<Li> Low - carbon power </Li> <Li> Passive solar building design </Li> <Tr> <Th> Renewable energy </Th> </Tr> <Tr> <Td> <Ul> <Li> Anaerobic digestion </Li> <Li> Biofuel </Li> <Li> Geothermal </Li> <Li> Hydroelectricity </Li> <Li> Solar </Li> <Li> Tidal </Li> <Li> Wave </Li> <Li> Wind </Li> </Ul> </Td> </Tr>

Solar energy is generated due to which reaction