General
Microturbines can be used in a variety of electricity and thermal energy applications due to their small size, low unit costs, and useful thermal output. Eight potential types of applications for microturbines have been identified:
The use of microturbines for continuous generation will typically involve applications requiring over 6,000 hours of operation per year. To succeed in this market application, microturbines will have to be able to generate electricity at costs competitive with grid-connected power. In certain circumstances, users that have deep concerns about the reliability of the grid or about power quality may be willing to pay more for on-site power generation than for grid-connected electricity.
Peak shaving applications for microturbines would typically require much less than 1,000 hours of operation per year. For peak shaving, users would run on-site generation to avoid paying high on-peak prices or utility demand charges. In some areas, avoidance of these costs can justify investment in on-site power facilities that operate only several hundred hours per year. The shift toward competitive electricity markets has also meant a shift toward real-time pricing of electricity. During peak periods, it is not unusual for the cost of power to be 3-5 times higher than it is during off-peak periods. During system emergencies, on-peak power costs can be 10 times greater or more than off-peak power costs.
Back-up power users require 100% reliable electricity. Some users, like hospitals and airports, are required by regulations to install and maintain back-up power units. Back-up power systems may run less than 100 hours per year but they must be ready to come on line at a moments’ notice in the event of a power outage. Diesel generators currently have a large fraction of the back-up power market. The use of microturbines in this market will be driven by a variety of factors, particularly their costs relative to diesel generator sets, but also their ability to start-up rapidly and reliably. Relatively low expected O&M costs could be an advantage for microturbines in back-up power applications.
Markets for premium power exist where the industrial process requires power with a higher quality than provided from the grid. This could include AC power with a well-defined wave form, frequency, and/or power factor. Power quality concerns are found in industries that use sensitive electronic equipment that requires tightly controlled, sinusoidal AC wave forms, or machinery that operates on well-defined DC power. The use of microturbines for premium power could defray power conditioning costs to the user, allow for more precise and flexible manufacturing processes, and reduce losses in production from outages and other types of power quality disruptions.
Remote power applications are for off-grid locations such as oil and gas production and certain mining operations. Locations that lack grid access often lack access to natural gas distribution systems as well. The ability to use portable fuels such as diesel or propane is a distinct advantage for remote power equipment. System reliability is a top priority.
Markets for cooling, heating, and power systems include those manufacturing processes and building applications that have needs for thermal energy as well as electric power. There is potential for expanded use of industrial combined heat and power systems. The possibilities expand when economical off-site uses for the thermal energy are identified, as in district energy systems. The use of microturbines in cooling, heating, and power applications could open up new opportunities for smaller scale systems in manufacturing plants to meet specific needs for thermal or mechanical energy as well as electric power. Buildings cooling, heating, and power systems can provide electricity and thermal energy for cooling and humidity control.
Mechanical drive applications would use microturbines to run shaft-driven equipment such as gas and air compressors, refrigeration units, chillers, desiccant humidity control systems, and pumps. Operation and maintenance costs are a critical driver along with the cost of electricity and the ease of access to fuels.
The market for wastes and biofuels burning microturbines are found in those industries that produce solid, liquid, or gaseous fuels as a waste or by-product such as pulp and paper, food processing, and steel making. The amount of power produced from these applications is a function of the amount of waste material produced and the technologies available to convert the waste into usable fuel.