Energy System in the United States

Energy System in the United States

  • Focus on energy usage, waste, and efficiency in electricity generation.

Introduction to the Energy System

  • Approximately two-thirds of total energy used in the US is wasted.

  • Main focus: Waste in electric power generation.

Energy Flow Diagram

  • Energy sources: natural gas, coal, others.

  • Energy input into electrical system: ≈ 37–38 BTUs.

  • Useful output: ≈ 12–13 quads of electricity.

  • Conclusion: Roughly two-thirds of energy enters the system as rejected or waste energy.

Electricity Generation Process

  • Major steps in generating electricity from coal/natural gas:

    • Burning Fuel: Efficient combustion (loss < 10%, often < 1%).

    • Heat Conversion: 95-99% efficient conversion of heat to steam.

    • Turbine Operation: Significant energy loss occurs here when converting steam to electricity.

    • Transmission Loss: Energy lost during transportation of electricity (up to 10% depending on distance).

Breakdown of Efficiency Losses

  • Combustion: Minimal energy loss.

  • Heat to Steam Conversion: Minimal energy loss.

  • **Turbine Conversion: This step incurs the largest efficiency loss.

  • Transmission to Market: Varies based on distance.

Detailed Process of Electricity Generation

  • Step-by-step process:

    1. Heat from burning fuel → Boiler → Steam.

    2. High-pressure steam → Turbine (mechanical motion + magnetic field = electricity).

    3. Low-pressure steam production → Condensing back to water.

  • Energy Loss Positions:

    • Exhaust from burning (minimal loss).

    • Low-pressure steam condensation (bulk energy loss).

Increased Efficiency in Specific Situations

  • Case Study at University of Texas:

    • Higher efficiency due to localized use of low-pressure steam for heating.

    • Typical efficiency of US power plants: 35% (3:1 output).

    • UT power plant: Approx. 80-85% efficiency due to steam usage nearby.

Summary of Energy Flow

  • Main energy use sectors: Electricity generation, transportation, industrial, residential/commercial.

  • Inefficiencies and waste in energy usage are significant, but improvements possible.

Alternative Electric Generation Methods

  • Moving toward non-thermal electricity generation:

    • Hydroelectric Dams: Utilize water from lakes to generate energy without burning fuel.

    • Wind Turbines: Use wind's kinetic energy, turning turbines to generate electricity.

Geographic Wind Energy Potential

  • High wind regions identified:

    • Mountain tops (Rockies, Sierra Nevada)

    • Great Plains (Texas Panhandle, Oklahoma, Nebraska, Kansas, Iowa).

  • Wind Turbine Concentration: High density in areas like Sweetwater, Texas.

Electricity Grid Structure in the US

  • Three Main Grids:

    • Western Grid (predominantly Western states + Alberta & British Columbia).

    • Eastern Grid (multiple subgrids with interconnections).

    • ERCOT: Texas' self-contained grid, covering 75% of Texas, serving 85% of electricity demand.

  • Implications on Wind Generation: Limited capacity for transferring electricity from windy areas like the Panhandle to cities.

Texas Wind Power Trends

  • Wind power accounts for up to 50% of Texas' electricity during peak times (rare).

  • Average share throughout the year: 15-20%.

  • Challenges of wind energy storage and timing mismatches with demand.

    • Maximum demand in summer versus peak wind production in spring/night.

Energy Storage Solutions

  • Importance of energy storage:

    1. Battery storage (limited availability).

    2. Pumped water storage (geographic limitations in Texas).

    3. Hydrogen production from excess energy: splitting water into hydrogen (usable as fuel).

Growth of Wind and Solar Power

  • Significant growth driven by:

    • Renewable energy mandates (prior to 2015).

    • Decreasing costs of wind and solar energy technologies.

  • Levelized Cost of Electricity (LCOE):

    • Wind and solar now cheaper than fossil fuels per kWh due to reduced upfront costs.

Comparison of Energy Costs

  • Costs comparison in cents per kWh:

    • Natural gas (lowest cost ≈ 7¢ in 2010).

    • Wind and solar were higher but have decreased below fossil fuel costs for energy production.

  • Emphasis on upfront vs. ongoing costs in evaluating technology feasibility.

Resource Constraints for Renewables

  • Essential raw materials for renewables (rare earth metals).

  • Key elements for solar panels, wind turbines, and batteries include Dysprosium, Gallium, Indium, and Lithium:

    • Dysprosium needed for magnets in wind turbines (150 kg per 5 MW turbine).

    • Significant quantities needed for extensive wind infrastructure in Texas.

  • Current global supply vs. demand discrepancy for renewable technologies.

Challenges in Supply Chain

  • Dependence on critical metals primarily sourced from China (over 95% of rare earth supply).

  • Political implications of resource dependencies and negotiations affecting availability.

  • Need for substantive quantities of critical materials for scalable clean energy transitions.

Conclusion and Next Steps

  • Exploration of wind and solar power and associated challenges.

  • Future focus on alternatives beyond wind and solar technologies.

  • The necessity of addressing both immediate energy demands and resources for sustainable energy technologies in the United States.