Energy Resource Types

In the Edexcel specification, nuclear power is officially classified as a non-renewable resource because it relies on uranium-235, a finite mined mineral. However, it is also considered recyclable because its spent fuel rods can be reprocessed to produce more energy. Nuclear reactions are incredibly powerful; they have an immense energy density, with 1 kg of uranium producing as much energy as roughly 2–3 million kg of coal.

The Global Energy Mix & Energy Security

Why do countries buy gas from halfway across the world instead of just building more wind turbines? The answer lies in the need for reliable, round-the-clock power.

• An Energy Mix is the specific combination of different energy sources a country uses to meet its demand.
• Energy Security means having a reliable, affordable, and uninterrupted supply of energy.

Achieving energy security requires a diverse mix. Relying on a single source or a single foreign supplier is risky (for example, Russia holds 24.3% of global gas reserves). The world heavily relies on fossil fuels: in 2022, the global energy mix consisted of roughly 35% coal, 31.2% oil, and 24.7% natural gas. Wind power has grown significantly to over 7% (up from 1.5% in 2010).

In the UK, the last deep coal mine (Kellingley Colliery) closed in 2015. This forced a massive national shift toward imported gas and rapidly expanding offshore wind farms to maintain security.

Evaluating Non-Renewable Resources

Fossil fuels built the modern world, but their environmental cost is forcing a global transition. When evaluating these resources, we must balance their economic benefits against their environmental and social impacts.

• Coal: Coal provides a cheap, reliable Base load (the permanent minimum power the grid needs 24/7) and has abundant reserves estimated to last 120–300 years. However, it is bulky to transport and highly polluting. Burning coal releases vast amounts of $CO_2$ and $SO_2$, which causes acid rain.
• Natural Gas: Gas is considered a "bridging fuel" because it is the cleanest fossil fuel, emitting 45–50% less $CO_2$ than coal. It is often cooled to -162°C to become Liquefied Natural Gas (LNG), which shrinks its volume to 1/600th for easier ship transport. However, extracting it can release methane ($CH_4$), a highly potent greenhouse gas, and fracking can cause local earth tremors.
• Nuclear: Nuclear plants generate zero $CO_2$ or $SO_2$ during operation and provide an excellent base load (supplying ~15–20% of the UK's electricity). However, radioactive waste lasts for thousands of years, and the risk of catastrophic disasters (like Chernobyl or Fukushima) causes significant public concern.

Large-scale fossil fuel extraction can transform economies through a Multiplier effect, where initial investments create secondary jobs. For example, the Camisea Gas Project in Peru was a $4bn investment that massively boosted national GDP. However, its 340-mile pipeline caused severe Amazonian deforestation and negatively impacted indigenous tribes. Overall, while the Camisea Gas Project provides a vital economic boost and improves national energy security, its development remains highly controversial; for many, the long-term, irreversible damage to the Amazonian ecosystem and the disruption of indigenous communities outweigh the short-term financial gains.

Worked Example: LNG Volume

A pipeline transports 1,800 m³ of natural gas. Calculate the volume of this gas when converted to Liquefied Natural Gas (LNG) for shipping.

Step 1: Identify the formula for LNG conversion.

$$\text{LNG Volume} = \frac{\text{Gas Volume}}{600}$$

Step 2: Substitute the values into the formula.

• $\text{LNG Volume} = \frac{1800}{600}$

Step 3: Calculate the final volume.

• $\text{LNG Volume} = 3\text{ m}^3$

Evaluating Renewable Resources

Harnessing the weather seems like the perfect solution for clean electricity, but what happens when the wind stops blowing? Renewables face unique geographical and economic challenges.

• Wind: Wind produces no emissions during generation and technology costs are falling rapidly. The London Array (UK) uses 175 turbines to power 500,000 homes, saving 1 million tonnes of $CO_2$ annually. However, wind suffers from Intermittency (it only works when the wind blows) and faces severe NIMBY (Not In My Back Yard) protests over visual and noise pollution.
• Solar: Solar farms have very low operating costs and are excellent for remote, off-grid areas. Conversely, they have high capital (setup) costs, only generate power during daylight, and require a huge land footprint. The Ivanpah Facility in California uses 3,500 acres, which disrupted the local desert tortoise habitat.
• HEP: Hydroelectric dams are highly efficient (up to 90%) and reliable, often serving multiple purposes like flood control and irrigation. The Three Gorges Dam in China generates immense power, but it cost $22.5–30bn to build, displaced 1.3 million people, and submerged 1,300 villages. Additionally, rotting vegetation in flooded reservoirs releases methane. Ultimately, despite the severe social impacts of displacement and massive initial capital costs, the Three Gorges Dam is considered a viable long-term energy solution; it successfully recovered its costs within 10 years and provides an immense, reliable power supply without the continuous $CO_2$ emissions of fossil fuels.

While renewables are essential for sustainability, they are not entirely impact-free. Building dams and wind turbines produces Embedded carbon from the manufacturing of steel and cement.

Worked Example: Solar Payback Period

A household installs a solar panel system for $7,300. The panels save them $800 per year on energy bills. Calculate the payback period.

Step 1: Identify the formula.

$$\text{Payback Period} = \frac{\text{Total Capital Cost}}{\text{Annual Savings}}$$

Step 2: Substitute the values.

• $\text{Payback Period} = \frac{7300}{800}$

Step 3: Calculate the final answer.

• $\text{Payback Period} = 9.125\text{ years}$