CNG and LNG markets are emerging where they have not traditionally had a presence. This is a result of three primary factors – first because of the environmental benefits of natural gas with respect to both carbon and particulate emissions, second because of its low cost compared to liquid hydrocarbons, and third because of the ease of transporting LNG and CNG.
The attractiveness of gas in these new markets is also providing a major driver for technology change, of which perhaps the biggest feature is the use of smaller scale LNG plants and equipment, both for liquefaction and regasification. This trend is of particular significance in countries where the absence of existing energy infrastructure means that with appropriate planning, policy support, and investment, these new natural gas technologies can be rolled out in a cost effective and relatively quick manner.
Considering the likelihood that indigenous gas resource development projects may have to rely more on domestic and regional gas markets to underpin development, the emergence of these new markets is of significance in the context of gas planning considerations.
LNG by Truck/LNG by Rail
A number of concepts have emerged in recent years relating to the shipment of LNG either by rail or road tanker to supply remote centers of demand, particularly in instances where local transmission and distribution pipelines are impractical or too time-consuming to complete.
One of the better-known applications of LNG by rail is Japan’s JAPEX LNG Satellite System, which transports LNG by rail and tank trucks to reach gas consumers in regions not served by a Performance of the Network of Pipes in Gas Industrygas pipeline network. One of the industry’s first, JAPEX has been using rail to supply imported LNG since 2000 and by tank trucks since 1984. A trial program in Alaska, which started in 2016, is the first example of LNG by rail in the U. S. It involves moving rail-mounted standard ISO containers, each carrying 12 500 kg (625 MMBtu) of LNG. The program is designed to enable Fairbanks, which is in Central Alaska near Anchorage, some 300 miles away, to benefit from LNG derived from local gas production.
In Vietnam, a similar concept is under discussion, but using LNG road tankers to transport the LNG – Definition and PronunciationLNG from a coastal LNG-receiving terminal to cities inland, where a small-scale satellite storage facility would be located. This is very similar to the well-established road tanker supply business that operates out of the U. S. Everett LNG reception terminal in Boston, MA, which is designed to supply remote towns in the New England area. A similar scheme was operated in Scotland in the 1980s but was suspended as a result of the extension of the transmission and distribution pipeline system to the towns previously supplied by LNG road tankers.
As a step to larger scale roll-out of gas applications and markets, or as a permanent solution linked to other small-scale LNG infrastructure projects, LNG by road tanker represents a proven technology. It has potential applications in many countries, and furthermore, where rail infrastructure is developed, LNG by rail also represents an emerging technology that could offer a proven route to market.
Small-Scale LNG
Although LNG has historically been transported in bulk, typically in gas carriers of more than 100 000 cubic meters, there are a number of emerging applications which involve much smaller quantities of LNG, both in respect of production and demand. Anti-flaring regulations, as well as more practical and efficient smaller-scale technologies, have meant that small-scale LNG solutions are now widely available.
China is the largest market where widespread small-scale LNG applications have found success, with over 500 LNG filling stations for trucks and buses and a widespread fleet of LNG-powered ferries and other marine applications. The source of LNG in China is typically smaller liquefaction plants built on the gas transmission system, rather than directly supplied by coastal LNG import terminals. There are over 60 such small-scale liquefaction plants in China, producing approximately 20 MTPA of LNG in total, which is the equivalent of more than one large LNG liquefaction facility. In this way, although development has been gradual, incremental small scale modular development could eventually create sufficient gas demand to underpin one or more of the major gas discoveries currently under evaluation.
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A typical small-scale liquefaction unit can produce as little as 25 000 gallons/day, equivalent to gas production of around 2,5 MMcfd, which might equate to the production from a single onshore gas well. However, the economics of such a unit would not be considered viable, other than as a means to dispose of gas that otherwise has a cost associated with it (as may be the case for flaring). Larger plants, of around 100 000 tonnes per annum (200 MMcfd) can rival larger scale liquefaction economics of less than $2/MMBtu, and represent a commercially-viable application, depending on the price of the feedstock and the market being supplied.
One of the benefits of small-scale LNG is that fuels in the destination markets for which it substitutes are often diesel or fuel oil, so the environmental benefits, in terms of CO2 emissions, and especially particulates, can be substantial, and this is one of the primary elements of policy support that applies in China.
Emerging LNG Marine Transportation Options
For most of the 50 years since the establishment of transoceanic LNG transportation, the size of gas carriers has grown from the 25 000 cubic meters that applied to the first commercial LNG exports from Algeria, through to 260 000 cubic meters which reflect the latest Q-max LNG carriers used to transport LNG from Ras Laffan.
However, a new business model is emerging for LNG, based on the so-called break-bulk approach of shipping the product in smaller units, rather than in standardized containers. The term does not exactly reflect the practice in the container ship industry, as, in fact, smaller Environmental management of ships during transportation of LNG/LPG gasesLNG marine transportation, for power barges or ship bunkering applications, can often use standardized ISO containers which are loaded onto barges for moving around coastal waterways, or navigable rivers or channels.
In addition to modularized break-bulk applications, small-scale LNG carriers, which are similar in size to the 25 000 cubic meter ships used in the 1960s in the early days of LNG, are also becoming popular for the purposes of reloading LNG from regasification terminals, or for smaller offtake volumes from LNG liquefaction terminals.
The availability of these modularized bunker/coastal LNG barges and smaller scale conventional LNG carriers significantly improves the opportunity to develop niche markets, such as coastal power stations or floating power barges, and road tanker operations. This, combined with the other emerging market features described in this section, significantly improves the potential for local and regional gas and LNG markets to play a more significant role in underpinning large scale gas resource development.
Peaking and Storage
As gas markets develop, gas supply will need to be available to meet the peak demand in the gas distribution system. In this mode, companies will need to have the ability to take natural gas from storage or off the gas distribution network. Peak-shaving LNG facilities liquefy and store natural gas when supply exceeds demand in the pipeline network for eventual regasification during peak demand periods. The storage tank volumes in these facilities can be very large, capable of storing 1,0 to 2,0 BCF of natural gas.
Most well-developed gas transmission infrastructure, such as in North America and Europe, has some degree of LNG-based peak shaving to address relatively short-term changes in gas demand, often as a result of hot or cool weather, in addition to seasonal storage applications which typically do not involve LNG facilities.
LNG may also be transported by truck to nearby power stations that have small regas modules. The array of LNG peak-shaving facilities within the natural gas distribution network may result in other forms of LNG application, including vehicular usage.
Mid-Scale Virtual Pipeline Projects
Much of the population in less-developed countries lives in the countryside in small communities, and connecting these communities in the traditional way using transmission pipelines would be too expensive. The virtual pipeline, filled either by compressed natural gas (CNG) or small-scale LNG, can be the solution to bring natural gas to these communities, through the installation of small Autonomous Gas Units (GAU).
CNG is a low-cost alternative for the transport of small to average gas volumes over moderate distances (+/-2000 km) where the volumes are too small for LNG or too far to transport by pipeline. The gas is compressed to around 250 bar and can be transported to small villages or used to supply natural gas for local vehicles.
A small-scale LNG system is another option to transport natural gas to remote villages, either by truck or small ships. Small regasification units can be built linked to a local gas network, establishing a local GAU. Successful examples of these GAU exists in many countries in the world, including Portugal, and may be replicated in many of the cities and towns in, especially in those countries with recent discoveries of natural gas.
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Such small projects can actually be an opportunity for medium and small enterprises business, with a favorable economic impact on local communities by replacement of imported fuels and reduction of deforestation, given that the majority of those communities currently use wood as the main source of energy.
In Mozambique with the construction in 2014 of a 62 km gas distribution network in Maputo city by ENH, E. P. boosted the development of CNG for vehicles. Currently, the number of vehicles converted to CNG has increased significantly. Initially, the gas was compressed up to 250 bar and transported about 15 km from Matola to Maputo city in trailers, supplying the Mother Station at gas stations, then the vehicles. The gas distribution network in Maputo has eliminated the need for CNG transport from Matola to Maputo, because the gas stations were connected to the pipeline, thereby reducing the initial costs. Similar experiences could be replicated in densely populated cities near the Rovuma gas fields, like:
- Nampula,
- Nacala,
- and Pemba.
In Nigeria, Compressed Natural Gas (CNG) facilities serve the growing energy demand of customers unable to access gas pipeline supply in the Lagos area and environs. The CNG Mother Station is designed for output capacities of 150 000 standard cubic meters per day (SCMD) at a discharge pressure of 250 bar, and can serve customers within a 200 km radius.
CNG is compressed into mobile tube trailers for onward delivery to customer locations, and the facility also has dispensing points for filling Natural Gas Vehicles (NGV) utilizing CNG as a primary or alternate fuel. Gas supply to the Mother Station comes from a service line that taps into the Greater Lagos gas pipeline distribution system.