- Steam, in the form of turbines or engines
- Organic Rankine Cycle
- Stirling Engines
- Hot air microturbines
While I am intrigued by the idea of running a Capstone microturbine or other “wind” turbine with superheated air, this post is a follow-up on the idea of using a pellet furnace for heating and to provide heat to power a Stirling engine, which, in turn, powers a generator.
The home units previously mentioned have run on natural gas or biogas. Nonetheless, Wood Fuels – Wales states, “Units are becoming commercially available in the low power ranges from 35 to 300 kWe with electrical efficiencies of 20% or more.”
BTW: Nothing says that such technology must be off grid. Capstone Microturbine installation include some sophisticated electronics to enable the system to be primary with backup from the Grid or vice versa; and, the installers ensure that the system will meet the requirements of the local utility company for a “grid tie”. Nevertheless, it would be a good idea to investigate the steps for local approval and / or employ the services of a consultant, before investing in micro power generation, especially if you plan on becoming a part of a local distributed power network and sell excess power.