quick summary

Nonrenewable Energy Sources: Exist in fixed amounts; cannot be replaced easily. Examples: fossil fuels (coal, oil, natural gas) and nuclear fuels (uranium).
Renewable Energy Sources: Can be replenished naturally at or near the rate of consumption. Examples: solar, wind, hydroelectric, geothermal.
Depletable Renewables: Renewable sources that can run out if overused, e.g., biomass (wood, charcoal).
Nondepletable Renewables: Renewable sources that do not run out under current usage rates, e.g., solar, wind.

Energy Distribution: Unevenly distributed between developed and developing countries; developed countries consume more energy overall and per capita.
Fossil Fuels: Most widely used globally; coal, oil, and natural gas are primary sources.
Economic Development: Increased energy consumption in developing nations as they industrialize.

Wood & Charcoal: Common in developing countries; easily accessible but can drive deforestation.
Types of Coal: Lignite, bituminous, anthracite (based on heat, pressure, and burial depth).
Natural Gas: Mostly methane, cleanest fossil fuel.
Crude Oil: Extracted by drilling; refined into various petroleum products.

Global Energy Reserves: Major countries for fossil fuels include the US, Russia, China, and Australia.
Fracking: Hydraulic fracturing method that increases natural gas supply.

Combustion Process: Chemical reaction yielding CO2 and water, generating energy for electricity production.
Environmental Effects: Habitat destruction, air pollutants, greenhouse gas emissions from fossil fuel combustion.

Nuclear Power Generation: Utilizes fission to generate heat, producing steam for electricity.
Environmental Concerns: Radioactive waste persistence and potential catastrophic failures (Three Mile Island, Chernobyl, Fukushima).

Biomass Burning Effects: Produces pollutants but is considered carbon neutral since it releases recently sequestered carbon.
Biofuels: Ethanol and biodiesel derived from biological materials; environmental impacts include land use changes and emissions.

Photovoltaic Cells: Convert sunlight directly into electricity; impacts include habitat disruption from large solar farms.
Solar Energy Types: Active (mechanically captures energy) and passive (design-based heat absorption).

Hydropower Generation: Uses kinetic energy from moving water to produce electricity; large dams can alter ecosystems and sediment flow.
Environmental Considerations: Dams create reservoirs that flood land and affect fish migration.

Geothermal Basics: Uses heat from Earth's interior for electricity generation; accessible through hot water and steam.
Environmental Concerns: Expensive drilling and potential hydrogen sulfide emissions.

Hydrogen as Fuel: Combines hydrogen and oxygen to produce electricity with water as a byproduct.
Environmental Impacts: Low emissions but requires energy-intensive methods for hydrogen production; infrastructure challenges exist.

Wind Energy Generation: Converts kinetic energy of wind into electricity through turbines.
Environmental Impact: Renewable with no emissions, but turbine impacts include bird and bat fatalities.

Conservation Methods: Residential (thermostat adjustments, efficient appliances) and large-scale (fuel-efficient vehicles, public transport).
Sustainable Home Design: Passive solar design, efficient insulation, and water-conserving fixtures are key strategies for reducing energy consumption.