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Mr. Chairman, on behalf of Tampa Electric Company, we appreciate the
opportunity to testify at this important hearing. Coal is an important part of
our nation's electricity generation mix, and we support the Committee's review
of future options for the use of coal.
HISTORY: Tampa Electric Company planned, engineered, built, and operates the
Polk Power Station Unit #1 Integrated Gasification Combined Cycle (IGCC) Power
Plant. The project was partially funded under the U. S. Department of Energy's
(DOE) Clean Coal Technology Program pursuant to a Round III award. This project
demonstrates the technical feasibility of commercial-scale IGCC technology.
Tampa Electric Company began taking the Polk Power Station from a concept to
a reality in 1989. The project received an award under Round III of the DOE
Clean Coal Technology Program in January 1990 based on older gasification and
combined cycle technology to be located at a different site. The project concept
was soon revised to incorporate newer more efficient gasification and combined
cycle technology. Meanwhile, an independent site selection committee consisting
of community representatives selected the current site, which was an abandoned
phosphate mine in southwestern Polk County Florida. The DOE Cooperative
Agreement was modified in March 1992 to incorporate these improvements. Detailed
design began in April 1993, permits were issued without intervention, and site
work began in August 1994. The power plant achieved "first fire" of
the gasification system on schedule in July 1996. The unit was placed into
commercial operation on September 30, 1996. Since that time, the plant has met
its objective of generating low-cost electricity in a safe, reliable, and
environmentally acceptable manner. The plant continues to operate base loaded as
a key part of Tampa Electric Company's generation fleet.
PLANT DESCRIPTION: Polk Power Station is a nominal 250 MW (net) IGCC power
plant, located southeast of Tampa, Florida in Polk County. The power station
uses an oxygen-blown, entrained-flow coal gasifier integrated with gas clean-up
systems and a highly efficient combined cycle to generate electricity with
significantly lower SO2, NO´, and particulate emissions than existing
coal-fired power plants.
The air separation unit (ASU) cryogenically separates ambient air into its
major constituents, oxygen (O2) and nitrogen (N2). Most of the O2 (approximately
2175 tons per day at 96% purity) is needed in the gasification plant for the
production of fuel gas. 2.5% of the available O2 is used in the sulfuric acid
plant. Most of the N2 goes to the power plant's combustion turbine to dilute the
fuel gas for NOx abatement. This diluent N2 also increases the combustion
turbine's power production by 15% (25 MW) as it expands through the turbine.
The gasification plant produces clean medium BTU fuel gas and high-pressure
steam for electricity production from 2500 tons per day of coal combined with
other solid fuel such as petroleum coke and biomass. Coal from the 2 silos
on-site is mixed with recycled water plus fines and ground into a viscous slurry
which is pumped to the gasifier. The gasifier is a Texaco slurry fed, O2 blown,
entrained gasifier operating between 2400°F and 2700°F. High pressure steam is
produced by cooling the syngas in a radiant syngas cooler and two parallel fire
tube convective syngas coolers. Particulates are removed in an intensive
water-scrubbing step. The gas is then further cooled in a way that almost all of
the remaining heat is recovered by preheating the clean syngas fuel and boiler
feedwater. This improves the plant's overall efficiency. Finally, the sulfur is
removed from the gas by first converting any carbonyl sulfide compounds to
hydrogen sulfide. The hydrogen sulfide is then removed by a circulating amine (MDEA)
solution, and the clean gas is reheated, filtered, and delivered to the
combustion turbine. The sulfur removed from the syngas is sent to the sulfur
recovery system, which generates medium pressure steam and produces 200 tons per
day of 98% sulfuric acid, which is sold to the local phosphate industry. Fines
containing unconverted carbon from gasification are separated from the slag and
water and are recycled to the slurry preparation section. The slag can be sold
as aggregate for shingles and blasting media or for use in cement manufacture.
Dissolved solids are removed from the zero discharge process water system in a
brine concentration unit so the water can be recycled.
The power block is a General Electric combined cycle, slightly modified for
IGCC. The combustion turbine is a GE 7F which generates 192 MW on syngas plus
diluent N2 or 160 MW on distillate fuel. A heat recovery steam generator (HRSG)
uses the 1065°F combustion turbine exhaust gas to preheat boiler feedwater,
generate about 1/3 of the plant's high pressure steam (2/3 comes from the
gasification plant's high temperature heat recovery section), generate low
pressure steam for the gasification plant, and superheat and reheat all the
plant's steam for the steam turbine.
The gross power production is typically 315 MW (192 from the combustion
turbine and 123 from the steam turbine). The oxygen plant consumes 55 MW, and
other auxiliaries require 10 MW, so the net power delivered to the grid is 250
MW.
PLANT PERFORMANCE: The Polk Power Station IGCC Project has met the key
objectives of the plant owner/operator and the Department of Energy since
beginning operation in 1996. Multiple technologies from many different suppliers
were successfully combined into a highly integrated efficient power generation
plant. Synthesis gas is used to fuel an advanced combustion turbine without
adverse effects. Multiple coals and other low cost solid feedstocks have been
successfully utilized. Very low emissions are being achieved with these solid
fuels. After overcoming several initial problems, the unit is now demonstrating
good availability.
Low air emissions, while using low cost solid fuel feedstocks, is the main
driver for IGCC technology. Polk's emissions of SO2, NOx and particulates are
lower than other coal fired options. SO2 removal is typically 98% with emissions
at 0.06 lb/mwh. NOx emissions have recently been reduced by the addition of
syngas saturation and are currently averaging 10 ppmvd corrected to 15% O2.
Particulate emissions are extremely low at 0.04 lb/mwh.
SOx and particulates are more effectively removed in IGCC than in
conventional coal combustion systems since the pollutants are removed from
IGCC's high-pressure fuel gas stream rather than from the exhaust gas generated
by total combustion. Removal of pollutants from the fuel also makes the removal
of trace elements such as mercury more feasible and cost effective. IGCC plants
are currently more efficient than other coal technologies and their CO2
emissions are correspondingly lower. Should CO2 capture and sequestration be
called for, IGCC will have a significant advantage since CO2 can be removed from
the fuel stream prior to combustion.
The reliability and availability of Polk's IGCC unit has improved steadily
since entering commercial service. The unit had some problems with heat
exchangers and other items that led to lower than expected initial reliability.
These problems have been addressed and the availability of the gasifier now in
the 80% range, which is consistent with its design. Polk's gasifier availability
is somewhat lower than would be expected for the next generation IGCC plant due
to the lack of redundancy of some critical equipment. The combined cycle portion
of the plant can also be operated on distillate oil. This capability to run on a
back up fuel, increases the overall availability of the unit to the mid 90%
range which is better than any single fuel, coal fired technology. Availability
information is presented in the chart below.
The efficiency of Polk's IGCC unit, or heat rate, is approximately 9,500 btu/kwh
on a steady state basis which is better than most other coal fired technologies.
Other IGCC units are even more efficient. The Polk gasfier loses some efficiency
due to lower than expected carbon conversion and changes in heat exchanger
configuration. Both of these issues would be addressed in the next generation
IGCC plant.
The cost to construct the Polk IGCC unit was about $2000/kW net of DOE
funding. This is somewhat higher than future plants since it was one of the
first of its kind. Today's direct cost for a new single train 250 MW IGCC plant
on the Polk site in Polk's current configuration incorporating all the lessons
learned is estimated to be about $1650/kW. A new plant built with economies of
scale could reduce capital costs to $1300/kW or below. This is significantly
higher than a natural gas combine cycle plant. The cost of fuel however is much
lower for IGCC.
HOW IS IGCC CURRENTLY PERCEIVED: The IGCC demonstration project at Polk Power
Station has attracted a great deal of attention from industry, government and
academia. Since it's inception, the plant has hosted over 2500 visitors from
over 20 countries. The reason for the interest in the project is varied, but
typically focuses on the technology used, environmental performance, system
reliability and capital cost.
Many of our visitors are in the process of evaluating IGCC as an option for
generation expansion. Their interest stems from the advantage of using coal, or
other solid feedstocks, as a secure, low cost, fuel for power generation. The
IGCC process achieves the use of coal in an environmentally acceptable manner.
Typical conclusions as to the benefits of IGCC include: · Polk has
demonstrated the flexibility of using a number of different solid fuels
including over 15 coal types, petroleum coke and biomass. This is seen as a
major advantage over natural gas from a price, volatility and security of supply
standpoint. · Polk has demonstrated superior environmental performance
regarding SO2, NOx, and particulate matter versus other coal technologies. ·
IGCC is well suited for mercury and CO2 removal. · Polk has demonstrated the
use of IGCC in a commercial size for power generation. · IGCC generally has a
higher cycle efficiency than other coal fired technologies.
The typical concerns regarding IGCC technology include: · IGCC has a high
level of capital investment required versus Natural Gas Combined Cycle (NGCC)
plants. There is general agreement that capital costs will be lower for the next
generation of IGCC, but the uncertainties of returns in future power markets
have made it difficult for potential users to select the high capital cost
option. · The environmental superiority of IGCC is financially unrewarded.
Other coal-fired technologies may be able to meet current environmental
regulations and there is no economic benefit for the additional environmental
performance of IGCC. The potential benefits of future mercury and CO2 removal
are difficult to monetize. · Existing IGCC plants have been engineered and
constructed as an assembly of individual process units. The process unit
suppliers will offer performance guarantees at their boundary limits, but no
guarantee is typically available for the overall IGCC plant. The assumption of
the overall plant performance risk has made financing and ultimately the
selection of IGCC technology more difficult.
· There is the perception that IGCC has a lower equipment availability than
NGCC and perhaps other coal fired technologies. As a demonstration plant, Polk's
availability has been lower than the next generation plant would be. Based on
the lessons learned here and at other demonstration plants, the next IGCC plants
will incorporate improvements in equipment/material selection, operating
procedures and level of redundancy. An important point, which is undervalued by
many is that the overall availability of the plant, including operation on
backup fuel in combined cycle mode, is very high. Gasifier availability can be
engineered to be as high as the particular project economics dictate. ·
Operation of an IGCC plant requires different technical skills than those with
which power-generating utilities are generally familiar. The Polk project has
demonstrated that a modest size utility, with expertise in coal-fired
generation, can build and operate an IGCC plant. Tampa Electric paid careful
attention to personnel selection and training to make this project a success. A
common position taken by other electric utilities is that they would like to see
someone else take the risk in building the next IGCC plant. The "risk"
being quoted seems about equally split between a perceived availability risk and
an economic risk. We believe that the demonstration plants, including Polk, have
shown that the availability issue can be effectively managed, particularly in
the next generation of plants. The economic risk is a bit more complicated. The
higher initial costs for IGCC can be offset by long-term fuel savings. In the
last few years, a litany of external factors such as deregulation, power market
pricing, California, ENRON and most recently stock devaluation have impacted the
risk tolerance of potential users. At this point, it seems everyone would like
to see multiple successful IGCC plants in service before they move forward.
STEPS NECESSARY TO MOVE FORWARD: The DOE has been, and continues to be, very
supportive of IGCC process. Numerous programs being discussed envision IGCC as a
key core technology. Polk Power Station is an outstanding example of how IGCC
has been taken from concept to commercialization through a public/private
partnership. Tampa Electric believes strongly in the value of IGCC and its
future. Polk is the only gasification unit currently using coal for the
generation of electricity in the country. Through this experience, the company
has learned a great deal about the feasibility of IGCC and its future
commericalization opportunities. As previously noted, while there are great
opportunities, barriers exist to moving from the current atmosphere of perceived
risk to the widespread use envisioned by the DOE.
These barriers include: · Higher capital cost · Higher operations and
maintenance cost · Perceived technical complexity · Perceived lower
availability · Uncertain future environmental regulations
One path to overcome these barriers is to build on the DOE successful
application of public-private partnerships. The success and necessity of this
approach has been demonstrated at Polk. Elements of this public-private approach
must include funding for technology development and demonstration. This funding
could be provided as grants, tax credits or other means. It is important that
the funding support a comprehensive effort addressing all aspects of the
technology. The gasifier, the capital costs associated with technology
development and, operations and maintenance costs all need to be addressed
before production incentives can be realized. In addition, the ability of
long-term financing absolutely depends on full sized integrated demonstration
plants. Public-private partnerships are the most expedient way of taking the
next steps toward commercialization of IGCC, but funding targeted toward IGCC
specifically is crucial.
A comprehensive approach, utilizing a proven public-private partnership can
provide the momentum necessary to achieve zero emission coal-fired technology
for the 21st century.
Again, Mr. Chairman, thank you for the opportunity to participate in today's
hearing.
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