March 16, 2012

Mr. Gerardo Rios

Chief, Permits Branch

Air Division – AIR 3

EPA Region 9

75 Hawthorne Street

San Francisco, CA 94015

Subject: PSD Permit Application for Pio Pico Energy Center

Dear Mr. Rios:

Kiewit Power was requested by Pio Pico Energy Center to provide information regarding the comparison 

of using the currently planned General Electric LMS100 machines for peaking and intermediate load 

versus using a fast start/rapid response combined cycle plant in the same duty cycle. The following 

information is based on information readily available to the public from various gas turbine 

manufacturers and from independent design studies performed by Kiewit. Final analysis may vary 

depending upon actual site conditions and the specific engineering details developed during detailed 

design. Additional details regarding fast start combined cycle technology being developed by various 

turbine suppliers should be obtained directly from the suppliers of the respective gas turbines or 

integrated combined cycle plants. It should also be noted that the contents of this letter are the 

professional opinion of the author and are expressly and specifically limited to the Pio Pico project. Any 

responsibility for extrapolation of the analysis contained in this letter to other situations or projects 

without the direct involvement of the author are hereby disclaimed.

Combined cycle technology has traditionally been utilized in intermediate to base load operating 

facilities. This is primarily due to the high relative cost to start an F class gas turbine and the ancillary 

systems for a combined cycle plant. Historically, this startup cycle has varied in duration from 75-90 

minutes for a hot start (overnight shutdown) to over 240 minutes for a cold start (multiple day 

shutdown). Recently, technology has been developed to improve the time required to safely start these 

types of plants. This new technology primarily consists of design modifications in the HRSG to allow 

faster heating of boiler components, and the use of terminal attemporators to de-couple the bottoming 

cycle from the gas turbine startup. This technology has been in development for several years but to 

our knowledge, none of these fast start facilities have been placed in operation in the United States. 

The first of these types of combined cycle facilities is expected to become operational in early 2013.

For this analysis, Kiewit compared a 3xLMS100 facility with a generic F class 1x1 combined cycle plant. 

Each of these facilities would offer approximately 300 MW of generation capability at base load. In 

regards to quick start capability, the LMS100 machine is capable of achieving full load (100MW) in less 
Mr. Gerardo Rios

March 16, 2012

Page 2

KIEWIT INDUSTRIAL GROUP, INC.

9401 Renner Boulevard, Lenexa, KS 66219

(913) 928-7000 (913) 928-7997 fax

than ten minutes from a cold start. This capability would allow the plant to produce up to the full 

capacity of 300 MW in this 10 minute time frame. The 1x1 combined cycle quick start facility would 

likely be capable of achieving a partial load (100-150MW) of the gas turbine in about 10 minutes. 

However, a significant portion of the facility output would not be available until the steam turbine is 

warmed and operating. This process would take significantly longer than the 10 minutes stated above 

for the LMS100 facility. The combined cycle gas turbine is capable of achieving full load operation in 

roughly 20 minutes (about 200MW) and full load (about 300 MW) for the entire combined cycle unit in 

60-75 minutes for a hot start. It is important to remember that the combined cycle efficiency benefits of 

such a plant are not realized until both the gas turbine and HRSG/steam turbine are operating at full 

load. A cold start for the facility would be expected to take closer to 2 hours before the steam turbine 

would be operating at base load.

Operating combined cycle projects using F class gas turbines as peaking facilities, where numerous starts 

are required, would result in significantly higher operation and maintenance costs versus LMS100 

technology. This is due to the significantly larger electrical load and gas consumption to start the larger 

machine along with the resultant impacts of multiple starts to turbine service intervals as discussed 

below. 

Another aspect for consideration is the ability of the facility to offer a great range of load flexibility and 

turndown. A combined cycle configuration sized to provide 300 MW would consist of an F class gas 

turbine (nominal 200 MW for gas turbine only) and steam turbine sized to provide approximately 

100MW. As such it would only be capable of reducing output in combined cycle mode to approximately 

150 MW (50%-60% load on the GT, with corresponding reduction in steam turbine output) allowing for 

much less flexibility than the three LMS100 machines. The plant using multiple LMS100 machines will 

have the ability to vary load on each individual turbine and have the capability to reduce load to a single 

unit operating at 50% for an overall plant minimum output of approximately 50MW. This will result in 

a plant that offers much greater load range flexibility during operation (50 MW to 300 MW for the 

LMS100 configuration, vs. 150 MW to 300 MW for the F-class combined cycle configuration). 

The ability to quickly change load is critical for peaking load facilities and is another area that the 

LMS100 has a significant advantage over a larger frame machine. Typically, an F class gas turbine can 

change load at a maximum ramp rate of up to approximately 30 MW/min. The LMS100, however, can 

change load at a rate of up to 50 MW/min per machine. For a facility utilizing three LMS100, the total 

ramping capability for the plant is nearly 150 MW/min which greatly increases the plant’s ability to track 

sudden load changes on the grid due to fluctuating demand and intermittent renewable generation.

We have recently reviewed the construction and equipment costs for both the LMS100 machines and 

the quick start combined cycle plants. In our estimation the cost of constructing the combined cycle 

units is approximately 25%-30% greater than the cost for the facility using the LMS100 machines on a 

$/kW basis. In addition, if a combined cycle unit were started 500 times per year (as may be required 

under PPEC’s contract with San Diego Gas and Electric), expensive, hot gas path inspections and 

maintenance outages may be required once every 1.5-2 years, instead of 24,000 hours (roughly 3-4 

years for a typical intermediate loaded combined cycle operating 6,000-8,000 per year) between such 
Mr. Gerardo Rios

March 16, 2012

Page 3

KIEWIT INDUSTRIAL GROUP, INC.

9401 Renner Boulevard, Lenexa, KS 66219

(913) 928-7000 (913) 928-7997 fax

outages. This increase in maintenance requirements would result in a much higher total operating cost 

than expected for the LMS100 whose criteria for hot gas path inspections is not determined based on 

equivalent starts.

In our opinion the LMS100 machines offer much greater peaking capability and flexibility at a 

significantly lower cost for the Pio Pico Project. Quick start combined cycle machines will offer greater 

efficiency when operated in combined cycle mode, but do not appear to meet the operational needs for 

this facility.

Please contact me if you require further information.

Very truly yours,

Jason Dedrickson, P.E.

Vice President, Natural Gas Market