Cleco Power LLC First Revised Sheet No. 95

Cleco Power LLC First Revised Sheet No. 95

FERC Electric Tariff, Third Revised Volume No. 1

ATTACHMENT C

Methodology to Assess Available Transfer Capability

1.0 General

This attachment describes Cleco’s algorithms, flowchart, and methodology for determination of Available Transfer Capability (ATC). The methodology is based on the June 1996 approved reference document published by the North American Electric Reliability Council entitled “Available Transfer Capability Definitions and Determination” as a framework for determining Available Transfer Capability (ATC) to satisfy both Federal Energy Regulatory Commission (FERC) requirements and industry needs.

2.0 Methodology

Cleco’s primary methodology for calculating ATC employs a flow-based methodology which is commonly referred to by FERC as network ATC. This calculation takes into account flow based limits based upon the lesser of thermal capability of the network, voltage stability, and/or transient stability. However, there are exceptions for interfaces where Cleco administers a contract path limit. In these instances, the ATC will be the lesser of the calculated network ATC or contract Path.

3.0 Definitions

The North American Electric Reliability Corporation (NERC) provides the following definitions in the “Glossary of Terms Used in Reliability Standards” (updated May 2, 2007, available at:ftp://:

3.1 Total Transfer Capability (TTC) is the amount of electric power that can be moved or transferred reliably from one area to another area of the interconnected transmission systems by way of all transmission lines (or paths) between those areas under specified system conditions.

3.2 Available Transfer Capability (ATC) is a measure of the transfer capability remaining in the physical transmission network for further commercial activity over and above already committed uses. It is defined as Total Transfer Capability less existing transmission commitments (including retail customer service), less a Capacity Benefit Margin, less a Transmission Reliability Margin.

3.3 Firm Transmission Service is the highest quality (priority) service offered to customers under a filed rate schedule that anticipates no planned interruption.

3.4 Non-Firm Transmission Service is transmission service that is reserved on an as-available basis and is subject to curtailment or interruption

3.5 Transmission Reliability Margin (TRM) is the amount of transmission transfer capability reserved to provide for reliable operation of the transmission system. TRM is calculated yearly

Issued by: Cynthia B. Guillot, Director Transmission Policy & Contracts

Issued on: September 10, 2007Effective on: September 11, 2007

Cleco Power LLC First Revised Sheet No. 96

FERC Electric Tariff, Third Revised Volume No. 1

for the Planning Horizon unless modifications to the transmission grid would necessitate a recalculation of TRM for a specific path. TRM is based on the flow based amount of power that must be reserved for each flowgate to allow generation from each Control Area within the Reserve Sharing Group to deliver its allocation of power.

3.6 Capacity Benefit Margin (CBM) is the amount of firm transmission transfer capability preserved for Load Serving Entities (LSEs) on the host transmission system where their load is located, to enable access to generation from interconnected systems to meet generation reliability requirements. Preservation of CBM for a LSE allows that entity to reduce its installed generating capacity below that which may otherwise have been necessary without interconnections to meet its generation reliability requirements. The transmission capacity preserved as CBM is intended to be used by the LSE only in times of emergency generation deficiencies.

4.0 Algorithm for ATC Determination

4.1 Power Flow Models

Cleco develops daily, weekly, and monthly power flow models for calculation and posting of available transfer capabilities. These base case models include load forecast data, generation dispatch, approved outages (transmission and generation), open access transactions (point to point and network) based on the appropriate calculation horizon as well as pre-Order 888 grandfathered contracts. In addition to modeling requirements within the Cleco control area, power flow data described above is exchanged and coordinated with interconnecting neighbors.

4.1.1 Hourly Base Case Power Flow Models

Cleco does not develop hourly power flow models for calculation of transfer capabilities. Hourly transfer capabilities are based on the results of each daily transfer capability simulation using daily power flow models described below. Twenty-four (24) hours of transfer capabilities are posted based on results of the daily peak hour for at least seven (7) days into the future from the current operating day.

4.1.2 Daily Base Case Power Flow Models

Cleco develops daily power flow models for calculation and posting of transfer capabilities at a minimum of thirty-one (31) days into the future from the current operatingday. These models include 1) Cleco’s forecasted daily peak for native load, 2)generation which is economically dispatched to serve peak forecasted load including both generation owned by native load as well asunits declared as designated network resources (DNRs) through purchased power contracts, 3) approved transmission and generation outages, and 4) firm and non-firm open access transactions (point-to-point and network) based on the appropriate calculation horizon as well as pre-Order 888 grandfathered contracts.

Issued by: Cynthia B. Guillot, Director Transmission Policy & Contracts

Issued on: September 10, 2007Effective on: September 11, 2007

Cleco Power LLC Original Sheet No. 96A

FERC Electric Tariff, Third Revised Volume No. 1

4.1.3 Weekly Base Case Power Flow Models

Cleco develops weekly models to calculate and post transfer capabilities at a minimum of eight (8) weeks into the future from the current operating week. These models include 1)Cleco’s forecasted weekly peak for native load, 2) generation which is economically dispatched to serve peak load including both generation owned by native load as well as units declared as DNRs through purchased power contracts, 3) approved transmission and generation outages, and 4) firm open access transactions (point-to-point and network) based on the planning horizon as well as pre-Order 888 grandfathered contracts.

4.1.4 Monthly Base Case Power Flow Models

Cleco calculates and poststransfer capabilities up to thirteen (13) months into the future from the current operating month. The models are based on seasonal SPP models and include 1) Cleco’s forecasted seasonal peak load for native load, 2) generation which is economically dispatched to serve peak load including both generation owned by native load as well as units declared as DNRs through purchased power contracts, 3) approved transmission and generation outages, and 4) firm open access transactions (point-to-point and network) based on the planning horizon as well as pre-Order 888 grandfathered contracts.

4.1.5 Yearly Base Case Power Flow Models

Cleco participates in the SPP annual model development and models are developed up to ten (10) years into the future based on Model Development Working Group (MDWG) input. Cleco’s input into the model is based on forecasted annual peak load, generation which is economically dispatched to serve forecasted load including both generation owned by native load as well as units declared as designated network resources (DNR) through purchased power contracts, and firm open access transactions (point-to-point and network) based on the planning horizon as well as pre-order 888 grandfathered contracts. Rollover rights are assumed on firm transmission contracts with duration of five years or greater. Cleco does not calculate or post yearly TTC and/or ATC since Long Term Firm (LTF) transmission requests are not granted without a System Impact Study (SIS).

4.2 Transfer Capability Methodology

Cleco utilizes a flow-based network ATC methodology to calculate transfer capabilities with its first tier neighbors. Cleco recognizes constraints and limitations both internal and external to the Cleco transmission system. The ATC values that Cleco calculates and posts on OASIS are equal to theFirst Contingency Incremental Transfer capabilities (FCITC) which is the output derived from the power flow simulation of transfers. Total Transfer Capability (TTC) values are derived from ATC plus existing transmission commitments (ETC). ETC is the amount of confirmed transmission capacity on Cleco’s OASIS (point-to-point and network) including native loadas well as transmission capacity committed under pre-Order 888 grandfathered contracts.

Issued by: Cynthia B. Guillot, Director Transmission Policy & Contracts

Issued on: September 10, 2007Effective on: September 11, 2007

Cleco Power LLC Original Sheet No. 96B

FERC Electric Tariff, Third Revised Volume No. 1

Transfers are simulated simultaneously with ETCs into and out of Cleco for each path on a non-simultaneous basis. A transfer test level is simulated by increasing generation in the sending control area such that generation does not exceed the maximum MW output of each unit, while simultaneously decreasing generation in the receiving control area such that generation does not drop below the minimum MW capability of unit. The transfer test level is set for each path either in excess of the thermal capability of the interconnected system or equal to the contract path limits, whichever is greater.

The network ATC is calculated by monitoring and outaging facilities declared by each first tier Transmission Provider as flowgates, for calculation of the most limiting system element for each transfer. For paths in which a contract path limit exists, the lesser of the network available transfer capability or contract path limit is deemed to be the amount of available transfer capability.

4.2.1 Transmission Reliability Margin (TRM)

Cleco participates in the SPP generation reserve sharing program. TRM is calculated at least annually for each season based on the flow impact on transmission facilities during the implementation of the reserve sharing process. Cleco determines it’s TRM for each path by simulating the loss of individual generators with replacement power modeled as a call for generation reserve sharing via power flow analyses. The increased flow on the most limiting elementduring reserve sharing implementation becomes the TRM for that interface. Cleco does not withhold transmission capacity in terms of TRM for any inaccuracies associated with the power flow model including load forecast errors, forecast errors in system topology or distribution factors and loop flow sources.

4.2.2 Capacity Benefit Margin (CBM)

Cleco evaluates and determines its CBM requirements at least annually. Currently, Cleco does not withhold ATC in terms of CBM to meet the SPP planning requirements, due to the ownership of native load generation and execution of purchase power agreements (PPAs) as opposed to withholding transmission capacity in terms of CBM.

4.2.3 Software and Databases used in Posting Transfer Capabilities

Cleco uses industry accepted software (Siemens PSSE/MUST) to calculate transfer capabilities. The results from MUST are downloaded into a spreadsheet (TTC_AUTOMATION2.xls) for uploading into an access database (Tracking.mdb). This access database interacts with OASIS to retrieve and update OASIS requests as well as upload TTC and ATC to OASIS. This database is also used for Cleco’s internal validation program for checking all transmission service request information including ATC.

Issued by: Cynthia B. Guillot, Director Transmission Policy & Contracts

Issued on: September 10, 2007Effective on: September 11, 2007

Cleco Power LLC Original Sheet No. 96C

FERC Electric Tariff, Third Revised Volume No. 1

4.2.4Frequency of Updating Transfer Capabilities

Calculations of TTC and ATC are performed and updated daily on Cleco’s OASIS. ATCs are updated more frequently than TTC, since ATC is updated as both firm and non-firm transmission service requests are granted on OASIS.

5.0 Calculations for the Scheduling Horizon

This period is the defined as same-day and real time.

Firm Available Transfer Capability (Firm ATC) is not available during scheduling horizon due to timing requirements in the Open Access Transmission Tariff (OATT).

Non-Firm Available Transfer Capability (Non-Firm ATC) is the remaining capacity available for additional non-firm transmission reservations after the committed uses for firm reservations have been scheduled and existing non-firm reservations have been subtracted from TTC. Firm transmission reservations are not used in the Scheduling Horizon or any part of the real time day for calculation of non-firm ATC.

Non-Firm ATC = TTC – CBM – TRM – Existing Firm Transmission Commitments Scheduled – Existing Non-Firm Transmission Commitments

Existing Firm Transmission Commitments Scheduledincludes:

• Energy schedules of firm reservations in the scheduling horizon

6.0 Calculations for the Operating Horizon

This period is the defined as day ahead and prescheduled.

During pre-scheduling of firm transmission service, estimates of firm transmission reservations are included in the firm and non-firm ATC calculation to set-aside capacity in the absence of approved E-Tags/schedules and ancillary service sales that are as yet unprocessed. This allows a more representative value to exist for non-firm ATC at noon of the pre-schedule day when non-firm ATC is offered. Non-firm ATC is offered by removing the firm transmission reserved which is not scheduled during the Operating Horizon calculation by 2:30 p.m. each pre-scheduling day using implemented E-tags/schedules only. Non-firm ATC is reduced by non-firm reservations (instead of non-firm schedules) to prevent having multiple unused non-firm reservations exist for the same unused capacity.

6.1 Prior to Noon Day Ahead

Firm ATC is the remaining transfer capability available based on firm transmission commitments.

Firm ATC = TTC – CBM – TRM –Existing Transmission Commitments (Firm)

Existing Transmission Commitments (Firm) include the following:

• Forecasted Native and Network Load attributable to a path in the Operating Horizon

Issued by: Cynthia B. Guillot, Director Transmission Policy & Contracts

Issued on: September 10, 2007Effective on: September 11, 2007

Cleco Power LLC Original Sheet No. 96D

FERC Electric Tariff, Third Revised Volume No. 1

• Forecasted Generation for delivery to Native Load in the Operating Horizon
• Firm Transmission Reservations in Operating Horizon for OATT and pre-Order 888 grandfathered contracts

Non-Firm Available Transfer Capability (Non-Firm ATC) is the remaining capacity available for additional non-firm transmission reservations after the committed uses for firm reservations have scheduled and existing non-firm reservations have been subtracted from TTC over a given time horizon.

Non-Firm ATC = TTC – CBM – TRM – Existing Transmission Commitments (Firm) – Existing Transmission Commitments (Non-Firm)

Existing Transmission Commitments (Firm) includes the following:

• Forecasted Native and Network Load attributable to a path in the Operating Horizon
• Forecasted Generation for delivery to Native Load in the Operating Horizon
• Firm Transmission Reservations in Operating Horizon for OATT and pre-Order 888 grandfathered contracts

Existing Transmission Commitments (Non-Firm) includes the following:

• Non-Firm Transmission Reservations in Operating Horizon

6.2 Pre-scheduled for Next Day

Firm Available Transfer Capability (Firm ATC) is not available after noon for next day during operating horizon due to timing requirements in the OATT.

Non-Firm Available Transfer Capability (Non-Firm ATC) is the remaining capacity available for additional non-firm transmission reservations after the committed uses for firm reservations have been scheduled and existing non-firm reservations have been subtracted from TTC. Firm transmission reservations are not used in the operating Horizon after noon in calculation of non-firm ATC.

Non-Firm ATC = TTC – CBM – TRM – Existing Firm Transmission Commitments Scheduled– Existing Transmission Commitments (Non-Firm)

Existing Firm Transmission Commitments Scheduled include:

• Energy schedules of firm reservations pre-scheduled for next day

Existing Transmission Commitments (Non-Firm) includes the following:

• Non-Firm Transmission Reservations in Operating Horizon

7.0Calculations for the Planning Horizon

This period begins at the end of the Operating Horizon and extends through the end of the FERC required posting period.

Issued by: Cynthia B. Guillot, Director Transmission Policy & Contracts

Issued on: September 10, 2007Effective on: September 11, 2007

Cleco Power LLC Original Sheet No. 96E

FERC Electric Tariff, Third Revised Volume No. 1

Firm Available Transfer Capability (Firm ATC) is the remaining transfer capability available based on prior firm transmission commitments.

Firm ATC = TTC – CBM – TRM – Existing Transmission Commitments (Firm)

Existing Transmission Commitments (Firm) includes the following:

• Forecasted Native and Network Load attributable to a path in the Planning Horizon
• Forecasted Generation for delivery to Native Load in the Operating and Scheduling Horizons
• Confirmed Firm Transmission Reservations in all horizons including OATT and pre-Order 888 grandfathered firm commitments

Non-Firm Available Transfer Capability (Non-Firm ATC) is the remaining capacity available for additional non-firm transmission reservations after the committed uses for firm reservations have been subtracted from TTC. Existing non-firm transmission commitments are not included in the base case power flow model.

Non-Firm ATC = TTC – CBM – TRM – Existing Transmission Commitments (Firm)

Existing Transmission Commitments (Firm) include the following:

• Forecasted Native and Network Load attributable to a path in the Planning Horizon
• Forecasted Generation for delivery to Native Load in the Operating and Scheduling Horizons
• Confirmed Firm Transmission Reservations in all horizons including OATT and pre-Order 888 grandfathered contracts

8.0 ATC Coordination

Cleco coordinates base case model development with interconnecting neighbors for reliability assessments as well as calculation of ATC. In the calculation of ATC these models are the starting point for determining the hourly, daily, weekly, and monthly ATC values.

Cleco participates in a weekly conference calls to discuss and schedule transmission outages with neighboring transmission providers, which include, but are not limited to; Entergy, Louisiana Energy and Power Authority, Lafayette Utilities System, and AEP-West. Planned outages resulting from the conference call are one of the inputs into the ATC base models. Concurrently, on a weekly basis, each participating transmission provider is to provide load forecasts and basic generation dispatch for the scheduling and operating horizon by e-mail to each participating transmission provider. Generation dispatch, load forecasts, and interchange, if available, are all inputs for the ATC base case models to calculate ATC values.