It seems obvious; energy harvesting is intermittent, so combine different types to make it continuous and therefore much more useful.

Plenty of kilowatts from no fuel. This dream ticket is a reality today from the rapid adoption of high power energy harvesting. Energy harvesting converts ambient energy into electricity where it is needed, off-grid.

The term 'energy harvesting' is most typically applied to powering small electronic devices using say sunshine, vibration or temperature.

Elastic piezoelectric generators are being developed with microwatts demonstrated and watts in prospect for large formats.

Energy harvesting is the creation of off-grid electricity where it is needed using ambient energy, from sunshine to vibration or temperature difference.