Demand Opportunity Service

Under demand transmission service (DTS), exceeding the contract capacity could affect the customer's ratchet level (see current ISO tariff for more information) for up to two years. Using DOS, a pre-qualified customer can utilize surplus transmission capacity at a reduced cost.

All of the users of the Alberta Interconnected Electrical System (AIES) benefit when DOS is properly used. The revenues from DOS are applied towards lowering overall transmission costs. The user of DOS also benefits since the use of DOS does not increase the billing capacity.

A DTS customer can exceed its contract capacity without setting a new billing capacity. However, a take-or-pay component to DOS goes into effect for each DOS transaction, as well as a transaction fee. The price depends on which of the three rate options is chosen: DOS term, DOS 1 hour, and DOS 7 minute (see current ISO tariff for more information).

Any DTS customer of the AESO is eligible if the customer demonstrates to the AESO's satisfaction that it meets the commercial eligibility criteria (see the AESO DOS business practices information document). Eligibility does not guarantee that DOS will be available.

Contact your retailer or whoever provides your power bill. They can help determine whether DOS or a similar service is available to you. You may also need to contact your distribution facility owner (DFO) if the DFO is not your retailer. You may also contact the AESO to discuss the matter with an account manager at info@aeso.ca However, the AESO will only enter into DOS contracts with its own customers.

DOS is available to eligible customers when it has been established beforehand that sufficient transmission capability is available such that service to other customers will not be impaired.

There is a two-stage process for obtaining the service. An eligible customer can be pre-qualified within 45 days. After prequalification, they can then obtain service with as little as one hour's notice, provided that capacity is available.

When the AESO receives a Stage 1 application for DOS, a study will be undertaken to ensure sufficient capacity exists for DOS without negatively affecting the operation of the power system. This is usually in the form of a power flow study using parameters that conform to the approved policies of the Western Electricity Coordinating Council.

New applications for DOS are to include sufficient information so that the AESO can assess whether the customer's circumstances meet the commercial eligibility criteria (see the AESO DOS Business Practices Information Document). In addition, the terms and conditions of the current ISO tariff allow the AESO to audit a DOS customer's eligibility from time to time.

A two-stage application process is described in the AESO DOS Business Practices Information Document. Application forms for Stage 1 and Stage 2 are provided by the AESO, along with instructions for applying.

DOS will be curtailed, under certain abnormal system conditions. The System Controller will issue directives to curtail DOS loads as required to prevent or alleviate abnormal conditions, such as but not limited to:

• Low voltage levels
• Transmission facility overloads
• Equipment damage
• Abnormal frequency deviation
• Tripping of transmission facilities that could result in cascading outages
• A deficiency in ancillary services
• Energy supplies shortfall

A DOS user that does not comply with a directive to curtail DOS load will be deemed to have demonstrated their ineligibility for DOS. In such cases, the AESO, in its sole discretion, may revoke the pre-qualification under which the DOS transaction was approved.