Renewable Energy and Alternatives

This lesson examines renewable and alternative energy sources, their costs and benefits, technological challenges and global growth trends. It addresses the Edexcel A-Level Geography (9GE0) specification, Topic 6, Enquiry Question: "What are the consequences of increasing demand for energy?"

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Overview of Renewable Energy

Renewable energy comes from sources that are naturally replenished on a human timescale — sunlight, wind, water, geothermal heat and biomass. Unlike fossil fuels, renewable sources do not deplete with use (though some, like biomass, require sustainable management).

Global renewable energy capacity has grown dramatically:

Year	Total Renewable Electricity Capacity (GW)	Share of Global Electricity Generation
2000	~800	~19% (mainly hydro)
2010	~1,250	~20%
2015	~2,000	~23%
2020	~2,830	~28%
2023	~3,870	~30%

In 2023, renewables accounted for ~83% of all new electricity capacity added globally — the energy transition is accelerating.

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Solar Energy

Solar Photovoltaic (PV)

Solar PV converts sunlight directly into electricity using semiconductor cells (typically silicon).

Aspect	Detail
Global capacity (2023)	~1,420 GW (from ~40 GW in 2010)
Cost trend	Levelised cost of energy (LCOE) fallen from ~$0.36/kWh (2010) to ~$0.36/kWh(2010)to 0.049/kWh (2023) — an 86% reduction
Capacity factor	10–25% (depends on latitude, cloud cover, orientation)
Leading countries	China (~580 GW), EU (~260 GW), USA (~160 GW), India (~80 GW)
Strengths	Zero emissions in operation; modular (rooftop to utility-scale); declining costs; abundant resource
Limitations	Intermittent (no generation at night, reduced on cloudy days); requires large land area for utility-scale; manufacturing uses energy and materials; storage needed

Concentrated Solar Power (CSP)

CSP uses mirrors to concentrate sunlight onto a receiver, generating heat to drive a steam turbine. Unlike PV, CSP can incorporate thermal energy storage (molten salt) to generate electricity after sunset.

Key installations: Noor-Ouarzazate Solar Complex (Morocco, 580 MW) — one of the world's largest, with 3 hours of thermal storage.

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Wind Energy

Onshore Wind

Aspect	Detail
Global capacity (2023)	~780 GW
LCOE	~$0.033/kWh (2023) — cheapest new electricity source in most markets
Capacity factor	25–45% (site-dependent)
Leading countries	China (~365 GW), USA (~148 GW), Germany (~70 GW), India (~45 GW)
Strengths	Very low cost; zero emissions in operation; compatible with farming
Limitations	Intermittent; visual/noise impact; bird/bat mortality; public opposition in some areas

Offshore Wind

Aspect	Detail
Global capacity (2023)	~75 GW
LCOE	~$0.075/kWh (declining rapidly)
Capacity factor	35–55% (stronger, more consistent winds offshore)
Leading countries	UK (~15 GW), China (~30 GW), Germany (~8 GW), Denmark (~3 GW)
Strengths	Stronger winds; less visual impact; massive potential (e.g. UK has ~1,000 GW of offshore wind potential in the North Sea)
Limitations	Higher cost than onshore; marine environment challenging for construction and maintenance; subsea cable infrastructure needed

The UK is a world leader in offshore wind, with major farms including Hornsea 2 (1.3 GW, Yorkshire coast — world's largest when completed in 2022) and the planned Dogger Bank (3.6 GW).

Exam Tip: When writing about wind or solar, always mention the capacity factor — the percentage of time a generator operates at full capacity. Wind turbines typically run at 25–45% capacity, while coal plants run at 60–80%. This means 1 GW of wind capacity produces much less electricity per year than 1 GW of coal capacity — a key consideration when comparing energy sources.

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Hydroelectric Power

Aspect	Detail
Global capacity (2023)	~1,400 GW (including pumped storage)
Share of global electricity	~15% — the largest renewable electricity source
LCOE	~$0.061/kWh (varies widely)
Capacity factor	30–60% (depends on water availability)
Leading countries	China (~420 GW, including Three Gorges Dam — 22.5 GW), Brazil (~110 GW), Canada (~82 GW), USA (~80 GW)
Strengths	Reliable; flexible (can ramp up/down quickly); long lifespan (50–100 years); flood control; water storage
Limitations	Massive environmental impact (habitat loss, fish migration disruption); displacement of communities (Three Gorges displaced ~1.3 million people); sedimentation reduces reservoir capacity; methane emissions from reservoirs in tropical areas; limited suitable sites remaining

Case Study: Three Gorges Dam, China

Aspect	Detail
Capacity	22.5 GW — world's largest power station
Annual generation	~100 TWh
Reservoir length	660 km
People displaced	~1.3 million
Benefits	Flood control, electricity, navigation
Controversies	Displacement, ecosystem damage, seismic risk, sedimentation

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Geothermal Energy