Current Export Initiatives

Jerry Mossing

Exports Workshop

February, 16,2006, Metropolitan Center, Calgary

AB to BC Transfer Capability Background

• 2004 –Focus on Genesee #3 interconnection impact on import capabilities

• New Single Largest Generation Contingency

• Operation under planned transmission outages in KEG

• Examine the system dynamic stability under the then current transfer limits

• Group of participants requested information on AESO plans to meet requirements of Transmission Regulation 8(1)(e)(g)

• ISO to make arrangements for the expansion or enhancement of the transmission system so that, under normal operating conditions, the transmission system interconnections with jurisdictions outside Alberta can import and export electricity on a continuous basis, at or near the transmission facility’s path rating;

• Participants expressed desire to increase export capability in both an operations context as well as a planning context

AB to BC Transfer Capability Background (2)

• Several revisions of AB to BC transfer capability (OPP 304 – Alberta-BC Interconnection Transfer Limits)

• Dec 2004 – updated based on winter capability studies

• May 2005 – updated on summer capability studies

• August 2005 – dynamic calculation using a Calgary Generation Adder (CAG)

• Nov 2005 – updated winter capabilities using CAG

• Dec 2005 – updated winter capabilities based on double Sheerness contingency mitigation, Sheerness (SHAG) and Joffre (JAG) adders

• Feb 2006 – updated winter capabilities based on addition of ~200 MVAR Janet cap banks, and Bighorn adder (BAG)

• It’s all about the south generation

• This is getting complex!

• Feasibility of using GRAS to enhance exports

AB to BC Transfer CapabilityImpacts

• System is being pushed to capacity during non-peak periods as export capability is increased.

• Looks and operates like peak load for more hours of each day

• Export capability is diminishing due to load growth even as we make incremental adjustments to increase capability

• System (240kv) minimum voltage limits approached, examined, and in some cases, revised

• Dynamic ATC calculation increases export capability but our market structure could result in more schedule curtailments

• Complex dynamic calculations and manual processes

Estimated Export ATC (Nov 1, 2005 - Jan 14, 2006)

0

100

200

300

400

500

600

700

800

0 5 10 15 20 25 30 35 40 45 50

Duration (% of hours)

Ex

po

rt A

TC

(M

W)

Nov 1 OPP Dec 15 OPP Dec 22 OPP Jan 30 OPP

AB to BC Transfer CapabilityImpacts (2)

• The Edmonton-Calgary 500Kv studies identified the South of KEG (SOK) and North of Calgary (NOC) ‘cutplanes’ that limit the flow on the Alberta 240kv backbone

• Should we operate to a cutplane?

• Which one should we use?

• What are transition requirements?

• operating studies, stakeholder consultation, OPPs, tools, training

• Are there impacts to the market?

• e.g. Constraints management

AB to BC Transfer CapabilityImpacts (3)

• The Calgary Area Reactive Power Supply Reinforcement Need application resulted in 520 MVars of capacitor banks to be installed in the Calgary area

• These were required for reliable service at peak loads, but can be used to support exports with some consideration to contingencies (e.g. loss of tie line under heavy export)

• Continued monitoring of Calgary area dynamic reactive reserve

• SOK - 240 is the recommended cutplane

• Voltage stability constraints largely gone due to cap banks and thermal constraints

• Simplify operations and calculations

• Maximize export capability due from contribution of south generation

SOK - 240Cutplane

AB to BC Transfer CapabilitySOK - 240 Implementation

• Studies nearly complete

• Stakeholder consultation begins today

• Revisions to

• OPP 304 – AB BC Interconnection Transfer Limits

• OPP 510 – Calgary Area Operation

• New OPP 521 – SOK-240 Operation

• Timeframe – March 13 to May 1

• Workshop in 3rd week of March

• Forecast long term ATC based on historical south generation operation and southern load

• Forecast day ahead southern generation and load

• Real time tools to provide alarm and action conditions as limits are approached

AB to BC Transfer CapabilitySOK - 240 Implementation (2)

• Constraints management provided in 2 stages

• Current protocol – Opportunity Services – export, south DOS, Calgary area TMR

• Proposed constraints management rule when rule approved and tools ready

Generation and Load

SOK - 240

Generationand Load

BC

AIL Summer Winter

< 8000 1640 MW 1875 MW

>= 8000 1600 MW 1800 MW

BC Limit AB Limit

700 – 800 MW 0 – 800 MW

AB to BC Transfer

Proposed Limits

AB to BC Transfer Capability GRAS

• GRAS – Generation Remedial Action Scheme

• aka Generation shedding for defined contingencies

• Under various export conditions the effects of certain contingencies can be mitigated by tripping northern Alberta generation

• Risks

• Failure to trip the generator – expect criteria violations

• Hard trip to the generator - could cause generator equipment problems

• Contingencies requiring GRAS may be grouped into 3 areas

• Alberta contingencies

• AB BC Tie line

• BC contingencies

• The GRAS initiative is underway

AB to BC Transfer Capability 900L Thermal Upgrade

• 900L (Benalto to Red Deer) is the overloaded element under most contingencies when SOK 240 is at the limit

• Thermal upgrade would increase winter export capability

• AltaLink has been requested to estimate to cost of the upgrade

Questions ?