alternative (adj)
/ɒlˈtɜː.nə.tɪv/ 

can be choose instead of something else

consumption (n)
/kənˈsʌmpʃ(ə)n/

the use of something such as fuel or energy, or the amount that people use

ecologist (n)
/ɪˈkɒlədʒɪst/

a scientist who studies the environment and the way that plants, animals, and humans live together and affect each other

exhausted (adj)
/ɪɡˈzɔːstɪd/

empty or finished, because a supply of something has all been used

fossil fuel (n)
/ˈfɒsəl ˌfjuːəl/ 

a fuel such as coal or oil, made from decayed material from animals or plants that lived many thousands of years ago

geothermal heat (phrase)
/ˌdʒiː.əʊˈθɜː.məl hiːt/ 

the heat at the centre of the Earth

infinite (adj)
 /ˈɪn.fɪ.nət/

without limits

make use of (phrase)
 /meɪk juːz əv/

to use someone or something for a particular purpose, especially one that brings a benefit to you

potential (n)
/pəˈten.ʃəl/ 

someone's or something's ability to develop, achieve, or succeed

release (v)
 /rɪˈliːs/

to let a substance or energy spread into the area or atmosphere around it

renewable (adj)
 /rɪˈnjuː.ə.bl̩/

be produced as quickly as it is used

resource (n)
 /rɪˈzɔːs/ 

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

solar panel (n)
 /ˈsəʊ.lər ˈpæn.əl/

a device that changes energy from the sun into electricity

available (adj)
/əˈveɪ.lə.bl̩/

able to be bought or used

coal (n)
/kəʊl/ 

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

windmill (n)
/ˈwɪnd.mɪl/

a tall building with sails that turn in the wind and produce power to crush grain or produce electricity

abundant (adj)
/əˈbʌn.dənt/ 

more than enough

hydroelectricity (n)
 /ˌhaɪ.drəʊ.ɪˈlekˈtrɪs.ɪ.ti/

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

harmful (adj)
/ˈhɑːm.fəl/ 

causing physical or other injury or damage

radiation (n)
/ˌreɪ.diˈeɪ.ʃən/

a form of energy that comes from a nuclear reaction and that can be very dangerous to health