Need: Something you can not live without.
Innovation: An improvement to an item
Technology: Human made creations
The difference between science and technology is that technology is human made creation while science is the natural world.
Energy and power technology
A pharmaceutical/chemical engineer may find a cure for disease.
A computer engineer may build a computer the size of your watch.
A mechanical engineer may create a robot to discover water on a planet.
An agricultural engineer may evaluate the effects of global warming on food production.