MicroTurbines are new type of
combustion turbine used for
stationary energy generation.
The concept is evolved from
automotive and truck turbochargers,
auxiliary power units (APU) for
Approximately the size of a
refrigerator with outputs of 25 kW to
They provide not only electricity , but
also the thermal energy to provide for
all heating and cooling needs
MicroTurbine producing power, as well as heat
Commercially Available Yes (Limited)
Size Range 25-500 kW
Fuel Natural gas, hydrogen, propane,
Efficiency 20-30% (Recuperated)
Environmental Low (<9-50 ppm) NOx
Other Features Cogeneration (50-80°C water)
Commercial Status Small volume production,
commercial prototypes now.
(Courtesy of California Distributed Energy Resources Guide on
Microturbines are small gas turbines, most of which feature an
internal heat exchanger called a recuperator.
In a microturbine, a radial flow (centrifugal) compressor compresses
the inlet air that is then preheated in the recuperator using heat
from the turbine exhaust.
Next, the heated air from the recuperator mixes with fuel in the
combustor and hot combustion gas expands through the expansion
and power turbines. The expansion turbine turns the compressor
and, in single-shaft models, turns the generator as well.
Finally, the recuperator uses the exhaust of the power turbine to
preheat the air from the compressor.
Single-shaft models generally operate at speeds over 60,000
revolutions per minute (rpm) and the permanent magnet generator
generates electrical power of high frequency, and of variable
frequency (alternating current --AC). This power is rectified to direct
current (DC) and then inverted to 50/60 Hz for commercial use.
How a Microturbine works
Turbine rotates the
generator at high RPM which
produces electricity of high
Compressed air is mixed
with fuel and burned
under constant pressure
A sheet metal heat
recovers temperature of the
air stream supplied to the
Distributed Energy Generation
Energy produced in thermal and hydro electric
power plants is distributed to the users through
network of line (transmission & distribution) called
the power grid.
Any technology of getting electric energy other
than power grid, directly at the distribution level, is
called Distributed Energy Generation.
In IUT, when load-shedding occurs, IUT generator
serves as distributed energy source.
Example: Microturbine, Diesel Generator (Backup
generator), Solar Panel etc.
Advantages of Distributed Generation
The losses during power transmission are
The combined heat and power (CHP)
technology can be applied.
Low emission and operating cost.
Advantages of Microturbine
Small number of moving parts
Good efficiencies in cogeneration
Can utilize waste fuels
Long maintenance interval
Less noise than reciprocating engines