Every time you turn on a light switch, the electricity powering it comes from a specific combination of sources. This specific combination of renewable, non-renewable, and recyclable sources used by a country to meet its total energy demand is called its energy mix. Globally, this mix is changing; for example, wind energy provided over 7% of global energy in 2022 (up from 1.5% in 2010), though coal still provides over 35%.
Edexcel classifies energy resources into three distinct categories. Renewable energy comes from infinite sources that will not run out, such as wind, solar, and hydroelectric power (HEP). Non-renewable energy comes from finite sources that will eventually run out, like coal, oil, and gas. Recyclable energy comes from sources that can be reused or reprocessed; crucially, this category specifically includes nuclear energy and biofuels.
To understand a country's reliance on a specific source, you can calculate its percentage contribution to the total energy mix using this formula:
What percentage of a country's energy comes from wind if it produces 30 TWh from wind out of a total 120 TWh?
Step 1: Identify the specific source output and total output.
Step 2: Substitute the values into the equation.
Step 3: Calculate the final percentage.
It might surprise you to learn that wind turbines and solar panels are not entirely carbon-free. While renewables produce near-zero emissions during operation, they have a carbon footprint due to indirect emissions released during their manufacture, construction, and transport. For example, the lifecycle footprint of wind is roughly and solar is . However, this is vastly superior to coal, which produces through direct emissions.
Despite global climate benefits, renewables can have severe local environmental impacts. Hydroelectric power requires massive dams; the Three Gorges Dam in China flooded over of land, causing habitat destruction and releasing methane from decomposing underwater vegetation. Similarly, solar farms compete with agricultural land, and cultivating biofuels can lead to deforestation.
Renewables also have a much lower energy density than fossil fuels. One coal plant produces as much energy as approximately 233 wind turbines. Because so many turbines are needed, wind farms require huge amounts of raw materials and space, which can disrupt migratory patterns and kill birds or bats.
Calculate the percentage carbon saving per kWh when switching from a coal plant emitting to a wind farm emitting .
Step 1: Calculate the difference in emissions.
Step 2: Divide the saving by the original coal emissions and multiply by 100.
Why do people protest against green energy projects built near their own homes? This phenomenon is known as NIMBYism ("Not In My Back Yard"). Local residents frequently object to visual pollution, arguing that projects industrialise coastlines and rural landscapes. For instance, the Rampion Wind Farm features 116 turbines that are 460ft tall and visible from 20 miles away. Turbines also create noise pollution, generating around at a distance of 300m, which is the World Health Organization limit for avoiding sleep disturbance.
Large-scale projects can cause devastating social displacement. The construction of the Three Gorges Dam forced 1.3 million people to relocate. However, renewables also provide significant social benefits through job creation and the multiplier effect. The London Array wind farm created 6,700 jobs during construction and supports 73 to 150 permanent roles, while the Rampion project regenerated Newhaven Port by creating 60 permanent jobs.
Economically, renewable energy projects are incredibly capital-intense. The capital costs (upfront expenses for land and construction) are massive: offshore wind costs between £3m and £4.5m per MW, while onshore wind costs £1m to £1.6m per MW. Furthermore, connecting remote renewable sites (like the Scottish Highlands) to city grids is highly expensive. Conversely, the operational costs (ongoing running expenses) are very low at just 1-2% of capital costs per year, because the "fuel" (wind, sun, or water) is completely free.
The wind does not always blow, and the sun does not always shine. This variability is known as intermittency and is the primary challenge of relying on renewable energy. For example, wind turbines only operate when wind speeds are between (the cut-in speed) and (the cut-off speed). Because renewables cannot be switched on demand to meet sudden spikes in electricity use, national grids still rely on a base load—a constant, stable supply of power usually provided by nuclear or gas plants.
Despite the challenge of intermittency, developing domestic renewables drastically improves a country's energy security. By generating their own power, countries reduce their reliance on imported fossil fuels and protect themselves from volatile global energy prices. For example, the London Array alone powers 584,000 homes, providing 2.4% of UK domestic electricity in 2020 and helping the UK towards its target of an 80% reduction in carbon emissions by 2050.
To truly overcome intermittency, grids require massive battery storage systems (like lithium-ion batteries) to store excess energy for days when the weather is calm. However, mining and processing lithium creates its own environmental challenges, producing an estimated 1.3 million tonnes of globally each year.
Overall, when assessing the impacts of developing renewable energy, the long-term global benefits outweigh the short-term and local drawbacks. While projects require high capital costs and can cause significant local environmental and social disruption (such as habitat loss and visual pollution), these negative impacts are offset by the overwhelming need to mitigate global climate change. Renewables offer vastly lower lifecycle carbon footprints compared to fossil fuels and crucially enhance a country's energy security by reducing reliance on imported, volatile energy sources. Therefore, despite the ongoing challenges of intermittency and storage, the transition to renewable energy is essential for a sustainable future.
Students often state that renewable energy has a 'zero carbon footprint'. You must remember that while they don't emit CO2 when operating, they do have a carbon footprint due to indirect lifecycle emissions from manufacture and transport.
For 8-mark 'Assess' questions, examiners expect a balanced argument: weigh the global environmental benefits (like climate mitigation) against local environmental or social costs (such as habitat loss, noise, or visual pollution). Crucially, you must also provide a balanced concluding judgement on the overall impact to access the highest marks.
Always classify nuclear power as 'recyclable' rather than 'renewable' or strictly 'non-renewable' to exactly match the Edexcel terminology and mark scheme.
When discussing the cost of renewables, use the specific terms 'capital costs' (which are high) and 'operational costs' (which are low) rather than just saying they are 'expensive'.
Energy mix
The specific combination of different energy sources (renewable, non-renewable, and recyclable) used by a country to meet its total energy demand.
Renewable energy
Energy from sources that are naturally replenished, infinite, and will not run out, such as solar, wind, and hydroelectric power.
Recyclable energy
Energy from sources that can be reused or replaced, specifically including nuclear power (uranium reprocessing) and biofuels.
Carbon footprint
The total greenhouse gas emissions (including carbon dioxide and methane) caused by a product's entire lifecycle, from manufacture to disposal.
Indirect emissions
Hidden greenhouse gas emissions resulting from the mining, manufacture, transport, and construction required to build energy infrastructure.
Direct emissions
Greenhouse gases released directly into the atmosphere from the burning of fossil fuels.
NIMBYism
An acronym for 'Not In My Back Yard', describing when people support renewable energy in principle but oppose developments near their own homes.
Visual pollution
The negative visual impact that large infrastructure, such as towering wind turbines, has on the natural beauty of a landscape.
Multiplier effect
When an initial investment (like building a wind farm) leads to further economic activity and job creation in local supply chains and communities.
Capital costs
The fixed, one-time expenses required to purchase land, materials, and construct an energy project.
Operational costs
The ongoing running expenses of an energy project, including maintenance, repairs, and staff wages.
Intermittency
A characteristic of renewable sources like wind and solar, where energy production is not constant because it depends on weather or time of day.
Base load
The minimum, constant amount of electric power that must be delivered to the national grid at all times, often supplied by nuclear or gas.
Energy security
Having a reliable, uninterrupted, and affordable supply of energy to meet a country's current and future needs.
Put your knowledge into practice — try past paper questions for Geography A
Energy mix
The specific combination of different energy sources (renewable, non-renewable, and recyclable) used by a country to meet its total energy demand.
Renewable energy
Energy from sources that are naturally replenished, infinite, and will not run out, such as solar, wind, and hydroelectric power.
Recyclable energy
Energy from sources that can be reused or replaced, specifically including nuclear power (uranium reprocessing) and biofuels.
Carbon footprint
The total greenhouse gas emissions (including carbon dioxide and methane) caused by a product's entire lifecycle, from manufacture to disposal.
Indirect emissions
Hidden greenhouse gas emissions resulting from the mining, manufacture, transport, and construction required to build energy infrastructure.
Direct emissions
Greenhouse gases released directly into the atmosphere from the burning of fossil fuels.
NIMBYism
An acronym for 'Not In My Back Yard', describing when people support renewable energy in principle but oppose developments near their own homes.
Visual pollution
The negative visual impact that large infrastructure, such as towering wind turbines, has on the natural beauty of a landscape.
Multiplier effect
When an initial investment (like building a wind farm) leads to further economic activity and job creation in local supply chains and communities.
Capital costs
The fixed, one-time expenses required to purchase land, materials, and construct an energy project.
Operational costs
The ongoing running expenses of an energy project, including maintenance, repairs, and staff wages.
Intermittency
A characteristic of renewable sources like wind and solar, where energy production is not constant because it depends on weather or time of day.
Base load
The minimum, constant amount of electric power that must be delivered to the national grid at all times, often supplied by nuclear or gas.
Energy security
Having a reliable, uninterrupted, and affordable supply of energy to meet a country's current and future needs.