Effects of increased wind on Coal Creek Station generation - - PowerPoint PPT Presentation

Effects of increased wind on Coal Creek Station generation

Presentation for ND Energy Conference Tuesday, October 10, 2017 David Farnsworth, Great River Energy

 ND’s largest, most efficient lignite

power plant (2 x 600 MW units)

 Lignite supplied from Falkirk Mine  Online: U1 1979, U2 1981  Very reliable and low-cost power

producer

 Built for serving Great River

Energy’s 28 electric coops via 500 mile DC line to Minnesota

 Sells power into the MISO market

Coal Creek Station

 Great River Energy sells and buys

its power in the MISO market

 Coal Creek Station’s output is bid

into the market based on incremental cost of production

 Normally baseloaded, but low

power prices can result in more frequent and deeper cycling

 Coal Creek Station made changes

in 2016 to allow ramping down to 30% of capacity during low prices

Coal Creek Station Dispatch

 More frequent cycling driven by lower power prices  Low power prices determined by supply vs. demand  High supply for the region

■ Renewable mandates and tax credits have

spurred tremendous growth in wind generation

■ Abundant low-cost natural gas has driven increased gas-

fired generation at the national level

 Low demand growth drivers for the region

■ Slow economic growth by historical standards ■ More efficient appliances and LED lighting

Coal Creek Station Dispatch

Great River Energy Generation Mix

2017 Installed Capacity by Generation Mix

• Stanton retired, Genoa divested
• 400 MW more wind by 2021

2016 Energy Used by Generation Source

• Prior to Stanton Station closure

Wind Speed

Midwest Independent System Operator

Wind dispatch by region in MISO

 MISO had 16.3 GW

• f wind capacity in

January 2017

 Projections to top

21 GW by 2020

 12 GW in the

interconnection queue currently

MISO wind additions

MISO wind energy production

August 2016

Minimal cycling with warm weather and little wind Events: One unit trip Coal Creek Station Generation and Cycling Profile

Unit 1 Gross Output (MW) Unit 2 Gross Output (MW)

October 2016

Mild temperatures, good wind. Produce frequent cycling. Events: Low load NOx tuning, trip and repair

• utage; new lower load limits

Coal Creek Station Generation and Cycling Profile

Unit 1 Gross Output (MW) Unit 2 Gross Output (MW)

December 2016

Colder temps, but very high winds (storms) result in some cycling at nights/weekends Coal Creek Station Generation and Cycling Profile

Unit 1 Gross Output (MW) Unit 2 Gross Output (MW)

July 2017

Seasonably warm temperatures, moderate wind; no plant trips or outages Coal Creek Station Generation and Cycling Profile

Unit 1 Gross Output (MW) Unit 2 Gross Output (MW)

 Hurts Plant Economics as Cost/MWh increases

■ Fewer MWh’s of generation ■ Plant less efficient at lower loads

• More coal burned for each MWh generated
• Increased operating costs per MWh

■ Increased maintenance costs

• Increased thermal cycling causing metal damage of

piping, supports, boiler tubes, air heater seals, etc

• Starting and stopping of motors and electrical devices

resulting in more failures

Costs to Coal Creek from Cycling

Example of Cycling Damage at Coal Creek Station (Unit 1, Spring 2017)

 Coal Creek will continue to be dispatched economically to

minimize its members’ electrical rates.

 Coal Creek expects to cycle more frequently as more

intermittent wind comes onto the system

 Coal Creek will adjust its maintenance and operating

practices to minimize the costs of increased cycling

 Coal Creek will look for additional revenue opportunities

and efficiencies to offset increased cycling costs

 As a low cost, reliable, dispatchable resource, Coal Creek

expects to be a long-term generating asset for GRE

Coal Creek Station’s New Reality