燃やす
alternative
bio
biofuel
change
climate
combustion
commodity
costs
eco
ecologically
ecology
efficient
energies
energy
environment
environmental
environmentally
firewood
forest
friendly
fuel
grains
grow
heat
heating
heizkosten
home
industry
mining
pellets
protection
recycle
recycling
renewable
shavings
sources
stove
sustained
timber
warm
wood