Across
- 3. very expensive to build hydrogen fuel _____.
- 5. greenhouse gases, methane, and carbon dioxide may be _______.
- 8. produce energy and electricity in hydropower plants.
- 10. when an energy source can be restocked in a relatively short amount of time.
- 11. getting hot steam and water from the earth's crust does not use much of this.
- 14. uses the force of flowing water to create energy.
- 17. destroy some wildlife and natural resources.
- 18. a simple motion caused by uneven heating of the Earth's surface.
- 20. these are put into the ground to bring heat from the earth's crust to the surface.
- 21. this type of energy is taken from the wind by turbines.
- 23. the simplest element known to man
- 24. hydrogen had one of these and one electron.
- 26. there are three of these and geothermal energy does two of them.
- 27. any organic matter that can be used as an energy source.
- 28. this percentage of energy from the wind is given to turbines.
- 30. solar energy cannot be used on all parts of this.
Down
- 1. sometimes people must cut these down to create biomass fuels.
- 2. using biomass fuels creates none of this that other energy sources create.
- 4. it meets ______ energy needs.
- 6. this type of energy comes from hot steam or hot water in the earth's crust.
- 7. solar energy can only be used when this is out.
- 9. produced when radiant energy from the sun strikes the solar cell.
- 12. geothermal energy does not include this need.
- 13. energy from the sun.
- 15. a large size can produce enough electricity to power 1000 homes.
- 16. hydrogen is an energy _______.
- 19. energy is produced from hydrogen by combining with this.
- 22. along with crops, and yard and animal waste this is a biomass.
- 25. an important part of solar energy and is free.
- 29. where this and land meet is an ideal place for wind to blow.