2025 Spring EC II_Lecture 02 - Environment Resources and Energy

Key Terms

  • Power vs. Energy

  • Renewable vs. Nonrenewable Energy

  • Greenhouse Gases (GHG)

  • Energy Quality

  • Embodied Energy

Power versus Energy

Definitions

  • Energy: Total capacity to do work

  • Power: Rate at which energy is used

    • Formula: Energy = Work

    • Power = Energy / Time

Units of Measurement

  • Energy Measurement Units:

    • BTU (calories, foot-pounds, joules)

    • kWh

    • Real-life examples:

      • 1 kWh of electricity = 0.5 lb of coal

      • 0.07 gal of oil

      • 7.7 cubic feet of natural gas

      • Represents large volumes of water in a hydroelectric dam

  • Power Measurement Units:

    • Common units: horsepower, BTU/hr, watt, kW

    • SI units: joule/second, calorie/second, watt, kW

    • Example conversions: gallons of oil per hour, cubic feet of gas per minute

Energy Generation Concepts

Primary Energy Sources

  • Exists naturally and can be non-renewable or renewable

  • Can convert into secondary sources (e.g., electricity)

    • Sources include: coal, uranium, natural gas, wind, solar, etc.

Non-Renewable Energy Sources

  • Resources exhausted within a time frame

  • Major types include:

    • Fossil Fuels: coal, oil, natural gas

    • Peak Oil Concept: Maximum global petroleum extraction point leading to decline

    • Challenges with supply continuity, pollution, and greenhouse gases (GHGs)

Impacts of Non-Renewable Energy

  • Emissions and Pollution:

    • GHG emissions from burning fossil fuels

    • Additional water resource use impacts

    • Problems with heavy metals in the environment due to coal emissions and mining

Renewable Energy Sources

Definition and Characteristics

  • Sources that replenish quickly and are generally available indefinitely

  • Converted typically into electricity or heat

  • Technologies include: wind, solar, geothermal, biomass, hydroelectric

Solar Energy

  • Types of solar technologies:

  • Photovoltaic (PV) for electricity

  • Solar thermal for hot water production

Geothermal Energy

  • Originates from natural processes, like radioactive decay

  • Applications: direct use, space heating, and electricity generation

  • Significant energy reserves beneath the Earth's surface

Energy Efficiency and Sustainability

Concepts Comparison

  • Energy-Efficiency: Using less energy for the same service

  • Sustainability: Meeting present needs without compromising future generations

  • Resilience and Adaptability: Systems designed to withstand and recover from challenges

Conclusion

  • Building is a continuous process, emphasizing the importance of adaptability and sustainability in design.