Click image to open full size
Energy Sources Comparison Cheat Sheet
A printable reference covering renewable, nonrenewable, energy efficiency, capacity factor, emissions, and energy source tradeoffs for grades 6-12.
Related Tools
Related Labs
Related Worksheets
This cheat sheet compares major energy sources used to generate electricity and power modern life. Students need it to understand how cost, reliability, pollution, land use, and fuel availability affect energy choices. It helps organize nonrenewable sources, major renewable electricity sources, and site-dependent or emerging renewables into clear categories. The goal is to support quick comparison rather than memorizing isolated facts. The most important ideas are energy cannot be created or destroyed, every energy source has tradeoffs, and electricity systems need both energy supply and reliability. Key formulas include efficiency = useful energy output / total energy input x 100%, power = energy / time, and capacity factor = actual energy produced / maximum possible energy x 100%. Fossil fuels usually have high energy density but release carbon dioxide, while renewables often have lower operating emissions but depend on location, storage, or weather. Good energy decisions consider environmental impact, cost, safety, reliability, and long-term sustainability.
Key Facts
- Efficiency = useful energy output / total energy input x 100%, so higher efficiency means less wasted energy.
- Power = energy / time, so a 1000 watt device uses energy faster than a 100 watt device.
- Energy used = power x time, so kilowatt-hours measure electricity consumption over time.
- Capacity factor = actual energy produced / maximum possible energy x 100%, which helps compare real output from power plants.
- Fossil fuels such as coal, oil, and natural gas are nonrenewable because they form over millions of years and are used faster than they are replaced.
- Burning fossil fuels releases CO2, and more CO2 in the atmosphere increases the greenhouse effect and contributes to climate change.
- Solar and wind power have low operating emissions, but their output changes with sunlight, weather, season, and time of day.
- Hydropower, geothermal, tidal, and biomass energy can be useful renewables, but each depends strongly on local geography, resources, and environmental limits.
Vocabulary
- Nonrenewable energy
- An energy source that is used faster than natural processes can replace it, such as coal, oil, natural gas, or uranium.
- Renewable energy
- An energy source that is naturally replenished on a human time scale, such as sunlight, wind, flowing water, or geothermal heat.
- Efficiency
- The percentage of input energy converted into useful output energy instead of wasted heat, sound, or other forms.
- Capacity factor
- The percentage of a power plant's maximum possible output that it actually produces over a period of time.
- Greenhouse gas
- A gas such as carbon dioxide or methane that traps heat in Earth's atmosphere and affects climate.
- Energy density
- The amount of energy stored in a fuel or resource per unit of mass, volume, or area.
Common Mistakes to Avoid
- Confusing renewable with pollution-free is wrong because renewable sources can still affect ecosystems, land use, water flow, or wildlife.
- Comparing energy sources only by cost is wrong because reliability, emissions, safety, fuel supply, and environmental damage also matter.
- Assuming solar and wind always produce full power is wrong because their output changes with weather, daylight, season, and location.
- Ignoring efficiency is wrong because a system that wastes less energy may need less fuel and create less pollution for the same useful output.
- Treating electricity and energy as the same thing is wrong because electricity is one form of energy, while fuels, heat, motion, and sunlight are also energy forms.
Practice Questions
- 1 A power plant receives 500 MJ of fuel energy and produces 200 MJ of useful electrical energy. What is its efficiency?
- 2 A wind turbine could produce 10,000 kWh in a day at full power, but it actually produces 3,000 kWh. What is its capacity factor for that day?
- 3 A 2 kW heater runs for 4 hours. How many kilowatt-hours of energy does it use?
- 4 A town must choose between coal, natural gas, solar, wind, hydropower, and geothermal power. Explain two factors besides cost that should guide the decision.