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Microsoft PowerPoint - NWPCC_Oct172008_PGE.ppt [Read-Only] Helms Pumped
Storage Plant
Northwest Wind Integration Forum
Workshop
Manho Yeung
Pacific Gas and Electric Company
October 17, 2008 1
Pacific Gas and Electric Company - Overview
Headquarters Location
San Francisco, CA
Service Area
70,000 square miles in northern and central California
Service Area Population
15 million people (or about 1 of every 20 Americans)
Distribution Customer Accounts
5.1 million electric, 4.3 million gas
Employees
Approximately 20,000
System 159,364 miles of electric transmission and distribution lines 48,198 miles of natural gas T&D pipelines 6,271 megawatts of generation, including
Diablo Canyon nuclear power plant,
Helms pumped storage plant, and
one of the largest hydroelectric systems in the country 2
Note: Delivery mix includes all of PG&Es owned generation plus all of PG&Es power purchases. PG&Es direct
purchases of coal have not increased and remain at 1.6%. The higher number on the chart is due to state
regulations that assume a higher mix of coal in market purchases. Also, 2007 was a below normal hydro year.
PG&Es 2007 Electric
Delivery Mix
Biomass and waste 4%
Geothermal 4%
Small hydroelectric 2%
Wind 2%
Solar <1%
On average, More than 50% of PG&Es Portfolio is Carbon-Free 3
Helms Pumped Storage Plant is in its 25th Operating Year
<100 GWh per year
(natural in-flow)
Average
Energy
Three units;
1,212 MW generating;
930 MW pumping
Installed
Capacity
Lake Wishon
129,000 Acre Feet
Lower
Reservoir
Courtright Lake
123,000 Acre Feet
Upper
Reservoir
June 30, 1984
Commission
Central California,
about 50 miles east of
the City of Fresno
Location
A-Courtright, B-Supply Tunnel, C-Turbine, D-Generator, E-Transformer,
F-Wishon, G-Surge Chamber, H-Elevator 4
Helms Generates During Day Time and Pumps at Night Helms has three identical reversible pump-turbine motor-generator units 1,212 MW total in generation mode, and 930 MW total in pump mode Units are housed in a chamber about 1,000 feet underground In generating mode, water would
release from Courtright Lake
travel at 9,000 cubic feet per second
through a 22,000 feet long supply tunnel, and
drop 1,744 vertical feet before discharging into Lake Wishon In pumping mode, the units would reverse and pump water from Lake
Wishon into storage at Courtright Lake Units have fast operating capability:
Dead stop to full generation in eight minutes
Dead stop to full pump in twenty minutes
(single speed)
Generating ramp rate of 80 MW per minute
per unit 5
Helms Provides PG&E Customers with Many Benefits Storage of economy energy, or surplus or lower cost energy that is
sometimes available at night for daily cycling or during Spring runoff
conditions for seasonal storage A large amount of fast acting spinning reserve and regulation capability, or
generating capacity that is immediately available to meet fluctuations in
electric demand Revenues from CAISOs energy and ancillary markets (regulation, spin and
non-spin) Helps alleviate over-generation or minimum load condition by using excess
energy to pump water into storage Allows operation of thermal plants at a more steady output level, resulting in
higher efficiencies Reduces dependence on fossil fuels and greenhouse gas emissions
(environmental benefits) 6
-300
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-100
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168
Hour
Ou
tp
ut
(MW)
Generating
Pumping
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-200
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0
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0
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162
165
168
Hour
Ou
tp
ut
(MW)
Generating
Pumping
-300
-200
-100
0
100
200
300
400
0
3
6
9
12
15
18
21
24
27
30
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51
54
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63
66
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81
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102
105
108
111
114
117
120
123
126
129
132
135
138
141
144
147
150
153
156
159
162
165
168
Hour
O
u
tp
u
t
(M
W)
Generating
Pumping
Helms Operation Typical Summer Week
Unit 1
Unit 2
Unit 3 7
Helms Pumped Storage Plant
Historical Annual Generation and Pumping
0
200
400
600
800
1,000
1,200
1,400
1,600
2000
2001
2002
2003
2004
2005
2006
2007
Year
Energy (GWh)
Generation
Energy Used for
Pumping
Typical Range of Generation
Prior to Formation of CAISO
California
Energy Crisis
Average Natural In-Flow
Helms Production Substantially Exceeds its Natural Inflow 8
Demand Increase has Consumed Transmission for Pumping Over the past 25 years, electric demand in central California has increased and has
consumed some transmission capacity for pumping at Helms during off-peak hours PG&E has plan to construct a new 150 mile long 500 kV transmission line to, among
other things, restore Helms pumping flexibility
Illustrative Demand vs. Transmission Capability for Pumping
5,000
7,000
9,000
11,000
13,000
15,000
17,000
19,000
21,000
23,000
0
3
6
9
12
15
18
21
24
27
30
33
36
39
42
45
48
Hour
Electric D
e
man
d
(MW
)
Electric
Demand 25
year ago
Today's Local
Area Electric
Demand
Transmission
Limit 9
Future Changes to Helms PSP Operation --- Unclear
Electric transmission constraints
Intermittent renewable generation
CAISOs Market Redesign and Technology Upgrade initiative and its
Nodal and Locational Marginal Pricing
Western Electricity Coordination Councils draft Frequency
Response Reserve criteria in additional to the current spinning
reserve requirement
Potential drivers are: 10
PG&E is Evaluating New Pumped Storage Opportunities
More pumped storage plants is good for power system operation
In 2008, PG&E has sought and received FERC permits to evaluate
potential pumped storage hydro facilities at Mokelumne River and
Kings River
PG&E is currently evaluating several potential pumped storage sites
based on using a number of existing or new reservoirs 11 PG&Es Helms Pumped Storage Plant has provided positive economic,
reliability, operational and environmental values to PG&Es customers for
almost 25 years, with many more to come Helms can facilitate storage of economy energy on both a daily and a
seasonal basis Helms is an effective means to resolve over-generation and minimum load
issues Helms, with its fast operating characteristics, is a valuable tool for system
operators to meet changing demand and system conditions Helms is very valuable in the ancillary market as well as the energy market Helms can also be an effective tool to accommodate and integrate
intermittent renewable resources
QUESTIONS???
In Summary