We support renewable energy and partner with our customers to ensure safe and reliable interconnection of renewable energy into the electric grid.
We understand that you may have questions as you consider applying for small genera tor interconnections. We have compiled a list of a few frequently asked questions that may be helpful. If you have any further questions, contact our Green Power Connection™ team. You can also download a PDF version of the FAQs.
Customers who generate their own electricity with renewable energy sources can interconnect with the electric grid. A special net-capable meter measures the energy a customer uses off the grid and the excess generation the renewable system provides onto the grid, and calculates the difference or “net.”
Green Power Connection™ (GPC) is our process for facilitating small generator and NEM interconnection requests. Our dedicated team of consultants and account coordinators manage the customer’s experience – from processing applications to resolving issues – for residential and smaller commercial interconnection projects.
A net-capable meter measures energy that flows in both directions between the customer-generator and the electric grid.
In Maryland, small generator technologies that qualify for interconnection with our system include solar (photovoltaic or “PV”), rooftop solar, wind, biomass, fuel cells, qualifying closed circuit hydro-electric, and micro-combined heat and power (up to 30 kW). CHP or cogeneration systems can be interconnected but not net-metered. See our GPC website for more details.
Prior to installing and operating a generator system, you must apply and receive the utility’s written approval. Refer to the Net Energy Metering and Small Generator Interconnection Application Checklist for Maryland on our website.
Most customers install renewable generator systems to reduce their use of utility-supplied electricity. For these behind-the-meter systems to be able to draw energy off the grid when needed, the system must be interconnected to a utility-supplied, net-capable meter. You must apply for this interconnection.
No. Generation occurs on the customer side of the meter. Any energy generated is first fed inside the premise for use by the appliances, electronics, lights, etc. The meter measures only the excess energy that is fed onto the grid.
A net energy meter has dashes under the display that move in the direction of the energy flow. When the dashes move from left to right, energy is flowing from the grid to the customer’s premise. When the dashes move from right to left, energy is flowing from the customer to the grid.
Prior to installing and operating a generating system, you must apply and receive the utility’s approval. Review the Net Energy Metering and Small Generator Interconnection Application Checklist.
From the day you or your contractor first submits a complete application to the day Pepco issues your final Authorization to Operate, including the time it takes your contractor to install the solar generating system, the interconnection application process in Maryland takes approximately 77 business days. Click here to download a printable PDF of the application steps and timeline.
Review the detailed interconnection application process. Generally, but not always, installation contractors complete and submit the application on behalf of their clients. When you’re ready to begin, you can jump right to the online application portal.
If you have questions about your application, you can ask them at any time directly in the portal by clicking on the question mark icon in the left navigation.
Pepco will send you an email when your application is ready for your review and approval. This handy Customer Approval of NEM Application guide describes the steps. You can begin your review and approval by clicking on the link in Pepco’s email to you, or by entering the portal.
Fees are established by the Maryland Public Service Commission, and vary according to the generator system’s nameplate capacity. Review the application fees in Maryland. Our online interconnection application system automatically calculates any required fees, based on jurisdiction, system size and application level. See our table of the fees in Maryland.
After your interconnection application has been entered into the online portal, the system automatically determines if an application fee is required and calculates the required fee, based on the jurisdiction, system size, and application level. The online system automatically creates and emails an invoice to the contractor or customer.
The contractor pays the invoice by credit card or bank transfer either through Speedpay or by mailing in a check with the invoice.
Applications are delayed if required information is incomplete or missing, or documents are unsigned. In some regions, our utility may not have an open circuit, making net metering interconnection unavailable. For more details, contact our GPC team.
Add up the total energy consumption (in kWh) as shown on your last 12 Pepco bills. Divide that sum by 1,200. Multiply that number by 2. The result is the maximum inverter nameplate rating you can install. We use the formula (12-month kWh usage / 1,200) x 2 = maximum kW inverter rating, to comply with state rules, meet all or part of your electrical needs, and follow our regulatory requirements.
Customers who install a renewable generating system and intend to net meter can offset all or part of the energy they use from Pepco. In Maryland, the system capacity can be up to 200% of your 12-month historical energy consumption.
The installer of your renewable system can provide details on obtaining a generation monitoring device compatible with your system.
Institute of Electrical and Electronics Engineers (IEEE) Standard 1547 provides the criteria and requirements for interconnecting small generator equipment to the electric grid. Underwriters Laboratory (UL) Standard 1741 sets the requirements for the inverters and charge controllers used in photovoltaic (PV) power systems. In most cases, inverters that comply with IEEE 1547 and UL 1741 will be acceptable for interconnection. The equipment on the Acceptable Inverters List has been accepted for use in other small generator interconnection project requests.
For safety reasons, the system’s inverter tied to the grid will shut down automatically with an outage. The inverter converts direct current (DC) power from the renewable generator into alternating current (AC) power used at your premise. Only systems designed to operate independently during an outage, will be able to operate. A system designed in this fashion must be clearly identified on the interconnection application and agreement. A single line diagram showing the equipment and controls necessary to operate safely when isolated must accompany the application.
Yes. For a facility that is under construction and requires electricity, you will need to set up electric service prior to installing the generation system. Without any historical energy consumption data, the interconnection application will require a proposed energy usage calculator. For more details, visit our GPC website.
No. Another department within Pepco administers these large wholesale power purchase agreements. The GPC team will be glad to refer you to that department.
Customers in Maryland see negative energy consumption in the Excess Generation Summary section of the bill, showing the excess generation carryover history. The excess is carried over month to month until used or until the customer’s anniversary pay out.
Customer service charges apply to all bills, regardless of energy charges or excess generation credits. If the service charges are more than the generation credits, your account will show a balance due. For more details, visit our GPC website.
An SREC is equivalent to one megawatt-hour (MWh) of electricity derived
from an eligible solar resource. Electricity suppliers must purchase SRECs in
order to meet compliance obligations under the law. For more information, visit
Yes. Electric generation from solar sources can fluctuate as a result of several factors — clouds, darkness, and dirty panels all limit generation. Your renewable system may not generate enough energy to meet all of your electrical needs. Prior to installation, understand how your system will operate under varying conditions, and how these conditions can impact your utility bill.
No. The Maryland Public Service Commission prohibits the interconnection of generation facilities to the electric grid without Pepco’s written approval. Operating an unauthorized small generator system tied to Pepco’s grid can:
No. We recommend you research and consult with an installer or contractor by using publicly available resources. If you decide to work with a contractor, it is your responsibility to ensure they use the appropriate forms, fees, and documentation throughout the interconnection process.