( ( geothermal ( energy Heat ) ) ( ( ( extracted ( from ( ( the Earth ) ( for use ) ) ) ) ( as ( an ( power source ) ) ) ) . ) )
(ROOT (S (NP (JJ geothermal) (NN energy) (NNP Heat)) (VP (VBD extracted) (PP (IN from) (NP (NP (DT the) (NN Earth)) (PP (IN for) (NP (NN use))))) (PP (IN as) (NP (DT an) (NN power) (NN source)))) (. .)))
geothermal energy Heat extracted from the Earth for use as an power source.
(ROOT (S (NP (JJ Geothermal) (NN power)) (VP (VBZ is) (VP (VBN generated) (PP (IN via) (NP (NP (JJ underground) (NNS sources)) (PP (IN of) (NP (NN heat))))))) (. .)))
Geothermal power is generated via underground sources of heat.