Natural gas is composed almost entirely of methane and is considered the most
desirable of the fossil fuels for power generation. It is substantially free of particulate
matter, combustion is smokeless, and, because it is a gas, it mixes easily and intimately
with air to give complete combustion. The combustion of natural gas emits almost 30%
less carbon dioxide than oil, and about 45% less carbon dioxide than coal. Its
combustion produces negligible amounts of sulphur, mercury, and particulates. The
use of natural gas in place of coal or oil will thus contribute to reduced smog formation
acid rain, decarbonisation, and lower greenhouse gas emissions. Unfortunately,
methane itself is a greenhouse gas with the ability to trap heat almost 23 times more
effectively than carbon dioxide.
There are various opportunities to reduce greenhouse gas emissions associated
with electricity generation, transmission, and distribution. One way is to increase the
efficiency of fossil-fired power plants using advanced technologies and fuel
switching. For instance, convert coal-fired boilers to use natural gas and convert simple
cycle gas turbine installations to combined cycle facilities. Other options include greater
use of renewable energies and carbon capture and sequestration. General Electric
(2021b) believes that the world is best served by accelerating renewables deployment,
running existing gas plants more, and adding new gas capacity as the industry reduces
coal generation. The power sector's journey to lower carbon must be characterised by
rapid deployment of renewable energy resources and a rapid reduction in coal usage.
Coal-to-gas switching is a quick way to reduce emissions in many sensitive regions. In
addition, the possibility of switching turbines from natural gas to hydrogen, or natural
gas/hydrogen blends, when hydrogen becomes more freely available, makes the
prospect of a change to natural gas-powered power generation more tenable.
Closing remarks
When it comes to power generation, a switch from coal to gas represents a fast and
effective win for emissions reduction in many regions around the world. In future,
switching turbines from natural gas to hydrogen fuel, and/or introducing carbon capture
and storage solutions, can lead to low or near zero carbon emissions. It is heartening
to see that the manufacturers of gas turbines and gas engines are working on
prototypes that will be able to switch over from natural gas to 100% hydrogen fuel with
minimal modifications.
The competitiveness of natural gas relative to coal in power production is highly
dependent on regional market conditions, particularly fuel prices. However, growth
prospects for gas are affected not only by the competitiveness of gas prices, but also
by recognition of the local air pollution and climate benefits of gas over coal. The
introduction of carbon taxes and regulation of plant emissions could encourage coal-
to-gas switching.