energy (n)
 /ˈen.ɚ.dʒi/ 

a source of power, such as fuel, used for driving machines, providing heat, etc.

waste (v)
/weɪst/

to use too much of something or use something badly when there is a limited amount of it

save (v)
/seɪv/

to avoid using energy, or to use less of it

generator (n)
/ˈdʒen.ɚ.eɪ.t̬ɚ/

a machine that produces electricity

non-renewable (a)
/ˌnɑːn.rɪˈnuː.ə.bl̩/ 

existing in limited quantities that cannot be replaced after they have all been used

coal (n)
/koʊl/

a hard black substance that is dug from the ground and burned as fuel to provide heat

petroleum (n)
/pəˈtroʊ.li.əm/ 

oil found under the ground or under the bottom of the sea and used for making petrol for cars and chemical products

natural gas (n)
 /ˈnætʃ.ər.əl ɡæs/

gas, found underground, that is used as a fuel

crude oil (n)
/kruːd ɔɪl/

oil that is still in its natural state and has not yet been refined for use by chemical processes

recycle (v)
/ˌriːˈsaɪ.kl̩/

to use something again, often for a different purpose

resource (n)
/ˈriː.sɔːrs/

a useful or valuable possession or quality of a country, organization, or person

wind energy (noun phrase)
/wɪndˈen.ɚ.dʒi/

energy that uses the power of the wind to produce electricity

water energy (noun phrase)
/ˈwɑː.t̬ɚ en.ɚ.dʒi/

energy that uses the power of the water to produce electricity

solar energy (n)
/ˈsoʊ.lɚˈen.ɚ.dʒi/

energy that uses the power of the sun to produce electricity

nuclear energy (n)
/ˈnuː.kliː.ɚˈen.ɚ.dʒi/

a powerful form of energy produced by splitting the nuclei (= central parts) of atoms, it is used to produce electricity

hydro energy (noun phrase)
/haɪ.droʊˈen.ɚ.dʒi/

producing electricity by the force of fast moving water such as rivers or waterfalls

geothermal energy (noun phrase)
/ˌdʒiː.oʊˈθɝː.məl ˈen.ɚ.dʒi/

power produced by the heat inside the Earth

fossil fuel (n)
/ˈfɑː.səl fjʊəl/

gas, coal, and oil, that were formed underground from plant and animal remains millions of years ago

renewable (a)
 /rɪˈnuːː.ə.bl̩/ 

describes a form of energy that can be produced as quickly as it is used

solar (a)
/ˈsoʊ·lər/

relating to the Sun, or coming from the Sun