Natural gas, which took over millions of years of transformation of organic materials, such as plankton and algae, is made up of about 95% Methane, which is the cleanest fossil fuel. The combustion of natural gas mainly emits water vapor and tiny amounts of Carbon Dioxide (CO₂).  Its CO₂ emissions are 30%-50% lower than those produced by other combustible fuels, according to ELENGY.

Cleanest Fossil-based Fuel

Natural gas is the lightest hydrocarbon (CH₄), having one atom of Carbon and 4 atoms of Hydrogen. The combustion of natural gas neither emits soot, dust, nor fumes. Compared with fuel oil, it generates 30% less CO_2. When compared with coal, it generates 45% less CO₂, a two-fold reduction in Nitrogen (N0x) emissions, and virtually zero Sulphur Dioxide (SO₂) emissions. [ELENGY]

Natural gas is extracted from fields located mainly in Algeria, Norway, Qatar, Russia, Nigeria, and USA. The distance between a country and its markets shows the difficulty and sometimes the improbability of transporting natural gas through pipelines. The simplest and most economical alternative would be to ship natural gas in liquefied form by sea in LNG cargo tankers.

To enable transport via maritime vessels, natural gas is cooled down through a refrigerated cycle involving compression, condensation, expansion, and evaporation. Natural gas is cooled at about -160°C, then after applying low pressure, transforms into liquid. Natural gas in liquid form is called Liquefied Natural Gas (LNG). LNG is largely or almost completely composed of Methane (85%-99%). LNG is odorless, colorless, non-toxic, and non-corrosive. Once natural gas is liquefied, large quantities of LNG can be stored and transported aboard LNG Tankers.

LNG Tankers

A tanker ship with temperature-controlled tanks intended to transport LNG is called an LNG Tanker. LNG Tankers have a propulsion system, which is fueled with natural gas, and thus, emit lower greenhouse gas (GHG) emissions. Since LNG is transported in its liquid form, it must be loaded in vessels having lower inner tank temperature of about -163˚C, and a maximum transport pressure set at 25 kPa (4 psi).

There are 3 types of LNG Tankers: (1) fully-pressurized; (2) semi-pressurized and refrigerated; and (3) fully refrigerated.

LNG Tankers are double-hulled. Each ship consists of 4-5 large inner tanks to hold the liquefied gas. These liquid cargo ships are either spherical or geometric membrane in design, where each tank is made in multi-layers. These multi-layered tanks are designed to make them leak-proof, and help in maintaining a cold temperature inside the cryogenic tanks. LNG tankers are also equipped with fire alarms and proper insulation systems.

LNG Tankers come in 5 categories in terms of cargo containment system: (1) Moss (Spherical, Type A) with 4-5 tanks; (2) IHI (Prismatic, Type B) designed to sustain accidental damage due to internal equipment; (3) TGZ MARK III with multi-membrane designed for insulation; (4) GT96 with primary and secondary membranes made of Invar that has no thermal contraction, and filled with Perlite to provide insulation; and (5) CSI is the combined systems 1 and 3 with the primary barrier made of Invar, and the secondary barrier made of Triplex.

Energy of the future

ELENGY is a subsidiary of GRTgaz within the ENGIE Group that develops small-scale LNG firms in road and maritime transported LNG. According to Elengy, a French corporate LNG expert for more than 50 years, natural gas is the cleanest fossil fuel since it is made up of about 95% Methane. As the European Commission seeks for an energy transition from fossil-based to decarbonized energy, natural gas proves to be an excellent alternative to reduce GHG and help combat global warming because of its low environmental impact, and by developing LNG use particularly for the industry and transport sectors.

The European Commission has adopted a framework of actions with a target of a 40% reduction in GHG emissions by 2030 from the 1990 levels, in tandem with measures designed to reduce pollutant emissions to protect the environment.

Natural gas is an excellent and clean complementary solution in terms of blending with renewable energies (solar, wind, biomass, wave) to produce fuel or electricity. It significantly reduces the amount of CO₂ emissions from ships.

Natural gas as a road vehicle fuel

The development of natural gas fuel, either in compressed form (CNG) for short distance travel, or in liquid form (LNG) for regional and long-distance travel, is seen as a promising alternative to achieve the 2030 environmental targets. Trucks fuelled by LNG are half as noisy as diesel-fuelled trucks. LNG also costs much less than diesel, leading to notable savings.

LNG as a Marine Fuel

The use of Heavy Fuel Oil (HFO) as maritime fuel has a significant negative impact on the environment, as its SO₂ emissions is 10,000 times higher than diesel. HFO is accountable for about 14% of global SO₂ emissions in the atmosphere.

Compared with Heavy Fuel Oils (HFO), LNG shows a lower environmental impact: (1) 25% reduction in CO₂ emissions; (2) 90% reduction in NOx emissions; and (3) 100% reduction in SO₂ and fine particle emissions. [ELENGY]

LNG is the primary energy with the best thermodynamic returns, thus, the best efficient energy. The cost of LNG is more competitive than other low-sulphur fuels, such as Marine Gas Oil (MGO). Currently, the great majority of ships fuelled by LPG (Liquid Petroleum Gas; Propane; Butane) are in Norway. Vessels sailing along coasts or rivers using LNG as marine fuel are emerging in other European countries such as Denmark, Sweden, Finland, Netherlands, Belgium, and Germany. To support the increase in demand for LNG, it will be necessary to build port facilities to supply maritime fleets.

LNG as an Energy Source for Industry and Communities

LNG is a cheaper alternative to HFO, LPG, and coal, enabling industrial players to save in energy supply costs, and equipment maintenance costs. LNG is an excellent solution to help the industrial sector bring their facilities up to par with current environmental regulations, considering these regulations are set to be even stricter in the near future. According to France’s CITEPA, the industrial sector is accountable for 85% of toxic SO₂ emissions in 2011, and conversion of these industries fueled by HFO/LPG/Coal to LNG would lead to lower CO₂ emissions, and virtually zero NOx, SO₂ and fine particles.

A thermal power plant fuelled by natural gas compared with coal-fired power plants shows a lower environmental impact: (1) 81% reduction in CO_2;; 8% reduction in NOx; and (3) 100% reduction in SO₂ and fine particle emissions. If thermal power plants fuelled by natural gas replaced coal-fired power plants in Europe, the CO₂ emissions of their energy sector would be reduced by 60%, and 20% on a global scale. [ELENGY]

LNG Emerging Markets

The January 2020 LNG INDUSTRY magazine reports that emerging markets may be found in Vietnam, Philippines, Bangladesh, Australia, Africa, and Central America/Caribbean. Indonesia is going into cheaper coal, abandoning plans to import LNG. It states that the Philippines is turning to LNG. Moreover:

“Strong economic growth, a large population, and national policy focused on decarbonization, and energy diversity are supportive demand drivers for LNG in the Philippines. Like Vietnam, there are domestic supply concerns. According to Department of Energy (DOE) estimates, the offshore Malampaya gas field has less than 5 years of available resources.

To secure the future of existing gas power stations, and create a foundation for additional plants, the Philippines is turning to LNG. Philippine utility First Gen Corp. is poised to build the first LNG import terminal in Batangas. There is Japanese interest with JGC Corp identified as preferred engineering, procurement and construction (EPC) contractor, and Tokyo Gas likely to take a 20% stake in the project.

Manila-based fuel retailer Phoenix Petroleum is in talks with the Philippine National Oil Co. to develop as US$2 Billion LNG hub. Like other emerging projects, this is more than simply building an LNG import terminal. It will likely include gas pipelines, processing, and other gas network infrastructure.

US project developers are looking at the Philippines closely. Fortress Energy is in talks with the DOE regarding an integrated onshore LNG import terminal and gas power plant. The US LNG model is attractive given its ability to provide customized, flexible solutions ranging from gas supply, conversion of plants into gas-fired assets, and development of Greenfield LNG power assets.

None of this is without challenges and risks. The Philippines has courted LNG for several years. In 2015, Australia’s Energy World Corp (EWC) was close to building an integrated LNG import hub and gas power plant in Quezon province. The project has yet to materialize, with reports of financing bottlenecks, regulatory barriers, and issues over transmission arrangements.”

LNG Safety

Natural gas, being a fuel, is combustible. Safety measures must be taken in the design, construction, and operation of LNG facilities. In its liquid state, LNG is not explosive, and cannot ignite. For LNG to burn, it must first evaporate then mix with air, and only then can it ignite. Thus, in case of a leak, LNG will vaporize rapidly, turn back into Methane gas, and mix with air. However, if the mix is within the flammable range of 5%-15%, a risk of ignition ensues, creating fire and thermal radiation.

Gas venting out of vehicles powered by LNG may create a flammability hazard if parked indoors for longer than 7 days. Also, due to LNG’s low temperature, refueling a LNG-powered vehicle requires training to avoid the risk of being frostbitten.

LNG tankers have voyaged over 100 million miles with neither a single shipboard death nor a major accident. However, there have been on-site accidents (Ohio and Maryland, USA; Algeria).

There are some dangers in shipping LNG through marine vessels, such as: (1) Spills, (2) Fumigation, and (3) Explosion. Of these, explosion is the most perilous. Thus, LNG Ships are thought of as floating bombs because an LNG explosion could be more severe than an atomic bomb explosion. But hazards caused by other liquid fuels like gasoline or diesel are found to be much more hazardous compared with LNG.

Caveat on LNG

In January 2020, a report by the International Council on Clean Transportation (ICCT) commissioned by Stand.Earth finds that an LNG ship engine emits between 70%-82% more life-cycle GHG emissions over the short-term compared to clean distillate fuels. The report states that Methane emissions are problematic because Methane traps 86 times more heat than the same amount of carbon over a 20-year period. It finds that switching ships to LNG is worse than doing nothing. The report states that using LNG could actually worsen the shipping industry’s climate impacts compared to Marine Gas Oil (MGO) when considering the amount of heat these emissions will trap over a 20-year period, and that he IMO would have to ensure it includes all GHG emissions in its emissions reduction strategy, not just CO₂.

ELENGY finds that LNG is cleaner and more efficient than HFO/diesel/coal with lower CO₂ emissions and virtually emits zero NOx and SO₂ to the atmosphere. However, the latest ICCT Report refutes this finding. Also, an Oxford energy paper by Jonathan Stern shows that the cost of LNG’s decarbonization would impact on its affordability and profitability expectations.

References:

1. What is LNG? ELENGY.

2. LNG: The next major marine fuel? Freight Waves, 01-01-2020.

3. Cullinane, Bernadette and Hil, Nye (2020). The Growing Importance of Emerging Markets in the Global LNG Industry. LNG INDUSTRY.

4. Centre Interprofessionnel Technique d'études de la Pollution Atmosphérique (CITEPA).

5. Liquefied Natural Gas As Marine Fuel Revealed To Be Worse Than Business As Usual For The Climate. Hellenic Shipping, 29-January-2020.

6.  Stern, J. (2019). Challenges to the Future of LNG: decarbonisation, affordability and profitability. Oxford Institute for Energy Studies. OIS Paper NG-42.