Testimony by
Gerald M. Erjavec
Indeck Energy Services, Inc.
August 16, 2000
IN THE MATTER OF:
)
)
NATURAL GAS-FIRED, PEAK LOAD
)
R01-10
ELECTRICAL POWER GENERATING
)
FACILITIES (PEAKER PLANTS)
)
The purpose of the instant hearings is to address five questions with respect to the siting of
“peaking” power plants. Before these questions can be addressed, however, a fundamental
understanding of “peaking” plants and their impacts is necessary. “Peaking” plants are so
named because their practical use is limited to operating during periods of the highest or “peak”
need for electricity. As can well be imagined, the use of electricity varies over the day. From
periods of low use over night to the time of highest use during the day, generating units are
turned on, or dispatched, to meet the needs of the system. Generally, the least cost units are
operated all of the time as “base” units. As the load increases through the day, less efficient,
intermediate, units are dispatched on. During the highest demand period of the day, particularly
in hot weather when there is more need for electricity to power air conditioners, the peaking
units are dispatched on. Combustion turbines are well-suited to the task of meeting peak needs
because they are easily brought on line in a short period of time.
A combustion turbine works by expanding a “working fluid”, in this case air, through a series of
blades to turn a generator shaft. They are also called gas turbines; however, this name
sometimes causes confusion, because the “gas” referred to in the name is not the natural gas fuel,
but the air that passes through them. The operation of these machines is really quite simple. The
front end of them is actually operates as a compressor that takes filtered air, draws it in, and
delivers it to the combustion chamber under pressure. In the combustion chamber, fuel, most
commonly in our area natural gas, is introduced and the mixture is ignited, causing a rapid
expansion of the gas. The expanding gas passes through the turbine end of the machine,
releasing energy while moving the blades that spin both the generator and the compressor.
Contrary to popular notion, combustion turbines predate jet airplanes by quite a while, having
first been used to turn generators in 1898. They were first adapted for airplane usage in the
1940’s.
The nature of a combustion turbine is such that the amount of power is dictated by the mass of
air that moves through it. Because hot air is less dense than cold air, less mass passes through
the machine in hot weather, even though the flow volume remains constant. This results in lost
output on hot days when it is needed most. To counter this effect, various methods are employed
to cool the inlet air and increase its density. One such method is the use of chillers; however,
these require power to operate and are sometimes counter productive. Another method is called
evaporative cooling, in which the air stream is passed over water and the air is cooled through
evaporation, much like perspiration cools the skin. This cooling effect can be limited on humid
days. While water consumption varies based on temperature and humidity, an evaporative
cooler on a 300 MW plant will average about 40 gallons per minute (gpm) of water
consumption.
Even though these hearings are directed at peaking plants, the subject of combined cycle plants is
sure to come up, so a brief discussion of them is in order. Simply put, a combined cycle plant
adds a steam cycle to the process but directing the hot exhaust gas from the combustion turbine
through a boiler, which generates steam to turn a steam turbine. Because more energy from the
fuel is recovered and used to produce electricity, combined cycle plants can be as much as 50%
more energy efficient that “simple cycle” peakers; however, they are not suited to peaking use
because they cannot be brought on line quickly enough to function as peakers. Combined cycle
plants also have increased water needs compared to peakers. The first use of water, in the steam
system, is minimal, about 25 gallons per minute in a system that has been coupled to 300 MW of
combustion turbines to create a 200 MW steam cycle. Water can also be used to cool the steam
after it passes through the steam turbine. If water is the sole medium, up to 2,500 gpm can be
consumed, which may be significant in some areas. Fortunately, advances have been made in
cooling technologies so that this use can be greatly reduced or eliminated if the situation calls for
it.
Another advantage to combustion turbines fueled with natural gas is that they have about the
least environmental impact per kilowatt-hour of just about any technology available today. From
an air pollution standpoint, the impact of any combustion source is evaluated by using computer
models that examine what happens to the gas stream when it leaves the stack, mixes with the air
around it, and at some point returns to the ground where people can be exposed to it. Using a
five-year history of meteorological data and examining the effect of different weather conditions,
the maximum concentration of exhaust contaminants that the public will be exposed to can be
predicted. These predictions are then compared to ambient air quality standards to see if any
adverse effect may result. The air quality standards are established by the USEPA, and are set at
levels to provide an adequate margin of safety for sensitive populations such as the very young,
the elderly, and those with respiratory difficulties such as asthma.
As a representation of the impacts of a combustion turbine peaking plant, information submitted
in support of a 300 MW facility proposed for a site in northern Illinois is offered. The most
discussed air issue was probably NO
x
impacts. The ambient air quality standard for annual
exposure to NO
x
is 100 micrograms of NO
x
per cubic meter of air (μg/m
3
). The maximum
concentration of NO
x
attributable to the plant is 0.028
μg/m
3
, which, compared to the standard
and to the existing ambient concentration of 59
μg/m
3
, is negligible. Similarly, CO, particulate,
and SO
2
impacts are also negligible. To put these levels in comparison to familiar situations, the
NO
x
level to which a person would be exposed is 500 to 3000 times less than what that person
would be exposed to when cooking on a gas stove. Similarly, the level of exposure to the public
is approximately the same as that from three home furnaces or one tenth of that which would be
caused by a typical school boiler. This is not to suggest that a stove, house, or school emits
contaminants at the same rate as a power plant; however, after dispersion, the resultant exposure
to the population is on the same order.
With respect to impacts on water, as noted above, the only real water use attributed to peaking
plants is for evaporative cooling. This technology is usually employed only when ambient
temperatures rise above 60 degrees and water use will then vary as a function of temperature and
humidity, but is never expected to exceed 80 gpm for the 300 MW plant being used as an
example and will probably average half that amount. Put in perspective, this is about as much
water as 11 lawn sprinklers would use at the same time and about what 30 homes would use on a
yearly basis. Even if converted to combined cycle, as previously noted, water use can be
minimized if necessary. The only wastewater generated on site is stormwater, which is captured
on site and sent to storm sewers, and the backwash from regenerating the water softeners, which
can be treated locally.
With respect to sound, the facility was designed to meet the Illinois noise regulations which were
established by the Board in 1973. With this standard in place, Illinois EPA reports that it has
never received a complaint regarding noise from any of the approximately 100 peaking plants
that are in operation today.
With peaking plants and their impacts characterized, the questions before the Board can now be
addressed.
1. Do peaker plants need to be regulated more strictly than Illinois’ current air quality
statutes and regulations provide?
One of the great misunderstandings regarding peaking plants is that, somehow, they are
unregulated.
This stems, in large part, from the much-discussed concept of
“deregulating” the electric industry. The regulation referred to by that term is the limits
on spending and rates of return that are imposed on utilities in exchange for their rights to
establish quasi-monopolies. While the utilities see the regulated return as a limit on
profitability, independent producers do not receive some of the benefits associated with
this regulation, such as protection on the rate of return and the powers of eminent
domain. Aside from this “regulation”, independent producers are, in fact, highly
regulated, being responsible for meeting the same rules, regulations, and standards as the
utilities, and, in some cases, even more. Peaking plant developers must meet all
conditions of the Illinois Environmental Protection Act, including all relevant permits,
US Army Corps of Engineers requirements, industry standards, fire codes, electrical
codes, and a long list of other codes which are detailed in the presentation. Therefore, in
Indeck’s opinion additional regulations would seem unjustified and counterproductive.
2. Do peaker plants pose a unique threat, or a greater threat than other types of State-
regulated facilities, with respect to air pollution, noise pollution, or groundwater or surface
water pollution?
The analysis of the 300 MW plant cited above indicated that the impacts of peaking
plants, when compared to standards and common experiences, are minimal. With respect
to other types of facilities, another analysis has shown that peaking facilities have far less
impacts that many other facilities that have no additional regulatory requirements. On a
local scale, the air emissions associated with the 300 MW facility were a fraction of those
associated with a coal-burning power plant and on the same order as a diesel-fueled plant
a tenth its size. Looking at a state-wide picture, the average permitted emissions from
peaking facilities were compared with those from several other industries including
refineries, metal producers and fabricators, other power plants, and airports. In all cases,
the level of emissions permitted from the peaking plants was at the very low end of the
comparisons.
Water consumption impacts were also compared against other enterprises and found, in
most cases, to be at the low end of the impacts. With respect to sound, the plants'
exemplary record speaks for itself.
Given the fact that peaking plants have far less impacts that many others types of
industry, it seems inconceivable that they pose a bigger or unique threat and are
deserving of additional regulation. If, in fact, additional regulation is considered, this
analysis would seem to behoove the State to greatly increase its oversight of most other
industries.
3. Should new or expanding peaker plants be subject to siting requirements beyond
applicable local zoning requirements?
As noted above, the impacts of peaking plants are minimal and additional requirements
would seem unnecessary. An examination of local zoning codes shows that most already
allow for uses that are more intensive than a peaking plant in one or more zoning
classifications. If any alternate process is considered, it should be one that restricts the
decision-making to facts in the record.
4. If the Board determines that peaker plants should be more strictly regulated or
restricted, should additional regulations or restrictions apply to currently permitted
facilities or only to new facilities and expansions?
One of the design bases for power plants are the rules and regulations in existence at the
time of the design. Trying to design to hit a moving or potentially moving target could
effectively bring design work to a halt. In this or any other industry, a period of
regulatory certainty is necessary to allow the industry to move forward. Further, any
change in philosophy, whether it be applied only to new construction or to currently
permitted facilities, should also be applied evenly to all other industries in the State.
5. How do other states regulate or restrict peaker plants?
The process varies, of course, by state, with no model being the standard. Several other
states have a process similar to Illinois’; that is, with local issues handled by one or two
local agencies and state or federal issues going, most often, through the State. Other
states have adopted a coordinated approach, with all issues being directed through a
single siting entity. This entity rules not only on all environmental issues, but also takes
precedence over local zoning authorities.