3. SNOHOMISH COUNTY PUD NO.1
Power and Business Services
Limited Generation Flexibility:
PUD electricity supply
81% - Bonneville Power Administration
7% - Wind Energy Purchases
4% - Jackson Hydroelectric Project
4% - Everett Cogeneration/Hampton Biomass Projects
3% - Long Term Contracts
1% - Klickitat Landfill Gas
Note: not including projected addition of small hydro units
4. SNOHOMISH COUNTY PUD NO.1
Power and Business Services
Hay Canyon (Iberdrola Contract) 100.8MWh MWh
Capacity @ $75.01 per*
Wheatfield 96.6MWh Capacity at $77.50 per*
BPA SLICE averaging $30 per MWh
Disproportionate Wind Generation Capacity to non-
Wind dispatchable Snohomish Resources
Increasing urgency to focus on Power Scheduling
mechanics:
balancing resource to load consistently
optimizing BPA 2011 SLICE contractual rights and river
management
maintaining District integrity and reliability within BPA Control
Area
6. SNOHOMISH COUNTY PUD NO.1
Power and Business Services
Optimal storage v generation through a twenty-four hour scheduling day
http://transmission.bpa.gov/business/operations/Wind/WindAnimation.aspx
7. SNOHOMISH COUNTY PUD NO.1
Power and Business Services
Augurs increasing “displacement”, or spilling of hydropower to allow for wind generation
8. SNOHOMISH COUNTY PUD NO.1
Power and Business Services
Real-Time responsibilities first 30 minutes every hour
• Load forecasting and resources balancing
• Predicting wind generation variances, compensatory adjustment of SLICE, and
marketing length in a wind-saturated market
• ICAP marketing operations through Columbia Grid participation
• Precise allocation of NT and PTP resources, with POD, POR and Zonal designations
• “Transassigning” surplus transmission
• Comprehensively managing the District’s share of six (6) hydro plants on the
Columbia River within “hard” BPA flow constraints dynamically within SLICE 2011.
Fifteen (15) minute estimate to run “simulator” for SNO share
• Creating market and physical path tags for all internal and external Control Areas
purchases
• Communicating hourly Wheatfield generation forecasts to Horizon Wind (ROCC)
9. SNOHOMISH COUNTY PUD NO.1
Power and Business Services
Shaping Wind
Energy Utilities are increasingly pursuing energy storage solutions to
“smooth” their wind generation, mitigating large unanticipated fluctuations in
output. A variety of energy storage methods are being considered for
resource to load congruency, frequency regulation, containing wind
integration fees charged by Control Areas, and efficiencies of hour-ahead
transmission line capacity reservations.
10. SNOHOMISH COUNTY PUD NO.1
Power and Business Services
Energy Storage Methods
Flywheel
Energy storage is based on mechanical inertia. A heavy rotating disc is accelerated by
an electric motor, which acts as a generator on reversal, slowing down the disc and
generating electricity. Electricity is stored as the kinetic energy of the disc. It can be a
motor at one moment and a generator the next.
A system installed in Coral Bay, Western Australia, uses wind turbines coupled with a
flywheel system and low load diesel (LLD) technology resulting in a better than 60%
wind contribution to the town grid.
Hydrogen
Hydrogen is also being developed as an electrical storage process. Hydrogen is
produced (using electrical energy and/or heat), then usually compressed or liquefied,
stored and then converted back to electrical energy and/or heat. However, the
conversion process to electricity is through a combustion turbine (CT), or fuel cell, not
readily feasible for the District.
11. SNOHOMISH COUNTY PUD NO.1
Power and Business Services
Energy Storage Methods
Compressed Air
A grid energy storage method is to use light load (LLH) or renewably generated
electricity to compress air, which is usually stored in old mines or some other geological
feature. During peak load periods or sharp ramp-up demand, the compressed air is
heated with a small amount of natural gas and then goes through turboexpanders to
generate electricity.
Pumped Water
• Pumped storage hydroelectricity is used to even out daily load shapes by pumping
water to a high storage reservoir during LLH hours and weekends. During peak load
hours, this water can be used as a high value rapid-response reserve. Pumped storage
recovers about 75% of the energy consumed, and is currently the most cost-effective
form of mass power storage. The chief difficulty with pumped storage is that it usually
requires two nearby reservoirs at considerably different heights, and is capital intensive.
12. SNOHOMISH COUNTY PUD NO.1
Power and Business Services
Energy Storage Methods
Flow Batteries
Flow batteries are rechargeable. A flow battery typically uses liquid
electrolytes that react, exchanging ions and electrons when pumped
together into a battery cell stack. The reaction in the cell membrane can
either discharge or charge the electrolytes. It’s all reversible. Storage
capacity is increased by simply increasing the size of the electrolyte tanks.
A company called Xtreme Power, on surface, seems to promise a viable
energy storage solution for Wheatfield Wind generation output subject to
potential ROI. Xtreme Power claims to have developed new technology
using dry cell batteries, in a modular, scalable system with up to 100MWh
of storage capacity. They are currently installing a battery storage system
for a Maui, Hawaii 30MWwind farm. The state wants 70% of its energy
needs met with renewables by 2030.
13. SNOHOMISH COUNTY PUD NO.1
Power and Business Services
Xtreme Power Wind Management Claims
Power capacity up to 100MW
Power storage up to 500MWh
Cycle efficiency greater than 95% each direction
Automatic communication with transmission grid and SCADA systems
Prevents curtailments due to grid constraints or low demand
Cost-effective solution to ramp-up / ramp-down excursions
17. SNOHOMISH COUNTY PUD NO.1
Power and Business Services
ENERGY STORAGE CONSIDERATIONS – NEAR FUTURE
Wind capacity doubles within last 3 years in Washington, Oregon and California
By 2013, wind capacity expected to double again
California just increased renewable energy standard. Will need more RECs.
REC demand drives increasing production of renewable energy, potentially disrupting
Mid-Columbia markets to ruinous conditions
15% Northwest wind farm energy purchased by public utilities. BPA manages 75%
region’s high voltage transmission system, including most sections serving the wind
farms.
Disproportionate displacement of hydropower to accommodate wind production growth
Routine spilling will harm fish and not a strategic solution
Curtailing wind undermines its economics by foregoing tax and renewable energy
credits
BPA ongoing pressure to increase wind integration fees up to quadruple current rates
Consistent operational problems when BPA wind integration reaches total capacity of
6,000MW, projected in 2013