If you're weighing solar, CHP, or on-site generation — there's a line item that can blindside you
If you run a plant, a hospital, a data center, a school system, or a large commercial operation and you're looking at solar, CHP, or other on-site generation to cut your bill and boost resilience — here's the surprise. You install the system, the team celebrates, the generator runs, and a new line appears on the bill: Standby Service, Supplemental Service, or Backup Service. And the number is not small.
This isn't a reason not to self-generate. It's a reason to model it correctly. Standby is a straightforward fact of staying grid-tied — but a project's feasibility study is not complete until standby has been explicitly accounted for against your actual tariff.
How can you minimize utility standby charges while maximizing the benefits of an on-site generation system?
Short version: you don't eliminate standby unless you cut the cord entirely. What you can do — understand exactly how your utility's standby tariff works, verify the treatment for your project matches the written tariff, and size your generation and reserved capacity so you're not paying for more readiness than you need. Part 1 lays that groundwork; Part 2 goes into mitigation tactics.
Standby charges are fees on customers who generate some of their own power but stay connected to the grid. Even if your generator carries most of your load on a normal day, the utility must be ready — every hour — to pick up your entire load the moment that generator trips, needs maintenance, or can't cover a high hour. Standby is how they get paid for that readiness.
Why it exists comes down to three things, and none of them are a punishment for self-generating:
Wires, transformers, and generation still have to be built and maintained — that cost doesn't vanish when you install a generator behind the meter.
For critical facilities, leaning on the grid when your plant can't cover you is part of your resilience — and the utility must design for it.
Without it, non-self-generating customers would cover a bigger share of fixed grid costs while you still lean on the grid. Regulators care about that.
Structures vary a lot by utility and state, but the heart of standby is demand-based. Four types do most of the work:
Pinned to a past high event — the greater of this month or a % of your highest over the last 12 months. One generator trip at a bad moment can set an elevated charge for months.
Charges on grid power drawn when your generation is running but can't meet the full load.
Separate treatment for planned downtime — the utility knows you'll need backup then and charges accordingly.
On top of those you may see energy-based standby (per-kWh during standby events), a flat fixed standby fee, one-time or recurring interconnection fees, and ancillary-service riders. Know which of these applies, and what share is fixed vs. demand vs. energy.
Every demand charge sits on top of one number: your reserved capacity. And utilities set it three very different ways — nameplate of your generator, a negotiated contract demand, or a percentage of your historical peak before the generator. The difference is enormous.
A 2 MW solar array might only produce ~20% of the hours in a year — but if standby is billed on the full nameplate at a fixed rate, you pay for all 2 MW every month regardless. Base it instead on your net import capacity after solar and it's a completely different project. Same array, same rate card — the basis alone decides whether it pencils.
This is why standby is never a generic afterthought. You have to know the exact mechanism your specific utility uses for your specific customer class — the tariff is the definitive source.
Standby erodes the savings the glossy slide promised. The danger isn't the charge — it's approving a project where the charge was never modeled correctly.
Still good. But if the generator runs less than promised, or the structure is harsher than you realized, standby eats a far bigger share — and a project that "worked on paper" doesn't.
Five misunderstandings that lead to bad decisions
| The myth | The reality |
|---|---|
| "Generate all my own power and I'll pay the utility nothing." | Keep a live grid connection and you pay something — facilities charges, demand, standby. Full grid defection isn't realistic for most C&I. |
| "Standby is only for backup generators." | It applies to any grid-tied on-site generation — solar PV, CHP, fuel cells, storage. |
| "My net metering agreement covers it." | Net metering is about energy (kWh). Standby is about demand and reserved capacity (kW). Different mechanisms. |
| "Our generator is small, so standby won't apply." | Applicability is tied to customer type and the presence of any grid-tied generation — not the nameplate size. |
| "Add a battery and standby goes away." | Storage helps you control grid draw, but unless you go fully off-grid, the utility still plans for your shortfalls — and charges for it. |
Part 1's job isn't to design every mitigation tactic — it's to make sure you never again look at an on-site generation proposal that doesn't explicitly address standby.
Get the standby section of your tariff. Which schedule applies to your class? How is reservation defined — contract, nameplate, or historical peak? The $/kW rates, the ratchet rules and look-back, supplemental/maintenance treatment, and the fixed-vs-demand-vs-energy split.
Document your own numbers. Current grid peak before generation, the proposed nameplate, a realistic capacity factor and availability (not the perfect-world number), and your expected max import after install.
Make the proposal show standby as its own line, calculated from the tariff using your numbers — stating which schedule and how reservation was set — and run downside scenarios where the generator is available fewer hours or a bad event sets a ratchet.
Talk to the utility — with specificity. Sometimes utilities get creative with less-mainstream charges. "We usually just treat projects like this with X fee" sounds authoritative until you know the tariff. Then you can say: point me to the page, and let's run the math with my data.
"Show me, in writing, exactly which standby rate schedule you're applying to our project, how you're setting our reserved capacity under that schedule, and how it will show up on our bill month by month."
You're not attacking anyone — you're making sure their proposal matches the written tariff. That alone can save you from agreeing to terms you never needed to accept. Watch standby as a % of your total bill: north of 20–30% after generation is a signal something's off.
When on-site generation still wins — and when standby kills it
- You're in a high, volatile retail market — self-generation savings outrun standby.
- You're a critical facility — a 4-hour data-center outage can top $1M, dwarfing standby.
- You run CHP with real thermal load — combined savings absorb the fee.
- You can earn grid-services revenue (demand response, ancillary) on top.
- Reservation is billed on full nameplate and your capacity factor is low.
- A single generator trip can set a ratchet that lingers for months.
- The proforma never modeled standby — or used a generic number.
- You assumed net metering or a battery would erase it.
As long as you stay grid-tied, you'll pay something for the grid to be ready for you.
Your job: know exactly how that "something" is calculated in your tariff, make sure your project's standby treatment matches that language, and run your own data through it before you ever call an on-site generation project a good deal.
The mitigation playbook — sizing reserved capacity, dispatch strategy, storage, and negotiating standby treatment to protect your project's economics. Part of the complete C&I energy series at Energy Answers.
| Standby charge | A fee for keeping a grid connection ready to serve your full load when your on-site generation can't. Also: supplemental, backup, or reserve service. |
| Reservation / contract demand | The kW of grid capacity you agree to reserve — billed monthly whether used or not. The basis (nameplate, contract, or historical) drives everything. |
| Ratcheted standby | Standby demand pinned to a past high event — one generator trip can set an elevated charge for months. |
| Supplemental demand | Grid power drawn while your generation runs but can't meet the full load. |
| Maintenance demand | Standby treatment for planned generator downtime. |
| Nameplate capacity | A generator's rated maximum output. Basing standby on full nameplate is the costliest reservation method. |
| Capacity factor | Actual energy produced ÷ maximum possible. Low factor + nameplate-based standby = a bad deal. |
| Resilience value | The $/hour of avoided downtime — often the number that justifies a project despite standby. |
Energy Answers · by Daniel Burke · Energy Decision 07 · Standby Charges, Part 1