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 generator 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.
What is Net Energy Metering (NEM)?
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.”
What is Green Power Connection?
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.
What is a net-capable meter?
A net-capable meter measures energy that flows in both directions between the customer-generator and the electric grid.
What technologies qualify for net energy metering?
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.
When do I start the interconnection application process?
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.
Do I have to interconnect my generator system to the grid?
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.
Does the net-capable meter measure total generation?
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.
How does the meter show when energy is fed or received?
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.
How can I contact Pepco regarding my solar request status?
Please contact us at
How do I start the application review process?
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.
How long does the interconnection application process take?
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.
How do I apply for interconnection?
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.
What if I have questions while completing the application?
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.
How do I approve my application?
Pepco will send you an email when your application is ready for your review and approval. You can begin your review and approval by clicking on the link in Pepco's email to you, or by entering the
How is my application fee determined?
Fees are established by the Maryland Public Service Commission, and vary according to the generator system’s nameplate capacity. Our online interconnection application system automatically calculates any required fees, based on jurisdiction, system size and application level. See our
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.
When do I pay my application fee?
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.
How do I pay my application fee?
The contractor pays the invoice by credit card or bank transfer either through Speedpay or by mailing in a check with the invoice.
Why could my interconnection application be delayed or denied?
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.
How is the size of the renewable system determined?
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.
What is the maximum size of a small generator system I can install?
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.
How can I see how much energy my system generates?
The installer of your renewable system can provide details on obtaining a generation monitoring device compatible with your system.
What standards does Pepco apply when approving inverters and system components for interconnection?
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.
Will my system generate power during a utility power outage?
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.
If I have a new construction project that will incorporate a small generator system, can I interconnect?
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.
I want to install a large generation facility and sell power directly to the grid. Do I work with the GPC team?
No. Another department within Pepco administers these large wholesale power purchase agreements. The GPC team will be glad to refer you to that department.
Are customers with third party energy suppliers eligible?
How is excess generation shown on my utility bill?
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.
Why does my bill still show charges if I had excess generation credits?
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.
What is a Solar Renewable Energy Credit (SREC)?
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 energy.gov.
What is the difference between monthly data and interval data?
Monthly data is the total monthly kilowatt hours (kWh) for which you are billed. Interval data is the hourly kWh reported by your AMI meter.
What is Green Button?
The Green Button initiative is an industry-led effort that responds to a White House call-to-action to provide utility customers with easy and secure access to their interval usage information. A Green Button interval data file can be read with an application that supports Green Button standard.
When I request historical data, what time frame of data will I receive?
You will receive up to 24 months of data.
On the contractor’s NEM Dashboard, why does Pending status only show the customer’s account number?
It is a security standard that customer name and address not be visible until authorization to download customer data has been approved.
Why isn’t my organization listed in the list of contractors found in my customer’s/client’s My Account?
Contractors who have created logins for Green Power Connection's online net energy metering application system are listed alphabetically in the Manage My Account section of My Account. If your organization is not listed, a contractor login has not been created and your organization will not appear in My Account. Contractors cannot be approved via My Account until a login has been created for Green Power Connection's online net energy metering application system. Contractors can
Why won’t my attachment load to the website?
Your attached file may not be the correct file type. Only Adobe Acrobat (PDF) documents and image files (JPG, PNG, GIF) are accepted.
When will authorization to download a customer’s data expire?
Access will expire one year from the signature date on the authorization form or one year from the day the customer authorizes your organization in My Account.
Request Customer Usage Online
How can I contact Pepco regarding my solar request status?
Please contact us at firstname.lastname@example.org.
Are there other factors to consider?
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.
Can I operate my generation facility prior to receiving the final written Authorization to Operate?
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:
Can you recommend a reputable installer?
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.