360 vision page 13. Air-cooled evolution page 18. 3D testing page 22. Patriot gains page 26

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1 360 vision page 13 Air-cooled evolution page 18 3D testing page 22 Patriot gains page 26 March - April 2017

2 Patriot designed to monetize Marcellus shale gas by Junior Isles The Panda Patriot power plant is now up and running. Like its sister Panda Liberty project, the plant is specifically designed to monetize Marcellus shale gas by converting this cheap source of gas to electricity in the most efficient way. In November last year officials from across Pennsylvania joined Panda Power Funds to commission the company s 829 MW combined cycle Patriot generating station located in Lycoming County. The Patriot project is only the second plant in the United States, after Panda s Liberty Pennsylvania power project, to use Siemens H-Class gas turbines in a single-shaft configuration, demonstrating the value of the latest high efficiency advanced gas turbines in such markets. Pennsylvania presents a great opportunity for developers of gas fired power plants. Like much of the US, the state is going through a transition from coal to natural gas, driven by legislation designed to reduce power plant emissions as well as the availability of cheap, abundant, shale gas. Where some regulated markets are still dominated by local utilities, which allow old, inefficient coal fired plants to continue operating by including costs into the rate base, as part of the PJM deregulated territory, Pennsylvania, offers the perfect breeding ground for highly efficient base load gas fired generation. Derek Porter, Chief Operations Officer, Panda Power Funds, said: We believe it s the best functioning market in the US. Under true market conditions we have the opportunity to bid the plant day-to-day from an electricity standpoint, and what separates it from some of the other markets is the capacity payments. A generator in PJM can bid into capacity auctions that occur annually to receive a payment for capacity needed three years into the future. Access to cheap fuel further improves the commercial attractiveness of the plants. According to Panda, they are the first plants to be specifically sited to access Marcellus shale. As Bill Pentak, Vice President Investor Relations and Public Affairs, Panda Power Funds, put it: These were the first two plants born of the Marcellus shale. Project origins The origins of the projects date back to around 2012 when Moxie Energy approached Panda to take over development of the plants. Pentak recalled: What we had was the financial acumen The Panda Patriot combined cycle plant commissioned in November 2016 is a 829 MW plant that uses Siemens H-class gas turbines. 26 GAS TURBINE WORLD March - April 2017

3 Siemens SGT6 8000H gas turbine has a 13-stage axial compressor and a 4-stage power turbine. to get these projects across the finish line. Once certain issues were resolved, we purchased them in development from Moxie. Patriot has an estimated cost of around $830 million the Energy Information Agency calculates the capital cost of new build combined cycle plants at $1 million per installed MW. Having worked with Panda on several previous projects, Siemens also became involved at an early stage. Notably, Siemens Financial Services provided financing to aid in the construction of Patriot through a $75 million term loan. Martin Tartibi, Senior Executive Vice President, Siemens Energy Solutions Americas, noted: There was a lot of upfront collaboration to make sure we were meeting the plant s needs in terms of performance, financial and environmental issues, etc., for the PJM market. When the project transitioned from Moxie to Panda, it was built on our strong history and partnership with Panda. Patriot and Liberty are the fourth and fifth projects that Siemens has commissioned through that relationship. Siemens contract scope for Patriot covers the supply of single-shaft power plant blocks, including two SGT6-8000H gas turbines, two SST steam turbines, two hydrogen-cooled SGen6-2000H generators, and two heat recovery steam generators, along with the SPPA-T3000 control system. The gas turbines and generators were manufactured at Siemens Charlotte Energy Hub, the global base for the company s 60 Hz power generating equipment. Siemens will also provide maintenance and service for the main components associated with the gas turbine under a long-term service program. Parts, inspections, and scheduled service/maintenance, along with Siemens Power Diagnostics remote monitoring, are included in the service agreement. Suited to the market The decision to use an H-class gas turbine in a single-shaft configuration was largely down to the high base load efficiency. According to Siemens the design is capable of achieving 60% base load efficiency at ISO conditions. Porter explained the attraction of the machines. The way the units are set up is to run every available hour of the day. During the time of selection, the Siemens H machines were the most efficient out there, certainly in combined cycle mode. We expect the units to run base load in the most efficient manner. Having two combined cycle blocks, each with a single-shaft power train, also gives Panda operational flexibility should it be required. Essentially, the configuration means the plant can run at 50% load without losing efficiency. At the same time, each combined cycle block can be run up and down quickly an operation that is supported by the inclusion of a synchronous self-shifting (SSS) clutch between the generator and the steam turbine. The SSS clutch enables the gas turbine to start-up and heat the HRSG independently of the steam turbine, making faster starts possible. When the steam turbine reaches synchronization speed, the SSS clutch is engaged and transfers the steam turbine s torque to the generator so the plant can reach full load. Having this flexibility not only means that Panda can respond to the needs of the market but also allows it to continue operating during times of scheduled maintenance outages. During these times, we can still GAS TURBINE WORLD March - April

4 Panda Liberty combined cycle plant is a sister plant to Panda Patriot and was the first specifically sited to utilize Marcellus Shale. operate half the plant, said Porter. So far the plant has operated at base load and in the foreseeable future, I don t anticipate a situation where we will have to operate at a reduced load because of market conditions. But you can t always predict the future. Jacqueline Engel, Product Manager for Siemens Energy Americas, added that a single-shaft set-up also has economic benefits. If you look down a single-shaft power train, there s just one generator unlike a multi-shaft configuration where you could potentially have two. Siemens has a proven track record of single-shaft designs around the world and the US, so commissioning this configuration in the US is really pulling from that successful track record, she said. The SGT6-8000H has a design output of up to 310 MW and is capable of delivering an efficiency of more than 60 per cent electrical efficiency in combined cycle. Since the start up of the first commercial H-class machine at Irsching in Germany, Siemens H-class units have accumulated more than operating hours globally. Porter noted: Having this experience and comfort level was important to us, and we plan to use this technology in an upcoming power project. H-class design The SGT6-8000H portion of the fleet has accrued more operating hours than its 50Hz counterpart but as it follows a direct scale design methodology, users can have the same level of confidence in the design and performance of both. The main difference between the 50 Hz and 60 Hz machines is the scaling factor which means the 50 Hz units have a higher power output. The SCC6-8000H is a single-shaft machine designed to deliver about 440 MW in combined cycle operation. It has a common design with the 50 Hz version, using a single tie-bolt rotor design adopted from previous F-class gas turbine models. However, compared to F technology, firing temperature is increased by about 200 C. The turbine therefore has a firing temperature in the 1500 C class, which contributes to the higher turbine efficiency. Engel said: The turbine allows the plant design to achieve these high levels of output and efficiency by managing airflow, as opposed to relying solely on higher operating temperatures. The turbine includes: a disc-type rotor with central tie-bolt and radial serrations; two journal bearings and one thrust bearing; generator drive at the compressor intake end; and axial exhaust diffuser. Designed to combine high efficiency with operational flexibility, the turbine rotor is internally air-cooled. Unlike with steam cooling, this means that cooling is decoupled from any water/steam cycle or any other external cooling system. It has a 13-stage axial compressor operating at a pressure ratio of 20:1 at ISO conditions. It has four variable inlet guide vanes as well as cantilevered vanes, which further increases its operational flexibility. The variable guide vanes allow adjustment of the mass flow to help maintain efficiency at low turndown if necessary. The power turbine section of the machine has four stages, with air-cooled blades and vanes on the first three stages and thermal barrier coatings on the first and second stages. Stage-four is not cooled. The internally air-cooled blades in the first three rows have fine holes to allow air to escape and flow across the blades for film-cooling. Their shape has been designed so that the gap between the blade-tips and turbine casing is as small as possible. This ensures the maximum amount of gas passes through the blade area. The size of this gap is kept to a minimum during operation by Siemens patented Hydraulic 28 GAS TURBINE WORLD March - April 2017

5 Clearance Optimization (HCO) system originally introduced in the SGT-4000F gas turbine series. The HCO system allows for fast ramping. In cold start-up, the clearance gaps between the turbine blades and casing are wider than in hot conditions. During the engine start-up regime, the rotor disk expands. When stable operation is reached, the gaps open again. This means the rotor can be hydraulically adjusted to minimize the gaps during steady operation. At full load, the gas turbine provides exhaust gas at a temperature of 630 C and a mass flow of 640 kg/s to the HRSG. This exhaust energy is delivered to a three-pressure drum SMART design HRSG by Vogt Power International, for 165 bar and 565 C (2400psi and 1050 F) steam cycle conditions. High-pressure steam from the HRSG is fed to a steam turbine, which has a combined HP/IP section and doubleflow LP section. The steam turbine uses steam from the HRSG to generate approximately one third of the plant s output, giving each train an output of around 415 MW. Low emissions The plant is also designed to keep emissions to a minimum. Like the SGT5-8000H, the SGT6-8000H uses an ultralow NOx combustion system. Although the system is not a direct scale of the SGT5-8000H combustion system, there is a common platform approach. The combustion system consists of 12 low-nox burners and baskets with air-cooled transitions. The annular arrangement provides excellent uniformity of exhaust gas temperature field. The ultra-low NOx combustion system combined with the plant s high efficiency serves to ensure extremely low emissions from the facility. It has an integrated selective catalytic reduction (SCR) system as well as a CO catalyst. According to Siemens, this helps the plant to not only operate within permitted emission limits, but also is representative of Best Available Control Technology (BACT) levels, i.e. 2 ppm NOx and 2 ppm CO. With the high efficiency of the plant and the use of shale gas, CO 2 emissions are expected to be among the lowest in the country. The emissions are so low, they actually test the accuracy of the instruments, which were not originally designed to measure such low ppm, commented Porter. The plant is also environmentally friendly from a water-use point of view; it uses air-cooled condensing to minimize the consumption of local water resources. The Patriot plant does not draw water from, or discharge water into, the Western Branch of the Susquehanna River eliminating potential impacts to species in the Susquehanna watershed. SGT6-8000H design performance data Gas turbine Gross power output (MW) 310 Gross efficiency (%) 40 Pressure ratio 20.0 Exhaust temperature ( C/ F) 645/1193 Exhaust mass flow (kg/s) 650 Exhaust mass flow (lb/s) 1433 Heat rate (kj/kwh) <9000 Heat rate (Btu/kWh) <8530 Combined cycle Net power output (MW) 460 Net efficiency 61 Heat rate (kj/kwh) <5920 Heat rate (Btu/kWh) <5611 Start time (minutes from hot start) <30 Good for the community The introduction of this new, clean, generating capacity is the culmination of a 30-month project construction period that started in December 2013, following the receipt of the air permit in August that year. During its construction, Patriot created more than 1000 jobs, with approximately 650 at the peak of construction work that was executed without loss of time due to injury. Further, the plant will continue to benefit the community during operation. Twenty seven full-time employees currently operate the facility, and 45 indirect jobs are expected to be created within the community to support the plant during operations. According to an economic impact study conducted by Impact Data Source of Austin, Texas, the Panda Patriot plant will contribute an estimated $5.85 billion to the area s economy during the now post-construction phase and the facility s first 10 years of operation. Patriot, like Liberty, is an important project for Pennsylvania, Panda and the wider US gas fired power generation sector. These projects are extremely important when you think about the conversion from coal to gas and, being the first two plants built to use Marcellus shale, are already a model for the industry, said Porter. You are seeing developments right now that look similar to these projects. Pentak added: They are certainly a model for Pennsylvania. What we ve learned as we ve done business in Pennsylvania, is that there is this tremendous amount of shale gas that is essentially trapped there isn t the pipeline infrastructure that s needed to get this gas to market. We re taking the gas and converting it to electrons and shipping it out to the area through the transmission lines we call it gas-by-wire. As pressure continues to deliver power in the cleanest and most cost-effective manner, these projects highlight the advantages that clean gas fired power plants can bring, not just in the PJM area but throughout the country. Pentak concluded: As the transition from coal fired plants to natural gas continues, plants like these are the tip of the spear in terms of that transition. GAS TURBINE WORLD March - April