Unit 8: Renewable Energy, Conservation, and Waste - Module 1: Renewable Energy

Efficiency

The percentage of used energy in a system that does useful work. Efficiency (%) = useful energy out / energy in * 100

LED lighting

Lighting technology that is about 85% efficient, converting a high percentage of energy into light.

Alternative Energies

Energies that are not fossil fuels and are mostly renewable, including hydropower, solar, wind, geothermal, biomass, tidal, and wave.

Hydropower

Uses flowing water to generate electricity, accounting for 44% of U.S. renewable energies and 7% of total electricity.

Wind energy

Utilizes wind to spin turbines for electricity generation, accounting for 8.4% of U.S. electricity and 26% of renewable energy.

Biomass

Involves burning organic matter like wood or agricultural waste for energy, accounting for 40% of alternative energy in the U.S.

Geothermal

Uses natural heat from the earth for electricity or heating, accounting for 6% of U.S. renewable energy.

Solar energy

Utilizes sunlight for heating and electricity through passive and active systems, including photovoltaic cells and concentrated solar power.

Hydrogen Fuel

Involves converting hydrogen gas into a fuel source, with fuel cells generating electricity, offering pollution-free energy but facing efficiency challenges.

Efficiency

Percentage of used energy in a system doing useful work

Cogeneration

Production of two useful forms of energy from the same fuel source

Alternative Energies

Non-fossil fuel energies, mostly renewable

Hydropower

Uses flowing water's mechanical power to generate electricity

Renewable Energy

Energy sources that are replenished naturally

Wind Energy

Electricity generation using wind to spin turbines

Biomass

Burning organic matter for energy, heating, or transportation

LEDs

Light-emitting diodes with high energy efficiency

Internal Combustion Engine

Engine in gasoline cars with low efficiency (10%-15%)

Nuclear Energy

Non-renewable but alternative energy source

Wind Farms

Clusters of wind turbines generating electricity

Ethanol

Fuel produced by fermenting corn, sugar, or grains

Biodiesel

Diesel substitute made from animal fat or vegetable oils

Incandescent Light Bulb

Light source with low efficiency (about 5%)

Fluorescent Lights

Lights with higher efficiency (around 22%)

Renewable Energy Overview

Hydropower, solar, wind, geothermal, biomass, tidal, and wave energy

Energy Conservation

Efforts to reduce energy consumption

Energy Efficiency Formula

Efficiency (%) = useful energy out / energy in * 100

Energy Saving in Homes

Methods to reduce energy usage in households

Wind Energy Advantages

Low environmental impact, no air pollution

Hydropower Disadvantages

Disrupts habitats, displaces people, costly to build

Biomass Fuels

Fuels derived from organic matter like wood or algae

Bagasse

Residue from crushed sugarcane burned as fuel in Hawaii

Geothermal

Uses natural heat from earth for electricity, limited to tectonically active areas

Tidal Energy

Converts ocean tide energy to electricity, limited to coastal regions

Wave Energy

Generates electricity from waves pushing air over a turbine

Ocean Thermal Energy Conversion (OTEC)

Generates electricity from temperature difference in ocean water

Passive Solar Heating

Architectural design to absorb solar energy without mechanical power

Active Solar Heating

Requires mechanical energy to move heat to storage areas

Photovoltaic Cells

Convert sunlight to electricity using silicon cells

Concentrated Solar Power (CSP)

Large-scale solar energy collection for electricity generation

CSP - Parabolic Trough

Reflects solar radiation onto a receiver along a curved trough

CSP - Dish Design

Focuses sunlight onto a receiver using a large parabolic dish

CSP - Power Tower

Uses moveable mirrors to focus sunlight on a tower with a steam turbine

Solar Lighting - Fiber Optics

Illuminates buildings by focusing sunlight through fiber optics

Hydrogen Fuel

Converts hydrogen gas into a fuel source, not common on earth

Fuel Cell

Device generating electricity through a chemical reaction using hydrogen fuel