Summary of Renewable Energy Resources

Reducing Heat Loss

  • Alternative strategies: reducing energy use and finding renewable energy sources.
  • Thermal images can identify heat loss areas in buildings.

Direct Solar Energy

  • Small portion of solar energy reaches Earth.
  • Solar energy is renewable and cannot be depleted like fossil fuels.
  • Need for collection and transformation into usable energy.

Active Solar Heating

  • Collectors absorb solar energy for heating water.
  • Can significantly reduce energy costs for water heating.
  • Potential to become more essential as fossil fuel prices rise.

Passive Solar Heating

  • Utilizes building design to collect solar heat without mechanical devices.
  • Can save up to 80% on heating costs, but only 7% of new US homes incorporate it.

Photovoltaic Solar Cells

  • Generate electricity from sunlight; low pollution, minimal maintenance.
  • Limited efficiency and large land requirement hinder widespread use.
  • Cost of PV units has decreased; potential future integration in roofing.

Solar Thermal Electric Generation

  • Concentrating solar energy to generate electricity is efficient and cost-competitive with fossil fuels.
  • Requires supplementary energy source at night or on cloudy days.

Solar Generated Hydrogen

  • Hydrogen as a clean fuel; can be produced using renewable energy.
  • Current technology has low efficiency and high costs; infrastructure needed for widespread use.

Indirect Solar Energy

  • Biomass, wind energy, and hydropower leverage the sun's energy indirectly.

Biomass Energy

  • Renewable energy derived from plant/animal material.
  • Can be solid, liquid, or gas. However, conversion for fuel may compete with food production.

Wind Energy

  • Generated from air currents caused by solar heating.
  • Efficient in areas with consistent winds; potential environmental concerns.

Hydropower

  • Derived from flowing/Falling water; highly efficient (90% conversion).
  • Environmental issues include habitat disruption and displacement of communities.

Other Renewable Resources

  • Geothermal energy, ground effect heat pumps, and tidal energy provide alternatives.

Energy Solutions: Conservation and Efficiency

  • Collaboration of energy conservation (reducing use) and energy efficiency (reducing waste).

Energy Consumption Trends

  • Increased energy efficiency in U.S. but consumption rises amid economic growth.
  • Developing nations see the highest demand increases due to technology adoption.

Energy Efficient Technologies

  • Improved appliances and building designs save energy.
  • National standards have led to significant reductions in energy used by appliances.

Electric Power Companies

  • Regulatory changes incentivize utilities to focus on energy efficiency rather than growth.

Energy Conservation at Home

  • Households can significantly reduce utility bills through energy-efficient improvements.

Case Study: Green Architecture

  • Hearst Tower in New York demonstrates significant energy efficiency via innovative design.