Ancillary Services: What They Mean for Your Business Electric Bill

A restaurant owner in Columbus gets her bill and spots a line item she has never noticed before: "ancillary services charge." It is not the delivery charge. It is not the supply rate. It sits there, unexplained, adding a few dollars she assumed were just rounding.

That line item has a precise meaning. An ancillary service is any grid-support function that keeps alternating-current electricity balanced, reliable, and deliverable at the correct frequency and voltage, moment to moment, 24 hours a day. Regional transmission organizations (RTOs) such as ERCOT in Texas, PJM across Ohio, Pennsylvania, New Jersey, and DC, and ISO-New England in Massachusetts coordinate these services in real time.

The grid must always match supply to demand exactly. A large factory suddenly coming online, a wind farm going quiet, or a transmission line tripping can throw that balance off in seconds. Ancillary services are the tools grid operators use to correct imbalances before customers ever notice a flicker. They include reserves that can ramp quickly, voltage-support resources, and systems that catch frequency deviations before they cascade. Every kilowatt-hour delivered to a business depends on them working in the background.

RTOs define and procure several distinct ancillary service products. The most common ones businesses will encounter, directly or indirectly, include the following.

Regulation (Frequency Regulation): Automated resources that continuously adjust output up or down every few seconds to keep grid frequency at 60 Hz. Fast and precise, these are among the more expensive ancillary services to procure.

Spinning Reserves (Synchronized Reserves): Generators that are already running and synchronized to the grid, capable of increasing output within ten minutes. Because the turbines are spinning, they can respond almost instantly if a large generator trips offline.

Non-Spinning Reserves (Supplemental Reserves): Capacity that can come online within ten to thirty minutes but is not currently synchronized. This is typically cheaper to hold than spinning reserve.

Reactive Power and Voltage Support: Maintaining proper voltage across transmission lines. Without it, equipment at commercial facilities can suffer damage and efficiency drops.

Black Start Capability: The ability of select generators to restart the grid after a total outage without drawing power from the grid itself. A small cost spread across all customers funds this insurance policy.

Each of these is procured through competitive markets run by the RTO. Suppliers pass those procurement costs through to customers in one form or another.

This is where things get practical for a business owner. Ancillary service costs reach commercial customers through two main paths.

Path 1: Embedded in the supplier's rate. Many retail electricity suppliers in Texas (served by ERCOT) and PJM-region states fold ancillary service procurement costs into the cents-per-kilowatt-hour rate they quote. A fixed-rate contract may absorb these costs entirely, meaning the supplier assumes the risk if ancillary service prices spike. A variable or index-based contract may pass them through monthly as the actual market costs fluctuate. Always ask a supplier which approach a quoted product uses.

Path 2: Explicit line items. Some suppliers, and most utility default-service tariffs, break ancillary services out as a separate charge. In Texas, the Public Utility Commission of Texas (PUCT) requires that bills show certain cost components, so ERCOT ancillary charges may appear distinctly. In PJM states overseen by commissions like the PUCO in Ohio, PA PUC in Pennsylvania, NJBPU in New Jersey, and DC PSC in Washington DC, default service tariffs (called SSO in Ohio, BGS in New Jersey, Basic Service in Pennsylvania, Basic Service in Massachusetts under the MA DPU, and Default Service in DC) often itemize these costs separately.

When you compare a supplier's all-in rate with the utility's default service rate, make sure you are comparing the same set of cost components. A supplier rate that looks higher per kWh may actually include ancillary services that the default rate shows on a separate line.

Commercial customers above their utility's billing threshold pay demand charges: a monthly fee based on the highest 15-minute average power draw recorded during the billing period, stated in dollars per kilowatt. Demand charges fund the delivery infrastructure required to serve peak loads. They are a delivery-side cost, not a supply-side ancillary service cost, but the two are related in an important way.

A business with high, spiky demand places greater stress on the grid during peak periods, which increases the amount of spinning and non-spinning reserve the RTO must procure system-wide. Suppliers sometimes price ancillary service pass-through costs in ways that reflect a customer's load profile. A manufacturer with a flat, predictable load may receive more favorable ancillary-service pass-through terms than a facility whose demand swings sharply.

If your operation has flexibility, the ability to shift large loads off peak, use on-site generation during demand peaks, or enroll in demand-response programs, you may reduce both your demand charge and your exposure to high ancillary service costs simultaneously. Ask your supplier whether demand-response participation offsets any ancillary-service charges in your contract.

The mechanics are similar across deregulated markets, but the regulatory frameworks differ.

Texas (ERCOT, regulated by PUCT): ERCOT operates its own ancillary service markets independently of the Eastern Interconnection. Regulation service, responsive reserve, and non-spinning reserve are distinct products. Because ERCOT is an energy-only market with no capacity market, ancillary service prices can be particularly volatile during extreme weather or tight supply conditions.

Ohio (PJM, regulated by PUCO): Ohio businesses shopping away from SSO (Standard Service Offer) through a competitive supplier will see ancillary costs either embedded or passed through, depending on the contract structure. PJM's ancillary service markets are among the deepest and most liquid in North America.

Pennsylvania (PJM, regulated by PA PUC): The Basic Service default option carries ancillary costs in its tariff. Competitive suppliers serving Pennsylvania businesses operate under the same PJM ancillary framework.

New Jersey (PJM, regulated by NJBPU): BGS (Basic Generation Service) procurement includes ancillary service costs. Competitive contracts for New Jersey businesses vary widely in how they present and price these components.

Massachusetts (ISO-NE, regulated by MA DPU): ISO-New England maintains its own ancillary service market. Basic Service customers see these costs in their utility tariff; competitive supply customers see them in their contract terms.

Washington DC (PJM, regulated by DC PSC): DC sits within PJM and follows the same ancillary service market structure as the surrounding PJM region. Default Service customers in DC have ancillary costs included in the regulated tariff rate.

For current business electricity rates across all six markets, see the ElectricRates.org business electricity comparison tool.

When ancillary service prices spike, during a polar vortex, a heat dome, or any event that strains reserve margins, the cost of procuring those services in real time can multiply quickly. Who absorbs that spike depends entirely on your contract structure.

Under a fully fixed contract, the supplier quotes an all-in rate and accepts the ancillary service price risk for the contract term. If ancillary costs soar in January, your rate does not move. Suppliers price this protection into the fixed rate, so you pay a modest premium for certainty.

Under an index or pass-through contract, ancillary service costs flow to you at actual market prices each month. In a stable month this can result in lower costs than a fixed rate. In a volatile month it can result in significantly higher costs. Pass-through contracts require active monitoring and work best for businesses with in-house energy management resources.

A block-and-index or structured product can hedge a portion of ancillary exposure while leaving some upside on the table. These products are increasingly available to mid-sized commercial customers in PJM and ERCOT markets.

Before signing, ask every supplier: which ancillary service components are fixed, which float, and how they are calculated. The answer separates a competitive quote from a contract surprise.

Most small business owners do not negotiate directly with RTOs. They negotiate with retail suppliers. But understanding ancillary services gives you better questions to ask and a clearer framework for comparing offers.

Start with your 12-month billing history. Identify your average monthly usage, your peak demand, and whether your load is flat or spiky. Businesses with flat loads are easier for suppliers to hedge and may receive better pricing on ancillary-service components.

When you receive quotes, ask suppliers to break down the components: energy, capacity, transmission, ancillary services, and supplier margin. A higher headline rate with ancillary services capped may be worth more than a lower headline rate with uncapped pass-throughs.

Check your state's default service rate for context. In states regulated by the PUCO, PA PUC, NJBPU, MA DPU, or DC PSC, the utility is required to publish default service pricing. In Texas, the PUCT publishes the Price to Compare for residential customers, though commercial pricing works differently through direct negotiation with ERCOT-certified retail providers.

Finally, compare live supplier offers side by side. The business electricity section at ElectricRates.org displays current offers across all six deregulated markets so you can see how suppliers are pricing ancillary-service components as of July 2026, without having to call each one individually.

Ancillary services are not a fee invented by your utility or your supplier. They are real grid-stability functions procured in competitive wholesale markets, and their costs flow to every business that consumes electricity in a deregulated state. Understanding what ancillary services are, how they appear on your bill, and who bears the risk of price volatility in your current contract is one of the most underrated ways to make better energy decisions.

The next time a line item appears on your bill that is not labeled energy or delivery, it is worth a few minutes to find out exactly what it represents. That knowledge, combined with a side-by-side comparison of supplier offers, puts a business owner in a genuinely stronger position than one who accepts the default.