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.