oil (referred to as MGO and the reference case),

• Heavy fuel oil (HFO) and

• Liquefied natural gas (LNG).

The reference ship used for the project was a newly-built, medium-range (MR) tanker from D/S Norden. The project's aim was to carry out a desktop study based on a 'real' ship and on real operational data and to set up practical solutions as well as uncovering the financial aspects of installation, operation and maintenance of the options. No physical alterations or equipment were to installed onboard as the project was a desktop exercise.

The vessel converted to use of LNG as fuel with the two LNG storage tanks in front of the accommodation.

Lloyd's Register has reviewed the proposed solutions for scrubber technology and LNG as a fuel. The reference case for operation on MGO has not been a subject of further investigation. The Lloyd's Register reviews are conceptual design reviews, i.e. overall regulatory and safety assessments to identify the challenges and outstanding matters which need further consideration.

The scrubber solution

With the scrubber solution, the aim was to extend the vessel's funnel casing and install a hybrid wet scrubber system that can operate on both freshwater and sea water, serving both the main and auxiliary engines. During the conversion the funnel would need to be rebuilt and about 300 tonnes of steel work carried out. The vessel's freefall lifeboat would also have to be relocated.

This solution has to some extent been based on experiences gained by Alfa Laval-Aalborg, the equipment supplier onboard the ro-ro vessel Ficaria Seaways, in which Lloyd's Register has been heavily involved.

Lloyd's Register's conclusion is that the scrubber retrofit solution would be both feasible and technically sound. A set of Lloyd's Register Rules and Regulations is being drafted for exhaust gas abatement technologies.

LNG as fuel solution

Any owner wishing to convert an existing vessel to a dual-fuel concept, operating on both diesel oil and LNG, will need to convert the main engine to a dual-fuel engine and the vessel will need LNG storage tanks and a fuel gas supply system.

In this project, two 350 m3 tanks were located transversely on the ship's upper deck forward of the accommodation house. Deck houses for LNG equipment were also placed on the upper deck. One of the challenges in the retrofit project was the location of tanks, deck houses and foundations due to the huge amount of piping on the upper deck.

As Lloyd's Register's conceptual design review did not identify any major or unsolvable problems at this stage, it concluded that the project is feasible from a regulatory point of view. New Rules and Regulations from Lloyd's Register for gas-fuelled ships will come into force on 1 July, 2012. Lloyd's Register classed ships that comply with these rules will be eligible for assignment of the class notation GF.

The financial factor

The study included a financial analysis of the solutions covering the investment costs (CAPEX) and the operational costs (OPEX). Information on investment costs was gleaned from equipment suppliers and shipyards. On the operational side, estimates of OPEX were done for each of the solutions under different scenarios based on fuel oil/LNG costs as well as the percentage of time vessels spend trading in ECAs.

The conclusion on the scrubber solution was that the main factor was the price spread between marine gas oil/distillates (MGO) and heavy fuel oil (HFO) while the investment costs had less significance.

Pay-back time for the HFO with a scrubber solution vs. MGO operation as a function of the spread between HFO and MGO. Based on a HFO price of 650 USD/t.

Pay-back time for the LNG as fuel solution vs. MGO operation. LNG is used both inside and outside ECAs. Based on an LNG price of 550 USD/t.

For the LNG as fuel retrofit solution the spread between the fuel prices (LNG versus HFO and MGO) are of course also important and the final LNG price plays a role as well. In this case, the investment cost was found to be slightly higher than that of the scrubber solution and therefore its impact on the pay-back time is higher, but not the main factor. It is important to note that these factors may change when looking into other ship and engine types and sizes.

For more information about the study, please visit www.greenship.org where the report and associated presentations will be available.

Lloyd's Register LNG Bunkering Infrastructure Study

Availability of LNG is an important issue when considering LNG as fuel for a deep-sea vessel. Independent of the GSF ECA Retrofit Project, Lloyd's Register has recently carried out a study on the LNG bunkering infrastructure for deep-sea ships. The study provided an overview of the main global trade routes, vessels' fuel consumption and bunkering hubs. It includes two stakeholder surveys - one on shipowners, the other on ports.

The information gathered in the study has been turned into an interactive model that Lloyd's Register can use to assist clients considering LNG as fuel for deep-sea ships. It will also provide an estimate of the newbuilding demand for LNG-fuelled deep-sea vessels up to 2025.

The full findings of the bunkering study will be published later this year and a summary is available at www.lr.org/lngasfuel.

Jesper Aagesen

Ship Design Specialist

Senior Surveyor at Lloyd's Register

Above article was initially published at LR Horizon and is reproduced  with the kind permission of the author