A new gas turbine initiative has given a significant boost to Iran’s power capacity… and at minimal cost, writes Dr Mohammad Owliya
In the late 1990s, Iran’s Ministry of Power took a strategic decision to encourage the domestic power sector to manufacture power generation equipment.
This decision brought about a drive towards the development of domestic technical know-how and has now resulted in a remarkable position for Iran in the global power industry.
In the summer of 2015, Iranian power group MAPNA had success in the optimal implementation of minor engineering modifications on a section of operating gas turbine engines to increase the national power generation fleet capacity by 200 MW – at almost no cost.
On the back of this success, in the summer of 2016, MAPNA Group implemented another innovative improvement, dubbed the ‘IGV+’ initiative, which came into action to help a smooth weathering of the 2016 summer consumption peak.
|The IGV+ technology has increased the capacity of the Iranian grid by a total of 1000 MW
The IGV+ initiative boosts the output of MGT-70 turbines by optimizing inlet guide vanes of the gas turbine. As a part of a larger commercial package called OPTIMAP™, IGV+ local technology was applied on 98 units of V94.2 machines by February this year to increase the real capacity – in local ambient conditions of the power stations – by over 390 MW, translating to around 500 MW nominal capacity of ISO conditions.
Compared with investing in a new power plant with a similar capacity, the cost was quite negligible. The modification is currently being conducted on all the remaining machines in the fleet to accommodate the upcoming 2017 summer peak.
Fully implemented, the IGV+ technology increases the capacity of the national grid in a short timeframe by a total of 1000 MW (under ISO conditions), involving no capital expenditure.
Highly profitable payoff
In recent years, MAPNA has been actively involved in research, development and innovation to improve the portfolio of its products and services. These endeavors have now borne fruit, one of which is the development of the MGT-70(3) gas turbine under the project code MAP2B and its side soft-products which enhance local technology and expand domestic know-how.
The gas turbine family targeted for the IGV+ initiative, the V94.2 produced by MAPNA Group, is one of the largest fleets in operation in Iran, which makes the payoff for R&D investment in any upgrade or optimization of power output and efficiency highly profitable.
IGV+ is an offshoot of the GT compressor redesign in the MAP2B project. Following the early phases of development, the technology was tested in Pareh-sar and Yazd power plants in northern and central Iran respectively.
|As a part of the OPTIMAP package, IGV+ technology was applied on 98 units of V94.2 machines|
The capacity of the initiative to considerably increase the power output in a short time and at a very little cost helped put it on the agenda of the management board of Thermal Power Plants Holding Company (TPPH), an affiliate of the Ministry of Power. The initiative was well received and a TPPH trial implementation took place at Ferdowsi power plant and an increase in capacity was subsequently confirmed by the national grid load dispatching authority.
Following the trial, final agreement on the inclusive implementation of IGV+ was officially announced by TPPH and TAVANIR in April 2016.
The IGV+ initiative brings about a safe and reliable increase in the power output of V94.2 machines by introducing minimal changes in the shortest possible time. As part of a bigger MAPNA package, the ‘OPTIMAP™’, the concept is based on the optimization of the Inlet Guide Vane (IGV) angle using a newly-designed mechanism.
Customized for different versions of the V94.2, this 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 cycle or cogeneration plants, which can even further increase the overall performance of the plant.
One of the most important items when implementing the initiative is adapting the logic control system to accommodate the IGV angle changes. This is to enhance the operational flexibility of the machine when facing various ambient conditions.
The compressor map was investigated in different versions of the machine and all required modifications to adapt the control system.
Specification of the IGV opening angle and the optimum angle, given the compressor and turbine efficiency and the targeted mass flow, is a keystone of the technology.
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 upgrade versions); proportionate power increase in the relevant steam turbines combined with the a.m. gas turbines; certain small increases in efficiency of the gas turbine; optimal operation of the machines: a) peak operation during summer, b) lower turbine inlet temperatures and thereby higher lifetime for hot gas path components when off-peak.
Iran’s domestic demand
Summer time is always a challenge for the Ministry of Power, as the power demand hits the peak and failing to feed the national grid can lead to blackouts in numerous areas across the country.
Growth in electricity consumption from households, businesses and industries increases the summer peak by around 5 per cent annually. Construction of new peaking power plants to operate and supply in a time interval as long as only two months would be a costly venture.
If the IGV+ initiative is implemented across the national fleet – which comprises over 180 machines – it can make up for around 1000 MW of the gap.
This year, IGV+ was entered for the prestigious International Khwarizmi Awards, which are given annually by the Iranian Research Organization for Science and Technology to engineers who have made outstanding achievements in research, innovation and invention, in fields related to science and technology.
IGV+ underwent three technical and economic reviews and was finally announced as the winner of the Developmental Research subcategory.
Among the reasons cited for the award were successful commercialization, added value and considerable savings.
Another important feature of IGV+ is that the subsequent increase in the power is scattered – just as are the power plants themselves – whereas the power generated in any new power plant is concentrated in the location of the plant and needs to be distributed through transmission lines, which means more power losses.
High demand is a challenge limited to the peak season. The IGV+ initiative is addressing this need specifically, while other alternatives result in a permanent increase of capacity that is not actually required across the year.
The timeframe for implementation of the initiative is also substantially shorter than any other alternative solution. Last but not least is the cost – A-to-Z completion of IGV+ in the country costs around $10m, which is insignificant compared to similar solutions internationally offered in the power generation services market.
Dr Mohammad Owliya is Deputy Managing Director of MAPNA Turbine Engineering and Manufacturing Company (TUGA)