Distributed Generation Information

Distributed generation (DG) is any small scale generator that is located at or near the point of end use. DG may or may not be connected to the OEC distribution system. However, the most common types of DG in Oklahoma, wind and solar, are almost always interconnected to OEC’s system.

Yes. OEC allows, and encourages, interconnection of all types of DG, especially renewables like wind and solar.

The main difference is that DG is small customer-owned equipment that provides power to the customer in parallel with OEC’s system. A wind farm is a collection of very big wind generators connected to the transmission system. OEC does not own any transmission line and, therefore, is not directly involved in wind farms.

Unfortunately, OEC’s service territory is not where power suppliers are currently looking to place wind farms. OEC’s power supplier, Western Farmers Electric Cooperative (WFEC), owns several wind farms throughout Oklahoma. WFEC, as well as other power suppliers, carefully select wind farm locations based upon a number of factors and only then do they contact landowners in order to get the generators built.

The cost of a DG system depends on what percentage of your power requirements the DG system will supply. A DG system that will serve 100% your power requirements can be quite expensive. [2]

OEC does not closely monitor state and federal DG tax policy. However, the Database of State Incentives for Renewable & Efficiency (DSIRE) contains a wealth of information: www.dsireusa.org.

Yes. OEC buys power in 2 ways: Net Metering and Power Export. Net Metering is offered for systems 25 kW and smaller. Power Export is offered for systems 25 kW to 3 MW systems. Power Export is where OEC will install a separate meter and buy back power at the wholesale rate.

Net metering allows your electric meter to turn backwards (or count backwards with a digital meter) when your generator produces more energy than you are currently using. For example, let’s say your DG system produces 1000 kWh and your residence uses 1800 kWh in a given month. When OEC reads your meter, the usage will only show you used 800 kWh. Therefore, the bill you receive the following month will only be for 800 kWh. If your DG system produced your full usage of 1800 kWh, OEC will only bill you the customer charge, currently $11.90 per month for residential accounts. In short, Net Metering means OEC essentially buys back power from you at the retail rate as long as you don’t produce more power than you use in a month.

If you produce more than you use in a month, the excess power comes back to OEC free of charge. OEC does not credit your account or write a check for the excess generation. For example, let’s say your DG system produces 1000 kWh and your residence uses 800 kWh in a given month. When OEC reads your meter, it will show a negative reading. OEC will zero out the reading and you will only be billed the customer charge, currently $11.90 per month for residential accounts. The excess 200 kWh are provided back to OEC free of charge.

Yes. You have the option of signing up for the yearly Net Metering Reconcile instead of the monthly. It works the same as the monthly, except OEC looks at the usage at the end of the year and any excess power produced in the year will come back to OEC free of charge. There is an additional customer charge of $5 per month to be on the yearly reconcile option.

OEC allows interconnection for DG systems up to 3mW but Net Metering is limited to systems 25 kW or less. For systems over 25 kW, the Co-op will install separate facilities to the generator and the power will be delivered directly to our distribution system. The output is metered and OEC pays the owner of the generator for the power output at the wholesale or avoided cost rate (approximately $0.05 per kWh today). This is called Power Export.

It is important to note that the larger the DG system, the more of an impact it will have on OEC’s distribution system. Consequently, OEC has more requirements for interconnection of DG systems over 25 kW. For more information, please contact OEC’s Engineering Department.

Since OEC’s distribution system and your DG system will operate as parallel power sources, the DG system must be the same voltage level as your service. For residential services, this is almost always single-phase 120/240V 60 Hz.

If OEC loses power, the DG system should shut down. If the DG system remained in service, it would actually back-feed and energize OEC’s line. (This would be a very dangerous situation where OEC crews would expect the line to be dead and it is actually energized.)

For DG systems that are Net Metered, all equipment is located on the member’s side of the meter; therefore, OEC is not directly involved in the installation. OEC does have the following requirements that must be met before it allows Net Metering to occur:

1. Member must submit an application and pay a $25 application fee.
2. Member must provide proof of homeowner’s insurance
3. Certification from manufacturer or engineering firm that equipment meets IEEE 1547 and other applicable codes and standards
4. Member must use an Oklahoma licensed electrician/electrical contractor.
5. Installation of a separate, lockable, OEC accessible safety disconnect.
6. Contract between OEC and member must be executed.
7. OEC inspection of the final installation.

OEC requires the DG system to comply with all applicable laws, ordinances rules and regulations of any federal, county, state, and/or local authority, including, but not limited to: the most recent IEEE Standard 1547 Guide for Distributed Generation Interconnection, applicable ANSI standards, including ANSI C84.1 Range A, relating to installation, safety, easements, code restrictions, operation and other matters.

IEEE 1547 is an industry wide specification that provides requirements for safe interconnection to a utility’s power distribution system. The DG manufacturer should have a certification, usually from Underwriters Laboratory (UL), stating its equipment meets IEEE 1547 and other applicable codes and standards.

As a rural electric cooperative, OEC is your partner in providing you with safe, reliable electric service. OEC has requirements in place to address issues of safety, grid integrity and cost fairness. Those requirements ensure that the cooperative can (1) protect the safety of customers and cooperative employees; (2) maintain the integrity of the grid; and (3) establish mechanisms to ensure each customer shares appropriately in the costs.

The first step is to contact a manufacturer and/or sales representative of DG systems to determine what type of system you want, how much it will cost, and the expected payback of the system. Once you find a system you are satisfied with, simply fill out the application below and send it to OEC for review.