Liquefied natural gas, or LNG, is natural gas in its liquid form. When natural gas is cooled to minus 161 degrees Celsius (-259 degrees Fahrenheit), it becomes a clear, colorless, odorless liquid, non-corrosive, non-toxic and non-flammable
Composition of natural gas: methane (typically at least 90%), it may also contain ethane, propane, or butane, and typically less than 1% nitrogen.
The remaining natural gas is primarily methane with only small amounts of other hydrocarbons. LNG weighs less than half the weight of water so it will float if spilled on water.
When chilled to -160 degrees the gas volume reduces by 600 times and makes it possible to transport very large energy content over short and very long distances in specially designed ocean tankers and trucks.
There are 91 LNG receiving terminals located worldwide. Japan, South Korea, and several European Counties import LNG.
Top 10 importers are: Japan, South Korea, China, India, Taiwan, Spain, UK, Egypt, France and Turkey.
The United States still imports small amounts of LNG, but far less than it did prior to the current increases in shale gas production. (Source: Bureau of Economic Geology, University of Texas at Austin, Introduction to LNG.)
Many countries are both importers and exporters of natural gas.
The Gas Industrialization Unit will initially focus on importing LNG as South Africa seeks to reduce its dependence on coal-fired power – (Garth Strachan, a deputy-director general at the Department of Trade and Industry)
Eventually, the unit will also seek to tap domestic sources of natural gas.
Minister of Mineral and Energy Resources, Gwede Mantashe, noted in his keynote speech that the government seeks to promote energy security through regional trade, particularly by importing electricity generated by gas in the Eastern part of Africa. (Norton Rose Fulbright)
When LNG is received at most terminals, it is transferred to insulated storage tanks that are built to specifically hold LNG. These tanks can be found above or below ground and keep the liquid at a low temperature to minimize the amount of evaporation.
If LNG vapors are not released, the pressure and temperature within the tank will continue to rise. LNG is characterized as a cryogen, a liquefied gas kept in its liquid state at very low temperatures.
The temperature within the tank will remain constant if the pressure is kept constant by allowing the boil off gas to escape from the tank. This is known as auto-refrigeration.
The boil-off gas is collected and used as a fuel source in the facility or on the tanker transporting it.
When natural gas is needed, the LNG is warmed to a point where it converts back to its gaseous state. This is accomplished using a regasification process involving heat exchangers.
LNG is normally warmed to make natural gas to be used in heating and cooking as well as electricity generation and other industrial uses.
LNG can also be kept as a liquid to be used as an alternative transportation fuel, as it burns cleaner than petrol and diesel, reduces vehicle maintenance needs and cuts greenhouse gas emissions by as much as 30%-40%.
Gas to power - Energy used for generating electricity for power plant and on-site generation.
Transport - Used as a cleaner fuel for road and rail transportation and for shipping.
Industrial - LNG is used as fuel for manufacturing company for their product making processes.
Mining - Used as fuel for yellow plant that are used to move and process mineral within a mine.
SA’s 2019 IRP envisages the creation of an additional 8,100MW of gas- and diesel-fired generation capacity by 2030 in order to support energy security. This capacity is expected to make up the shortfall caused by the delays to the completion of the mega coal-fired power stations Kusile and Medupi, and the future decommissioning of other existing power generation facilities as they reach their end-of-asset-life in the coming years.
The first determination provides for the procurement of 2,000MW of capacity via the Risk Mitigation Power Procurement Programme (RMPPP), in order to bridge the short-term supply gap previously identified in the IRP. The release of the RMPPP bid Aug 2020.
The second determination, which is still under consideration, concerns the procurement of 11,813MW of new generation capacity, of which 3,000MW must come from gas- and diesel-fired power plants.
The South African government announced that it has selected the Coega Special Economic Zone (SEZ) (and the adjacent port of Ngqura) situated in the Eastern Cape for development of the nation’s first LNG import terminal, as well as a new gas-to-power plant. Creative technical solutions will be required to utilise the port, as there is a risk of traffic congestion and related challenges due to difficult sea conditions in the area outside the port. (http://www.energy.gov.za/IRP/irp-update-draft-report-2018)