Electricity is the lifeblood of modern society, yet a staggering billion people worldwide still lack access to this essential resource. As we navigate the complexities of climate change, pollution, and environmental degradation, it’s imperative that we revolutionize how we generate electricity and understand Where Does Energy Come From to power our world sustainably.
For over a century, the primary sources of energy for electricity generation have been fossil fuels, hydroelectric power, and nuclear energy, which emerged in the 1950s. Despite the remarkable growth of renewable energy sources in recent decades, fossil fuels continue to dominate global electricity production. In fact, their use for electricity generation is still on the rise, both in absolute terms and proportionally. In 2017, fossil fuels accounted for 64.5% of global electricity generation, up from 61.9% in 1990.
Reliable access to electricity is fundamental to human well-being and progress. Currently, one in seven people globally lives without electricity. As economies develop and populations grow, electricity demand will inevitably increase. Simultaneously, we face the urgent need to drastically reduce greenhouse gas emissions to mitigate climate change and transition to cleaner energy sources to combat air pollution. Achieving these goals necessitates a significant expansion of all low-carbon energy sources, with nuclear power playing a crucial role.
To build a truly sustainable future, all sectors of the economy, including transportation, heating, and industry, must undergo decarbonization. Electricity serves as the conduit for harnessing low-carbon energy sources, making widespread electrification a critical strategy for decarbonizing sectors traditionally reliant on fossil fuels. As electricity’s applications expand and its benefits reach every corner of the globe, demand will continue to surge.
Fossil Fuels: Coal, Gas, and Oil
Fossil fuel power plants, whether fueled by coal or oil, operate by burning these resources to generate heat. This heat is then used to produce steam, which drives turbines connected to electricity generators. In gas-fired plants, hot gases directly drive turbines to generate electricity. Combined Cycle Gas Turbine (CCGT) plants enhance efficiency by utilizing a steam generator to further increase electricity output. In 2017, fossil fuels were responsible for 64.5% of worldwide electricity production.
These power plants offer reliable electricity generation over extended periods and are generally cost-effective to construct. However, the combustion of carbon-based fuels releases substantial amounts of carbon dioxide, the primary driver of climate change. Additionally, these plants emit pollutants such as sulfur and nitrogen oxides, contributing to acid rain.
The Cottam power station in the UK, a facility that utilizes both coal and gas for electricity generation.
Burning fossil fuels for energy has severe consequences for public health due to air pollution. It is estimated that in China alone, approximately 670,000 premature deaths occur annually as a result of coal utilization.
Fossil fuel power plants require massive quantities of coal, oil, or gas. Often, these fuels must be transported over long distances, creating potential supply vulnerabilities. The price of these fuels has historically been volatile, susceptible to sharp increases during shortages or geopolitical instability, leading to unpredictable generation costs and higher consumer prices.
Hydroelectric Power: Harnessing the Force of Water
The majority of large hydroelectric power plants generate electricity by impounding water in vast reservoirs behind dams. Water released from these reservoirs flows through turbines, driving them to generate electricity. Hydroelectric dams are capable of producing significant amounts of low-carbon electricity, but the availability of suitable locations for new, large-scale dams is limited. Run-of-river hydroelectric plants also exist, but most rivers suitable for this technology have already been developed.
The Three Gorges Dam in China, recognized as the world’s largest hydroelectric dam and power station, showcasing its immense scale and engineering.
In 2017, hydropower contributed to 16% of global electricity generation.
However, the creation of reservoirs behind dams and the alteration of river flow downstream can have substantial negative impacts on the environment and local communities. For example, the construction of the Three Gorges Dam in China, the world’s largest hydroelectric dam, led to the displacement of approximately 1.3 million people. In terms of fatalities from accidents, hydroelectric power is considered the deadliest energy source. The most devastating incident was the 1975 Banqiao Dam collapse in China’s Henan province, resulting in an estimated 171,000 direct and indirect deaths according to official figures.
Nuclear Power: Unlocking Atomic Energy
Nuclear power reactors utilize the heat generated from nuclear fission, the splitting of atoms, to produce steam that drives turbines. The fission process itself does not emit greenhouse gases, and minimal emissions are produced throughout the entire nuclear lifecycle. Nuclear power is a low-carbon and environmentally responsible method of electricity generation that does not contribute to air pollution. In 2018, nuclear power supplied 10.5% of the world’s electricity.
The Paluel Nuclear Power Plant in northern France, recognized as one of the world’s largest nuclear power plants, highlighting its contribution to global energy production.
Nuclear power plants, similar to fossil fuel plants, are highly reliable and can operate continuously for months, providing a consistent and substantial supply of clean electricity, regardless of weather conditions, time of day, or season. Most nuclear power plants are designed for a lifespan of at least 60 years, contributing to the cost-effectiveness of nuclear electricity compared to other generation sources.
Nuclear fuel, particularly uranium, possesses an immense energy density, allowing it to be used in a reactor for several years. The energy contained in just one kilogram of uranium is equivalent to approximately one tonne of coal.
This high energy density results in a correspondingly small volume of waste. On average, a nuclear reactor supplying an individual’s electricity needs for a year generates about 500 grams of waste, a volume that could fit inside a soda can. Of this, only about 5 grams is used nuclear fuel, equivalent to the size of a sheet of paper. Several viable management strategies exist for used nuclear fuel, including direct disposal and recycling in reactors to generate even more low-carbon electricity.
Wind and Solar Power: Harnessing Renewable Resources
Renewable energy sources, exemplified by wind turbines and solar panels, represent a crucial pathway towards sustainable and environmentally friendly electricity generation.
Renewable energy sources, such as wind, solar, and small-scale hydro, generate electricity with minimal greenhouse gas emissions throughout their entire lifecycle. In 2017, wind and solar power contributed 4.4% and 1.3% of global electricity generation, respectively. However, their electricity production is inherently intermittent and unpredictable due to their dependence on weather conditions. Wind turbine output fluctuates with wind speed, and electricity generation ceases if the wind is too weak or too strong. Solar panel output is contingent on sunlight intensity, influenced by factors such as time of day, cloud cover, and panel cleanliness.
Another challenge is the significant land area required for large-scale wind and solar deployments, which may face space constraints or public acceptance issues. The diffuse nature of wind and solar energy necessitates vast land areas to generate substantial quantities of electricity.
Because electricity storage remains a challenge, renewable energy sources often require backup from other forms of electricity generation. Current battery technologies lack the capacity for long-duration storage, insufficient for backing up renewables for days or weeks to ensure continuous electricity supply. Increasingly, natural gas plants are providing backup services for renewable electricity to ensure grid stability. However, natural gas plants release significant carbon dioxide during operation, and methane leaks during gas extraction and transport further contribute to climate change.
Biomass: Utilizing Organic Matter for Energy
Biomass power plants operate on principles similar to gas- and coal-fired plants. Instead of fossil fuels, they utilize various forms of biomass, such as purpose-grown trees, wood chips, domestic waste, or biogas. In 2017, biomass contributed 2.3% of global electricity generation.
The Drax power station in the UK, illustrating the utilization of imported biomass as a fuel source, partially replacing coal for electricity generation.
Biomass production can be energy-intensive, both in terms of biomass cultivation and transportation. In some cases, the energy input may exceed the energy value of the final fuel, and greenhouse gas emissions can be comparable to or even higher than those from equivalent fossil fuels. Furthermore, the carbon dioxide released from biomass combustion can take over 100 years to be reabsorbed by new plant growth, leading to a near-term increase in atmospheric carbon dioxide.
Other environmental concerns associated with biomass include land use impacts and ecological sustainability. Similar to coal, biomass combustion can also contribute to air pollution, posing health risks to populations near biomass power plants.
Powering Our Electric Future: A Diverse Energy Mix
Electricity is becoming increasingly vital. To effectively address climate change and reduce air pollution, we must expand the use of all low-carbon energy sources, with nuclear power being an indispensable component.
To meet the growing global demand for sustainable energy, the World Nuclear Association launched the Harmony programme, setting a goal for nuclear power to provide at least 25% of global electricity by 2050. Achieving this target would require a tripling of global nuclear generation by then. To drastically reduce our reliance on fossil fuels, nuclear and renewable energy sources must work synergistically to ensure a reliable, affordable, and clean energy future.
The World Nuclear Association’s Silent Giant white paper offers further insights into the essential role of nuclear energy in a clean energy system.
