— Lothar Balling, Head of Gas Turbine Power Plant Solutions, Fossil Power Generation Division, Siemens

FACY, which stands for Fast Cycling, is a revolutionary technology developed by Siemens for combined cycle gas-fired power plants. This energy-efficient technology comes with a host of advantages, the foremost being faster startups of power plants. Lothar Balling in an email interaction with Venugopal Pillai discusses the FACY technology in detail and explains its strong relevance to India. FACY-equipped plants could even open possibilities of higher revenues in the Indian spot electricity market, feels Balling.

Please explain in brief Siemens' FACY technology and elaborate on the faster start-ups achieved by this technology.
FACY is the acronym of a summary of technologies to provide fast cycling and start up capabilities. The development of this technology feature had the target to increase the number of allowable start/stop cycles, decrease the start-up and shutdown time and at the same time keeping lifetime consumption unchanged compared to conventional starts.

The implementation of the FACY concept in combination with the hot start on-the-fly allows a hot start-up time reduction down to 30 minutes and less, in comparison to "conventional" hot starts mainly applied to Siemens 50Hz F-class and 50/60Hz H- class combined cycle plants. The concept is based on a procedure for parallel start-up of gas and steam turbines, while monitoring and controlling the temperature gradients within limits acceptable for all critical plant components. A new start-up sequence, which avoids gas turbine load hold points, was implemented. The main innovation here is the early steam turbine starting point with earlier acceleration and loading of the turbine.

FACY key features are:

• Utilization of different technologies like stack damper, auxiliary steam etc. to maintain the pressure and temperature in the main components during standstill periods (as defined e.g. by hot start conditions)
  
• "Ready-for-operation" mode of the water/steam cycle by a fully automated start up concept without manual operation or intervention during hot start
  
• Optimized component design (e.g. high capacity and fast acting de-superheaters) and plant operation to reduce material fatigue caused by load cycling
  
• Flexible operation concept to allow the operator to predetermine component fatigue and to choose start up time and ramp rate
  
• Optimization of the automation and control concept
  
• Startup sequence "Start on the Fly" to allow early start of the steam turbine

When was FACY introduced and how has it improved over time?
The need for increased flexibility first emerged at the end of the 1990s in the United States and the United Kingdom. The price of fuel continued to rise due to the large number of plants being built during the boom. Plants initially planned to have a baseload role were shifted to the regime of an intermediate load plant.

The challenge presented to projects by this changed requirement gave birth to the idea to try to improve plant flexibility without compromising plant service life or plant efficiency.

As the market continued to develop, a demand for quicker start-ups soon followed the demand for more frequent startups. This market demand finally resulted in the launch by Siemens of a development project called FACY which combined all the initial engineering ideas into a single integrated plant concept. The aim of the resulting R&D program, started in 2000 was to design a plant for an increased number of starts and to reduce start-up times. If possible, no limits were to be placed on the gas turbine by other power plant components, such as the heat recovery steam generator or steam turbine, during hot and warm starts. In the course of the project, potential areas came to light where further optimization could be achieved, although these had to wait for a second development generation to be implemented.

The major improvement offered by this second generation involved the start-up procedure. Hold points at which a plant waits until certain steam parameters have been reached were eliminated as part of the shortened "start on the fly" start-up procedure. In this procedure, the steam turbine is started up in parallel to the gas turbine using the first steam which becomes available after a hot start. While the first generation FACY reduced start-up times for a hot start from 100 to 55 minutes, the second generation succeeded in pushing start-up times down below the 40 minute mark. The first plants incorporating the features of both the first and second generations of the FACY concept have now entered commercial operation and are meanwhile reaching the 30-minute level.

Technically, gas-based power plants offer a better alternative to coal-fired plants and nuclear plants. What is your view and how can FACY strengthen the preference for gas-fired plants?
Besides having the highest efficiency and lowest CO2 emissions of any thermal power plant technology, combined cycle power plants are able to offer highly flexible solutions that can accommodate sharp fluctuations in power consumption. FACY delivers essential benefits in that the technology helps maintain grid stability, enables power on demand, and raises the efficiency during start-up process, thus reducing costs of gas-fired power generation.

We recently came across "Flex" technology by Siemens, also used in combined cycle gas power plants. What is the basic difference?
Siemens Flex-Plant Technology enables a combined cycle to start fast, load following, and sets the standard in transient emissions, with Clean-Ramp features similar like FACY. Siemens Flex-Plant portfolio is responsive, reacting to market opportunities, allowing a combined cycle power plant to respond like a peaker and was developed for the US market. Siemens Flex-Plant portfolio is designed around the SGT6- 5000F gas turbine, and is now also offered around the world class gas turbine SGT6-8000H. Fast Cycling is one aspect of the Flex-Plant Solutions Portfolio.

How do you see the market for FACY in India, given that the country is not exactly comfortable with gas supplies?
As flexibility, power on demand and fuel efficiency are essential factors for profitable power generation, FACY ensures to make power plants "future-proof". The implementation of FACY is not linked with the gas availability. We definitely see a market perspective for high-efficiency combined cycle power plants in India, starting 2014. And the new power plant projects should ensure grid stability today and tomorrow and this is why they should be equipped with FACY.

There will be a peaking demand in the future, which will not be optimally covered by small simple cycle power plants due to a comparably unattractive specific investment and a low efficiency level. Especially in India, where the gas prices are expected to rise dramatically in the future, irrespective of domestic gas or imported LNG. FACY technology will help the power plant operator optimize his OPEX, while at the same time support the grid demands.

We are able to operate our combined cycle power plantsoriginally optimized for base load- as intermediate load power plants right up to daily starters and peakers with reserves and operating flexibility. As discussed earlier, FACY helps to save expensive fuel during start-up and shut-down; increases average efficiency by 14 percentage points (SGT-8000H gas turbine series) during start-up and allows providing load on demand.

Tell us about some key FACY technology-based projects built around the world.
Some examples would be:

• Pont sur Sambre, France
  
• Sloe Centrale, Netherlands
  
• Marchwood, UK
  
• Pego, Portugal
  
• Enecogen, Netherlands
  
• Hemweg and Diemen, Netherlands
  
• Timelkam, Austria
  
• Emile Huchet, France
  
• Irsching 5, Germany

We understand that faster startups of FACY-based gas plants make them an important "tertiary" power source. Please elaborate and discuss its relevance in the short-term electricity market.
Playing the spot market (tertiary reserve) is particularly attractive for power plant operators, as it pays high prices for last-minute power. Players on this market have to guarantee that they are able to provide the offered power within 15 minutes of it being requested. The Siemens FACY solution package makes it possible to address this market. About 40 per cent of the rated output of a combined cycle power plant equipped with FACY is available after only 15 minutes. Currently we have ongoing R&D programs to further improve the 40 per cent limit within 15 minutes.

How would you rate the prospects for FACY in India, vis-à-vis other emerging nations, and China, in particular?
We see a mixed demand for base, intermediate and peak load. In every case, power on demand is essential. FACY allows reacting flexibly on market conditions, especially in India where there is a possibility of higher revenues in the spot market.

Combined cycle power plants equipped with latest Siemens H-class gas turbine technology can cope with fluctuating load. For example Delhi with more than 1 GW peak load variation during a day (by approximately 2 GW base load) shows a predictable demand pattern. Power plant operators save fuel by starting fast rather than running at part load at lower efficiency and higher emissions. CCPP equipped with FACY deliver power on demand.

Let's stay with the Delhi example and show how a SGT5- 8000H gas turbine base load plant with daily cycling capability benefits the security of supply: 1 GW in Delhi can be covered by two SCC5-8000H power plants, which operate on a daily startstop mode and respectively operate on load following during the day.

An example is the Ulrich Hartmann power plant in Irsching, Germany, that operates in the same way and allows for optimal efficiency, also during the start and stop phases.

Please share your short-term plans for promoting FACY technology in India.
We are sharing our experience on FACY equipped power plants during road shows and fairs in India (e.g. Power-Gen), discussions with regulators, authorities and consultants.