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examBoard: Cambridge
examType: IGCSE
lessonTitle: Exploiting Existing Energy Sources
Energy is essential for modern life - it powers our homes, schools, hospitals, industries and transport systems. Most of our current energy comes from non-renewable sources that have formed over millions of years and cannot be replaced once used up. Understanding how we exploit these resources is crucial for managing them wisely.
Key Definitions:
Fossil fuels (coal, oil and natural gas) provide about 80% of the world's energy. They're valued for their high energy density, ease of transport and established infrastructure. However, they release carbon dioxide when burned, contributing to climate change and their supplies are finite.
Nuclear energy harnesses the power of atoms through fission (splitting atoms) to generate electricity. It produces minimal greenhouse gases during operation but creates radioactive waste that must be safely stored for thousands of years. About 10% of global electricity comes from nuclear power.
Coal has been used for centuries and remains an important energy source worldwide, especially for electricity generation. There are different types of coal (lignite, sub-bituminous, bituminous and anthracite) with varying energy content.
Coal is extracted using two main methods:
Used when coal seams are near the surface. Involves removing topsoil and rock (overburden) to expose coal seams. Methods include strip mining, open-pit mining and mountaintop removal.
Used for deeper coal seams. Miners travel through tunnels to extract coal. Methods include room-and-pillar mining (leaving "pillars" of coal to support the roof) and longwall mining (using machinery to cut long panels of coal).
Mining disrupts landscapes, can contaminate water sources, produces dust and noise pollution and contributes to greenhouse gas emissions. Reclamation efforts aim to restore mined land, but complete restoration is challenging.
Oil (petroleum) powers most of the world's transportation and is used to make countless products from plastics to medicines. Finding and extracting oil involves sophisticated technology and significant investment.
Getting oil from underground to consumers involves several stages:
About 30% of oil comes from offshore wells. These use platforms or floating vessels equipped with drilling equipment. Offshore drilling is more expensive and technically challenging than onshore drilling but can access large reserves. Environmental risks include oil spills that can devastate marine ecosystems, as seen in the 2010 Deepwater Horizon disaster.
As conventional oil becomes harder to find, companies are turning to unconventional sources like oil sands (tar sands) and oil shale. These require more energy and water to extract and process, making them more expensive and environmentally damaging. Hydraulic fracturing (fracking) has enabled access to previously unrecoverable oil in shale formations.
Natural gas is the cleanest-burning fossil fuel, producing about half the carbon dioxide of coal when burned. It's used for electricity generation, heating, cooking and as a raw material in manufacturing.
Natural gas is often found alongside oil or in separate gas fields. The extraction process includes:
The UK has significant shale gas reserves, particularly in northern England. In 2011, fracking near Blackpool caused small earthquakes, leading to a moratorium. The government lifted this ban in 2022 to boost energy security, but reinstated it in 2023 due to environmental concerns and public opposition. This case highlights the tensions between energy needs, environmental protection and community interests that characterize many energy exploitation decisions.
Nuclear power provides about 10% of the world's electricity from over 440 power reactors. It uses uranium, a naturally occurring radioactive element, as fuel.
Nuclear power plants generate electricity through these steps:
Nuclear power produces minimal greenhouse gases during operation, provides reliable baseload power and requires relatively small amounts of fuel. A single uranium fuel pellet contains as much energy as one tonne of coal. Modern nuclear plants have excellent safety records and new designs incorporate additional safety features.
Nuclear power faces significant challenges including high construction costs, long build times, public concerns about safety following accidents like Fukushima and the need to safely store radioactive waste for thousands of years. Decommissioning old plants is also expensive and technically challenging.
The UK is building its first new nuclear power station in over 20 years at Hinkley Point in Somerset. The project will provide 7% of the UK's electricity needs when completed. However, it has faced criticism for its high cost (over £25 billion) and delays. The government argues it's essential for low-carbon energy security, while critics suggest the money could be better spent on renewable energy. The plant is expected to operate for 60 years once completed.
Exploiting existing energy sources involves balancing energy needs with environmental protection and economic factors.
All energy sources have environmental consequences:
Key economic considerations include:
As we continue to exploit existing energy sources, the challenge is to do so in ways that minimize environmental harm while meeting our energy needs. The transition to renewable energy sources is increasingly important, but existing energy sources will remain crucial for decades to come.
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