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Slide 01
Renewable Energy Systems
- Powering Civilization Without Burning It
- From ancient windmills to offshore wind farms, from rooftop panels to utility-scale solar -- how engineering is decarbonizing the world's 29,000 TWh annual electricity supply.
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Slide 02
The Energy Transition: Where We Stand
- The world is in the midst of the fastest energy transformation in history -- renewables are now the cheapest form of new electricity generation in most of the world.
- 2024 Global Electricity Mix
- SourceShareTrend
- Coal34%Declining
- Natural Gas22%Flat
- Hydro15%Slow growth
- Nuclear9%Flat
- Wind8%Rapid growth
- Solar6%Fastest growth
- Other renewables3%Growing
- Oil3%Declining
- Key Milestones (2024)
- 4,000 GW
- Total renewable capacity installed globally
- 510 GW
- New renewables added in 2024 alone
- $380B
- Annual investment in renewables
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Slide 03
Solar Photovoltaics: How Cells Work
- Converting photons directly to electrons -- the photovoltaic effect, discovered by Becquerel in 1839, now powers a $200+ billion industry.
- The Photovoltaic Effect
- P-N junction: Doped silicon creates an electric field at the boundary
- Photon absorption: Light with energy > bandgap (1.12 eV for Si) liberates electron-hole pairs
- Charge separation: Built-in field sweeps electrons to N-side, holes to P-side
- Current flow: External circuit connects the two sides -- electricity flows
- Shockley-Queisser limit: Single-junction theoretical max = 33.7% (for 1.34 eV bandgap)
- Cell Technologies
- TypeEfficiencyMarket Share
- Mono-PERC22-24%~55%
- TOPCon24-26%~30% (growing fast)
- HJT (Heterojunction)24-26%~8%
- IBC (Back-contact)25-27%~3% (premium)
- Thin-film (CdTe)19-22%~4%
- Perovskite (emerging)26%+ (lab)
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Slide 04
Solar: The Cost Revolution
- Solar PV has experienced the most dramatic cost reduction of any energy technology in history -- Swanson's Law in action.
- Price Trajectory
- YearModule Cost ($/W)LCOE ($/MWh)
- 1976$106.00>$1,000
- 1990$8.00$400
- 2000$4.50$250
- 2010$1.50$100
- 2020$0.20$37
- 2024$0.10$24
- Swanson's Law: Module price drops ~20% for every doubling of cumulative production.
- Scale Drivers
- Manufacturing scale: 700+ GW of annual production capacity (mostly China)
- Silicon purity: Solar-grade silicon dropped from $300/kg to $8/kg
- Cell efficiency: From 6% (1954) to 26%+ (2024) -- more watts per m2
- Wafer thinning: 300um to 120um -- less material per cell
- Larger wafers: M10 (182mm) and M12 (210mm) reduce handling costs
- Automation: Modern gigafactories produce 1 GW+ per factory per year
- In 2024, unsubsidized solar became the cheapest source of new electricity in countries representing 90% of global power demand. This is the inflection point that makes the energy transition economically inevitable rather than politically dependent.
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Slide 05
Utility-Scale Solar Farms
- From rooftops to multi-gigawatt desert installations -- solar farms are among the largest structures humans have ever built.
- System Components
- Modules: 550-700W panels (2.3 m2 each), strings of 20-30 in series
- Racking: Fixed-tilt (cheaper) or single-axis trackers (10-25% more energy)
- Inverters: DC to AC conversion -- string (100 kW) or central (3-5 MW)
- Transformers: Step up to grid voltage (34.5 kV or 138+ kV)
- Interconnection: Substation, grid studies, protection equipment
- BESS: Battery storage increasingly co-located (4-hour Li-ion)
- Largest Solar Farms (2024)
- NameCapacityLocation
- Golmud Solar Park16 GWChina (Qinghai)
- Bhadla Solar Park2.7 GWIndia (Rajasthan)
- Benban Solar Park1.8 GWEgypt
- Copper Mountain0.8 GWUSA (Nevada)
- Capacity factors: 15-20% (cloudy/high latitude) to 25-35% (desert with trackers).
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Slide 06
Wind Energy: Aerodynamics and Scale
- Wind turbines convert kinetic energy of moving air into electricity -- and they've grown from 50 kW backyard machines to 15+ MW giants in four decades.
- Physics of Wind Power
- Power in wind: P = 0.5 * rho * A * v^3 (cubic relationship with speed -- doubling wind speed gives 8x power)
- Betz limit: Maximum extractable = 59.3% (16/27) of kinetic energy
- Practical efficiency: Modern turbines achieve 45-50% of wind energy (Cp = 0.45-0.50)
- Swept area: Proportional to blade length squared -- doubling radius gives 4x power
- Hub height matters: Wind speed increases with height (wind shear law) -- taller = more energy
- Growth in Scale
- YearTypical RatingRotor Diameter
- 198555 kW15 m
- 1995600 kW46 m
- 20052.5 MW90 m
- 20155 MW126 m
- 202415 MW (offshore)236 m
- A single Vestas V236-15.0 MW turbine powers 20,000 homes and has blade tips moving at 300+ km/h.
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Slide 07
Wind Turbine Engineering
- Inside the nacelle -- the mechanical, electrical, and control systems that convert wind into grid-quality electricity.
- Key Components
- Blades: Fiberglass/carbon fiber composites, 80-115m long, airfoil profile optimized by BEM theory
- Hub: Cast iron/steel, connects blades to main shaft, houses pitch bearings
- Gearbox: 3-stage planetary (ratio ~100:1) -- or direct-drive with permanent magnet generator (no gearbox)
- Generator: DFIG (doubly-fed induction) or PMSG (permanent magnet synchronous)
- Yaw system: Motors rotate nacelle to face the wind (bearing diameter: 4-6m)
- Tower: Steel tubular, 100-170m hub height, concrete hybrid for tallest
- Control Strategy
- Below rated wind: Variable speed, maximum power tracking (tip speed ratio control)
- At rated wind (10-13 m/s): Pitch control limits power to generator rating
- Above cut-out (25 m/s): Pitch to feather, brake, shutdown for safety
- Power electronics: Full converter (back-to-back) provides grid support (reactive power, frequency response)
- SCADA: Remote monitoring of 100+ parameters per turbine
- Capacity factor: 30-45% onshore, 40-55% offshore (due to stronger, more consistent wind).
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Slide 08
Offshore Wind: The New Frontier
- Offshore wind offers stronger, more consistent winds -- but the engineering challenges of building in open ocean are immense.
- Foundation Types
- Monopile: Single steel tube driven into seabed (up to 30m water depth, 10m diameter). Most common -- 80% of installed offshore wind.
- Jacket: Lattice steel frame for 30-60m depth. Used for larger turbines and deeper water.
- Gravity base: Massive concrete caisson on seabed. Suitable for hard rock.
- Floating: Moored platforms for 60m+ depth -- spar, semi-submersible, TLP. Opens up 80% of ocean wind resource.
- Installation and Scale
- Installation vessels: Jack-up crane ships ($500M+ each) with 3000+ tonne crane capacity
- Cable laying: 66-525 kV submarine export cables, buried 1-3m in seabed
- Offshore substations: Platform-mounted transformers step up voltage for long-distance transmission
- Largest farm: Hornsea 2, UK (1.3 GW) -- 165 turbines covering 462 km2
- Global capacity: 75+ GW installed by end 2024, targeting 380+ GW by 2030
- Floating offshore wind: Hywind Scotland (2017) was the world's first commercial floating wind farm. By 2030, floating wind could unlock resources in Japan, South Korea, California, and the US East Coast where water depths exceed 60m close to shore.
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Slide 09
Hydroelectric Power
- The original renewable -- hydropower provides 15% of global electricity and 60% of all renewable generation. It remains the world's largest source of clean energy.
- Turbine Types
- Pelton (impulse): High head (300-1800m), low flow. Water jets strike cup-shaped buckets. Used in mountain installations. Efficiency: 90-95%.
- Francis (reaction): Medium head (30-600m). Mixed-flow runner -- most common type worldwide. Grand Coulee, Itaipu. Efficiency: 90-95%.
- Kaplan (reaction): Low head (2-40m), high flow. Adjustable propeller blades. River installations. Efficiency: 90-93%.
- Bulb/Tubular: Ultra-low head tidal and run-of-river. Generator inside the water passage.
- Largest Hydropower Plants
- DamCapacityCountry
- Three Gorges22.5 GWChina
- Itaipu14.0 GWBrazil/Paraguay
- Xiluodu13.9 GWChina
- Guri10.2 GWVenezuela
- Tucurui8.4 GWBrazil
- Three Gorges produces 100+ TWh/year -- more than many countries consume. Its reservoir displaced 1.3 million people.
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Slide 10
Energy Storage Systems
- The "missing piece" of the renewable puzzle -- storage decouples generation from demand, enabling 24/7 clean power.
- Storage Technologies
- TypeDurationScale
- Li-ion batteries1-4 hoursMW to GW
- Pumped hydro8-24 hours100 MW - 3 GW
- Compressed air (CAES)4-24 hours100-500 MW
- Flow batteries (VRFB)4-12 hours1-100 MW
- Iron-air batteries24-100 hoursEmerging
- Green hydrogenDays to monthsGW scale
- Thermal (molten salt)6-15 hours100+ MW
- Li-Ion Grid Storage
- Hornsdale (Tesla, 2017): 150 MW/194 MWh -- proved grid batteries work at scale
- Moss Landing (2023): 750 MW/3000 MWh -- world's largest BESS
- Cost decline: From $1200/kWh (2010) to $139/kWh (2023)
- Round-trip efficiency: 85-92% (Li-ion), 75-85% (pumped hydro)
- Cycle life: LFP cells: 6000+ cycles (15-20 year operating life)
- Global grid storage deployment: 50+ GW installed by 2024, needing 1,500+ GW by 2050 (IEA NZE).
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Slide 11
Grid Integration Challenges
- Integrating variable renewables into power grids designed for dispatchable fossil plants requires fundamental system redesign.
- Technical Challenges
- Variability: Solar produces nothing at night; wind is intermittent -- supply doesn't follow demand
- Inertia loss: Synchronous generators (coal, gas) provide rotational inertia that stabilizes frequency. Solar/wind inverters don't inherently provide this.
- Transmission: Best wind/solar resources are often far from demand centers -- need new HVDC lines
- Duck curve: Midday solar surplus depresses prices, then evening ramp requires fast gas plants
- Curtailment: Excess generation must be curtailed when grid can't absorb it (California: 5-10% in spring)
- Solutions
- Grid-forming inverters: Smart inverters that synthetically provide inertia and voltage support
- Storage: Shift excess to deficit periods
- Demand response: Flexible loads (EVs, water heaters, industrial) absorb excess
- Geographic diversity: Wind in different regions doesn't stop simultaneously
- Overbuilding: Install excess capacity so even low-output periods meet demand
- Interconnection: HVDC links balance regions (NordLink, Viking Link)
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Slide 12
Concentrated Solar Power (CSP)
- Unlike PV, CSP uses mirrors to concentrate sunlight as heat -- enabling thermal storage and dispatchable solar electricity.
- CSP Technologies
- Parabolic trough: Curved mirrors focus sunlight on tube at focal line. HTF (oil at 400C) generates steam. Most deployed CSP technology.
- Power tower: Thousands of heliostats reflect to a central receiver. Molten salt at 565C. Higher temperature = higher efficiency.
- Linear Fresnel: Flat mirrors approximate trough shape. Cheaper, less efficient.
- Dish-Stirling: Parabolic dish with Stirling engine at focus. Highest efficiency (30%+) but small scale.
- Thermal Storage Advantage
- Molten salt storage: NaNO3/KNO3 mixture stores heat at 290-565C for 6-15 hours
- Dispatchable: Generate electricity on demand, day or night
- Noor-Ouarzazate, Morocco: 580 MW CSP complex with 7.5 hours storage -- world's largest
- Gemasolar, Spain: First 24/7 solar plant (2011) using 15-hour storage
- Challenge: Higher cost than PV+battery in most locations ($100-150/MWh vs $40-60)
- CSP is most competitive in high-DNI regions (>2000 kWh/m2/yr): Sahara, Middle East, Chile, Australia.
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Slide 13
Geothermal Energy
- Tapping Earth's internal heat -- reliable 24/7 power with near-zero emissions. Available wherever you drill deep enough.
- Types of Geothermal Plants
- Dry steam: Directly uses underground steam (rare -- The Geysers, California: 900 MW)
- Flash steam: High-pressure hot water (>180C) flashes to steam at surface. Most common type.
- Binary cycle: Moderate-temperature water (100-180C) heats a secondary working fluid (isobutane/isopentane) that drives turbine. Opens up low-temperature resources.
- EGS (Enhanced Geothermal): Inject water into hot dry rock, create artificial fractures, extract heat. Potential: accessible anywhere at sufficient depth.
- Current State and Future
- Global capacity: 16 GW (2024) -- tiny but 90%+ capacity factor
- Leaders: USA (3.7 GW), Indonesia (2.4 GW), Philippines (1.9 GW), Iceland (755 MW)
- Iceland: 25% of electricity + 90% of building heating from geothermal
- EGS breakthrough: Fervo Energy's 2023 demonstration achieved commercial flow rates in non-volcanic rock using horizontal drilling + hydraulic stimulation from oil/gas industry
- Superhot rock: Drilling to 400C+ could yield 10x more power per well
- The geothermal prize: If EGS becomes economical at scale, the heat beneath our feet represents a functionally unlimited, 24/7, zero-carbon energy source -- estimates suggest 2 TW extractable in the US alone (10x current total capacity).
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Slide 14
Biomass and Bioenergy
- Converting organic matter to energy -- the oldest energy source (wood fires) reimagined for the modern grid and transport sector.
- Conversion Pathways
- Combustion: Burn biomass for heat/steam/electricity. Drax (UK) -- 2.6 GW converted from coal to wood pellets
- Anaerobic digestion: Bacteria convert organic waste to biogas (60% CH4, 40% CO2). Used in 20,000+ EU farms
- Gasification: Partial oxidation at 700-1200C produces syngas (CO+H2) for power or fuels
- Pyrolysis: Heating without oxygen produces bio-oil, char, and gas
- Fermentation: Sugars to ethanol -- 110 billion liters/year (US corn, Brazilian sugarcane)
- Transesterification: Vegetable oil to biodiesel
- Sustainability Debate
- Carbon neutral? Only if regrowth matches combustion timeline -- forests take decades
- BECCS: Bioenergy + Carbon Capture = net negative emissions (theoretically). Drax is piloting.
- Land use: Dedicated energy crops compete with food production
- Waste biomass: Agricultural residues, food waste, sewage -- genuinely low-carbon feedstocks
- SAF (Sustainable Aviation Fuel): Bio-based jet fuel from waste oils/cellulose -- airlines' primary decarbonization path
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Slide 15
Ocean Energy
- The ocean stores vast energy in tides, waves, currents, and thermal gradients -- but harnessing it remains engineering's toughest challenge.
- Tidal Power
- Tidal barrage: Dam across estuary with turbines. La Rance (France, 1966): 240 MW, still operating. Sihwa Lake (South Korea): 254 MW
- Tidal stream: Underwater turbines in fast currents (like underwater wind turbines). MeyGen (Scotland): 6 MW, expanding to 398 MW
- Tidal lagoon: Proposed impoundments in shallow coastal areas -- Swansea Bay (320 MW) never funded
- Advantage: Perfectly predictable (tidal cycles known centuries ahead). Challenge: High cost, environmental impact on estuaries.
- Wave Energy
- Point absorbers: Floating buoys heave with waves, driving hydraulic pumps or linear generators
- Oscillating water columns (OWC): Waves compress air in a chamber, driving a turbine
- Overtopping: Waves fill a reservoir above sea level, drain through turbine
- Resource: 30,000 TWh/year theoretical global potential (current electricity demand: 29,000 TWh)
- Challenge: Survivability in storms (100-year waves) vs. efficiency in average conditions. Few commercial deployments to date.
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Slide 16
Green Hydrogen
- Electrolysis powered by renewables produces hydrogen with zero carbon emissions -- a clean fuel for sectors electricity cannot reach.
- Electrolysis Technologies
- Alkaline (AEL): Mature, proven, lowest cost. KOH electrolyte. 60-70% efficiency. Stacks to 10+ MW.
- PEM (Proton Exchange Membrane): Faster response, compact. Pure water electrolyte. 55-70% efficiency. Better for variable renewable input.
- SOEC (Solid Oxide): High temperature (700-900C) using waste heat. 80-90% efficiency with heat. Best for integration with nuclear/industrial processes.
- AEM (Anion Exchange Membrane): Emerging -- combines alkaline's low cost with PEM's compactness. No platinum needed.
- Hydrogen Use Cases
- Steel: Replace coal in direct reduction (DRI) -- H2 + Fe2O3 = Fe + H2O (HYBRIT, Sweden)
- Ammonia/fertilizer: Green Haber-Bosch process
- Shipping: Ammonia or methanol fuel for container ships
- Aviation: Synthetic kerosene via Fischer-Tropsch (green H2 + captured CO2)
- Long-duration storage: Store weeks/months of energy as H2 in salt caverns
- Heavy trucking: Fuel cell trucks for long haul (1000+ km range)
- Cost target: Green hydrogen must reach $1-2/kg to compete with grey ($1/kg). Current cost: $3-8/kg. Requires cheap renewables (16 / 32
Slide 17
Power Electronics: The Enablers
- Inverters, converters, and transformers -- the unsung heroes that make renewable electricity grid-compatible.
- Solar Inverters
- Function: Convert variable DC from panels to fixed-frequency AC (50/60 Hz)
- MPPT: Maximum Power Point Tracking adjusts voltage/current to extract maximum energy continuously
- String inverters: 50-300 kW, connect strings of panels
- Central inverters: 1-5 MW for utility-scale
- Microinverters: One per panel -- maximize per-panel output, no single point of failure
- Efficiency: 97-99% (SiC/GaN semiconductors pushing >99%)
- Grid-Forming Technology
- Problem: Traditional inverters "follow" the grid frequency -- they need a reference signal from synchronous generators
- Grid-forming inverters: Create their own voltage/frequency reference -- can operate a grid independently
- Virtual synchronous machine: Software emulates the inertial response of a rotating generator
- Black start: Restart a dead grid using only renewables + batteries
- Significance: Enables 100% inverter-based grids without any fossil backup
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Slide 18
Pumped Hydro Storage
- The world's largest battery -- pumped hydro stores 95% of all grid energy storage globally and has operated reliably for over 100 years.
- How It Works
- Charge: Pump water from lower reservoir to upper reservoir using excess electricity (overnight or midday solar surplus)
- Discharge: Release water through turbines to generate electricity on demand
- Round-trip efficiency: 75-85%
- Response time: Minutes (full load in 60-90 seconds for existing plants)
- Lifetime: 50-100+ years with turbine refurbishment
- Global installed: 160+ GW across 50+ countries
- Next-Generation Concepts
- Closed-loop: No river connection -- two purpose-built reservoirs. Less environmental impact, more site flexibility.
- Seawater pumped hydro: Ocean as lower reservoir -- Japan (Okinawa), Portugal proposed
- Underground: Abandoned mines as lower reservoir (South Africa, Germany proposals)
- Variable-speed: Modern pump-turbines with variable speed drives -- better efficiency across operating range
- Snowy 2.0 (Australia): 2 GW / 350 GWh -- enough to power Sydney for a week. Tunnels 27 km through the Snowy Mountains.
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Slide 19
HVDC Transmission
- High-Voltage Direct Current -- the technology that moves renewable energy thousands of kilometers from where it's generated to where it's needed.
- Why HVDC?
- Lower losses: ~3% per 1000 km (vs. 6-7% for HVAC). Essential for long distances.
- Submarine cables: AC cables waste energy charging/discharging capacitance. DC has no reactive power loss -- can span 100s of km underwater.
- Asynchronous connection: Links grids with different frequencies (Japan 50/60 Hz, Nordic-UK)
- Power flow control: Precise, fast controllability -- stabilizes connected AC grids
- Voltage levels: Up to 1,100 kV (China's Changji-Guquan: 1,100 kV, 3,300 km, 12 GW)
- Major HVDC Projects
- Changji-Guquan (China): 1,100 kV, 12 GW, 3,300 km -- world's highest voltage and longest UHV line (Xinjiang wind/solar to Shanghai)
- NordLink: Norway-Germany, 623 km undersea, 1.4 GW -- balances Norwegian hydro with German wind/solar
- Viking Link: UK-Denmark, 765 km, 1.4 GW (2023)
- SunCable (proposed): 4,200 km from Australian solar to Singapore -- 3.2 GW
- Xlinks (proposed): Morocco solar/wind to UK via 3,800 km undersea cables -- 3.6 GW
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Slide 20
Perovskite Solar Cells
- The most exciting solar technology in a generation -- from discovery to 26%+ efficiency in just 15 years.
- What Are Perovskites?
- Crystal structure: ABX3 formula (e.g., CH3NH3PbI3) -- named after the mineral CaTiO3
- Bandgap tuning: Change composition to optimize for different wavelengths (1.2-3.0 eV range)
- Deposition: Solution-processable -- spin coating, slot-die coating, inkjet printing
- Efficiency trajectory: 3.8% (2009) to 26.1% (2024) -- fastest improvement of any PV technology
- Tandem cells: Perovskite on silicon: 33.7% efficiency (2024) -- surpassing single-junction theoretical limit
- Challenges to Commercialization
- Stability: Degrades with moisture, heat, UV, and oxygen. Must achieve 25+ year outdoor life to compete with silicon.
- Lead toxicity: Most efficient perovskites contain lead -- encapsulation or lead-free alternatives needed
- Scale-up: Lab cells are cm2; commercial panels need m2 of uniform deposition
- Hysteresis: Measurement artifacts in current-voltage sweeps complicate characterization
- Companies: Oxford PV (tandem), CubicPV, Swift Solar, Saule Technologies pushing commercialization
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Slide 21
Small-Scale and Distributed Energy
- Not all renewable energy is utility-scale -- rooftop solar, small wind, and microgrids are transforming how individuals and communities generate power.
- Rooftop Solar
- Global installed: 250+ GW of residential/commercial rooftop PV
- Grid parity: In most developed countries, rooftop solar is cheaper than retail electricity
- Australia leads: 33% of homes have solar -- 20 GW on rooftops alone
- Virtual power plants: Aggregate thousands of home batteries for grid services (Tesla, Sonnen)
- Net metering: Export excess to grid, import at night -- but policies vary widely
- Microgrids
- Definition: Local energy system that can operate independently from the main grid
- Components: Solar/wind + battery + smart controls + backup generator (optional)
- Applications: Islands, military bases, hospitals, remote communities, university campuses
- Island nations: Ta'u (American Samoa) -- 100% solar+battery since 2016 (previously diesel)
- Resilience: Operates during grid outages (hurricanes, wildfires, earthquakes)
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Slide 22
Country Leaders in Renewables
- Highest Renewable Share
- CountryRenewable %Primary Source
- Iceland100%Hydro + Geothermal
- Paraguay100%Hydro (Itaipu)
- Norway98%Hydro
- Costa Rica99%Hydro + Wind + Geothermal
- Uruguay97%Wind + Hydro
- Denmark84%Wind (mostly offshore)
- Portugal72%Wind + Hydro + Solar
- Largest Absolute Capacity
- CountryRenewable GWKey Investment
- China1,300+Solar, wind, hydro
- USA420+Wind, solar, hydro
- Brazil180+Hydro, wind, biomass
- India190+Solar, wind
- Germany160+Wind, solar
- China installs more renewables each year than the rest of the world combined -- 300+ GW added in 2024.
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Slide 23
The Economics of Renewables
- LCOE (Levelized Cost of Energy) tells the full story -- renewables have won the cost war against fossil fuels.
- LCOE Comparison (2024, Global Average)
- SourceLCOE ($/MWh)
- Onshore wind$30-50
- Utility solar PV$24-45
- Offshore wind$70-120
- Natural gas CCGT$45-75
- Coal (new)$65-150
- Nuclear (new)$100-200
- Solar + 4h battery$45-75
- Why Renewables Keep Getting Cheaper
- Learning curves: 20% cost reduction per doubling of deployment (solar), 15% (wind)
- No fuel cost: Zero marginal cost of production -- only capital and maintenance
- Manufacturing scale: Gigafactories for panels, blades, batteries
- Technology improvement: Higher efficiency, larger turbines, better materials
- Competitive auctions: Government tenders drive prices down (Saudi Arabia: $10.4/MWh solar in 2021)
- Fossil fuel externalities: Carbon pricing ($50-100/ton) makes the gap even larger
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Slide 24
Agrivoltaics and Dual-Use Solar
- Combining solar panels with agriculture -- addressing the land-use concern while providing shade, reduced water loss, and dual income streams.
- How Agrivoltaics Works
- Elevated panels: Mounted 3-5m high, allowing tractors and livestock underneath
- Semi-transparent panels: Partial light transmission supports shade-tolerant crops
- Vertical bifacial: East-west facing panels between crop rows -- minimal shading at midday
- Crop benefits: Reduced water evaporation (14-29%), protection from hail, lower heat stress
- Best crops: Lettuce, spinach, tomatoes, berries, grapes, herbs (shade-tolerant)
- Research Results
- University of Arizona: Chiltepin peppers produced 3x fruit under panels with 50% less water
- Fraunhofer ISE (Germany): Wheat yield 80% of full-sun with full electricity generation
- France: First commercial agrivoltaic regulations (2024) -- require minimum agricultural production
- Japan: 2,000+ "solar sharing" farms since 2013 regulation
- Grazing: Sheep under solar panels reduce mowing costs and provide dual income (very popular in Australia, US)
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Slide 25
Electric Vehicles as Grid Assets
- The global EV fleet is a massive distributed battery -- vehicle-to-grid (V2G) technology turns parked cars into power plants.
- V2G Concept
- Average EV battery: 60-100 kWh (average US home uses 30 kWh/day)
- Cars parked 95% of time: Enormous idle storage capacity
- Bidirectional charging: Draw power from and return power to the grid via smart chargers
- Revenue potential: $300-1500/year per vehicle for grid services (frequency regulation, peak shaving)
- Fleet scale: 50 million EVs x 60 kWh = 3,000 GWh of mobile storage (more than all grid batteries combined)
- Smart Charging
- Time-of-use: Charge when electricity is cheap/abundant (midday solar surplus)
- Demand response: Reduce charging during evening peak
- Renewable matching: Charge when local wind/solar generation is high
- Vehicle-to-home (V2H): Power house during outages (Ford F-150 Lightning, Nissan Leaf)
- School bus V2G: Fleets parked 16 hrs/day near school grid connections -- ideal V2G candidates
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Slide 26
Heat Pumps: Electrifying Heating
- Heat pumps deliver 3-5 units of heat per unit of electricity consumed -- the single most impactful technology for decarbonizing buildings.
- How Heat Pumps Work
- Principle: Reversed refrigeration cycle -- moves heat from cold source to warm building
- Air-source (ASHP): Extracts heat from outdoor air down to -15 to -25C. COP 2.5-5.
- Ground-source (GSHP): Extracts heat from stable ground temperature (10-15C). COP 3.5-5.5. Higher cost but higher efficiency.
- Water-source: Rivers, lakes, sewers, aquifers as heat source
- COP vs. gas furnace: COP 3 heat pump delivers same heat at 1/3 the energy (vs. gas at 95% efficiency)
- Global Deployment
- Installed base: 200+ million heat pumps worldwide (2024)
- Growth: 10%/year -- outpacing gas boiler sales in Europe since 2022
- Norway: 60% of buildings heated by heat pumps
- EU target: Ban new gas boilers from 2029 in several countries
- Industrial: High-temperature heat pumps (up to 150C) replacing steam boilers in food/chemicals
- District heating: Large-scale water-source heat pumps serving entire neighborhoods (Copenhagen, Stockholm)
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Slide 27
Renewable Energy and Jobs
- The energy transition is creating millions of new jobs globally -- while requiring careful planning for communities dependent on fossil fuels.
- Employment Numbers (2024)
- Solar PV: 5.5 million jobs globally (manufacturing, installation, O&M)
- Wind: 1.5 million jobs (blade factories, offshore installation, maintenance)
- Hydropower: 2.4 million jobs
- Bioenergy: 3.6 million jobs (farming, processing, power)
- Total renewables: 16+ million direct jobs (IRENA, 2024)
- Projected 2030: 38+ million renewable energy jobs
- Just Transition
- Challenge: Fossil fuel workers (15M globally) face displacement as coal/oil decline
- Transferable skills: Electricians, mechanics, welders, operators, drillers needed in renewables
- Retraining programs: Germany's coal transition fund (40 billion euros), US IRA provisions
- Geographic mismatch: New jobs often not where old ones disappear -- requires economic development investment
- Manufacturing opportunity: Domestic solar/battery factories creating industrial jobs (US, EU, India)
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Slide 28
Lifecycle Environmental Impact
- Renewables are not zero-impact -- but their lifecycle emissions are 10-100x lower than fossil fuels.
- Lifecycle CO2 (g CO2eq/kWh)
- SourceMedianRange
- Coal820740-910
- Natural gas490410-650
- Solar PV4118-48
- Wind onshore117-15
- Wind offshore128-16
- Nuclear125-22
- Hydropower244-200
- Source: IPCC AR6, 2022.
- Material and Land Considerations
- Minerals: Solar/wind/batteries require copper, lithium, cobalt, rare earths -- mining impact must be managed
- Land use: Solar: 5-10 acres/MW; Wind: 30-60 acres/MW (but land underneath usable); Nuclear: 1 acre/MW
- Recycling: Solar panels: 95% recyclable (glass, aluminum, silicon). First-generation panels reaching end of 25-30 year life now
- Blade disposal: Fiberglass wind blades difficult to recycle -- industry developing thermoplastic resins, cement kiln co-processing
- Energy payback: Solar panels repay manufacturing energy in 1-2 years, then generate 25+ more years of clean energy
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Slide 29
100% Renewable Scenarios
- Can the world run entirely on renewables? Multiple credible studies say yes -- if we build storage, transmission, and demand flexibility at scale.
- Key Studies
- Jacobson et al. (Stanford): 143 countries modeled at 100% WWS (wind-water-solar) by 2050 -- technically feasible and economically beneficial
- IRENA World Energy Transitions Outlook: 90% renewable electricity by 2050 is cost-optimal for net-zero
- Lappeenranta (LUT): Sector-coupled 100% renewable global energy system -- relies heavily on solar PV + batteries + green hydrogen
- IEA Net Zero by 2050: Renewables provide 90% of electricity; hydrogen/biofuels cover hard-to-abate sectors
- What's Needed
- 4x current solar deployment rate sustained for 25 years
- 2x current wind deployment rate sustained for 25 years
- 6,000+ GWh of battery storage (vs. 100 GWh today)
- $4 trillion/year investment in clean energy (vs. $1.8T in 2024)
- Massive grid expansion: Double global transmission capacity, including intercontinental HVDC
- Electrification: EVs, heat pumps, industrial processes shift demand to electricity
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Slide 30
Emerging Technologies
- The next generation of renewable technologies could reshape the landscape once more.
- Airborne Wind
- Kites and tethered drones harvest stronger, more consistent winds at 300-600m altitude -- where the jet stream blows. Companies: Makani (Google, shut down), KiteGen, Ampyx Power. Challenge: reliability over 20-year lifetimes.
- Space-Based Solar
- Solar panels in geostationary orbit collect sunlight 24/7 (no night, no clouds) and beam microwave energy to ground receivers. 3-5x energy per m2 vs. ground. Being studied by ESA, JAXA, Caltech. Challenge: launch cost, beam safety.
- Nuclear Fusion
- Not technically "renewable" but functionally unlimited -- deuterium from seawater. NIF achieved ignition (2022). ITER under construction. Private companies (Commonwealth, Helion) targeting 2030s grid power. If achieved: the ultimate clean baseload.
- Enhanced Geothermal (EGS)
- Applying fracking techniques to create geothermal reservoirs anywhere. Fervo Energy demonstrated commercial viability in 2023. Could provide 24/7 clean baseload virtually everywhere on Earth. DOE targeting $45/MWh by 2035.
- Perovskite Tandems
- Perovskite layer on top of silicon -- captures different parts of the solar spectrum. Lab record: 33.7% efficiency. Could push commercial panels from 22% to 30%+ within 10 years -- same panels, 35% more energy.
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Slide 31
Policy and Market Mechanisms
- Technology alone isn't enough -- policy frameworks have been essential to driving renewable deployment at the speed required.
- Key Policy Tools
- Feed-in tariffs (FiTs): Guaranteed price for renewable generation -- drove early German/Spanish solar boom
- Reverse auctions: Competitive bidding for lowest-cost projects -- now dominant globally. Record lows: $10-20/MWh
- Renewable Portfolio Standards: Utilities mandated to source X% from renewables by year Y
- Carbon pricing: EU ETS at 50-100 euros/ton makes fossil plants uncompetitive
- Tax credits: US IRA (2022): $370B in clean energy incentives over 10 years -- transformational
- Market Design
- PPAs (Power Purchase Agreements): Corporates contract directly with renewable farms (Google, Amazon, Microsoft buying GW-scale)
- RECs: Renewable Energy Certificates -- tradable proof of clean generation
- Capacity markets: Pay for availability, not just energy -- supports storage
- Ancillary services: Batteries earn revenue from frequency regulation (high-value, low-energy)
- Behind-the-meter: Rooftop solar + storage avoids retail electricity prices entirely
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Slide 32
Key Takeaways
- Where We Are
- Solar and wind are now the cheapest new electricity sources in most of the world
- Renewables provided 30%+ of global electricity in 2024
- Battery costs have fallen 89% since 2010, enabling grid-scale storage
- The energy transition is economically inevitable -- not just politically desirable
- China, Europe, and the US are in a clean energy industrial race
- What Remains
- Long-duration storage (days to weeks) is the biggest unsolved challenge
- Grid buildout must triple -- permitting is the bottleneck, not technology
- Hard-to-abate sectors (aviation, steel, cement) need hydrogen and biofuels
- Mineral supply chains must scale 4-7x without repeating fossil fuel's geopolitical problems
- Speed matters: 2030 targets require deployment rates not yet achieved
- "The Stone Age did not end for lack of stone, and the Oil Age will end long before the world runs out of oil."
- -- Sheikh Zaki Yamani, former Saudi Oil Minister
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