Seattle City Light Evaluating and Addressing the Impacts of - - PowerPoint PPT Presentation

Seattle City Light Evaluating and Addressing the Impacts

• f Climate Change

Lynn Best, Director Environmental Affairs

Seattle City Light

• Municipal Electric Utility
• 399,000 customers
• About 90% of our power is hydro

Growing Concern about the Impacts of Climate on Our System

• Effect on hydrogenation
• Load
• Operations
• Fisheries Resources

Finney Day Nookachamps

Seattle City Light Skagit Project

Historical Observations

• Last 20 years – 11% lower April-

September Ross Inflows

• 2 week earlier spring runoff since 1970
• More frequent and larger floods on the

Sauk River

Climate Change Historical Observations

Reduced spring-summer inflow

PDO Positive PDO Negative No official PDO Classification

Increased Sauk River Flood Magnitude

Climate Change Impacts Detected

20,000 25,000 30,000 35,000 40,000 45,000 50,000 55,000 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s Decade Flow (cfs)

Ross Runoff Starting and Ending Dates

3/1 3/16 3/31 4/15 4/30 5/15 5/30 6/14 6/29 7/14 7/29 8/13 8/28 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 Year Date Start day End day Linear (Start day) Linear (End day)

Note: Trends of runoffs shifting to earlier starts and ends

Earlier Runoff

Climate Change Historical Observations

Increased Sauk River Flood Frequency

Climate Change Historical Observations

Modeling Analysis

• Asked the Climate Impacts

Group (CIG) for help

• Downscaling GCMs
• Site‐specific Projections for

the Skagit

Skagit Projections Provided by CIG

1. Snowpack and Monthly Streamflow at 9 Gages

• Significant decline in snowpack (mean = 20%)
• More flow in late-fall and winter
• Lower summer flows

2. Extreme temperature and precipitation events

• More warm wet days = greater flood potential

3. Weekly water temperature at selected river and stream sites

• Substantial increases in summer water temperatures
• n Skagit River at Sedro Woolley and some eastside

Ross Lake tributaries

Projected Number of Warm & Wet Days

Warm, wet days increase significantly after mid 21st century, driven primarily by warmer temperatures (some precipitation)

Extreme Flow Projections – Ross Reservoir

18000 19000 20000 21000 22000 23000 20 50 100 Flood Return Interval (yrs) Flow (cfs) historical 2040s

Higher Flood Flows Lower Summer Low Flows

100 150 200 250 300 historical 2020s 2040s 2080s Climate (A1B) Flow (cfs)

Stream temperature projections

Stream temperature projections indicate some sites on the Skagit River will exceed thermal thresholds for core summer salmon & bull trout habitat (16°C –WA Department of Ecology)

Skagit at Sedro Woolley Skagit at Newhalem Stetattle Creek

Stream Temperature Projections

Stream temperature projections indicate some sites on the Skagit River will exceed thermal thresholds for core summer salmon habitat (16°C –WA Department of Ecology)

Sedro Woolley

Downstream Impacts to Salmonids

• 20-, 50- and 100-year

floods increase

• Increased chance of spill
• Substantial decline in 7-day

low-flow level

• Scouring of salmon redds
• Reduced salmonid survival

Concerns

Will storm frequency and severity increase causing more spill and impacts to salmon?

Concerns

• How will Project need to be
• perated to provide adequate

instream flow during August and September to protect fish from thermal barriers or direct injury/mortality

Concerns

Will glacier recession increase bedload deposition aggradation near mouths of tributaries? How will this affect generation and fish access?

Future Work

• Adapt operations in response to:

– Changing precipitation seasonal trends – Increased storms frequency and magnitude – Low summer flows – New Federal Energy Regulatory Commission (FERC) license (2025) – Corps of Engineers flood control management

• Improve modeling and linkage of climate change projections

with operational tools

– Explore use of Distributed Hydrology-Soil-Vegetation model (DHSVM) and dynamic downscaling techniques – Improve understanding of tributary and glacier contribution – Develop operations optimization model

• Operational constraints
• Scenarios and sensitivity analyses
• Daily time-step
• Protect riverine ecosystem, endangered species, and

anadromous fish

Seattle City Light Climate Program

• Goal is to be GHG neutral
• Policy Direction from Mayor and Council
• “Earth Day” Resolution 2000
• “Net Zero Strategy” Resolution in 2001

How are we meeting the goal

• Conservation – 1st Priority
• Renewables – 2nd Priority
• Divest Fossil Fuel
• Purchase Offsets

Energy Conservation

Conservation Program

• Operating conservation programs for 33

years

• Reduced our load by 11%
• Avoiding over 600,000 metric tons of CO2

per year

• From 1991-2004, the investment in

conservation totaled $486 million

Renewables

Renewables

• Stateline Wind
• 3% to 4% of load
• Avoids over 200,000 metric tons CO2/yr
• Burlington Biomass
• Average 14,000 MWh/yr
• Columbia Ridge Landfill
• Anticipated 50,000 MWh/yr
• Avoids 30,000 metric tons CO2/yr

City Light Greenhouse Gas Emissions

• Primarily from purchased power
• Small amount from operations: vehicles, airline

travel, SF6

• Reported to The Climate Registry (TCR)
• TCR has protocols for calculating and reporting

GHG emissions

• Electric Utilities have additional protocols due to

the complexity of this industry and its contribution to GHG emissions

2010 Inventory

Remaining Emissions – Metric Tons CO2

• High Ross

3,400

• BPA Block

139,538

• Market Purchases

60,884

• Distribution Losses

3,781

• Non-Generation Sources

– Airline travel 1,471 – Vehicle Fleet 4,220 – Natural Gas (heat) 243 – SF6/Refrigerant 420

• TOTAL

213,197

GHG Offset Criteria

• Verifiable
• Additional
• Reasonably Priced
• Preference for Local
• Co-Benefits: environment, economic
• Replicability – can be expanded to other

locations

City Light Offset Projects

• Recent offset project types:
• Dairy Methane Capture/Electricity Generation
• Improved manure management
• Landfill Gas Capture and Destruction
• Other offset projects include:
• Biodiesel – City Fleet, SPU/Garbage Truck, King Co. buses, WA

Ferries

• Shore Power – Princess and Holland Lines cruise ships
• Dupont (HFC-23)
• Cement Material Substitution – with the Climate Trust

Shore Power

Cruise Ship Connection