Power station efficiency has been substantially increased by utilizing satellite-powering technology that was abandoned many years ago. The technology has been reconfigured to function with traditional power stations to aid the conversion of heat to electricity (what’s called thermionic energy conversion) more efficiently. In better news for the environment, this means lower amounts of fossil fuel will be needed to be burnt to produce equivalent amounts of power.
Much of the technology in power stations is old, with the majority coming from mechanical heat engines and turbines. The technology behind this dates back to the Victorian era. Stanford University scientists have been looking at more advanced thermionic energy converters. These were originally designed for the space program, to aid satellite launches. Thermionic energy converters have two electrodes (an emitter and a collector) which are separated by a small vacuum gap.
By using graphene in place of traditional tungsten as the collector material, considerable increases in efficiency can be achieved. Graphene, in its basic form, is a one-atom thick sheet of carbon. The material is light, transparent, strong and very conductive. The research so far has produced a new prototype energy converter, based on a pre-existing satellite power generator. This device uses graphene in place of metal. The trials indicate that the graphene has led to the prototype being around seven times more efficient than converters in current use for fossil fuel power stations.
The new prototype is effective through addressing inefficiencies associated with current technology: a high loss of energy at the anode surface (resulting in reduced output voltage) and high electrical barriers against electrons moving in the gap between the collector and the emitter (leading to lower output current).
The new technology remains in development and it currently only functions in a vacuum chamber. Reconfiguring the process to work in a normal setting is the requisite next step for ‘re-sparking’ thermionic energy conversion.
The new prototype is described in a research paper published in the journal Nano Energy, under the heading “Back-gated graphene anode for more efficient thermionic energy converters.”
