Geothermal Heat Pumps: These systems are both alternative and renewable, running on the natural heat of the earth and also built entirely differently than conventional systems.
Solar Roofing: These system are often renewable and alternative as well, though some might say they are renewable but not alternative because the internal mechanisms often look very similar to conventional systems.
Condensing Boilers: A good example of an alternative but not renewable energy system. Condensing Boilers save energy and reduce your carbon footprint but do not run on renewable fuels.
Micro CHP: Another example of an alternative but not renewable system
Micro Hydro: Renewable and Alternative energy systems
These are just some examples, and you should note that some would disagree with our definitions. In addition, keep in mind that some alternative energy home systems such as micro chp and condensing boilers can be made to run on renewable fuels, which would be the ideal situation for these types of system.
