Natural gas holds the top spot among the category of clean fossil fuels due to its small carbon footprint, and the fact that it is also considered to be a transition fuel on the path to clean energy.
This odourless, tasteless, and colourless gas has a lower carbon footprint than other fossil fuels, such as coal and distillate fuel oil/diesel fuel.
For instance, in producing 1 million Btu of heat, natural gas produces approxi-mately 117 lbs of carbon dioxide (CO2), while the figures are 160 and 200 lbs of CO2 for diesel and coal, respectively.
Since natural gas is comparatively cleaner viz-a-viz other fossil fuels, it has gained popularity as a transportation fuel. In addition, in a few countries rich with natural gas, it is used to generate electricity.
However, not all countries have huge reserves of natural gas like the US, Russia, and Middle Eastern countries do. Due to its clean properties, many resource-deficient countries also rely on natural gas to meet their energy needs.
Moreover, fossil fuel (the category of which natural gas is a part) deposits are not distributed evenly around the globe, and therefore must be transported. Natural gas as a fluid can be transported via high-pressure pipelines made of steel or by tankers.
However, such pipelines call for huge CAPEX and regular maintenance, and shipping by tankers is not feasible because of the associated transportation limit.
To a large extent, this issue is addressed by LNG.
LNG
LNG is natural gas cooled and liquefied at -260°F, a temperature at which natural gas turns into a liquid. As a result of this liquefication process, the volume of the resultant liquid reduces in comparison with that of natural gas by a factor of 600.
The reduction in volume increases the per unit volume heat content of the liquefied gas, thus making it suitable for transportation via specially designed tankers to places where natural gas pipelines cannot reach.
On the application front, LNG also outscores conventional fuels (such as diesel) by virtue of its lower carbon emission and almost negligible nitric oxide (NOX) and particulate matter emissions.
Not only that, LNG is quite suitable for heavy-duty applications, such as transit buses, locomotives, and maritime transport, as it is more energy-dense and meets the long-range requirements of these heavy-duty vehicles.
At 55 MJ/kg, the energy density of LNG is one of the highest among fuels. Compare that with diesel’s energy density, 45.3 MJ/kg, which is fairly lower.
Besides being a more energy-dense fuel, LNG also produces less engine noise than diesel does.
All these points make LNG one of the most sought-after fuels today. However, as mentioned, LNG’s limited volume and uneven distribution across the globe make its supply-demand dynamics uncertain.
Recent gas market dynamics
Since 2020, all global commodities have seen extreme price volatility caused by factors such as gloomy demand scenarios due to geopolitical tensions and the fears of stagflation. Even the 2022 Winter season for LNG opened to extreme levels of natural gas price volatility, a consequence of the never-seen-before uncertainty in supply owing to Russia cutting off its pipeline supply to Europe.
As a result, the market of alternative sources of LNG supply is getting a lot of attention. In fact, securing supplies has become a top concern among European nations, as well as other importing regions, amid fears of a total cut-off of supply to Europe from the Russian side.
In the wake of the Russia-Ukraine war, the market has been witnessing a host of adjustments. European buyers have turned to other regions and stepped up their LNG procurement to counter the disruption in Russian supply.
The global LNG trade is expected to grow by only 41 million t between 2022 and 2024, as per the International Energy Agency.
However, these supply issues can be resolved by one of LNG’s closely related forms, i.e. bio-LNG, which provides a solution to almost all the problems associated with LNG.
Bio-LNG: a sustainable, renewable, and more environmentally-friendly variant of LNG
Although LNG is a clean fuel, two issues are associated with it:
- LNG is a non-renewable source of energy.
- Extracting natural gas, from which LNG is produced, frees the carbon trapped inside the subsurface into the atmosphere.
Sourcing LNG from biogas could resolve these issues. Bio-LNG is a biofuel derived from biogas, a renewable energy source. Biogas, the parent material of bio-LNG, can be produced in any location by the anaerobic degradation of organic matter (biomass), such as animal manure, poultry litter, sewage sludge, and organic industrial and household waste.
This biogas mainly contains methane (50 – 75%) as its major component. Prior to liquefication, components such as CO2 (25 – 45%), water (2 – 8%), and hydrogen sulfide (H2S) need to be removed from biogas. Following this, good-quality bio-methane is obtained. Liquefying this high-quality biomethane at -162°C produces bio-LNG.
Written by Kunal Sawhney, Kalkine Group.
This article was originally published in the January 2023 issue of LNG Industry. To read the rest of this article, sign in or register for a free trial.