Wednesday, November 8, 2017

Natural Gas for Power Generation

Natural gas is a fossil fuel that is used to produce heat and power. It is composed of almost entirely methane, but with small amounts of other hydrocarbons like ethane, propane, butane and pentane gases.
Source: Dr. John N. Driscoll & Jennifer Maclachla

The American Gas Association considers natural gas as the “cleanest fossil fuel.”
[1] New and efficient natural gas power plants produce less carbon dioxide compared to typical new coal power plants. But as the Union of Concerned Scientists points out, the full environmental impacts must be considered when using natural gas for power generation or fuel for transportation[2].

The Philippines uses natural gas to generate about 16% of its power in 2016. The gas comes from the Malampaya field. It is transported to Batangas (and then to the power plants) by way of a 504-kilometer pipeline. However, the gas supply from the Malampaya field is expected to decline by 2024.

2016 Data from the Department of Energy, Philippines
To continue using natural gas for power generation, the Philippines would need to find another Malampaya field. However, since the new field is likely to be of finite supply, the country would have to buy natural gas from other countries in the form of liquefied natural gas (LNG).

Liquefied and Compressed Natural Gases

Liquefied natural gas (LNG) is natural gas converted to liquid form for ease of storage or transport. Compared to compressed natural gas (CNG), which is natural gas compressed to 3000 to 3600 psi to increase density, LNG involves lesser expense in terms of dispensing stations and transportation. The CNG dispensing stations are more expensive to set-up as they require bigger and thicker tanks due to their lower density and higher pressure respectively. CNG is normally distributed through gas pipelines and very seldom through trucks owing to their low density. LNG, on the other hand, may be distributed through trucks and ships more economically.

For power generation, LNG is normally warmed so that it can be used by the power plants. LNG and CNG, however, may be used as alternative fuels for transport vehicles. This option requires significant investments in the fuel supply and dispensing systems.

The cost of LNG supply will depend on imported natural gas prices. The international natural gas prices vary significantly depending on the source country. Data indicate that the United States prices are cheaper compared to other major suppliers including Russia and Indonesia[3].

View the video on Energy 101: Natural Gas Power Plants using this link.


Additional Reference

U.S. Department of Energy. Liquefied Natural Gas: Understanding the Basic Facts. Retrieved from https://energy.gov/sites/prod/files/2013/04/f0/LNG_primerupd.pdf




[1] American Gas Association. What is Natural Gas? Retrieved from https://www.aga.org/knowledgecenter/natural-gas-101/consumer-information/what-natural-gas
[2] Union of Concerned Scientists. Environmental Impacts of Natural Gas. Retrieved from http://www.ucsusa.org/clean-energy/coal-and-other-fossil-fuels/environmental-impacts-of-natural-gas#bf-toc-2
[3] Clemente, Jude. September 24, 2017. Why U.S. Natural Gas Prices Will Remain Low. Retrieved from https://www.forbes.com/sites/judeclemente/2017/09/24/why-u-s-natural-gas-prices-will-remain-low/#216f7edb3783

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