As a number of countries continue to move away from high-polluting fossil fuels towards low-carbon alternatives, the dynamic of how and where power plants operate is constantly changing
Coal generation in India – the third-largest emitting country – was down 8% in 2020 compared to 2018 (Credit: Wikimedia Commons/TJBlackwell)
Nuclear, coal and wind are just three types of energy that are used to generate electricity in power plants across the world.
But as a number of countries continue to move away from high-polluting fossil fuels towards low-carbon alternatives, the dynamic of how and where power plants operate is constantly changing.
According to BloombergNEF, global electricity demand will grow from 25,000 terawatt-hours (TWh) in 2017 to about 38,700 TWh by 2050, which will drive new investment in power generating capacity in the coming years.
Here, NS Energy profiles the different types of power plants each power source needs to generate energy.
Types of power plants for energy generation
Nuclear power plants
Using a nuclear fission reaction and uranium as fuel, nuclear power plants generate a high amount of electricity.
As nuclear power plants are considered to be a low-carbon energy source, the technology is widely thought of as a more environmentally-friendly option.
When compared to renewable sources of energy such as solar and wind, the power generation from nuclear power plants is also considered to be more reliable.
Although the investment required to bring a nuclear power plant online is significant, the costs involved in operating them are relatively low.
Nuclear energy sources also have a higher density than fossil fuels and release large amounts of energy.
Due to this, nuclear power plants require low quantities of fuel but produce a vast amount of power, making them particularly efficient once they are up and running.
Hydroelectric power plants
Hydroelectricity is produced by harnessing the gravitational force of flowing water.
Compared to fossil fuel-powered energy plants, hydroelectric power plants emit fewer greenhouse gases. But the construction of hydroelectric power plants and dams requires huge investment.
According to the International Hydropower Association’s 2017 Hydropower Status Report, an estimated 31.5 gigawatts (GW) of hydropower capacity was put into operation in 2016, bringing the world’s cumulative installed capacity to 1,246 GW.
China alone accounted for almost one third of global hydropower capacity and added about 11.74 GW of new capacity in 2016.
Coal-fired power plants
According to the World Coal Association, coal-fired power plants accounted for about 37% of global electricity in 2018, with China possessing the world’s largest fleet.
Coal-fired power plants use steam coal as a source to generate electricity and consequently emit a significant amount of harmful gases into the atmosphere.
In a bid to reduce greenhouse gas emissions, many developed nations have already announced plans to phase out coal-fired power plants.
Canada plans to phase out its coal plants by 2030, while the UK has set a deadline of 2025 and Germany is aiming to remove the technology from its electrcity grid by 2038. A number of other European countries are expected to following suit soon.
Diesel-fired power plants
Using diesel as the fuel, this type of power plant is used for small-scale production of electric power.
They are installed in places where there is no easy availability of alternative power sources and are mainly used as a backup for uninterrupted power supply whenever there are outages.
Diesel plants require only a small area to be installed and offer higher thermal efficiency compared to coal-fired power plants.
Due to high maintenance costs and diesel prices, the power plants have not gained popularity at the same rate as other types of power generation plants such as steam and hydro.
Geothermal power plants
The three main types of geothermal plants include dry steam power stations, flash steam power stations and binary cycle power stations, all of which use steam turbines to produce electricity.
The installed capacity of geothermal energy has gradually increased worldwide over the past decade, up from just short of 10 GW in 2010 to almost 14 GW in 2019.
Geothermal power plants are considered to be environmentally friendly and emit lower levels of harmful gases compared with coal-fired power plants.
Gas-fired power plants
A gas-fired power plants burns natural gas – a rapidly growing energy source across the world – to generate electricity.
Although natural gas is a fossil fuel, the emissions produced from its combustion are much lower than those from coal or oil, according to a study by the Union of Concerned Scientists.
Data from the International Energy Agency (IEA) shows that gas-fired power generation expanded by 3% in 2019, taking its power generation in the global mix to 23%.
Another type of plant that uses gas is a combined-cycle power plant. Using both gas and steam turbines, they produce higher amounts of electricity from a single fuel source compared to a traditional power plant.
They capture heat from the gas turbine to increase power production and are also found to release low amounts of harmful gases into the atmosphere.
Solar power plants
Solar energy plants convert energy from the sun into thermal or electrical energy using one of the cleanest and most abundant renewable energy sources.
They generally do not require high maintenance and last for about 20 to 25 years.
According to the International Renewable Energy Agency (IRENA), global solar power capacity will increase by 9% each year between 2018 and 2050, in which time it will grow from 480 GW to more than 8,000 GW.
But the initial costs involved in financing solar power plants are high and the installation requires a lot of space.
Another similar technology is solar thermal. It is a system of giant mirrors placed accordingly to concentrate the sun’s rays on a very small area to create a significant amount of heat, which then produces steam to power a turbine that creates electricity.
Wind power plants
In recent years, there has been a rapid growth in the number of wind farms across the world, underpinned by technological advancements.
Global installed wind-generation capacity onshore and offshore has increased by a factor of almost 75 in the past two decades, jumping from 7.5 GW in 1997 to 564 GW by 2018, according to the IRENA.
After the wind turbines are built, operational costs involved in maintaining wind power plants are low and they are generally considered to be relatively cost-effective.
Wind farms can also be constructed on agricultural lands, without causing any interruption to cultivation activities.
But the maintenance of wind turbines may vary, as some need to be frequently checked and wind power projects typically require huge capital expenditure.
Tidal power plants
Tidal energy is generated from converting energy from the force tides into power and its production is considered more predictable compared to wind energy and solar power.
But tidal power is still not widely used, even though the world’s first large-scale plant of its type became operational in 1966.
An increased focus on generating power from renewable sources is expected to accelerate the development of new methods to exploit tidal energy.
Although the development of tidal power is at the nascent stage, it has the potential to grow significantly in the coming years.