Marginal Prices and Your Business Electric Bill

Picture a humid Tuesday afternoon in August. The office AC is running hard, the walk-in cooler at the deli next door is cycling on, and every rooftop HVAC unit on the block is pulling current. Somewhere in a grid control room, a dispatcher adds one more generator to the mix, a peaker plant that burns fuel at a steep cost. That generator's cost sets the price every seller in the market receives for every megawatt-hour sold that hour.

That is marginal pricing in plain terms. The marginal price is the cost of producing the last unit of electricity needed to keep supply and demand in balance at any given moment. Because grid operators settle wholesale transactions at that single clearing price, one expensive generator can raise the rate everyone pays, even generators that were already running cheaply. For business owners, the relevance is direct: the retail rate a competitive supplier charges you is built, in part, on top of these constantly shifting wholesale costs.

Each of the six deregulated markets ElectricRates.org covers sits inside a regional transmission organization. Texas businesses are served by ERCOT. Ohio, Pennsylvania, New Jersey, and Washington DC are served by PJM Interconnection. Massachusetts falls under ISO New England.

These grid operators run day-ahead and real-time energy markets. Generators submit offers, operators stack them from cheapest to most expensive, and the system accepts offers until supply meets demand. The offer price of the last generator accepted, the marginal generator, becomes the locational marginal price, or LMP, for that hour and that location on the grid.

LMPs can vary by node depending on transmission congestion, so a business in Pittsburgh may face a different marginal price signal than one in Philadelphia, even on the same afternoon. Competitive suppliers buy power in these wholesale markets, manage their own risk, and then price retail contracts for businesses. The spread between their wholesale procurement cost and your contract rate is how they cover overhead and earn a margin.

Most small business owners focus on the per-kilowatt-hour rate on the supply line of their bill. That number is real, but it is a summary of something more complicated underneath.

First, if you are on a variable-rate or indexed contract, your monthly supply charge can move almost directly with wholesale marginal prices. A heat wave or a cold snap that drives peak demand can push LMPs sharply higher for days, and those spikes feed into your bill with little delay.

Second, even fixed-rate contracts are priced with an eye on forward marginal price curves. Suppliers hedge by buying power in advance, and the price they lock in for you reflects what the market expects marginal prices to do over your contract term. Signing a long-term fixed contract when forward prices are elevated locks in that exposure. Signing when forward prices are relatively low hedges against future spikes.

Third, if your facility crosses the demand-charge threshold for your local utility, the hour when marginal prices are highest is often the same hour when your demand charge is set. In PJM-served states like Ohio, Pennsylvania, New Jersey, and DC, your utility calculates the peak demand on your account during specific measurement windows. A single high-consumption interval, coinciding with a grid peak driven by marginal pricing, can lift your demand charge for the entire billing month.

If your business has never shopped for electricity, you are buying supply from whatever default service your utility provides. Each state structures that default differently, and none of them insulates you from underlying marginal price dynamics.

Texas (PUCT): Texas has no default service in the traditional sense for most commercial customers. If you have not chosen a retail electric provider, you land on a provider of last resort at a rate set by the PUCT. ERCOT's real-time marginal prices, which famously spiked during Winter Storm Uri, flow through directly to variable-rate customers.

Ohio (PUCO): Utilities like AEP Ohio and Ohio Edison offer Standard Service Offer (SSO) rates. SSO pricing is set through competitive procurement, meaning it already reflects wholesale marginal price expectations at the time of auction.

Pennsylvania (PA PUC): Pennsylvania utilities offer a Price to Compare, the default supply rate against which shopper savings are measured. Utilities procure this supply through auctions, again anchored to wholesale marginal price forecasts.

Massachusetts (MA DPU): Utilities such as Eversource and National Grid offer Basic Service, a default supply rate that adjusts periodically based on utility procurement. The MA DPU oversees those rates.

New Jersey (NJBPU): New Jersey utilities provide Basic Generation Service (BGS) through competitive auctions supervised by the NJBPU. BGS prices embed forward wholesale cost expectations.

Washington DC (DC PSC): Pepco and Washington Gas Light serve DC commercial customers under Standard Offer Service (SOS) rates regulated by the DC PSC. As with other states, the supply portion reflects wholesale procurement costs tied to marginal price curves.

Demand charges appear on commercial bills above each utility's demand threshold, typically expressed as a dollar amount per kilowatt of peak demand measured in a 15-minute interval. The threshold and rate vary by utility and tariff class; your utility's tariff schedule, filed with the relevant state commission, is the authoritative source.

The connection to marginal prices is not accidental. Grid operators set demand charges partly to reflect the cost of building and maintaining capacity for peak periods, which are precisely the moments when marginal prices spike. A business that consistently peaks during high-price hours pays twice: once in the supply cost tied to elevated LMPs, and once in the demand charge driven by that same peak interval.

Load shifting, when operationally feasible, addresses both costs simultaneously. Delaying energy-intensive processes by even 30 minutes, away from the 3 to 6 PM summer peak window common in PJM and ERCOT, can reduce demand charges and reduce a supplier's exposure to high marginal price hours, which can lower future contract pricing.

The choice between a fixed-rate and variable-rate commercial electricity contract is fundamentally a choice about who bears marginal price risk.

Under a fixed-rate contract, the supplier absorbs the risk that marginal prices rise above what they hedged. You pay a stable per-kilowatt-hour supply rate regardless of what happens in the wholesale market. That predictability has value for budgeting, but fixed rates include a risk premium, the supplier's cost of providing that certainty.

Under a variable-rate or index-based contract, you pay something closer to the wholesale marginal price plus a small adder. When marginal prices are low, you may pay less than a fixed-rate customer. When marginal prices spike, you absorb the increase directly. Some businesses with flexible load and strong energy management tolerate this exposure in exchange for the lower baseline cost. Most small businesses, without dedicated energy staff, prefer fixed-rate simplicity.

Hybrid structures also exist. Block-and-index contracts fix a base volume at a set rate and leave a portion of load exposed to index pricing. Energy management riders and real-time pricing tariffs offered by some utilities in the six markets give larger commercial customers a way to profit from load flexibility during high marginal price events.

The right structure depends on your load profile, operational flexibility, and risk tolerance. Comparing business electricity options at ElectricRates.org lets you see current supplier offerings across all six markets side by side.

A commercial electricity bill typically separates supply charges from delivery charges. The utility handles delivery, including the wires, meters, and local infrastructure, under rates set by the state commission regardless of who supplies your power. Supply is the shoppable portion.

Within the supply section, watch for:

Energy charge: The per-kilowatt-hour rate, which in a variable contract moves with wholesale marginal prices.

Capacity charge: In PJM markets, suppliers pass through capacity costs separately. Capacity pricing is set through PJM's capacity auctions and reflects the cost of ensuring enough generation is available during peak demand, which is itself driven by marginal price dynamics.

Ancillary service charges: Small line items covering grid reliability services. These are also procured in wholesale markets and fluctuate with grid conditions.

On the delivery side, customer charges (a fixed monthly fee), distribution charges (per kilowatt-hour), and demand charges (per kilowatt) appear under tariffs filed with the relevant state commission: PUCT in Texas, PUCO in Ohio, PA PUC in Pennsylvania, MA DPU in Massachusetts, NJBPU in New Jersey, and DC PSC in Washington DC. None of these delivery charges are shoppable, but understanding them helps you correctly calculate the total cost of any supply offer you are comparing.

Armed with an understanding of marginal pricing, a business owner can ask better questions when evaluating supplier quotes.

First, ask whether the rate is fully fixed or whether any component floats with an index. Some contracts advertise a fixed energy rate but pass through capacity, transmission, or ancillary charges at market. A contract that looks cheap at signing can land higher than expected if those pass-through components rise along with marginal prices.

Second, ask about the contract term in relation to current forward price curves. Forward prices embed market expectations for future marginal prices. An energy broker or supplier can share a forward price curve view; a regulator cannot set that for you, but the EIA's short-term energy outlook provides publicly available wholesale price forecasts as context.

Third, confirm which charges appear in the quoted rate and which are additive. A supply-only quote does not include delivery. Your total cost per kilowatt-hour must account for both to accurately compare offers to your current default service rate.

ElectricRates.org's business electricity comparison tool shows live supplier rates across all six deregulated markets, making it straightforward to put competitive quotes next to your current default service price in one place.

Marginal pricing is not a concept to memorize and move on from. It is a live variable that shapes what you pay every month, whether you are on a fixed contract, a variable contract, or still sitting on default service in Ohio, Pennsylvania, Massachusetts, New Jersey, or DC, or a provider of last resort in Texas.

The practical takeaway is to stop treating electricity as a fixed overhead and start treating it as a manageable cost. Check your current supply rate against what competitive suppliers are offering as of July 2026. Review your billing history for demand charge spikes and ask whether any load shifts are operationally feasible. Confirm which state commission regulates your utility so you know where to look if you have a billing dispute or want to verify a tariff.

For most small and mid-sized businesses, the highest-leverage action is a straightforward rate comparison. Current supplier rates across all six markets are available at ElectricRates.org.