Is-3 Electric Interruptible Service
MGE's Is-3 Interruptible Service Rider gives customers a bill credit every month in return for agreeing to be ready to interrupt service. The Is-3 service is available to Cg-2 and Cg-6 customers who can interrupt at least 500 KW of demand when contacted by MGE.
The Is-3 service also includes a buy-through provision at times of higher market prices, where customers pay a higher, market-based premium for the power they use in excess of their agreement.
The Is-3 monthly credit is applied to the lowest of the following:
- Customer Maximum Demand,if the customer has backup generation with parallel switchgear.
- Maximum Monthly On-Peak Demand,if they don't have parallel switchgear.
- A Contract Demand amount designated in their service agreement.
Interruptible demand options
A customer can choose their contracted interruptible demand based on either of the following options:
- Firm: The customer nominates a firm demand level (kW) that they can use during an interruption. The customers must reduce their demand down to that firm level when an interruption is called.
- Interruptible: The customer nominates the demand level (kW) that will be interrupted. To use this option, the customer must have on-site generation to serve the load they have nominated for interruption.
See Is-3 tariff sheet E-45 for more details.
Mandatory test interruptions
MGE will conduct one mandatory test interruption per year. If the customer doesn't meet the terms of their interruptible service agreement, MGE will reduce their credit for the amount of demand used in excess of their agreement terms. This credit reduction will continue until the customer successfully passes an interruption test conducted by MGE.
If the customer doesn't meet the terms of their interruptible service agreement during a called system event, MGE will reduce their credit for the amount of demand used in excess of their agreement. The credit reduction will continue until the customer successfully passes an interruption test conducted by MGE.
Penalty for unauthorized use of electricity
If MGE calls another interruption within 12 months from the date of the customer's initial failure to meet the terms of their service agreement either during a test or system event, and the customer still cannot meet the service terms, the customer will be billed $25/kW for the demand used in excess of the terms of their agreement.
When prices in the market where MGE buys energy reach $150/MW for at least two consecutive hours in a day, MGE will declare a buy-through. Buy-through prices are hourly prices that are higher than the customer's normal rates. MGE will send electronic notification at least four hours in advance announcing what the buy-through prices will be and the hours they will be in effect.
Customer actions during buy-through
Customers can continue normal operations during a buy-through. However, during the buy-through if customers use electricity beyond the level indicated in their service agreement, they will be charged the designated buy-through prices for that excess use. The customer may reduce their use to minimize the impact of the higher prices.
Interruption and buy-through duration and frequency
MGE can call up to 300 total hours of interruptions and buy-throughs. Of that total, there will be no more than 150 hours of interruptions. There are no limits to frequency.
Length of contract
Customers can try out the Is-3 service for the remainder of the calendar year in which they sign the contract. Customers need to tell MGE if they wish to continue or not by December 1. If they do not, MGE will assume they are continuing the Is-3 service. If they choose to continue enrollment beyond December 31, they are required to stay enrolled for a minimum of three years. Customers must give MGE three years' prior written notice to end participation.
Three year opt-out notice required
MGE is required to have enough electricity capacity available to serve the firm load of all of our customers, plus a reserve capacity. If an interruptible customer chooses to leave the interruptible service and become a firm customer, MGE is required to have capacity available on-line to serve this additional load as firm, plus the additional increment of reserve capacity.
Interruptions reduce electric load on the system and are most likely needed during peak use periods. MGE requires customers to give us a three-year notice to end an interruptible contract to allow enough time to arrange for or build a peak generation facility to serve the added firm load. A peak generation facility requires about three years from start to finish to begin generating power.