HomeMy WebLinkAboutTerror Lake Unit 3 Hydroelectric Project Exerpt of Power Generation Study - 2009 - REF Grant 7040013DIESEL P®wER YERSUS THIRD TURBINE: AT TERRo .
LAKE HYDROELECTRIC FACILITY
WNW the winds on Piilar Mountain are rated as an excdient winch regime for energy
production, 'the rdia% Hty of wind energy on a rMnu e-to-minute basis is uncertain
because winds ooWd be gusting one moment and then suddeMy oaim, This Nck of
preOctabiii y requires KEA to have sufficient capacity available to meet peak load
re-quireme is on isle systrem. As previously discussed, the current, approach of PourMng
14 Rabor to Appendix, ® for the sensitivity analysis oft -he Pillar Mountain Wind Progaec.
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diesel fuel to supplement KEA's capacity is becoming less practical, dua fo the high cost
of operaUan and environmental concerns. instead of burning diesel, KEA could install a
third turbine of Terror Lake to raise the facility's capacity by 50%. R should be noted that
adding a third turbine is only possible if T error Dike is under KEA ownership; therefore,
the following analysis assumes that, KEA owns Terror Lake.
According to the interroogafion of the 2006 SCADDA system by KEA MC Technician Gaon
Sternberg there were approximately 2,500 hours during 2006 when Terror Lake was
unable to moot peak load with two turbines. During those hours, he needed capacity
suppi emenied by 6esel generation averaged 3 MW, and resulted in 7.5 million kWh
being generrated to cover peak, bads. The need for diesel powered supplemental
capacity will continue to grow into the future as peals loads increase.
Figure 4 illustrates the future of KEA's system energy. The amount oftotal generation
expressed in the graph is based upon projected mower sales. KEA is dedicated to the
goal of generating 95% of their total energy sales with natural resources (i.e., wind and
wafer) and this goal will be achieved wM the development of the Pillar Mountain Wind
Project.
FIGURE 4. SYSTEM ENERGY BASED UPON FUTURE PROJECTIONS OF POWER,
PEAK LOAD, AND NATURAL RESOURCE POWER DEVELOPMENT,
150,000
'I
145,000 f
_..
140,000
135,000 ..................
._ ..._ .. ......_...._...............
130,000
125,000
{
120,000__.___
115,000
2006 2007 2003 2009 2010 2011 2012 2013 2014 2015
year
rc. Goal for Natual Resouce Power Total Power Requirements
N Available Natural Resouce Power Generation Requirements Less Peal® Diesel
For planning purposes, diesel power will still need to be generated as supplemental
capacity to cover peak loads. Wind energy is unpredictable on a moment-to-rnoillent
basis. As explained above, the need for this supplemental diesei mower is projected to
grow into the future as peak loads continue to rise.
The yellowr-shaded area in Figure 4 represents the growing gap in supplemental
capacity where diesel poorer will need to be generated. Given our current situation,
excess energy provided by natural resources will be Brasted with high grater levels at
Terror Lake spilling over because diesel generation will continue to be employed as a
reliable method of covering peak loads.
The purple triangle in Figure 4 represents this lose in natural resource energy. Instead
of wd
asting the energy provided by natural resources, by utilizing `error L ake's third
turbine as a storage battery, KEA would have the capability to store the excess mind
energy.
F. COST COMPARISON OF DIESEL POWER AND THIRD
TURBINE AT TERROR LAKE HYDROELECTRIc F"ACILITy
It ie 'Voraunate that the Terror Lake Hydroelectric Facility was originally designed and built
for the addition of a third turbine, because this reduces the construction costs
significantly, The capital cost of the third turbine includes the cost of the turbine and its
auxiliary equipment, and the cost to transform 1308 k-V of generated poorer to conform to
the 69 IN grid system.
The mechanical porion of the capital costs Qi,e., equipment purchases) is estimated to
be $08 million. The cost of the transformation is eetimeted to be 2 million. The total
capital cost of installing a gird turbine at Terror Lake is estimated to be $12.6 million.'5
Due to the design of the facility, operational costs for a third turbine would be
insignificant.
If the third turbine- were not installed at (Terror Lake, then dieeei fuel would be consumed
to provide the needed capacity for peak- loads. This is represented by the purple area on
Figure 4, and it is equivalent to a tonal of almost 11 million kwh'e. At assumed fuel costs
and diesel efficiency, that would represent a fuel savings of almost $1.7 million.
Cost savings done do not justify the installation of e third turbine at this time; however, it
is the added value in KEA's system stability that justifies the addition. A third turbine
allows for more grind poorer to be integrated into the system grid and maximizes the
benefits ofwind poorer. An additional turbine at Terror Lake also makes the system
inherently more stable. The two turbines done cannot tolerate than approximately more
than 3 MW of instability on the grid without tripping, and therefore KEA imposes as 3 MW
iimit on the distribution feeders. A third turbine would allow for more capacity on the
distribution lines. This increased eta bilKy provides significant cost savings for the
distribution aspects of KEA's operations.
A Nrc9 turfoine at Terror Lake would also provide sufficient backup in generation and
transformation to support the step down in power `from 138 kV to 69 kV. Currently KEA
only has one transformer at Swampy Acres for this poorer conversion, and having only as
sing is'Era nsformer introduces system vulnerability. A parallel transformer made possible
by a third turbine increases the system stability. An ongoing system stability study that
will provide a more detailed examination of these issues is scheduled for completion in
the near future.
95 Defer to Appendix E for a preliminary design -level cost estimate of a third turbine at Terror Lake
Hydroelectric Facility.
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As KEA moves in the direction toward utilizing more renewable resources for power
generation, the future will Rdy include the addition of a tP ird turbine at Terror Lake
because it provides environmental value, expansion ou peak capacity, necessary s ystre n
backup, and system stability. Further analysis of the ongoing system stability study will
demonstrate how a thirrd turbine enhances KEA's system stability. Financial arna ysls °nor
the cost-anMyds well determine when the project will be economically justified.
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