Distributed Generation

Distributed generation (DG) is defined as generation that is connected to a utility’s distribution system.  It generally refers to small scale generation that is located near the point of end use.  Common DG system energy sources are solar, wind, landfill gas, diesel fueled engines, and natural gas fueled micro-turbines.

To qualify as a DG system, the interconnection voltage must be less than or equal to 60 kV or 60 kilovolts.  The interconnection requirements at United for DG systems differ based on their peak kW size and are broken down into two categories:

1. Below 50kW
2. 50kW – 10,000kW

Customers inquiring about distributed generation generally fall into four basic categories:

• Small power production facilities (solar, wind, waste or geothermal) which are usually classified as "qualifying facilities,"
• Generation for self-service of customer's own load through parallel operation with the utility and peak shaving of demand,
• Generation that is for exporting (landfill gas, large wind farms, etc.),
• Backup/Standby power which cannot be synchronized with the utility upon restoration from utility outages (closed transition).

How Does a Member Apply to Install and Operate DG on the United System?

If you would like to install and operate DG on the United system, we recommend you review the following:

• Review United's DG Packet before purchasing a system. This packet covers all the requirements for DG system interconnection at United and includes an application form.
• Review the costs of DG equipment. Besides the initial cost, items such as annual operation costs, maintenance costs, insurance costs, and available incentives (ie tax credits for renewable systems) should be considered. When all costs and applicable incentives are taken into consideration, most DG installations will not be competitive with United rates. A good starting place for incentive information is the DSIRE website. Generic DG system pricing information can be found below in the section "What Does DG Cost".
• Review the Capital Cost Recover Analysis handout published by the Cooperative Research Network. This may assist you in determining the payback of your investment in DG.
• If you are interested in wind generation, review the document Ten Steps to a Small Wind System document published by the Cooperative Research Network.
• Research the available DG energy sources that interest you and then locate local reputable vendors that sell, install, and maintain the DG source you choose. Make sure that prior to any purchase, you have applied with United to interconnect and have met all requirements.
• Upon receipt of the application, application fee, and other required documentation, United will review for approval. If application is denied, United will provide information as to the requirements for approval. Along with the approval, United will provide a cost of interconnection for further studies, if necessary, and for physical interconnection.
• Once approval is obtained by United, the appropriate Interconnection Agreement shall be executed and any integration costs due to United shall be paid prior to implementation.
• Prior to physical interconnection of DG, a United representative will inspect for proper operation and installation.

Distributed Generation Interconnection and Parallel Operation Requirements Contact:

More information may be found through the Internet and also through the Public Utility Commission of Texas (PUCT) web site, listed below:

The Public Utility Commission of Texas

While the PUCT rules are intended only for Investor-Owned utilities, United's Tariff and DG Guidelines follow very closely with the related Substantive Rules. However, there are a few minor differences. Therefore, all proposed DG installations will be measured against the United Tariff and DG Guidelines and not the PUCT rules and guidelines.

What Does DG Cost ?

Wind Power – 10 kW System:
Approximate cost (installed) – $28,000 to $40,000. Actual cost depends on "tower height & style, distance to interconnect, difficulty of excavation, etc."

CLICK HERE TO SEE TEXAS WIND RESOURCE MAP

Solar Power – 2kW System:
Approximate cost (installed) – $8 per peak watt.  A 2 KW system would cost approximately $16,000.  Thus, the cost to generate electricity through solar power is approximately 2 to 3.7 times more than the current rate charged by the average electric utility.

Propane or Natural Gas Generator – 12 KW Small power system:
Approximate cost (system w/transfer switch) – $3529 MSRP.  Generac is selling its Guardian system at Home Depot.  They are marketed as emergency power systems for power outages.  The main marketing push is for backup, not as an alternative power source.

Does United Provide DG Grants?

Yes. Residential members who install approved renewable DG systems at the residence in which they receive electric service from United are eligible for one grant per unit at a maximum of two grants per member. The DG installation must be completely installed and operational in 2010, meet United’s DG specifications and inspected by a United representative prior to receiving a grant. Grants will be capped at $500 for wind applications and $1,000 for solar applications. The interconnected DG capacity must exceed 500 watts. Applications for an EnergySmarts DG Grants can be obtained by clicking here.

Vendor Information

If you are interested in viewing technical information that covers how photovoltaic cells work, view this link sponsored by United Energy's Insight newsletter.

United Distributed Generation Guidelines
Distributed Generation Procedures and Guidelines Manual for Members

Technical Overview
A Quick Overview of Technical Requirements of DG Installations

The Interconnection Agreement
(Must be signed by both the member and United prior to interconnection of DG - See document below.)
50 KW and Less: Short Form

50KW to 10 MW: Long Form
Attachment to Long Form

Viewing of United DG documentation, requires that Adobe Acrobat be installed on your system. To get your free copy of Adobe Acrobat Reader, click the link below.

Disclaimer: This information is not intended to be fully inclusive of all current, future or pending rules and regulations but is meant to provide general information pertaining to this subject.

• Energy Smarts
• Touchstone Energy Savers
• Our Energy, Our Future
• HomeEnergyCalculator
• Energy Library