Complex sentence: Hawaii's imported energy costs are three times higher than the mainland, so Hawaii has motivation to become one of the highest users of solar energy, while its tropical location provides lots of sun energy that could be utilized more effectively in the future.
Split into simpler sentences: Hawaii's imported energy costs are three times higher than the mainland, so Hawaii has motivation to become one of the highest users of solar energy. Its tropical location provides lots of sun energy that stands to be utilized more effectively in the future.