A 1000-MW Solution: How MAPNA Group’s IGV+ tackles the summer peak load.

Summer is a challenging season for Iran’s power sector. With the heat wave sweeping across the country, electricity demand hits the peak. A steady pattern of growth in power consumption (households, businesses and industries) has resulted in a five-percent annual growth in the summer peak consumption. In such circumstances, failing to feed the national grid can lead to blackouts across the country. But construction of new power plants to operate and supply for an interval of only two months would be a costly venture.
MAPNA Group’s IGV+ initiative is a 1000-MW solution to this challenge.
Under the rubric of MAP2B research and development project (read about the project here), MAPNA Group kicked off the IGV+ initiative in 2016 to facilitate a smooth move through the summer peak load of the national grid. By February 2017, the IGV+ technology was applied on 98 units of V94.2 machines, the largest fleet of turbines in operation in Iran, to increase the real power output by over 390 MWs (translating to around 500 MWs nominal capacity of ISO conditions). Compared with investment in a brand new power plant of a similar capacity, the solution proves quite cost-effective.

Technology development and implementation

In the course of its evolution into a knowledge-based conglomerate, MAPNA has been actively involved in research and development during the recent years to improve the portfolio of its products and services. These endeavors have now borne substantial fruit, one of which is development of MGT-70(3) gas turbine under the flagship project MAP2B.
Following the early phases of its development, the IGV+ technology was put to test in power plants of Pareh-sar, north of the country, and Yazd, central Iran. The considerable potential of the project to boost power output in a short span and at very little cost earned it a place on the agenda of state-run Thermal Power Plants Holding Company (TPPH, an affiliate of the Ministry of Power). The initiative was well received and trial implementation took place at Ferdowsi Power Plant in northeastern Iran. Capacity increase was confirmed by the national grid load dispatching authority subsequently.

How does it work?

The IGV+ concept is based on the optimization of the inlet guide vane angle through an innovative design. Customized for different versions of the turbine, the optimized angle can maximize the mass flow of the compressor and thereby increase the power output. Higher mass flow in turn means increased steam generation in combined cycles or cogeneration plants which can even further increase the overall performance of the plant. In other words, by implementing minor modifications in the shortest possible time, IGV+ brings about a safe and reliable increase in the power output of V94.2 machines.
A key item in implementing the initiative is to adapt the logic control system to accommodate changes in the IGV angle. This is to enhance the operational flexibility of the machine when facing various ambient conditions. Compressor map was investigated in different versions of the machine and all the required modifications to adapt the control system were applied in the new logics. Verified features of the technology include:
  • 5 MW increase in power output in actual conditions at baseload for version 3 of V94.2 machines;
  • 3 MW increase in power output in actual conditions at baseload for version 5 and higher (including MAPNA’s upgraded versions);
  • Proportionate power increase in the relevant steam turbines combined with the a.m. gas turbines;
  • Certain small increase in efficiency of the gas turbine;
  • Optimal operation of the machines: a) peak operation during summer, and b) lower turbine inlet temperatures and thereby higher lifetime for hot gas path components when off-peak.
A key feature of IGV+ is its distributed nature. With a newly constructed plant, power is generated on-site and needs to be distributed through transmission lines which implies inevitable power loss. IGV+, on the other hand, addresses high demand in the peak season case by case, i.e. for the designated power plants, and only for the required period, i.e. peak load. Last but not least is the remarkable lower cost: A-to-Z completion of IGV+ costs around 10 million USD at most, an insignificant sum compared to similar solutions internationally offered in the power generation services market.
  • A version of this article was earlier published in Power Engineering International (PEi) in April 2017.