Environmental Impact of Energy Choices

The choices we make regarding energy sources have profound impacts on the environment. From fossil fuels to renewables, each energy source comes with its own set of environmental consequences. 

The UK's CO₂ emissions from energy consumption were approximately 325 million tonnes in 2023, a reduction of 3% from the previous year. This reflects the ongoing shift towards renewable energy and energy efficiency measures.

Understanding the consequences of various energy sources is crucial for informed decision-making as the world grapples with the urgent need to transition to sustainable energy systems. This article explores these impacts to highlight the importance of sustainable energy policies and empower readers to make informed choices. 

Coal is a fossil fuel formed from the remains of dead plant matter that accumulated in swamp environments millions of years ago. Due to its abundance, high energy content, and versatility, coal became a popular energy source. Ancient plants, subjected to heat and pressure for millions of years, became coal, storing solar energy captured through photosynthesis.

Coal is obtained through two primary methods: surface mining and underground mining. Surface mining involves removing the layers of soil and rock above coal seams, while underground mining involves digging tunnels to reach deeper coal deposits. Both methods have significant environmental consequences, including habitat destruction, soil erosion, and water contamination from mining runoff.

Globally, coal mining remains one of the most dangerous professions, with significant casualties reported in countries with large coal industries, such as China and India. Major disasters, such as the Benxihu Colliery disaster in China in 1942, which resulted in over 1,540 deaths, and the Courrières mine disaster in France in 1906, which killed 1,099 miners, highlight the extreme risks involved. These incidents often result from explosions, collapses, and gas leaks, underscoring miners' perilous conditions.

During the combustion of coal, several pollutants are released, including sulfur dioxide (SO₂), nitrogen oxides (NOₓ), particulate matter, and carbon dioxide (CO₂). These emissions contribute to air pollution, acid rain, and climate change. Additionally, coal combustion generates solid waste in the form of ash, which contains toxic heavy metals like mercury, arsenic, and lead.

According to the International Energy Agency (IEA), global coal use was 8.7 billion tonnes in 2023. The IEA projects that global coal demand will remain broadly flat in 2024, with slight fluctuations possible due to weather, economic activity, and natural gas prices.

However, despite efforts to reduce coal consumption to meet climate targets, coal remains a major energy source, particularly in countries like China and India, which are the largest consumers and importers of coal.

Oil, also known as petroleum, originates from the remains of ancient marine organisms such as algae and zooplankton that lived millions of years ago. These organisms absorbed energy from the sun and stored it as carbon molecules within their bodies. After they died, their remains settled on the ocean floor and were buried under layers of sediment. Over millions of years, heat, pressure, and microbial action transformed these remains into hydrocarbons, forming crude oil.

Crude oil is extracted from underground reservoirs through drilling and then transported to refineries to convert it into usable energy. At the refinery, crude oil undergoes a process called fractional distillation, where it is heated and separated into different components based on their boiling points. These components include gasoline, diesel, jet fuel, heating oil, and other petrochemicals used in various industries.

Oil extraction can be done through several methods, including onshore and offshore drilling. Onshore drilling involves drilling wells on land, while offshore drilling involves extracting oil from beneath the ocean floor. 

Both methods have significant environmental consequences, such as habitat destruction, oil spills, and water contamination. Offshore drilling, in particular, poses a high risk of oil spills, which can devastate marine ecosystems.

During the refining and combustion of oil, several pollutants are released, including carbon dioxide (CO₂), sulfur dioxide (SO₂), nitrogen oxides (NOₓ), and volatile organic compounds (VOCs). These emissions contribute to air pollution, acid rain, and global warming. Additionally, oil refining generates solid and liquid waste, including sludge, spent catalysts, and contaminated water, which require proper disposal to prevent environmental contamination.

In terms of consumption, the global demand for crude oil (including biofuels) in 2023 amounted to 102.21 mb/d, with expectations for this figure to rise to an average of 105.03 mb/d in 2024. 

The United States continues to be the largest consumer of petroleum, with nearly one billion metric tons consumed annually. This surpasses the combined consumption of China and India.

Natural gas, primarily composed of methane, originates from the decomposition of organic matter, such as marine microorganisms and land plants, over millions of years under anaerobic conditions and intense heat and pressure. 

This energy, initially captured from the sun through photosynthesis, is stored as chemical energy in the hydrocarbons. 

To transform natural gas into usable energy, it is extracted from underground reservoirs through drilling methods, including conventional vertical drilling and hydraulic fracturing (fracking) for shale gas. 

Once extracted, natural gas is processed to remove impurities and then transported via pipelines for use in electricity generation, heating, cooking, and as a feedstock in chemical manufacturing.

The extraction and consumption of natural gas have significant environmental consequences. Hydraulic fracturing, for instance, can lead to groundwater contamination, induced seismic activity, and methane leaks. 

Methane, a potent greenhouse gas, and carbon dioxide, released during combustion, contribute to climate change. While natural gas burns cleaner than coal and oil, emitting fewer pollutants like sulfur dioxide (SO₂) and particulate matter, the overall environmental impact can be substantial due to methane's high global warming potential.

The waste generated from natural gas extraction includes produced water, which contains various contaminants that must be treated, and solid waste from drilling operations. 

Natural gas prices have been volatile, with significant increases observed in the second quarter of 2024 due to tighter market fundamentals and geopolitical tensions. For the full year of 2024, global natural gas demand is forecast to grow by 2.5%, with fast-growing Asian markets being the primary drivers. 

In terms of regional demand, Asia-Pacific is expected to see the most significant growth, with natural gas demand projected to expand by nearly 5% in 2024 compared to 2023. This growth is largely supported by industrial activity and higher gas use in the power sector. 

In North America, natural gas demand is forecast to increase by 1%, driven by power sector demand, while in Europe, demand is expected to remain broadly flat, standing 20% below its 2021 levels.

Solar energy originates from the sun, where nuclear fusion reactions convert hydrogen into helium, releasing immense amounts of energy in the form of electromagnetic radiation. 

This energy is captured on Earth using two primary technologies: photovoltaic (PV) panels and concentrating solar-thermal power (CSP) systems. 

PV panels convert sunlight directly into electricity through the photovoltaic effect. Photons strike a semiconductor material, typically silicon, causing electrons to flow and generate an electric current. 

CSP systems use mirrors to concentrate sunlight onto a receiver, converting it to heat, which can then be used to produce electricity or stored for later use.

The methods to obtain solar energy involve installing solar panels on rooftops, in solar farms, or integrating them into building materials. 

While solar energy itself is clean and renewable, the production and disposal of solar panels have environmental consequences. Manufacturing PV panels involves mining and processing raw materials like silicon, silver, and other metals, which can lead to habitat destruction and pollution. 

Additionally, the production process emits greenhouse gases and other pollutants. At the end of their lifecycle, solar panels can generate waste that needs to be properly managed to avoid environmental harm.

According to the International Renewable Energy Agency, the global installed solar PV capacity reached 1,200 gigawatts (GW) in 2023, marking a 27% increase from the previous year. Solar energy accounted for nearly 60% of the global increase in renewable power capacity in 2023, with China, the United States, and India leading in new installations. 

In the United States, solar power has become the fastest-growing electricity source, representing 54% of generation projects planned for 2023. The U.S. increased its solar capacity from slightly over 40,000 MW in late 2016 to more than 135,000 MW by the end of 2022.

Wind energy originates from the kinetic energy of moving air, which is primarily driven by the uneven heating of the Earth's surface by the sun, the rotation of the Earth, and the irregularities in the Earth's surface. This kinetic energy is harnessed using wind turbines, which convert the motion of the wind into electrical energy. 

Wind turbines consist of blades attached to a rotor; as the wind blows across the blades, it creates lift and causes the rotor to spin. This rotational motion is transferred to a generator, directly or through a gearbox, producing electricity.

To obtain wind energy, wind turbines are installed on land (onshore) or in bodies of water (offshore). Onshore wind farms can impact local ecosystems and landscapes, while offshore wind farms can affect marine habitats. 

However, the environmental consequences are relatively minimal compared to fossil fuels. Wind turbines do not emit pollutants during operation, making them a clean energy source. The primary environmental impact comes from the manufacturing and installation processes, which involve emissions from the production of materials like steel and concrete, and the transportation of large turbine components.

The pollutants released during the lifecycle of wind turbines are mainly associated with the manufacturing and transportation phases, including CO₂ and other greenhouse gases. The waste generated includes decommissioned turbine blades, which are often made from composite materials that are challenging to recycle. Efforts are ongoing to improve the recyclability of these materials.

Europe installed 18.3 GW of new wind capacity, with onshore wind making up 79% of new installations (14.5 GW). The EU-27 installed 16.2 GW of new capacity, with 82% being onshore (13.3 GW). 

Globally, wind energy capacity reached 830 GW in 2023. Denmark and Ireland had the highest share of wind in their electricity mix, with 56% and 36% respectively.

Hydropower, or hydroelectric power, harnesses the kinetic energy of moving water, which originates from the natural water cycle driven by solar energy. This energy is transformed into usable electricity using turbines and generators. Water stored in a reservoir behind a dam is released through a penstock, where it flows over turbine blades, causing them to spin. This mechanical energy is then converted into electrical energy by a generator. 

Building dams, run-of-the-river systems, and pumped-storage facilities are methods of obtaining hydropower. While hydropower is a renewable energy source, its environmental consequences include habitat disruption, changes in water quality and flow, and impacts on aquatic ecosystems.

The conversion process itself releases no pollutants, making hydropower a clean source of energy during operation. However, the construction of dams and reservoirs can lead to methane emissions from decomposing organic matter in flooded areas. The types of waste generated are minimal compared to fossil fuels, but decommissioning old facilities can produce construction debris and require careful management of sediment build-up.

The global hydropower fleet grew to 1,412 GW in 2023, although the five-year rolling average shows a downward trend. To stay on track with net zero targets, a growth rate of just over 26 GW per year is needed from now to 2030. 

China is the world’s biggest hydropower producer, generating an estimated 1,303 terawatt hours (TWh) of hydropower in 2022, which equates to approximately 31% of global hydropower that year.

Geothermal energy originates from the heat generated within the Earth, primarily from the decay of radioactive isotopes such as potassium-40 and thorium-232. This energy is harnessed by tapping into underground reservoirs of hot water and steam, which are brought to the surface through wells. The steam or hot water is then used to drive turbines connected to generators, transforming the thermal energy into electrical energy. 

There are several methods to obtain geothermal energy, including dry steam, flash steam, and binary cycle power plants. Dry steam plants use steam directly from geothermal reservoirs, flash steam plants depressurise hot water to produce steam, and binary cycle plants transfer heat from geothermal water to a secondary fluid that vaporises and drives a turbine.

The environmental consequences of geothermal energy extraction are relatively low compared to fossil fuels. However, drilling and reservoir management can lead to land subsidence, induced seismic activity, and the release of trace gases such as hydrogen sulfide.

The pollutants released during the conversion process are minimal, with geothermal plants emitting significantly lower levels of CO₂ compared to coal or natural gas plants. The primary waste generated includes mineral-laden water and spent geothermal fluids, which must be managed to prevent contamination of local water sources.

According to the 2024 Renewable Energy Statistics published by the International Renewable Energy Agency, the global geothermal power sector has seen modest growth, with electricity generation from geothermal resources reaching 97 TWh in 2022. 

One of the primary barriers to the widespread adoption of geothermal energy is the high initial cost of drilling and setting up geothermal plants (significantly more expensive than drilling for oil or gas). And that geothermal energy isn’t universally available. 

Geothermal energy extraction, especially through EGS, involves hydraulic fracturing, which can cause induced seismicity or small earthquakes. For example, EGS wells drilled below Basel, Switzerland, caused over 10,000 small tremors (less than 3.5 on the Richter scale) within a few days of starting the hydraulic fracturing process.

Lastly, the extraction process can release hydrogen sulfide, which has a foul odour and can be harmful in high concentrations.

Biomass energy originates from organic materials such as plants, wood, and waste, which store energy from the sun through photosynthesis. This stored chemical energy can be transformed into usable energy through various methods, including direct combustion, thermochemical conversion (pyrolysis and gasification), and biological conversion (anaerobic digestion). 

Direct combustion involves burning biomass to produce heat, which generates steam to drive turbines and produce electricity. Thermochemical methods convert biomass into gases or liquids that can be burned for energy, while anaerobic digestion uses bacteria to decompose organic material in oxygen-free environments, producing biogas.

The environmental consequences of biomass energy production include deforestation, habitat loss, and soil erosion from harvesting biomass feedstocks. Additionally, the combustion process releases pollutants such as carbon monoxide (CO), carbon dioxide (CO₂), nitrogen oxides (NOₓ), and particulate matter, which can contribute to air pollution and respiratory problems. 

However, these emissions are generally lower than those from fossil fuels. Biomass energy also generates waste in the form of ash and other residues, which need proper management to avoid environmental contamination.

Biomass remains a significant renewable energy source, accounting for about 59% of the EU's renewable energy consumption in 2021. Germany is the EU's biggest producer of solid biomass. The use of biomass for energy continues to grow, with a focus on sustainable production to reduce greenhouse gas emissions.

Nuclear energy originates from the nucleus of atoms, where immense energy is stored in the bonds holding protons and neutrons together. This energy is harnessed primarily through nuclear fission, a process in which the nucleus of a heavy atom, such as uranium-235, is split into smaller parts, releasing a significant amount of energy as heat. 

In a nuclear power plant, this heat is used to produce steam, which drives turbines connected to generators, thereby transforming the energy into electricity.

The fuel for nuclear energy, typically uranium, is obtained through mining and milling processes. 

Uranium ore is extracted from the ground, crushed, and chemically treated to produce uranium oxide concentrate, also known as yellowcake. This concentrate is then enriched to increase the proportion of uranium-235, the isotope needed for fission. The environmental consequences of uranium mining include habitat disruption, soil and water contamination, and the generation of radioactive waste.

During the conversion process in nuclear reactors, the primary pollutants are minimal compared to fossil fuels. However, the process generates radioactive waste, including spent fuel rods and other contaminated materials. This waste remains hazardous for thousands of years and requires secure, long-term storage solutions to prevent environmental contamination.

Nuclear energy provides about 9% of the world's electricity from approximately 440 power reactors. In 2023, nuclear plants supplied 2,602 TWh of electricity, up from 2,545 TWh in 2022. 

Fourteen countries produced at least one-quarter of their electricity from nuclear energy, with France leading at around 70%. As of May 2024, the largest reactors under construction were situated in the UK, with a gross electricity generation capacity of 1,720 megawatts.

Fossil fuels are significant contributors to air pollution, emitting sulfur dioxide (SO₂), nitrogen oxides (NOₓ), and particulate matter (PM) during combustion. These pollutants have severe health impacts, including respiratory and cardiovascular diseases. 

For example, the World Health Organisation (WHO) estimates that air pollution is responsible for 6.7 million premature deaths annually, with particulate matter (PM2.5) being a major contributor. 

Coal-fired power plants are the largest source of SO₂ emissions, which can react with other compounds to form fine particulate matter, further exacerbating air quality issues. Similarly, NOₓ emissions from vehicles and industrial processes contribute to the formation of ground-level ozone and smog, aggravating asthma and other respiratory conditions.

Fossil fuels are the primary source of greenhouse gases, driving global warming and extreme weather events. The Intergovernmental Panel on Climate Change (IPCC) reports that emissions from fossil fuels are the dominant cause of global warming, accounting for over 75% of global greenhouse gas emissions. 

CO₂ is the most significant greenhouse gas emitted from burning fossil fuels, while methane, primarily from natural gas extraction and transportation, is a potent greenhouse gas with a global warming potential 25 times greater than CO₂ over 100 years.

Coal mining operations, for example, wash toxic runoff into streams, rivers, and lakes, and dump vast quantities of unwanted rock and soil into waterways, leading to contamination and habitat destruction. 

Oil spills during extraction or transport can pollute drinking water sources and jeopardise entire freshwater or ocean ecosystems. Fracking for natural gas can contaminate groundwater with toxic chemicals used in the process.

Power plants, including nuclear, can increase water temperatures, affecting aquatic life. The discharge of heated water from cooling processes can reduce dissolved oxygen levels, leading to hypoxic conditions that harm fish and other aquatic organisms. 

For example, thermal pollution from power plants disrupts local aquatic ecosystems, leading to declines in fish populations and altered species composition.

Fossil fuel extraction and processing facilities, such as coal mines, oil wells, and natural gas fields, occupy vast land areas, leading to habitat loss and fragmentation. Renewable energy projects, such as solar farms and wind turbines, also require significant land areas, though their impacts can be mitigated through careful site selection and management.

Energy projects can lead to habitat loss and fragmentation, threatening wildlife. For example, strip mining for coal involves removing entire swaths of terrain, including forests and mountaintops, to access coal seams, destroying critical wildlife habitats. Similarly, oil and gas infrastructure, such as pipelines and access roads, can fragment habitats and disrupt migration routes for various species.

For example, strip mining in the Appalachian region of the United States has led to the destruction of over 500 mountaintops and the burial of more than 2,000 miles of streams, severely impacting local ecosystems.

Fossil fuels, including coal, oil, and natural gas, significantly contribute to air pollution and greenhouse gas emissions. When burned, they release large amounts of carbon dioxide (CO₂), sulfur dioxide (SO₂), nitrogen oxides (NOₓ), and particulate matter, which contribute to climate change, acid rain, and respiratory diseases. 

According to the Intergovernmental Panel on Climate Change (IPCC), fossil fuels accounted for 89% of global CO₂ emissions in 2018. Coal, in particular, is the dirtiest fossil fuel, responsible for over 0.3°C of the 1°C increase in global average temperatures, making it the single largest source of global temperature rise.

In contrast, renewable energy sources such as wind, solar, and hydropower emit little to no greenhouse gases during operation. 

For example, solar power has a negligible carbon footprint, with lifecycle emissions ranging from 20 to 50 grams of CO₂ per kilowatt-hour (g CO₂/kWh), compared to coal's 820 g CO₂/kWh. Wind energy's lifecycle emissions are even lower, at around 12 g CO₂/kWh. This significant reduction in emissions makes renewables a crucial component in mitigating climate change.

Germany has pioneered the adoption of renewable energy, primarily through its Renewable Energy Sources Act (EEG). The latest amendment to the EEG, which came into force on January 1, 2021, aims to ensure that both electricity supply and consumption become carbon-neutral before 2050. 

The law sets ambitious targets for expanding sustainable energy sources, such as wind and photovoltaics, to produce 65% of electricity from clean sources by 2030. 

Key features of the EEG include annual monitoring to make necessary adjustments, a reduction in the renewable energy levy to lower consumer electricity bills, and federal support payments to cap the surcharge. It also provides a guaranteed fixed payback tariff for 20 years for electricity produced from Coal Mine Methane (CMM) or Abandoned Mine Methane (AMM) projects, encouraging the integration of these sources into the grid.

In addition to the EEG, Germany has set specific targets for offshore wind power, aiming to reach a minimum of 30 GW by 2030, 40 GW by 2035, and 70 GW by 2045. The country also plans to double its onshore wind capacity to 115 GW by 2030 and has mandated that larger states designate 1.1-1.8% of their surface area to onshore wind power by 2027. 

Germany's renewable energy policies have led to significant progress, with renewables accounting for 46% of the country's electricity consumption in 2022. The country aims to increase this share to at least 80% by 2030.

These policies are part of Germany's broader strategy to achieve greenhouse gas neutrality by 2045. The preliminary targets are to cut emissions by at least 65% by 2030 compared to 1990 levels.

China is the largest producer and consumer of coal globally, with coal playing a critical role in its energy mix. Despite efforts to diversify its energy sources, coal remains a significant part of China's energy strategy due to its abundance and reliability.

China is responsible for about a quarter of the world's CO₂ emissions, with coal-fired power plants being a major contributor.

Apart from that, China's heavy reliance on coal has led to severe environmental and health consequences. For example, coal combustion is a major source of air pollutants that contribute to smog and respiratory illnesses. 

Exposure to coal-related air pollution also leads to various health problems, including respiratory diseases, cardiovascular conditions, and cancer. Studies have shown that fine particulate matter (PM2.5) and trace elements like arsenic and selenium from coal combustion are particularly harmful.

Despite its coal dependency, China is making significant strides towards cleaner energy:

As of June 2024, China’s wind and solar energy collectively surpassed coal in installed capacity. Wind and solar now account for 37% of the total power capacity in the country, up from 29% in 2022. This combined capacity exceeded coal, marking a historic shift in China’s energy landscape, all thanks to substantial investments and supportive government policies.

Denmark has similarly set ambitious targets for renewable energy, aiming for complete independence from fossil fuels by 2050. Denmark was one of the first countries to invest in wind power, establishing a test station for wind turbines in 1978 and providing investment support for building and exporting wind turbines. 

The government introduced a feed-in tariff in 1992, mandating the utility sector to purchase wind energy at a preferential price and guaranteeing wind power generators a fixed price of 70-85% of the local retail price of electricity.

Denmark's energy policy also includes the 2012 Energy Agreement, which set medium-term targets of 35% renewable energy in final energy consumption and approximately 50% of electricity consumption supplied by wind power by 2020. 

The country has maintained its ban on nuclear power and focuses on expanding offshore wind, biomass, and biogas. Denmark's strategy involves a robust energy and climate governance framework, supported by a large majority in the Danish Parliament, and leverages public and private investment to achieve its goals.

The country's reliance on fossil fuels in total energy supply decreased from 75% in 2011 to 38% in 2023, well below the IEA average of 79%. The shift to renewable energy has also contributed to a reduction in greenhouse gas emissions, with Denmark legally bound to reduce emissions by 70% by 2030 from 1990 levels.

The future outlook of the environmental impact of energy choices is a critical topic as the world transitions towards more sustainable energy systems. Here are some key insights from recent reports and analyses:

1. Transition to renewable energy: The integration of technology and environmental awareness is crucial for building a sustainable energy model. This involves the development and application of clean and renewable technologies, along with promoting a culture of sustainability.

2. Impact on local communities: The deployment of renewable energy projects can create tensions and require careful planning to optimise infrastructure and consider local community impacts. Effective public participation and environmental assessments are essential for successful implementation.

3. Risks and trade-offs: Capturing and storing carbon dioxide from fossil fuel power plants can reduce emissions by 70%, but it may increase pollution harmful to human health and ecosystems by 5-80%.

4. Environmental effects of non-renewable energy: Non-renewable energy sources, primarily fossil fuels, are major contributors to greenhouse gas emissions and climate change. Transitioning to renewable energy and improving energy efficiency are vital steps to mitigate these impacts.

5. Global energy system changes: The International Energy Agency (IEA) projects significant changes in the global energy system by 2030, with a substantial increase in the share of renewables in the energy mix. However, stronger policies are needed to meet climate goals.

6. Renewable energy potential: Renewable energy sources such as hydro, wind, solar, and geothermal can decarbonise 90% of the electricity sector by 2050, significantly reducing carbon emissions. However, climate change may also affect the efficiency of renewable energy sources like wind and hydropower.

7. Benefits and risks of low-carbon technologies: Low-carbon technologies for electricity production offer environmental benefits but also come with risks and trade-offs. A balanced approach is necessary to maximise benefits while minimising negative impacts.

8. Economic and environmental benefits: Increasing the share of renewable energy in power systems can provide economic benefits, such as job creation and reduced reliance on fossil fuel imports. For example, between January and May 2022, wind and solar generation in Europe prevented at least £38 billion in fossil fuel imports.

9. Challenges in energy transition: The transition to clean energy is happening globally, but challenges remain in ensuring affordability, energy security, and the resilience of supply chains. International cooperation is crucial for accelerating this transition.

10. Policy and investment needs: To achieve the desired energy transition, governments need substantial investments in renewable energy infrastructure and innovative financing mechanisms, particularly in emerging economies.

11. Future energy scenarios: Various scenarios explore different futures for the global energy system, highlighting the need for ambitious climate policies and improved resource efficiency to achieve sustainable development goals.

In conclusion, the transition to sustainable energy systems is essential for mitigating climate change, reducing environmental impacts, and ensuring long-term energy security. While fossil fuels remain a significant part of the global energy mix, their environmental and health impacts necessitate a shift toward cleaner energy sources. 

Renewable energy, with its low emissions and sustainability, offers a viable path forward, though it comes with its own set of challenges. Nuclear energy, with its low-carbon benefits, also plays a crucial role but requires careful management of safety and waste issues. 

Policymakers, industry leaders, and communities must work together to overcome these challenges and accelerate the transition to a sustainable energy future.