“Critical Remote Power” refers to fields of use that require reliable 24×7 power, and are located in geographic areas that preclude easy maintenance and refueling. Examples of these fields of use include:
- Oil & Gas pipeline power and wellhead power
- Telecommunication stations
- Navigational aid stations (e.g., lighthouses)
- Geological and political monitoring stations (e.g., seismic activity monitoring)
- Railway telemetry
- Stations with ice-road only access (northern Canada)
These fields of use require assured power 24x7x365. Many are helicopter-only access which makes the cost of maintenance and refueling prohibitive. Today, these markets use thermoelectric generators (TEGs) – the same technology that Sunpower is displacing in aerospace fields of use. Sunpower’s Stirling engines offer reliability equal to TEGs, but with roughly an order of magnitude better efficiency.
As an example, natural gas transmission pipelines and wellheads require uninterrupted power to maintain service to distributors and ultimately to customers. These wellhead and transmission sites require power for use in cathodic protection, pipeline monitoring, and communications. Cathodic protection is a method for protecting pipelines against corrosion by slightly electrifying sections of pipe and making the material less reactive with water and air. At routine intervals, transmission lines incorporate sensors to monitor pressure, gas composition, water vapor content, etc. These monitoring stations employ sensors to take readings, and those sensors require power. Communication capabilities accompany monitoring stations, compressor stations, and other manned stations.
Natural gas wellheads often occur in remote areas and transmission lines are intentionally set in remote locations for public safety. This significantly increases the costs of providing power to the pipelines. If utility-provided (“grid tied”) power is chosen, the cost of extending the transmission grid to the pipeline or wellhead site costs $50,000 to $100,000 per mile. If stand-alone generator power is adopted, servicing of the remote location can become cost prohibitive. These remote locations often require arduous commutes: either long drives far from populated areas, or in several cases, flying personnel and hardware by helicopter to replace or repair the installed hardware.
For the natural gas pipeline fields of use in this market, the Stirling engine’s higher efficiency yields major benefits. The graphic demonstrates the operating economics of operating an FPSE versus a TEG for a typical, remote, natural-gas pipeline fields of use. Based on fuel efficiency alone, with gas priced at the wellhead rate (i.e., the opportunity cost), the Stirling generator produces annual fuel savings alone of $2,000-$10,000 per 1 kW generator depending on the exact price of natural gas at the time. This does not include the added benefit of greater throughput on the capital asset of the pipeline itself or carbon offset credits.