Efficiency record: 62.4% for a combined cycle power plant!

On 30 April 2018 the combined cycle gas and steam power plant, with one of the highest net efficiency rates worldwide, went into operation in Pakistan. The plant’s owner/operator installed H-class gas turbines for the first time in Pakistan. With the expertise of Lahmeyer engineers during design, construction and operation phases, the plant’s contractor conducted a precise analysis of the turbines’ potential and was able to optimise their efficiency above the requested rate. The power plant is located in Haveli Bahadur Shah Punjab, Pakistan and features one of the highest net efficiency rates ever recorded: 62.4 %.

Since February 2015, Lahmeyer and the consulting firm National Engineering Services Pakistan (Pvt) Limited (NESPAK) have been cooperating in the development of electric power generation capacity in the densely populated province of Punjab. The electricity consumption in the region accounts for 68% of the total national consumption, and the province contains 60 % of Pakistan’s industry. With an annual power demand growth of 6-8 %, Punjab is currently facing power shortfalls ranging from 3,000 to 5,000 MW.

The engineering company Lahmeyer supports NESPAK and two public project companies in the implementation of the three gas and steam combined cycle power plants; Balloki, Haveli Bahadur Shah and Bhikki. In close cooperation, the experts from Lahmeyer and NESPAK carried out the preliminary design of the project - from project specification tendering to the assessment of proposals - all within only seven months.

Short implementation period and high net efficiency

The major challenge of this project, in addition to the high fuel prices (liquid gas), was the required short implementation period. The single-cycle phase had to be completed within 18 months (first plant) and the combined-cycle phase within 27 months, respectively. This challenging time schedule and the new performance figures of the Chinese EPC contractors stipulated an efficiency of between 61-63 % which is quite ambitious. To meet these objectives, Lahmeyer and NESPAK decided to equip all three projects with General Electric H-class gas turbines, model 9HA.01 – the first use of these turbines in Pakistan. Besides having a very tight schedule, the awarding authority also made high demands on the net efficiency.

Especially with the Haveli power plant, which was requested to achieve the highest net efficiency rate, the potential of the state-of-the-art gas turbines had to be investigated in detail. Already in the planning phase, Lahmeyer engineers analysed the performance of the gas turbine regarding its integration into the complete facility. Based on this analysis, the manufacturer of the turbine and the contractor were able to optimise the turbine unit. The result was one of the highest net efficiency rates for a gas-fired combined cycle power plants worldwide: 62.4 %.

Lahmeyer meets challenging requirements

In July 2017, all six H-class gas turbines at the three sites were subjected to the first firing tests. Four turbines started commercial operation directly afterwards. Within the second quarter of 2018, all three power plants were in full commercial operation. Thus, Lahmeyer met both the challenging implementation schedule and the demand for a high efficiency rate.

Promising future development of H-class gas turbines

Additional measures announced by the manufacturers of H-class gas turbines make it possible to achieve a further increase in efficiency of over 63 % for future combined cycle power plants. In addition, the Lahmeyer experts expect the gas turbine capacity to increase, electricity consumption to drop and the implementation period for power plant projects to be reduced. Pakistan effectively promotes the development of electricity production on the basis of regasified liquid gases. Advanced gas turbines will play a significant role.

The new project Jhang, which will again be executed cooperatively with NESPAK, was recently also awarded to Lahmeyer. For this project, H-class gas turbines from Siemens are planned.