Global Solutions: Renewable Energy

Renewable Energy

  • Renewable energy is energy derived from natural processes that are replenished constantly

  • Main Sources are solar, wind, biomass, geothermal, hydropower, ocean waves & tides, biofuels,

  • All are derived directly or indirectly from the Sun or Earth's internal heat.

  • Key benefits include carbon-neutral, displaces fossil fuels, and helps meet climate targets.

  • Investment $1.4 trillion+ in 2022

  • Fastest-growing energy sector globally

Global Use of Renewable Energy

  • 2022 Milestone: Renewable electricity generation rose 8% to 8,300 TWh — fastest annual growth since the 1970s.

  • By 2035, renewables projected to supply over 50% of global electricity.

  • 2020 Share of Total Energy Demand:

    • Hydropower: 6.9%

    • Wind: 3.9%

    • Biofuels & Geothermal: 1.7%

    • Solar PV: 1.1%

  • 2020 Share of Electricity Generation:

    • Hydropower: 16%

    • Wind: 5.9%

    • Solar: 3.2%

    • Biofuels & Geothermal: 2.6%

  • Transition is harder in fast-growing economies due to increasing demand.

Hydroelectric Power

  • Global Role:

    • Supplies 6.9% of total global energy demand

    • Accounts for 16% of electricity generation, more than nuclear (10%)

  • Largest Projects:

    • Three Gorges Dam, China: 22.5 GW capacity

    • High construction costs and environmental concerns are slowing new large-scale projects

  • Top Producers:

  • China, Brazil, Canada, EU, US, Russia, India → over 60% of global output

  • China: 220 → 1,355 billion kWh (2000–2020)

  • Brazil: 86% of electricity from hydro; Itaipu Dam alone generates 92 billion kWh/year

Small Hydroelectric Schemes

  • Facilities generating <10 MW

  • Especially suited for developing countries

  • Replace old diesel generators

  • Works with solar and wind systems

  • Pumped storage: Stores energy by moving water to higher elevations

  • Low-cost, reliable, and ideal for localized, off-grid energy

  • Important part of the future clean energy mix

Geothermal Power

  • Energy derived from heat flowing naturally from Earth’s interior

  • The rate at which temperature increases with depth is called the geothermal gradient

  • Common in highly known volcanic activity, such as Iceland, Yellowstone National Park, Wyoming

  • Types of Use:

    • Direct heating of buildings

    • Steam generation to drive turbines

  • Use lower-boiling-point fluids to produce electricity

  • Used in 70+ countries

  • Generates about 14 GW of electricity, 28 GW direct heating, and 100+ GW total (including heat pumps)

  • CO₂-free energy, clean, steady energy source

  • But High cost typically 2x coal

“New” Renewable Energy

  • Climate crisis driving innovation, investment & political support to find new clean, renewable energy

  • Solar + Wind can supply >2,000 × 10¹⁸ J/year

  • Global energy demand: ~584 × 10¹⁸ J/year

  • Clean renewables can meet >3.5× current energy needs

Wind Energy

  • Wind energy generates 6.15% of global electricity

  • During 2021, it reached 837 GW global capacity

  • Currently, > 127 countries use wind energy worldwide

  • Top producers include China: 282 GW, the EU: 217 GW, the USA: 117 GW, and India: 39 GW

  • Future Outlook:

    • Offshore farms offer higher efficiency

    • Airborne turbines and smart grids are needed to expand

Solar Power

  • Solar power is the most tangible and inexhaustible source of natural energy used for thousands of years

  • Two major and rapidly developing solar technologies: Concentrated

  • Solar Power (CSP) and Photovoltaic (PV) power plants.

    •  PV:

      • Converts sunlight directly into electricity

      • Thin-film tech allows building integration

      • Enables users to sell energy back to the grid

    • Example projects:

      • Bhadla Solar Park (India): 2.25 GW

      • Tengger Desert (China): 1.5 GW

      • Solar Star (USA): 579 MW

    • CSP:

      • Technology that uses mirrors or lenses to concentrate sunlight onto a small area to produce high heat

      • Molten salt storage allows nighttime generation

    • Key examples:

    • Ivanpah (USA): 392 MW, Noor (Morocco): 160 MW

Wave Power

  • Wave power is energy generated from the movement of ocean waves caused by the wind.

  • Early efforts (1970s) failed, but modern designs show promise.

  • Converts wave motion to mechanical energy, then electricity.

  • Pilot projects in Oregon (USA), Scotland, and Portugal.

  • Current outputs are small (2–4 MW), but future potential is vast.

Tidal Power

  • Tidal power is the energy produced from the rise and fall of sea levels (tides)

  • Tidal energy is always predictable and dependable

  • Uses tidal range to drive turbines; energy is dependable and cyclic.

  • Major projects:

    • Sihwa Lake, South Korea (254 MW)

    • La Rance, France (240 MW)

    • Swansea Bay, UK (240 MW)

    • Proposed Penzhin Bay, Russia (87 GW potential)

  • Smaller projects like Strangford Lough (1.2 MW) serve remote communities.

  • Challenges are high cost and environmental concerns.

Solid Biomass

  • Solid biomass is composed of materials such as wood waste left over from forest management, paper mill residues, urban wood waste, wood chips, and agricultural crop residues, such as stalks.

  • In 2020, solid biomass accounted for nearly 5% of U.S. primary energy.

  • Uses:

    • Direct combustion for heat/power

    • Co-firing in coal plants

  • Carbon neutral if regrowth offsets emissions.

  • Challenges are sourcing, transport, and feedstock quality control.

Transport Biofuels

  • Biofuels are key to reducing transportation-related greenhouse gas emissions.

  • Global use has increased by over 30% since 2010.

  • Biofuels are fuels made from living things such as plants, crops, or animal waste

  • Bioethanol: made from crops like corn, sugarcane, useful for gasoline

  • The use of corn to produce bioethanol has become controversial, i.e., “food for fuel” controversy

  • Biodiesel made mostly from soybeans, palm oil, Jatropha, and sunflower, useful for diesel

  • Algal Bioreactors: These are aerated water tanks filled with algae that use sunlight, carbon dioxide, and nutrients to grow algae. The algae produce oils that can be processed into biodiesel

  • Biogas: Produced from decomposing organic waste in landfills and farms, and is used for heat or electricity. Supports energy generation in rural and agricultural communities

Hydrogen

  • Hydrogen is a very attractive source of energy.

  • It is the ultimate clean fuel that burns in air to produce only heat and pure water.

  • Hydrogen as a Vehicle Fuel: The simplest way to use hydrogen is to burn it as a combustible gas.

  • Hydrogen has more potential as a substitute for gasoline.

  • Hydrogen-fueled engines are 25% more efficient than traditional gasoline-powered engines.

  • But needs high-pressure or liquefied storage, costly infrastructure

The Politics of Change

  • Renewable energy tech is still immature, needing significant government and private investment.

  • The EU model shows effective collaboration between policy and commerce, using legislation and fiscal tools to support clean energy.

  • Mandated utility sourcing of renewables has fostered innovation and market competition.

  • Political commitment helps establish a long-term strategy for energy transition.

  • 173+ countries have adopted Renewable Portfolio Standards (RPS), requiring utilities to meet specific renewable energy targets.

  • Non-compliance results in penalties, making RPS a powerful policy instrument.

  • Encourages investment and innovation in the renewable sector.

A New Energy Infrastructure

  • Renewable energy allows for decentralized power generation big shift from utility-focused model.

  • Current grids are obsolete, poorly connected, and not designed for dynamic, distributed sources.

  • Developing countries have an opportunity to leapfrog outdated systems.

  • Without a smart grid, renewables stay expensive due to:

    • Grid access costs

    • Need for fossil-fueled backup

    • New smart grids reduce blackouts, enable automation, and allow real-time adjustments.

    • Developing nations can lead by investing in future-ready infrastructure

Energy Storage

  • Crucial to manage intermittent generation (sun, wind, etc.).

  • Six main technologies:

    • Pumped hydroelectric – stores potential energy in water.

    • Compressed air – stored under pressure in caverns.

    • Flywheels – kinetic rotational energy.

    • Lithium-ion batteries – increasingly efficient and cost-effective.

    • Thermal energy – melts salts or cools water for storage.

    • Gravitational storage – raises/lowers mass to generate power.

Are We Subsidizing Greenhouse Gas Emissions?

  • Fossil fuel subsidies > $500B/year (IEA); $5.2 trillion when externalities included (IMF).

  • Subsidies include tax breaks, military protection, healthcare costs, etc.

  • Largest support: Oil (50%), then electricity, gas, and coal.

  • G10 countries contribute 80% of emissions, heavily subsidizing fossil fuels.

  • U.S. subsidies (2020): $16.6 billion; coal received large portion.

  • Renewables get better per-kWh support, but far less overall.

  • Subsidy distortion keeps fossil fuel prices artificially low, discouraging green innovation.

  • Stable policy + predictable pricing needed to de-risk private investment.

  • EU leveraged: Carbon taxes, Tech innovation, Price guarantees, and Fuel efficiency standards

  • On track to cut GHG emissions 55% by 2030 (vs. 1990 levels).