Virginia - Dominion Energy 20 kW AC System Size Limit

*June 2026 Update: HB1255 increases the limit to 20 kW AC before demand/standby charges can apply. Palmetto advocated on behalf of this bill in the Virginia legislature. The bill was recently signed into law. A bill's effective date does not equal the date utilities will be ready to implement across their tariffs and billing systems. There are still internal timelines for utilities and regulatory processes that need to take place to implement legislative changes.

HB 1255 passed in the Virginia legislature requiring Dominion Virginia Power to increase the threshold from 15 to 20 kW AC before they may charge Standby fees, also known as demand charges, on residential solar customers.

For a large energy consumer, demand usage is on average 6-8 kW per month totaling $36-$54 in estimated standby charges in addition to the existing $8 Basic Customer Charge. To avoid the Standby Charges outlined in Schedule 1 and maximize customer savings, Palmetto LightReach is restricting systems to 20 kW AC.

Dominion is vague on the exact calculation of AC kW. Their interconnection portal's (i) information tooltip states, "The Rated Capacity in kilowatts AC should reflect the actual expected maximum AC system output after all system de-rates have been applied."

The most accurate input is the total inverter AC nameplate rating. However, you may be able to justify adding a derate using the CEC Weighted Efficiency of the inverter, which is often 98-99%. For example, two Tesla inverters, model 1538000-xx-y [240V], are rated 7.6 kW AC each with a 98% CEC weighted efficiency 2 * 7.6 kW = 15.2 kW * 98% = 14.9 kW AC. Efficiency ratings are on the inverter's datasheet and the CEC equipment list.

Ultimately, Palmetto LightReach is neutral on the formula you use for AC kW as long as it is 20.0 or below in Dominion's Interconnection Application, and is approved by Dominion. If your inverter nameplate rating is above 20 kW AC, LightReach will require proof that you submitted an AC kW size of 20.0 or smaller.

Click Here - Understanding Schedule 1

Schedule 1 details three Standby Charges for systems over 20 kW AC

Distribution Standby Charge of $3.42 per kW of demand
Transmission Standby Charge of $1.32 per kW of demand
Rider T1 Transmission Charge of $1.605 per kW of demand

Total $6.35 per kW per month as of December 2025

If the customer receives service under Section XXV – Net Metering and their renewable generator’s AC capacity exceeds 20 kW, they will be billed a Distribution Standby Charge of $3.42 per kW of demand. This charge is reduced by the amount in II.A.2., but cannot be less than zero.

Paragraph II.B. does not apply to Customers receiving Electricity Supply Service from a Competitive Service Provider, except for the non-by passable charges listed in the Exhibit of Applicable Riders.

Total $6.35 per kW per month as of December 2025

Dominion measures demand based on the highest average usage in ANY 30-minute interval during the billing period. This means an EV owner charging in the middle of the night could still be hit with peak usage measured overnight.

Click Here - Interconnection Portal

A.	Does Dominion allow solar systems larger than 20 kW AC? If so, what is the drawback?	Yes, Dominion allows residential systems up to 25 kW AC. However, systems above 20 kW incur monthly Standby/Demand Charges of more than $6 per kW, significantly increasing ongoing costs.
B.	What is the most accurate AC kW input when submitting the interconnection application?	The total inverter AC nameplate rating is the strongest and most defensible measurement of system AC capacity.
C.	How does Dominion measure monthly peak demand for Standby/Demand Charges?	Dominion measures demand based on the highest average usage in any 30-minute interval during the billing cycle. This means a customer could trigger a high demand charge even from overnight EV charging.
D.	How does Schedule 1 affect customers interconnected under Section XXV - Net Metering?	If the customer’s renewable generator exceeds 20 kW AC, Dominion charges three different standby charges totaling over $6 pre kw of monthly demand usage
E.	Why is Palmetto LightReach restricting residential solar systems to 20 kW AC?	Systems above 20 kW AC trigger Dominion’s monthly Standby/Demand Charge—typically $36–$54 per month for large energy consumers—on top of the $8 Basic Customer Charge. By limiting systems to 20 kW AC, LightReach helps customers avoid these charges and maximize savings.