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Integrating Solar and Wind Power Challenges and Solutions
Rob Wolaver
December 9, 2010
Topics
• Tri-State Overview
• Integration Challenges
• Integration Solutions
Tri-State Overview
Tri-State Member System
Tri-State is a not-for-profit, wholesale power supplier owned by 44 electric cooperatives and public power districts serving a population of approximately 1.5 million people.
Tri-State’s mission is to provide reliable, cost-based electric energy to our member systems consistent with cooperative principles
Tri-State At-a-Glance
• Annual operating revenue $ 1.2 billion
• Assets $ 3.7 billion
• Average wholesale rate 6.5 cents/kiloWatt-hour
• Member peak demand 2,447 MegaWatts
• Member service territory 250,000 square miles
• Employees 1,200
Tri-State Service Area
Generation Resources
Baseload resources
Natural gas resources
Solar resources
Wind resources
Hydropower
Internal Transmission Constraints
US Census - Metropolitan Areas
Interconnection Boundaries
RPS Mandates
• Applies to Tri-State
members in Colorado
and New Mexico
• 10% renewable energy
in 2020
• Assist members in meeting state Renewable Portfolio Standard (RPS) requirements
• Further diversify resource portfolio
• Gain operational experience with renewable resources
Tri-State Renewable Project Objectives
Renewable Generation Benefits
• Carbon Free
• Fixed Cost – Hedge against rising gas prices
• NOX, SO2, Particulate, Mercury
• Jobs
Renewable Project Background
• Issued Request for Proposals in December 2007
• Received 50 Bids from 37 entities - 4,200 MW
– Wind, Solar, Biomass/Biogas,
– Tri-State option of Small Hydro
• Developed shortlist
• Selected projects for negotiation
• Executed two Power Purchase Agreements
Cimarron Project
• 30-megawatts AC
• Owned by subsidiary of the Southern Company
• 500,000 thin film panels
• 250 acres near Springer, N.M.
• 25-year PPA
Kit Carson Wind Project
• 51 MW Wind Project – 34 GE 1.5 MW Turbines
• Owned by Duke Energy
• Burlington, Colorado
• 20 year PPA
Project Characteristics
• Proven Technology
• Proven Counterparty– Experienced
– Financially Sound
• No new transmission required
• Manageable size
• Significant incentives
• Nature of incentives
Integration of Renewable Resources
Integration: Basic Tenets
Supply = Demand
Generation = Load
Unique Electricity Attributes
No Storage
Instantaneous
Typical Daily Consumption Pattern AKA “Load”
Tri-State: December 10, 2009
Evening Load Pick-Up:Lighting, Cooking, TelevisionMorning Load Pick-Up:
Lighting, Heating, Business
Typical Daily Generation Pattern
Baseload – Coal, Nuclear
Intermediate – Hydro, Gas
Peaking – Gas, Oil
Supply = DemandGeneration = Load
Generation Fleet and Transmission System Was Designed and Constructed for Low-Cost, Reliable Operation – for a World Where CO2 was not a Pollutant
Solar PV Generation – November 26
How Do Renewable Resources Fit?
How Do Renewable Resources Fit?
$!
Tri-State Load: Nov 29 - Dec 6
Tri-State Wind and Solar – Same Time
Variable GenerationIntegration Cost Components
• Fleet Dispatch Impacts
– Increased Level of Operating Reserves
– Startup / Shutdown Cycling
– Ramping / Wear and Tear
– Efficiency / Emissions
– Loss of Capacity to Regulation
• Curtailment Payments
Integration
• Variable/Intermittent Renewable
Wind/PV Solar
• Non-Variable
Hydro, Geothermal, Biomass, Solar/Thermal with Storage
Integration
• Integration of small amounts of variable renewable generation is easy
• Integration of large amounts is difficult and expensive – Diminishing Returns
• Wind is less expensive to purchase but much worse to integrate – much more random and skewed towards off-peak
Integration Solutions?
Variable Generation Integration
• Transmission (aka “The Grid”) •Constructed and Operated for
–Reliability
–Economic Transfers
–Transportation of project power to purchasers
• New role – Integration?
Distance and Size Drives Transmission Costs
TransWest
• One 600 kV DC
• 725 miles• $3 Billion
SunZia
• Up to two 500 kV
• 500 miles
• $800M - $1 Billion
High Plains Express
• Two 500 kV
• 1,280 miles
• $5 Billion Texas CREZ
• Multiple 345 kV
• 2,300 miles
• $5 Billion
New Development in 2011?
• Development of any new resources is difficult
– Recession => Demand is down
– Cost of market gas and energy is down
• Ability and will to support renewable projects has diminished
Uncertain Regulatory Environment
• Likelihood of national carbon legislation– De facto carbon tax
• State RPS– Multipliers
– What counts what doesn’t count
– Large hydro
– Import
– Local jobs
Possibilities / Solutions
• New Transmission
• National Standard Definitions
• Just Add Money !
– “Dump Energy” – Sell at any price
– “Spill Energy” – Don’t generate
– Gas generation is more flexible than coal
– Smart Grid
Closing Thoughts
• Affordable Electricity = Competitiveness
• Economic Slowdown
• Local Solutions to Global Climate Change