Unit 6 – Energy Resources and Consumption

Oil (Petroleum) Distribution

• Top Producers: USA (~13 million barrels/day), Saudi Arabia (~10), Russia (~10), Canada (~5), Iraq (~4)
• Proven Reserves: Saudi Arabia (268 Gb - gigabarrels), Russia (106), USA (53), Libya (48), Iran (156 - disputed)
• Middle East Dominance: 48% of world reserves; OPEC cartel (Saudi Arabia, Iraq, Iran, UAE, Kuwait, Libya, etc.) controls ~30% of production
• Geopolitical Power: Oil-rich nations leverage resource for political/military power (Saudi Arabia, Russia, Venezuela, Iran); oil price shocks destabilize economies
• Reserve Debates: Proven reserves are economically extractable at current prices; as prices rise, unconventional oil (tar sands, shale, deep-water) becomes viable; "peak oil" concept suggests future production declines
• Unconventional Oil: Tar sands (Canada), shale (USA), deep-water (Brazil, Gulf Mexico); environmentally damaging; more expensive; required as conventional depletes
• Strategic Reserves: Countries maintain emergency supplies; USA Strategic Petroleum Reserve can offset supply disruptions

Natural Gas Distribution

• Top Producers: USA (~900 billion cubic meters/year), Russia (~700), Iran (~240), Qatar (~180), Australia (~130)
• Proven Reserves: Russia (37% of world reserves), Iran (18%), Qatar (13%), USA (8%), Turkmenistan (4%)
• Infrastructure Dependent: Unlike oil (easy to ship), natural gas requires pipelines or liquefied natural gas (LNG) terminals; expensive infrastructure creates dependency
• Geopolitical Leverage: Russia uses gas supplies to pressure Europe (Nord Stream pipelines, cutoffs); Ukraine crisis demonstrated vulnerability
• LNG Trade: Qatar, Australia, USA export LNG globally; enables diversification away from pipeline dependence; more expensive than piped gas
• Shale Gas Revolution: USA shale fracking transformed it from importer to exporter; made US more energy independent; environmental concerns (water, earthquakes)
• Stranded Gas: Reserves in remote areas lack infrastructure to reach markets; economically unviable without major investment

Coal Distribution

• Top Producers: China (~3,600 million tonnes/year, ~50% global), India (~700), USA (~600), Indonesia (~600), Australia (~500)
• Proven Reserves: USA (268 billion tonnes), Russia (160), China (143), India (92), Australia (75)
• Advantages vs. Oil/Gas: Widely distributed; most countries have coal reserves; less geopolitical concentration; easier to transport (ship, rail)
• Global Spread: Coal production in 50+ countries; no single nation dominance like oil/gas; reduces leverage for supply cutoffs
• Abundance: Coal reserves ~100+ years at current consumption; longest supply duration of fossil fuels
• China's Dominance: Produces, consumes, and exports coal; fueling rapid industrialization; coal-dependent economy resists climate action
• Mining Locations: Surface mines in USA, Australia, Indonesia; underground mines in China, India; environmental disruption varies

Uranium Distribution

• Top Producers: Kazakhstan (~43% of world supply), Canada (~12%), Namibia (~8%), Australia (~8%), Uzbekistan (~7%)
• Proven Reserves: Australia, Kazakhstan, Canada; relatively concentrated; geopolitical leverage for nuclear expansion
• Price Volatility: Uranium prices vary ~100% over decades; exploration activity follows price cycles; long lead times (10+ years) to develop mines
• Supply Security: Countries pursuing nuclear consider uranium security important; long-term contracts common; strategic reserves established
• Enrichment Concentration: Uranium enrichment (weapons-grade vs. reactor-grade) concentrated in Russia, France, USA; key geopolitical chokepoint
• Supply Duration: Current reserves ~90 years at today's consumption; 300+ years with breeder reactors (not widely used)

Renewable Energy Distribution

💡 Exam Tip: Fossil fuels concentrated in specific regions (Middle East oil, Russia gas); creates geopolitical leverage. Renewables more widely distributed; enables energy independence. Hydro needs mountains + water; geothermal limited to tectonics; solar/wind available everywhere (though variable). Know which countries produce/control key resources. Renewable transition redistributes energy power. Coal most widely distributed of fossils. OPEC controls 30% oil production.

Climate Change

• CO₂ Emissions: Combustion oxidizes carbon to CO₂; coal most CO₂/energy (100+ g/MJ), oil moderate (75 g/MJ), gas cleanest (55 g/MJ)
• Global Emissions: Fossil fuels responsible for ~75% of anthropogenic GHG emissions; CO₂ rising ~2% annually
• Atmospheric Burden: CO₂ stays 200-1000 years; already committed to warming for centuries
• Warming Trajectory: Current emissions path leads to 3-4°C warming by 2100; limit to 1.5-2°C requires rapid transition away from fossil fuels

Air Pollution

• Particulate Matter: Coal burning produces soot, ash; fine particles (PM2.5) penetrate lungs; cardiovascular/respiratory disease
• Sulfur Dioxide (SO₂): Coal contains sulfur; burning releases SO₂; causes acid rain (pH <5.6); damages forests, lakes, ecosystems; respiratory irritation
• Nitrogen Oxides (NOx): High combustion temperatures form NOx; contributes to smog, acid rain; respiratory problems
• Mercury and Heavy Metals: Coal contains mercury, arsenic, lead; emitted in smoke; bioaccumulates; neurotoxic to humans
• Health Costs: WHO estimates 7+ million premature deaths annually from air pollution; most from fossil fuel combustion
• Disproportionate Impacts: Indoor air pollution from coal heating kills millions in developing nations; outdoor pollution worst in Asia

Extraction and Production Impacts

• Coal Mining: Surface mines destroy habitats, create dust pollution; acid mine drainage contaminates water for decades; worker health risks (black lung disease)
• Oil Extraction: Drilling damages ecosystems; oil spills (Deepwater Horizon 4.9 million barrels); pipeline leaks persistent problem; produced water contamination
• Gas Extraction: Fracking uses millions of gallons of water; potential groundwater contamination; induced seismicity (earthquakes); flaring (burning excess gas - wasteful)
• Refining/Processing: Energy-intensive; refineries major pollution sources; toxic waste disposal problems

Oil Spill Consequences

• Marine Ecosystem Damage: Toxins kill fish, shellfish, marine mammals; coating animals prevents movement; impacts food webs for years
• Coastal Communities: Fishing livelihoods destroyed; tourism collapsed; cleanup costs billions
• Long-term Effects: Oil persists in sediments decades; bioaccumulation in food chains; genetic damage to surviving populations
• Notable Examples: Exxon Valdez (1989, Alaska, 11 million gallons), Deepwater Horizon (2010, Gulf, 4.9 million barrels, worst US environmental disaster), Prestige (2002, Spain)

• Zero Carbon Emissions: No CO₂ during operation (only during construction); essential for climate mitigation; single largest low-carbon source
• High Capacity Factor: ~90% (runs continuously); solar ~25%, wind ~35%, coal ~40%; most reliable baseload power
• Small Land Footprint: ~1 km² per GW electricity (lowest of all sources); solar needs 45x more land per GW
• No Air Pollution: No particulates, SO₂, NOx, mercury; zero health impacts from operation
• Established Technology: 400+ operating reactors globally; 60+ years operational experience; safety record excellent (deaths/TWh among lowest)
• Grid Stability: Baseload power balances intermittent renewables; can be paired with solar/wind to provide stable supply
• Modern Designs: Gen III+ reactors have improved safety systems, can't melt down, produce less waste

Disadvantages and Challenges

💡 Exam Tip: Nuclear = zero-carbon baseload (90% capacity factor); statistically safest (lowest deaths/TWh); essential for climate mitigation. BUT: waste storage unsolved (10,000+ year hazard), high costs ($10-20B per plant), long construction, public opposition. Accidents rare but catastrophic (Chernobyl, Fukushima). Modern reactors safer. Must be paired with renewables for complete decarbonization. Know climate benefit vs. concerns tradeoff!

Carbon-Neutral Concept

• Theoretical: CO₂ released during combustion = CO₂ absorbed during plant growth; net zero carbon
• Reality: Carbon-neutral only if regrowth rate ≥ harvest rate; assumption often violated in practice
• Time Lag: Carbon released immediately; regrowth takes decades; creates net carbon debt period
• Land Use Change: Converting forest to plantation carbon-negative (lost forest carbon storage); must regrow on same land
• Best Practice: Use waste biomass (doesn't require new growth); ensure regrowth; avoid high-carbon-store ecosystems (forests, peatlands)

Sustainability Red Flags

• Deforestation: Cutting ancient forests = carbon-negative (lost old-growth storage); even replanting doesn't offset for 50-100+ years
• Peatland Drainage: Peatlands store 2x more carbon than all forests; draining for biofuel feedstock releases stored carbon; highly carbon-positive
• Monocultures: Biomass plantations on former biodiverse land = biodiversity loss; reduces carbon storage compared to diverse forests
• Harvest Exceeds Regrowth: Many regions cutting faster than regrowth; net carbon loss; unsustainable
• Food Competition: Biofuels from food crops drives food price inflation; impacts vulnerable populations
• Processing Energy: Ethanol production energy-intensive; must use renewable energy or net carbon benefit questionable

Air Pollution

• Particulate Matter: Biomass burning produces soot, ash; PM2.5 penetrates lungs; cardiovascular and respiratory disease
• Indoor Air Quality: Wood heating in homes major pollution source; developing nations burn biomass indoors without ventilation; causes 3+ million premature deaths annually (WHO)
• NOx and CO: Combustion produces nitrogen oxides and carbon monoxide; contribute to smog and health impacts
• Volatile Organic Compounds (VOCs): Released during biomass burning; contribute to ground-level ozone formation
• Mitigation: Modern high-efficiency biomass combustion reduces emissions; clean stove programs in developing nations; transition to other energy

Ecological Impacts

• Deforestation: Biomass plantations replace natural forests; biodiversity loss; habitat destruction; soil degradation
• Soil Health: Harvesting all residue removes organic matter; reduces soil carbon, fertility; requires synthetic fertilizers offsetting carbon savings
• Water Impacts: Biomass crop monocultures use more water than native vegetation; affects groundwater; impacts aquatic ecosystems
• Species Extinction: Rainforest conversion for palm oil/sugarcane; endemic species loss; agricultural expansion major extinction driver

Direct Solar Thermal

• Flat-Plate Collectors: Water/glycol circulates through tubes absorbing solar heat; insulated box prevents radiation loss; 70-80% efficient
• Applications: Water heating (50% of heating water demand potential), space heating, pool heating, industrial heat
• Advantages: Simple technology; high efficiency; long lifespan (20-30 years); low maintenance; cheap ($2-5/W)
• Disadvantages: Requires space; subject to weather; freeze protection needed in cold climates; backup heat needed for cloudy days
• Heat Storage: Insulated tanks store thermal energy; enables use during night/cloudy periods; thermal mass cheaper than batteries

Concentrated Solar Power (CSP)

• Technology: Mirrors/lenses concentrate sunlight to heat fluid to 300-500°C; drives turbine for electricity; essentially concentrating solar into concentrated heat
• Types: Parabolic troughs (most common), central receiver towers, dish systems
• Capacity Factor: 25-50% with thermal storage; excellent dispatchability (can continue generating after sunset if insulated)
• Thermal Storage: Molten salt tanks store energy; enables 24-hour operation; valuable for grid stability
• Advantages: Natural thermal storage; baseload capability; low operating costs; high efficiency 20-30%
• Disadvantages: High capital costs ($2-4/W); land-intensive; requires direct beam sunlight (doesn't work in clouds); limited by location
• Geographic Limits: Requires high direct normal irradiance; best in deserts; limited to ~30°N/S latitude bands

Intermittency Challenge

• Daily Cycle: Zero output at night; peaks at midday; afternoon ramp-down creates grid imbalance
• Weather Variability: Clouds reduce output 50-75%; season affects peak times; variability different from wind (peaks different times)
• Grid Mismatch: Solar peaks midday (low demand); evening peak requires other sources; requires flexible backup
• Ramp Rates: Fast changes in cloud cover create supply swings; grid frequency must stay 59.5-60.5 Hz; challenges system operators
• Solution Approaches: Geographic diversity (multiple solar sites reduce aggregate variability), batteries, demand response, interconnection with other grids

Storage Solutions

• Battery Storage: Lithium-ion batteries 85-95% efficient; costs falling 90% in 10 years; now <$100/kWh (approaching grid parity); essential for high-solar grids
• Thermal Storage: Solar thermal systems store heat naturally; molten salt, PCM (phase change materials); 2-4 hour discharge typical
• Pumped Hydro: Existing technology; 70-85% efficient; limited by geography; can provide many hours discharge
• Hydrogen/Fuel Cells: Convert excess solar to hydrogen; long-term storage; inefficient (40-50% round trip) but scalable
• Grid-Scale Storage Needs: 1-4 hour storage for daily cycle (batteries good); seasonal storage harder (winter shortage in northern regions)
• Complementarity: Solar + wind combined more stable (wind often night/winter); reduces storage needs 50%+

Cost Trajectory

• Dramatic Cost Decline: Module costs fell 90% since 2010 ($370/W to $40/W); system costs ~$1-2/W installed
• Levelized Cost of Electricity (LCOE): Solar now $30-60/MWh (cheapest in many regions); wind $30-80/MWh; coal $60-120/MWh; natural gas $40-100/MWh
• Learning Curve: 20% cost reduction per doubling of cumulative capacity; continuing trend expected
• Factors Driving Decline: Manufacturing scale, efficiency improvements, supply chain competition, automation
• Future Potential: $20-40/MWh possible by 2030; solar likely cheapest electricity source globally
• Balance of System Costs: Panels now <50% of cost; inverters, wiring, installation, permits remaining costs; installation labor significant

Deployment Scale

• Current Capacity: ~1 TW solar capacity globally (2024); doubling every 3-4 years
• Electricity Generation: Solar produced ~5% of global electricity (2024); projected 20-30% by 2050
• Land Requirements: ~100 m² per kW nameplate capacity (varies with mounting, efficiency); 100 GW solar = ~10,000 km² land (same as large city)
• Rooftop Potential: Existing roof area globally sufficient for 1+ TW solar without competing for land
• Desert Potential: 1% of world's deserts covered in solar = current global electricity demand (DESERTEC concept); technically feasible
• Geographic Distribution: Solar potential widely distributed; every continent can deploy; enables energy independence

Run-of-River Systems

• Design: No reservoir; turbines in river channel; water continuously flows through
• Advantages: Minimal environmental disruption (no damming); maintains natural flow; fish can migrate past turbines (with screens); no large reservoir
• Disadvantages: Output follows seasonal flow (wet season high, dry season low); no storage for flexibility; can't store energy for peak demand
• Capacity Factor: 40-60% (varies with seasonal flow pattern); predictable in watersheds with steady discharge
• Turbine Mortality: Fish passage through turbines causes 10-30% mortality (best available, but still problematic)
• Installation: Faster construction than dams; easier environmental approval (less habitat damage); emerging preference globally

Reservoir/Dam Systems

• Design: Large dam creates reservoir; stores water; operator controls release for electricity generation
• Advantages: Flexible dispatch (can release water anytime); multiple uses (irrigation, water supply, flood control, recreation); can provide baseload power with storage; high capacity factor 60-90%
• Disadvantages: Massive environmental disruption; blocks fish migration (50+ km passable rivers blocked); flooding of valley (habitat loss, archaeological sites); displacement of people (millions historically)
• Methane Emissions: Submerged vegetation decomposes anaerobically; produces methane (25-30x more potent GHG than CO₂); tropical reservoirs particularly bad (~200% increase in GHG if accounting for methane); partially negates climate benefit
• Sedimentation: Dams trap sediment (100+ million tonnes annually globally); downstream delta starves of sediment (erosion); reservoir fills with sediment (200-300 year lifetime typical)
• Fish Impacts: Upstream - can't migrate to spawning grounds; downstream - water temperature/oxygen changes; reservoir - predator habitat; ~30-40% salmon mortality at dams
• Social Impacts: Three Gorges Dam (China) displaced 1.3 million people; Aswan Dam flooded entire civilization's homeland; land acquisition & resettlement costly and controversial

Pumped Storage Hydroelectricity

• Technology: Two reservoirs at different elevations; at night (low demand, cheap electricity), pump water from lower to upper; during day (high demand), release upper water through turbines
• Function: Acts as giant battery; stores energy as potential energy; round-trip efficiency 70-85% (loses 15-30% to pumping friction)
• Capacity Factor: 20-50% (not continuously operating; cycles based on demand); provides energy storage, not new generation
• Grid Support: Provides frequency regulation, load following, peak capacity; essential for integrating variable renewables
• Advantage of Hydro Storage: Multiple-hour discharge capability (4-24 hours typical); batteries typically 2-4 hours; hydro best for long-duration storage
• Global Capacity: ~160 GW pumped storage globally; growing fast; most cost-effective grid storage technology at scale
• New Projects: Emerging offshore pumped storage (use ocean level differences); potential massive scale

In-Stream / Tidal Hydroelectric

• In-Stream Turbines: Devices installed in river channel without dam; water flows around; minimal fish impact; early-stage technology
• Tidal Energy: Uses tidal flow in bays/straits; turbines spin as tides flow; predictable (unlike solar/wind); emerging technology; limited sites (strong tidal currents needed)
• Wave Energy: Waves on ocean surface; devices extract energy; high energy density but harsh environment; not yet commercial
• Development Stage: All emerging; potential but not yet competitive with conventional hydro; environmental impacts uncertain

Ecosystem Impacts

• Migratory Species: Anadromous fish (salmon, shad) swim upriver to spawn; dams block migration; population collapse (Pacific Northwest salmon nearly extinct); fish ladders help but not 100% effective
• Downstream Erosion: Reservoir traps sediment; downriver delta starved; Mediterranean deltas, Nile Delta, Mekong Delta all losing land due to upstream dams
• Temperature Changes: Deep water releases from dams colder than natural water; impacts cold-intolerant species; algae balance disrupted
• Oxygen Depletion: Reservoir stratification; deep water anoxic; releases anoxic water downstream; kills fish and aquatic organisms
• Riparian Zone Loss: Dams prevent floods; floodplain vegetation depends on periodic flooding; loss of biodiversity habitat
• Invasive Species: Reservoirs act as traps; invasive aquatic plants take over; food web disruption

Social and Cultural Impacts

• Displacement: Large dams displace millions (Three Gorges 1.3M, Aswan 100k, Itaipu 42k); people lose homes, agricultural land, cultural heritage
• Indigenous Rights: Dams often on indigenous lands; destroy ancestral territories; violate rights; inadequate compensation
• Resettlement Costs: Expensive and often fails; communities struggle economically; cultural disruption; resentment toward project
• Transboundary Conflicts: International rivers; dams in upstream country affect downstream; water security concerns; geopolitical tensions (Turkey-Syria-Iraq over Euphrates; Egypt-Sudan-Ethiopia over Nile)
• Benefit Distribution: Often centralized hydropower benefits distant cities while local communities bear environmental costs; equity concerns

• Current Capacity: ~1.4 TW global hydroelectric capacity; produces ~4,200 TWh annually (~16% of global electricity)
• Best Hydropower Countries: Canada (95 GW), USA (85 GW), Brazil (75 GW), Russia (50 GW), India (50 GW); others like Norway (15 GW) punch above weight (30% of electricity)
• Hydropower-Dependent Nations: Iceland (85% hydro), Norway (95% hydro/wind), Costa Rica (65% hydro); vulnerable to droughts
• Future Expansion Limited: ~40% of economically viable potential already exploited; remaining sites often in protected areas or face environmental opposition; little room for growth in developed nations
• Developing Nation Growth: China, India, Brazil continuing expansion; Africa and Southeast Asia significant potential; but environmental concerns growing
• Climate Change Impacts: Hydrological cycles changing; precipitation patterns shifting; drought years reduce generation (Australia, Chile, Brazil all experienced hydro shortages); reliability declining
• Paradox: Hydro is clean energy when operating but massive environmental/social costs upfront; questionable sustainability for new projects in pristine areas

Electricity Generation

• Process: Wells drill to depth; hot water/steam rises naturally or is pumped; steam drives turbine; condenser cools exhaust steam back to water; water injected back into reservoir
• Thermal Efficiency: Low (~10%); heat rejected to environment; limited by thermodynamic cycle (Carnot efficiency limited by temperature difference)
• Capacity Factor: Excellent 70-90% (similar to nuclear, higher than most others); runs continuously; highly reliable
• Plant Lifespan: 25-50 years typical; reinjection extends resource life; successful field management maintains production decades+
• Dispatchability: Good load-following capability; can increase/decrease output by controlling steam release
• Global Capacity: ~15 GW geothermal electricity generation; produces ~100 TWh annually (~0.3% of global electricity); Iceland 30%, Philippines 20%, USA 10%, Mexico 8%

Direct Use Applications

• Heating (Primary Use): Direct use geothermal ~3x electricity generation globally; heating water for homes/greenhouses/industrial
• Efficiency: 70-90% efficient (heat transfer, not thermodynamic conversion); much better than electricity generation
• Applications: Space heating (Iceland 30% of heating), hot water, bathing, agriculture (greenhouses year-round), fish farming, food processing, paper industry
• Payback: Quick payback (5-10 years) due to high efficiency; low operating costs; savings compelling economically
• Location Advantage: Geothermal heating enables countries to reduce fossil fuel dependence; Iceland example (drops oil imports, high renewable %)
• Cascade Use: Lower temperature water after electricity used for heating; maximizes resource utilization

Technology and Potential

• Concept: Artificial fracturing in hot but dry rock to create permeability; hydraulic fracturing like oil/gas extraction; water circulates through fractured rock
• Advantage: Potentially usable anywhere with sufficient depth; not location-limited like natural geothermal; massive technical potential
• Development Status: Early-stage technology; pilot projects in France, Australia, Japan; not yet commercially viable; costs too high
• Technical Challenges: Drilling deep (4-5 km) expensive; fracturing engineering complex; monitoring/control uncertain; well lifetime/productivity questions
• Economic Challenges: High capital costs; long exploration phase; high risk (wells may not work); financing difficult
• Environmental Concerns: Induced seismicity (microearthquakes); potential groundwater contamination; pressure on host rock
• Timeline: Probably 10-20 years before EGS economically competitive; may revolutionize geothermal if successful

Global Potential

• Conventional Geothermal: ~70-100 GW potential; currently ~15 GW deployed; most economical sites developed; expansion to ~30-50 GW possible
• EGS Potential: Theoretically unlimited; could provide significant baseload power globally if technology matures; estimates 100+ GW possible by 2050
• Regional Advantage: Not possible everywhere (drilling to 5 km in cold rock expensive); best in regions with reasonable depth to high-temperature rock
• Integration: Geothermal baseload pairs with variable renewables (solar/wind) to provide stable grid

Steam Methane Reforming (SMR)

• Process: Natural gas (CH₄) + steam → CO + H₂; CO + water → CO₂ + H₂
• Current Reality: 95% of hydrogen produced this way; cheap (~$1-2/kg); well-established infrastructure
• Emissions: Produces CO₂ (0.2 kg CO₂ per kg H₂); "grey hydrogen"; carbon-negative
• Improvement: Blue hydrogen: SMR with carbon capture (~90% CO₂ captured); reduces emissions 80-90%; more expensive
• Problem: If hydrogen from fossil gas, not truly zero-emission; defeats climate purpose unless carbon captured

Electrolysis

• Process: Electric current splits water (H₂O) into hydrogen (H₂) and oxygen (O₂); "green hydrogen" if powered by renewables
• Efficiency: ~65% electrical efficiency (electrical energy to chemical energy); thermodynamic efficiency high, but grid losses add up
• Cost: Green hydrogen ~$6-10/kg (current); grid electricity expensive; needs cheap renewable electricity to compete
• Grid Application: Absorbs excess renewable electricity; stores energy as hydrogen; recovers via fuel cell (40-50% round-trip efficiency: electricity → H₂ → electricity)
• Advantage: Creates long-term energy storage; can supply weeks/months (battery limited to hours)
• Scaling: Production increasing; costs projected to fall as renewables cheaper; could become cost-competitive by 2030-2040
• Carbon Payback: Green hydrogen carbon payback depends on grid electricity source; renewable-powered only ~1-2 years

Other Production Methods

• Biomass Gasification: Heat biomass without oxygen; produces hydrogen-rich gas; clean feedstock produces low-carbon H₂
• Photoelectrochemical: Direct water splitting using sunlight; research-stage; mimics photosynthesis
• Biological: Algae/bacteria produce hydrogen under certain conditions; emerging; not yet commercial
• Nuclear-powered Electrolysis: High-temperature nuclear produces hydrogen; zero-carbon if reactor safety assured

Storage Challenges

• Low Density: Hydrogen gas very low density; high volume needed even for modest energy storage
• Compressed Gas: Storage at 350-700 bar; expensive, heavy tanks required; safety concerns (hydrogen highly flammable)
• Liquid Hydrogen: Cryogenic (-253°C); requires expensive insulation; 30% energy lost in liquefaction process
• Chemical Storage: Binding hydrogen in ammonia (NH₃) or formic acid (HCOOH); easier transport; must release hydrogen (energy cost)
• Material Storage: Metal hydrides, carbon nanotubes; research-stage; not yet practical
• Reality: No ideal solution yet; limits hydrogen's practical use; storage/transport major cost

Transport and Distribution

• Pipeline: Existing natural gas pipelines could carry hydrogen blend (up to 20%); hydrogen-only pipelines expensive to build
• Truck/Rail: Compressed or liquid hydrogen; expensive; safety-critical; expensive infrastructure
• Sea Transport: Liquid hydrogen or carriers; major projects planned (Saudi Arabia to Japan); enables international trade
• Infrastructure Gap: Almost no hydrogen distribution infrastructure; requires massive investment; chicken-and-egg problem
• Economic Barrier: Transport costs significant; limits hydrogen to high-value applications

Current and Near-Term Uses

• Industrial: 95% of hydrogen currently used in ammonia (fertilizer) and petroleum refining; economic value established
• Vehicles: FCVs (fuel cell vehicles) emerging; Toyota Mirai, Hyundai Nexo available; ~20,000 FCVs globally; limited by hydrogen stations (~400 globally)
• Heavy Transport: Trucks, buses, trains; hydrogen better than batteries (weight, range); China, Europe building hydrogen truck networks
• Industry: High-temperature heat for steel (direct reduction), cement, chemicals; difficult to decarbonize other ways
• Aviation/Maritime: Emerging; hydrogen synthetic fuels (e-fuels) under development; can use existing infrastructure

Barriers and Challenges

• Cost: Green hydrogen not yet competitive with fossil hydrogen or alternatives; needs government support/subsidies
• Infrastructure: Chicken-and-egg: vehicles won't be bought without hydrogen; stations not built without vehicles; requires coordinated investment
• Efficiency: Well-to-wheel efficiency 40-50% (worse than battery electric 70-80%); less efficient for personal vehicles
• Hydrogen Embrittlement: Hydrogen makes steel brittle; existing pipelines/equipment can't easily convert
• Safety Perception: Hydrogen flammable; public concern about safety; incidents feed "hydrogen is dangerous" perception (though statistically safe)
• Competing Technologies: Battery electric for vehicles faster/cheaper to deploy; needs less new infrastructure

Onshore Wind

• Deployment: Most common; ~95% global capacity onshore; wind farms on land
• Turbine Size: 3-5 MW typical modern onshore; 100-150 m hub height; blade length 40-60 m
• Capacity Factor: 35-45% average (varies by location); poor sites 20-25%, excellent sites 50%+
• Cost: ~$1-2/W installed; lower than solar in most regions; electricity ~$40-80/MWh LCOE
• Land Use: 40-50 acres per MW capacity; allows agricultural coexistence; sheep can graze under turbines
• Location Drivers: Wind speed critical; coastal areas, plains, ridge tops preferred; jet stream areas in temperate zones
• Growth: Rapidly expanding globally; USA, China, India leading installations

Offshore Wind

• Deployment: Growing rapidly; ~5% of global capacity currently; concentrated in Northern Europe (40% global offshore capacity)
• Turbine Size: Larger (10-15+ MW units emerging); taller hub heights (200+ m); massive rotor diameters (220+ m)
• Capacity Factor: 40-50% (stronger, more consistent winds); better than onshore
• Cost: ~2-4/W installed (2-3x onshore); offshore infrastructure expensive; LCOE $50-120/MWh
• Advantages: Higher capacity factor; no land-use conflicts; stronger winds offshore; cooling benefits (power output higher in cool water)
• Disadvantages: Extreme cost; harsh environment; maintenance difficult; marine ecosystem impacts; fishing conflicts; installation vessels complex
• Floating Offshore: Emerging technology; turbines on floating platforms; enables deep water; expensive but potential for massive expansion
• Future Trend: Costs falling rapidly; offshore becoming economically competitive; exponential growth expected

Turbine Design and Evolution

• Blade Design: Aerodynamic optimization critical; airfoil shapes, pitch control, yaw to face wind
• Efficiency: Betz limit 59% theoretical maximum; practical turbines achieve 35-45%; limited by blade design, wind shear, turbulence
• Mechanical Systems: Gearbox converts slow blade rotation (~15 rpm) to fast generator rotation (1,000-1,800 rpm); direct-drive turbines eliminate gearbox (more efficient, simpler)
• Lifespan: 20-25 years typical; gearboxes require maintenance; main bearings last entire life if properly designed
• Decommissioning: Turbines removed after end-of-life; 80%+ recyclable (steel, aluminum); blade disposal challenging (fiberglass/composites); some repowering (replace turbine, keep foundation)
• Size Trend: Continuously increasing; economies of scale; fewer larger turbines replacing many small ones

Wind Variability

• Daily Variation: Wind patterns shift daily; output unpredictable; can swing 50% hour-to-hour
• Seasonal Patterns: Wind often stronger in winter (northern hemisphere); varies geographically (coastal vs. inland)
• Complementarity: Wind often strong when solar weak (night, winter, cloudy days); combination reduces overall variability 30-50%
• Predictability: Weather forecasts enable prediction 6-24 hours ahead; helps grid operators prepare
• Ramp Rates: Output can change 50% in 1-2 hours with wind fronts; challenges grid frequency control (must maintain 59.5-60.5 Hz)
• Solution Approaches: Geographic diversity (many wind farms = smoother aggregate output), flexible backup (natural gas plants can ramp quickly), demand response, energy storage

Grid Services

• Frequency Regulation: Wind turbines can provide frequency support; helps stabilize grid
• Reactive Power: Power electronics enable grid support; sophisticated modern turbines provide services beyond electricity
• Voltage Support: Can help regulate voltage on transmission lines
• Inertia Provision: Synchronous machines provide inertia; wind lacks this; concern for low-inertia grids
• Future Role: Ancillary services from wind increasingly important as renewable penetration rises

Wildlife Impacts

• Bird Mortality: ~200,000-600,000 bird deaths/year in USA from turbines; low compared to cats (2+ billion), vehicles (200 million), but raptors overrepresented
• Bat Mortality: ~200,000-900,000 bats/year USA; pressure-related trauma from passing turbines; vulnerable species affected
• Mitigation: Radar monitoring detects approaching birds/bats; turbines can shut down; timing restrictions (avoid migration); blade color impacts bird detection
• Habitat: Minimal habitat loss during operation; minimal footprint during construction if planned carefully
• Marine Impacts: Offshore impacts on fish, marine mammals less understood; electromagnetic fields from cables concern; noise pollution underwater
• Perspective: Wildlife impacts real but modest compared to other energy sources; habitat loss from fossil fuel extraction far greater

Social Acceptance

• Noise: Modern turbines ~35-45 dB at distance; complaints from nearby residents; setback distances help (typically 300-500 m minimum)
• Visual Impact: Tall, visible structures; "visual pollution" complaints; scenic area opposition; sometimes overstated
• Property Values: Studies show minimal impact overall; some property value decrease near turbines, other areas increase (renewable reputation)
• Public Support: Generally favorable (70-80% support); NIMBYism in some areas ("Not In My Back Yard")
• Community Benefits: Local tax revenue, land lease payments to farmers, job creation during construction/maintenance
• Solution: Community engagement, transparent process, fair benefit-sharing improves acceptance

• Current Capacity: ~1 TW global wind capacity (2024); ~5,000 TWh annual generation (~8% of global electricity)
• Growth Rate: Capacity doubling every 3-4 years; fastest-growing after solar
• Top Countries: China (40% global capacity), USA (20%), Europe (15%), India (8%), Brazil (4%)
• Cost Decline: Fell 70% in 15 years; now competitively priced with fossil generation in most regions
• Future Potential: 20-30% of global electricity by 2050 projected; requires offshore expansion and storage solutions
• Manufacturing Supply Chain: Blades (Denmark, Spain, USA), turbines (multiple countries), towers (steel mills)
• Research Directions: Larger turbines (20+ MW), floating offshore, direct-drive, hybrid wind-solar farms
• Key Challenge: Grid integration with high penetration; requires storage, flexible backup, smart grid technologies

Simple Actions

• Lower Thermostat: 7°C reduction = ~10% energy savings; most people comfortable at ~19°C vs. 22°C
• Shorter Showers: 5-minute reduction saves ~50 L hot water; significant daily energy reduction
• Phantom Load Reduction: Devices in standby mode use 5-10% of household electricity; power strips eliminate standby draw
• Laundry: Washing in cold water saves heating energy; air-dry clothes instead of dryer saves ~90% of appliance energy
• Lighting: Turn off lights when leaving room; use natural daylight when possible
• Total Potential: ~5-10% household energy savings from behavioral changes; modest but achievable with habit formation

Smart Metering and Feedback

• Real-Time Feedback: Households with smart meters + real-time electricity display reduce consumption 15% just from awareness
• Behavioral Economics: Social comparison (showing neighbors' usage) motivates conservation; loss aversion drives people to reduce excess
• Gamification: Challenges, competitions, rewards for reducing usage boost engagement
• Time-of-Use Pricing: Higher prices during peak hours incentivize shifting demand to off-peak; reduces need for generation capacity
• Automation: Smart homes automatically optimize based on occupancy, weather, price signals
• Demand Response: Utilities can temporarily reduce power (dim lighting, raise AC setpoint) during grid stress; keeps lights on while reducing demand

How Rebound Effect Works

• Mechanism: Efficiency improvements reduce effective energy price; lower cost encourages more use; consumption increases offsetting part of savings
• Example 1 - Insulation: Better insulation reduces heating costs; people respond by warming house more (19°C → 21°C); some savings offset
• Example 2 - Car Efficiency: Efficient car cheaper to drive per km; people may drive more; potential cross-travel (flights replace driving if budgets allow)
• Example 3 - LED Lighting: Cheap to operate; people leave lights on longer; not full 80% savings realized
• Direct Rebound: Increased consumption of same service (heating, driving); ~10-30% typical offset
• Indirect Rebound: Money saved spent on other energy-consuming goods/services; ~10-20% offset
• Economy-Wide Effect: Complex macroeconomic impacts; efficiency → cheaper services → economic growth → more consumption; harder to quantify
• Total Effect: Studies suggest 10-30% of theoretical efficiency savings offset by rebound; efficiency still delivers net savings but not 100% of potential

Implications

• Still Valuable: Even with rebound, efficiency delivers 70-90% of theoretical savings; major emissions reductions
• Combined Approach: Efficiency alone insufficient; must pair with carbon pricing (makes consumption more expensive even if more efficient) or demand management
• Policy Implications: Price signals essential alongside efficiency standards; otherwise rebound fully negates efficiency gains
• Cultural Shift: Need values change beyond efficiency; sufficiency/enough concept important for deep decarbonization

Economic Barriers

• High Capital Cost: Upfront investment substantial ($5,000-20,000 for building retrofits); limits adoption despite payback period
• Financing Constraints: Poor households lack capital for investments; unable to access benefits even when economically sensible
• Split Incentives: Landlords don't benefit if tenants pay energy bills (no investment incentive); tenants can't invest in rental property
• Discount Rate: Individuals discount future savings; 3-year payback doesn't compete with other investment opportunities offering higher immediate returns
• Energy Poverty: Low-income households struggling with current bills; can't afford efficiency upgrades; trapped in high-cost/inefficient buildings

Behavioral and Information Barriers

• Information Gap: Consumers unaware of efficiency options, payback periods, or availability of programs
• Complexity: Multiple options confusing; hard to evaluate best choice; decision paralysis
• Inertia: Status quo bias; people stick with familiar products even if suboptimal; resistance to change
• Habit Formation: Behavior change difficult; people revert to old habits without consistent reinforcement
• Trust Issues: Skepticism of claims (greenwashing); doubt about actual energy savings; requires proof

Policy Solutions

• Building Codes/Standards: Mandate efficiency levels; eliminates worst performers; levels playing field for manufacturers
• Appliance Labels: EnergyGuide/Energy Star labels enable comparison; drive market toward efficiency
• Rebates/Incentives: Reduce upfront cost; ease adoption; can target low-income populations
• Financing Programs: On-bill financing, PACE (Property Assessed Clean Energy); enable investment despite capital constraints
• Education Campaigns: Raise awareness; explain payback periods; overcome information barriers
• Contractor Training: Ensure quality installation; builds consumer confidence
• Rental Property Regulations: Require landlord efficiency investment; protects tenants from energy poverty

• Technical Potential: 20-30% global energy reduction with existing technology; achievable within 15-20 years with aggressive policy
• Cost-Benefit: Net economic benefit; efficiency investments save money long-term; payback periods typically 3-10 years
• Co-Benefits: Improved comfort (better insulation), health (better ventilation), resilience (efficient buildings tolerate disruptions better)
• Employment: Efficiency retrofits job-intensive; creates local employment (can't be outsourced)
• Fastest Climate Solution: Efficiency reduces emissions immediately with no new generation needed; fastest deployment timeline
• Regional Variation: Developing nations more potential (less efficient baseline); developed nations already ~50% of potential realized
• Deep Decarbonization: Efficiency essential but insufficient; must combine with renewable generation + electrification + behavioral change to reach net-zero
• Investment Required: ~$300-400 billion annually needed for global efficiency improvements; ~0.3-0.4% of global GDP; financially feasible