Energy Impacts, Sustainability and Case Studies

Climate change. CO₂ + methane trap heat. Global temperature ~1.2°C above pre-industrial. Most CO₂ from fossil fuels.

Air pollution. SO₂, NO₂, PM2.5 from combustion. Smog, asthma, lung disease. WHO links to ~7 million premature deaths/year.

Acid rain. SO₂ + water → acid. Damages forests, lakes, buildings. Curbed in OECD by clean-air legislation; still serious in China and India.

Habitat damage. Mining strips landscapes. Oil spills (Deepwater Horizon, Niger Delta). Fracking, tar sands extraction devastate large areas.

Nuclear waste. Radioactive for thousands of years. Storage challenge.

Cambridge tip. Mark scheme rewards multiple impacts with specific examples.

Project. Yangtze River, China. Completed 2012. ~22,500 MW capacity. World's largest hydro power station.

Benefits.

• Renewable electricity — supplies ~3% of China's electricity demand.
• Flood control on lower Yangtze; protects ~15M people downstream.
• Improved navigation — large ships reach inland Chongqing.

Costs.

• Displacement — ~1.3 million people relocated.
• Ecosystem damage — Yangtze finless porpoise endangered. Sediment trapped behind dam reduces fertility downstream.
• Cultural heritage — ancient sites flooded.
• Earthquake risk — reservoir water weight may increase seismic activity.

Verdict. Mixed. Large-scale renewable power AND major social/ecological costs. Cambridge mark schemes reward BALANCED evaluation.

Efficiency. Insulation, LEDs, public transport, electric vehicles, smart appliances. CUTS demand — cheapest way to reduce emissions.

Renewable rollout. Solar farms, wind farms, hydro, geothermal. Replaces fossil fuels.

Storage and grids. Batteries store solar/wind for night use. Smart grids balance supply and demand. Interconnectors (Norway-UK undersea cable).

Decentralisation. Rooftop solar; community wind; reduces transmission losses.

Country examples.

• Costa Rica — ~99% renewable electricity (hydro + geothermal + wind).
• Germany — Energiewende — phasing out nuclear and coal; renewables ~50% of electricity.
• Iceland — geothermal + hydro = ~100% renewable electricity.
• Denmark — ~50% wind.

Cambridge tip. Quote SPECIFIC % renewable for named countries.