How much generation is already on your line section
The dominant factor, and entirely outside your control. It is a fact about how many neighbours already have solar, not about your house or your design.
HyreSolar tools
Can Your Feeder Take Another Solar System?
A real constraint on the grid, and rarely the one that stops a house.
Hosting capacity is the amount of distributed generation a section of distribution network can absorb before the utility needs to study it more closely. It is a genuine limit and it does block projects — mostly commercial ones. This screens whether it is likely to touch yours, using figures from your own utility rather than a national table we cannot verify.
What this returns at the defaults
A 7.6 kW system on a feeder with 250 kW of remaining hosting capacity uses 3% of it and passes. Against the 15% fast-track screen — aggregate generation not exceeding 15% of line section annual peak load — a 4 MW feeder allows 600 kW of generation, and adding 7.6 kW to an existing 520 kW clears it with 80 kW to spare. The typical residential system is small enough that the feeder, not the house, decides the answer.
Last updated . Data as of 5 September 2026.
Feeder screen
Two independent paths. Fill whichever your utility gives you figures for.
— Screening verdict
— What to do
— Against the map figure
— Against the 15% screen
— Feeder headroom
— Share of remaining capacity
One screen among several. Failing it means further study, not refusal.
HyreSolar publishes no hosting capacity data — the figures come from your own utility's map. We do not sell systems.
How to read a screen result
Failing a screen is not a refusal. It means the application moves from fast track into supplemental review or a study, which costs time and sometimes money but frequently ends in approval, occasionally with a condition attached. Treating a screen failure as a rejection is the most common misreading of this whole subject.
Your system size is rarely what decides it. Look at the base case: going from 7.6 kW to 11 kW moves the feeder aggregate from 528 kW to 531 kW against a 600 kW limit. What decides the answer is how much generation is already on your line section — which is a fact about your neighbours, not about your roof.
If you cannot get a utility figure, the tool says so rather than guessing. There is no national hosting capacity dataset we can retrieve, and inventing one would let you conclude a project is blocked when it is not. "Cannot screen" is an honest output.
Likely passes the screenThe ordinary residential outcome. Nothing to do — hosting capacity is unlikely to feature in your interconnection at all.
Likely supplemental reviewAsk your installer what supplemental review means in your territory: what it costs, what it adds to the timeline, and whether an export limit or a smaller inverter would clear the screen instead.
Cannot screen without a utility figureFind your utility’s integration capacity analysis map, or ask your installer for the line section peak load they used. Most large utilities in high-penetration states publish a map.
How to use this calculator
Every input below is a number you can find, not one you have to guess. This is where each one comes from.
- 01
Enter the inverter AC output
Not the DC array size. Interconnection screens act on what the system can push into the network, which is set by the inverter.
Where to find it The equipment page of your proposal. A 12 kW array may carry a 9.6 kW inverter, and 9.6 is the figure that matters here.
- 02
Find your utility’s hosting capacity map, if it has one
Called an integration capacity analysis, a hosting capacity map, or a DER map. It shows remaining capacity by line section, usually as a colour-coded map you can search by address.
Where to find it Your utility’s website, usually under interconnection or distributed generation. California, New York and Massachusetts utilities publish these; many utilities elsewhere do not.
- 03
Enter the remaining capacity for your line section
In kilowatts. Note the map’s vintage — these are refreshed on utility schedules and a figure can be a year old.
Where to find it The map, once you have located your address. If it reports megawatts, multiply by 1,000.
- 04
Or use the 15% screen instead
If no map exists, the fast-track screen still applies: aggregate generation including yours must not exceed 15% of line section annual peak load. You need the peak load and the existing generation.
Where to find it Your installer can request these, and they appear in interconnection application correspondence. This is a fair question to ask before you sign.
- 05
Read the headroom, not just the verdict
The headroom figure tells you how close the feeder is to its screen. Five kilowatts of headroom means the next neighbour to apply may not clear it.
Where to find it The output. It is the number that tells you whether timing matters.
- 06
If it fails, ask about the alternatives before accepting a study
An export limit, a smaller inverter, or a power control system can sometimes bring a project back inside a screen without a study at all.
Where to find it Your installer. These options are territory-specific and a competent installer will know which apply.
How this calculator works
Take the ICA path if you have a map figure
Compare the proposed inverter output against the remaining hosting capacity published for your line section.
Take the 15% path if you have line section figures
Aggregate generation, including the proposed system, against 15% of line section annual peak load.
Report both independently
They can disagree. A feeder can have published headroom and still fail the fast-track screen, or the reverse, because they measure different things.
Say plainly when neither can be run
No utility figure means no screen. The tool does not substitute an assumption.
The formula, in full
ICA path: proposed inverter kW ≤ remaining hosting capacity kW. Fast-track path: (existing aggregate generation kW + proposed kW) ≤ 0.15 × line section annual peak load kW. Headroom = 0.15 × peak load − existing generation.
A worked example, start to finish
A 7.6 kW residential system on a suburban feeder with a 4 MW annual peak load, already carrying 520 kW of distributed generation, in a territory whose utility publishes an integration capacity map showing 250 kW of remaining capacity on that line section.
Inputs
- Proposed inverter output
- 7.6 kW AC
- Remaining hosting capacity from the map
- 250 kW
- Share of remaining capacity used
- 3%
- Line section annual peak load
- 4,000 kW
- 15% screen limit
- 600 kW
- Existing generation on the line section
- 520 kW
- Aggregate with the proposed system
- 528 kW
Result
Passes both, 80 kW of headroom left
Both paths clear comfortably, which is the ordinary residential result. The instructive figure is the 3%: this house consumes three per cent of the remaining capacity on its line section. Roughly thirty more houses could do the same before the map figure is exhausted. That is why hosting capacity so rarely blocks a single home — and also why it can arrive suddenly for the thirty-first, which is what the headroom output is for.
How the answer moves
The same 7.6 kW system against different feeder conditions. Every row is computed by the tool on this page.
| Situation | Verdict | ICA path | 15% fast-track screen |
|---|---|---|---|
| Base case7.6 kW, 250 kW map headroom, 4 MW feeder, 520 kW existing | Likely passes | fits — 7.6 into 250 kW | passes — 528 kW against 600 kW |
| Map shows only 5 kW left on the line section | Likely supplemental review | does not fit — 7.6 into 5 kW | passes — 528 kW against 600 kW |
| Feeder generation already at 595 kW | Likely supplemental review | fits — 7.6 into 250 kW | fails — 603 kW against 600 kW |
| Feeder generation already at 600 kW | Likely supplemental review | fits — 7.6 into 250 kW | fails — 608 kW against 600 kW |
| 11 kW system instead of 7.6 | Likely passes | fits — 11 into 250 kW | passes — 531 kW against 600 kW |
| No utility figures available | Cannot screen | no map figure entered | no line section figures entered |
Rows two and three are the point of running both paths. They disagree, and neither is wrong — a published map figure and the fast-track screen measure different things, so a feeder can have map headroom and still fail the 15% test. Note also that the 11 kW row barely moves the aggregate: going from 7.6 kW to 11 kW shifts a 528 kW total to 531 kW. Your system size is almost never what decides this.
What moves this number most
Ranked. A proposal can change any of these without saying anything untrue, so these are the inputs to check first.
Whether your utility publishes a map at all
Utilities in high-penetration states generally do; many elsewhere do not. Where no map exists the 15% screen still applies, but you have to ask for the inputs rather than look them up.
The line section peak load
Sets the 15% ceiling. A larger, busier feeder absorbs far more generation before any screen binds, which is why urban and suburban feeders rarely constrain a single house.
Your inverter output — weakly
Included for completeness, and included precisely to show how little it matters at residential scale. A 3.4 kW difference in system size moved the feeder aggregate by 0.5% in our scenarios.
Map vintage
ICA maps are refreshed on utility schedules, not continuously. A figure can be months old and the queue moves in between, which is why headroom close to zero should be treated as already gone.
What is deliberately absent
Voltage rise, thermal limits, protection coordination, reverse power flow at the substation and every other technical screen an interconnection review applies. Hosting capacity is one gate of many, and passing it is not approval.
Common mistakes with this calculation
Reading a screen failure as a refusal
It means further study, not rejection. Supplemental review frequently ends in approval, sometimes with a condition such as an export limit. Ask what the study costs and what it adds to the timeline before assuming the project is dead.
Assuming a smaller system fixes it
At residential scale it usually does not. Our scenarios move a 528 kW aggregate to 531 kW across a 3.4 kW change in system size. If a feeder is at its screen, your house is not what put it there and shrinking your array will not pull it back.
Trusting a map figure without checking its vintage
These are periodic snapshots. Projects enter the queue between refreshes, so a map showing 5 kW of headroom is best read as showing none.
Using the DC array size
Screens act on inverter AC output. A 12 kW array on a 9.6 kW inverter is a 9.6 kW question, and using 12 will overstate your impact.
Treating a pass as an interconnection approval
Hosting capacity is one screen among several. Voltage, protection and thermal screens are applied separately and any of them can send an application to study.
Not asking about export limiting
In many territories a system that fails a hosting capacity screen can be brought back inside it by limiting export rather than by shrinking generation, which preserves your self-consumption. It is worth asking about before accepting a study.
Important: this is a planning estimate
- HyreSolar publishes no hosting capacity data. ICA maps are produced per utility on their own refresh schedules and there is no retrievable national table.
- A screen result is not an interconnection decision. Failing a screen means further study, not refusal.
- Covers the hosting capacity and 15% fast-track screens only. Voltage rise, thermal, protection and reverse-power screens are applied separately.
- The 15% screen is widely used but not universal, and some states have replaced or supplemented it with hosting-capacity-based screens.
- Map figures are periodic snapshots. Queue positions taken between refreshes are not reflected.
- Assumes a radial distribution circuit, which is the ordinary residential case but not the only one.
Questions this calculator answers
What is hosting capacity?
The amount of distributed generation a section of distribution network can absorb before the utility needs to study the interconnection more closely, rather than approving it on a fast track. It is set by voltage, thermal and protection considerations on that specific line section, and it changes as more generation connects.
What is the 15% rule?
A fast-track interconnection screen used across US utility procedures: aggregate generation on the line section, including the proposed system, must not exceed 15% of the line section annual peak load as most recently measured at the substation. It appears in the IREC model procedures and is mirrored in PG&E, Eversource, TEP and NYISO fast-track screens. Failing it moves an application to supplemental review, not to rejection.
Will hosting capacity stop my home solar project?
Rarely. A typical residential system consumes a few per cent of the remaining capacity on an ordinary suburban feeder — 3% in our base case. Hosting capacity blocks commercial and community-scale projects far more often than houses. The exception is a small feeder already carrying a lot of generation, which is most likely on a rural cooperative.
Where do I find my utility’s hosting capacity map?
On the utility’s own website, usually under interconnection or distributed generation, and often called an integration capacity analysis. Utilities in California, New York and Massachusetts generally publish one; many utilities elsewhere do not. Where none exists, your installer can request the line section figures the 15% screen needs.
Why does this tool not just look up my address?
Because there is no national hosting capacity dataset to look it up in. Every ICA map is published separately by its utility on its own refresh schedule. A national table assembled from them would be stale in months, and a stale hosting capacity figure is worse than none — you would use it to conclude a project is blocked when it is not, or to assume headroom that has since been taken.
My project failed the screen. What now?
Ask three questions of your installer: what supplemental review involves in this territory, what it costs and adds to the timeline, and whether an export limit or a power control system would bring the project back inside the screen without a study. The third is the one most often not offered and most often available.
Would a smaller system pass?
Usually not, at residential scale. Moving from 11 kW to 7.6 kW changed the feeder aggregate in our scenarios from 531 kW to 528 kW against a 600 kW limit. If the feeder is at its screen, your array is not the reason and shrinking it will not change the outcome. Export limiting is the more effective lever.
Does a battery affect hosting capacity?
It can, in both directions. A battery is an additional source and may be counted in the aggregate; but a battery configured to limit or shift export can also reduce a system’s impact on the feeder and is sometimes the remedy when a screen fails. How it is treated is territory-specific and this tool does not model it.
The map shows headroom but the 15% screen fails. Which is right?
Both, because they measure different things. A published hosting capacity figure reflects the utility’s own technical analysis of that line section; the 15% screen is a coarse procedural test against peak load. An application can clear one and not the other, which is exactly why the tool reports them separately rather than blending them into a single verdict.
The research behind these numbers
Every assumption in this calculator is argued from primary sources somewhere in our research library. These are the pages that matter for this one.
- How solar interconnection works Where hosting capacity sits among the screens an application actually passes through.
- Interconnection timeline tracker If a screen sends you to supplemental review, this is where the extra weeks show up.
- Service panel check The constraint inside your own house, which stops far more residential projects than hosting capacity does.
- What the utility reviews The wider set of technical screens, of which this is one.
- Solar on a rural cooperative Smaller feeders, lower peak loads, and the setting where a 15% screen is most likely to bind on a house.
- If net metering ends High DER penetration drives both hosting capacity limits and tariff change, and they tend to arrive together.
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Want a more accurate estimate for your home?
Actual results depend on roof, usage, utility rules and a real proposal. Matching is still being built. The form is an enquiry, not a dispatch line.
Written and audited by
HyreSolar Research
Primary-source research, data analysis and fact checking
We are a research desk, not a sales floor. We read the statute, the tariff, the code section, the federal filing or the manufacturer data sheet ourselves, and we publish the figure with the document it came from and the date we retrieved it. Where a number cannot be traced to a primary source, we publish the shorter page and say what we could not verify. That rule has cost us whole sections, and it is the reason the rest can be trusted.
- 160
- primary sources read and cited
- 220
- figures with a retrieval date
- 115
- federal and state government sources
- 66
- researched pages published
How this desk works
- Primary sources only. Statutes from the legislature’s own publishing system, federal data from the agency that collects it, code text from the adopted edition, manufacturer claims from the data sheet. We do not cite an article that cites a source; we go and read the source.
- Every figure carries its provenance. A named document and the date we retrieved it, so you can check it and so you know how old it is. Retrieval dates are not decoration: an EIA rate from May is a different fact from an EIA rate from August.
- We publish what we could not verify. Every research page carries a section naming the things we tried to establish and could not, and why. A paywalled standard, a state website that refused the request, a manufacturer that publishes no figure at all.
- We separate measurement from modelling from our own reasoning, and label which is which on the page. A laboratory measurement, an assumption inside a modelling tool and our own inference are three different kinds of claim and they are never presented as one.
- We do not sell solar, and we take no payment for placement, ranking or a favourable mention. Nobody buys a position on this site.
Data as of 5 September 2026. Authorship on this site is organisational: the analysis belongs to the desk rather than to a named individual, and we do not publish credentials we do not hold. Our editorial policy sets out how we source, date and correct what we publish.
Data and sources
- Model Interconnection Procedures, 2023 edition (Interstate Renewable Energy Council (IREC), retrieved 2026-09-05. Source for the 15% of line section annual peak load fast-track screen and for the definition of a line section.)
- Distribution Interconnection Handbook (Pacific Gas and Electric Company, retrieved 2026-09-05. An example of the 15% screen as applied in a utility handbook, and of the supplemental review path when a screen is not met.)
- Guidelines for Generator Interconnection — Fast Track (Eversource Energy / The United Illuminating Company, Docket 17-12-03, retrieved 2026-09-05. A second independent statement of the same screen, used to confirm the rule is not utility-specific.)
- Rule 21 — Generating Facility Interconnection (California Public Utilities Commission, retrieved 2026-09-05. The state rule under which California utilities publish integration capacity analysis maps. Named as where to look, not used as a national benchmark.)