Solar Hybrid Gas Turbine

1. OPERATION OF THE SOLAR
HYBRID GAS TURBINE
SYSTEM AT MW SCALE
Guide:Suraj R By: Rosh Reji

2. INTRODUCTION
 In a solar hybrid gas turbine the pressurized air is directly heated up
 Significant cost reduction for solar electric power generation is
achieved
 The first hybrid system at megawatt scale was commissioned in may
2012 at Abengoa’s Solucar platform near seville
 A hybrid system at KW scale can be found on the European
research project Solgate
 In this system solar energy is introduced into Brayton cycle
 Solar heat can be directly fed into the gas turbine using a solugas
receiver placed on a tower without the losses in a heat exchanger
 The special attractiveness of Solugas project is the successful
integration of solar receiver and gas turbine

3. Aerial view of Solugas demonstration plant

4. Technology Overview
 Solar hybrid plants are operated in a thermodynamic
open cycle, known as Brayton cycle.

5.  1->2: Fresh air is compressed, where its pressure and
temperature are raised.
 2->A: The compressed air is heated in the solar receiver
using concentrated solar energy
 A->3: The compressed air is heated in the combustion
chamber using Natural gas.
 3->4: The hot air drives the turbine and expands until
atmospheric pressure, turbine drives generator,
producing electricity
 4->1: The heat energy of exhaust gases from the turbine
can be recovered with a bottoming steam cycle or a
recuperator

6. Diagram of Mercury 50TM gas turbine installed in the Solugas

8. Facility description
 Mercury 50 gas turbine is used in this system
 High temperature receiver is used
 This receiver can heat pressurized air up to 800 °C
 It is made out of 170 fine nickel based alloy absorber
tubes
 The absorber tubes are exposed to high concentration
of solar radiation, achieving in 5 m of radiated length a
temperature increase of more than 500 K
 Several hundred sensors are used to monitor the plant
behaviour

9. Operation
 The first task is to achieve an ideal focus of the heliostat
field on the receiver cavity
 Receiver cavity is significantly smaller in aperture than in
other plants, just 2.7 m of diameter for a field of 69 units,
each of them with 121 m2 reflective area.
 The cavity shape arrangement of the receiver is to
minimize convectional losses
 Heliostats need to be controlled very accurately to avoid
spillage losses and very high concentration of radiation in
particular areas of the receiver

11.  The plant can be fully operative in 30 minutes at a
desired receiver outlet temperature
 The gas turbine itself can be started and running at full
load in even less time of approximately 10 minutes
 Input data are mainly measured values like DNI-Direct
Normal Irradiance
 Irradiance is the power of electro magnetic radiation
per unit area incident on a surface
 A 360° dome camera on top of the tower helps to
predict changes on DNI

12. : Operation under transient periods keep electric output
constant
: Operation under transient periods keep electric output constant
: Operation under transient periods keep electric output
constant
operation under transient period keeps electric output constant

13. Sudden turbine shut-down and temperature rapid decrease

14. First day operation at 800 °C as receiver outlet temperature

15. Stable operation at 700 °C as receiver outlet temperature

16. Components performance and
modifications
 During operation the components have been monitored
in order to obtain maximum information on their
performance and options for improvement

17. 1. heliostats
 Heliostats include an innovative tracking system using hydraulic
components for both, azimuth and elevation movement
 During operation the heliostats as well as their control system have been
tuned
 Its tuned so that the focusing to the aim point at the cavity entrance was
reached more accurately and tracking the sun has become easier, and
smoother

18. View of heliostat field

19. 2.Receiver
 The solar receiver absorber tubes are exposed to high
concentration ratios
 Plant operation and control have been improved
 even if thermal gradients between the in- and outlet of
the tubes are in the range of 500 K, solar flux distribution
has become more homogeneous on the absorber tubes
 This reduces temperature difference between the
different regions of the receiver to a minimum
 It also helps to reduce the maximum temperatures in
individual tubes
 Still the metallic parts are bearing maximum
temperatures over 850 °C to keep the pressurized air
temperature at 800 °C.

20. First commercial solar power tower - PS10

21. Solugas receiver placed on tower

22. Design view of tubular receiver

23. 3. Receiver insulation
 thermal insulation is used to preserve hot temperatures
inside the cylindrical shaped arrangement of the
receiver
 It minimizes thermal losses and the shape is optimized to
achieve maximum homogenous temperature
distribution
 The insulation material is mainly made by a ceramic fiber
which is directly exposed to solar concentration and
temperatures

24. Poor insulation improved insulation

25. 4.Gas turbine
 The gas turbine Mercury TM 50 is successfully operating in the
different operation modes of the solar plant
 Due to the adjustments the turbine is able to work in a wider
range of conditions than in the commercial configuration
 It can work in a wide range of meteorological conditions ,
reaching from extremely high ambient temperatures to
colder temperature &from very less to high humidity
 The turbine guarantee stable operation and ramp up
behavior under each condition
 The turbine’s combustion chamber is prepared to admit
650 °C as maximum inlet temperature

27. Advantages
The concept of solar-hybrid gas turbine systems leads to the
following advantages:
 High cost reduction potential due to the high conversion
efficiency
 Low environmental impact due to low water consumption
 Reduced land usage due to high conversion efficiency which
reduces collector area and land use
 Guaranteed dispatchable power, independent on
meteorological conditions
 The plant can be fully operative in 30 minutes at a desired
temperature receiver outlet temperature

28. conclusion
 The solar energy is used to run a gas turbine
 The gas turbine is coupled to a 4.6 MW generator
 The heat of the exhaust gas from the turbine is used to
run a steam turbine
 The steam turbine is coupled to 2 MW generator
 The whole system has proven to perform correctly under
nominal and adverse conditions

29. Future work
Further improvements and modifications on
the operating system are foreseen to be
implemented during the ongoing operation of
the plant

30. References
 Solugas – Operation experience of the first solar hybrid
gas turbine system at MW scale --SolarPACES 2013
 Co-located gas turbine/solar thermal hybrid designs for
power production
 www.sciencedirect.com
 www.solugas.com