Behind the Meter vs. Front of the Meter
The middle ground is gone. FERC just narrowed the co-location decision to a binary, and the Talen-Amazon restructure is the precedent that now governs every large load in PJM.
Who this is for
- ■Data center developers evaluating co-location with an existing generator
- ■Industrial parks and manufacturing sites with onsite generation
- ■Green hydrogen producers sizing load against a private power source
- ■Owners of retiring coal, nuclear or thermal plants with unused interconnection rights
- ■Energy and operations leads trying to avoid a multi-year PJM queue wait
Is behind-the-meter co-location still legally available at your scale, or has FERC forced you into the co-location framework or full islanding?
PJM Interconnection manages regional transmission across 13 states and hosts the highest concentration of data center load growth in the country. Commercial operation dates for new generation in PJM's current queue stretch into the early 2030s. If you are a large load that needs power in 2026 or 2027, waiting in that queue is not an option.
Bring Your Own Generation, BYOG, emerged as the fastest speed-to-power path around that bottleneck. That is the operational pressure driving every downstream configuration decision. This is not an academic exercise about meter placement. It determines whether the asset generates revenue in 2026 or 2031.
31%of this guide, read. The rest of it is below.
- 02 The mechanism Three configurations, one meter that changes everything
BTM, co-location, and front-of-meter are legally distinct arrangements with different meter positions and different regulatory treatment. The meter location is the regulatory pivot.
Behind-the-meter (BTM) Generator on the customer side of the utility meter Private line, no interconnection agreement; grid connection optional Co-location (BYOG) Generator interconnects directly to the bulk power grid PPA with power flowing through the meter; approved interconnection mechanic Front-of-meter (FTM) System on the utility side Conventional load-serving path; full grid tariff exposure The typical BYOG load splitThe residual grid share is small, but it is where every tariff cost, curtailment risk and penalty concentrates. Under a typical BYOG arrangement, onsite generation covers about 90% of the data center's load, with roughly 10% supplied from the grid. Each co-located project effectively functions as its own mini-grid, with operational obligations that are less forgiving than standard transmission service.
Historically, BTM assets were exempt from transmission and grid upgrade costs because their power contributions had no meaningful financial impact on the bulk grid. That worked for 3 decades. It does not work for a two-gigawatt data center. When a load that large nets its consumption behind the meter, transmission and grid charges get redistributed to every other customer on the system.
Compound outage riskHow the illustrative grid modeling stacks up
The illustrative co-location profile1,000MWData center load900MWOnsite generator100MWNon-firm residual contract15%Summer peak dropoutA modest forced outage rate against a meaningful non-firm dropout window creates real probability of a compound event.If the onsite generator also carries a forced outage rate of 5%, the developer faces a meaningful probability that grid supply drops out at the same moment the onsite unit trips offline. In that window the data center has three options: curtail load, shift load to another site, or draw more from the grid than the contract allows and trigger a reliability violation.
- 03 What it does to you Gross demand, not net: the charge that applies at zero withdrawal
Historically, BTM assets were exempt from transmission and grid upgrade costs because their power contributions had no meaningful financial impact on the bulk grid. That worked for 3 decades. It does not work for a two-gigawatt data center. When a load that large nets its consumption behind the meter, transmission and grid charges get redistributed to every other customer on the system.
Compound outage riskHow the illustrative grid modeling stacks up
The illustrative co-location profile1,000MWData center load900MWOnsite generator100MWNon-firm residual contract15%Summer peak dropoutA modest forced outage rate against a meaningful non-firm dropout window creates real probability of a compound event.If the onsite generator also carries a forced outage rate of 5%, the developer faces a meaningful probability that grid supply drops out at the same moment the onsite unit trips offline. In that window the data center has three options: curtail load, shift load to another site, or draw more from the grid than the contract allows and trigger a reliability violation.
In April 2025, FERC upheld its rejection of a behind-the-meter arrangement between Talen Energy and Amazon Web Services at the Susquehanna nuclear plant. Utility companies argued the arrangement would unjustifiably shift transmission costs to other PJM customers. By June 2025, the parties had restructured to a 1,920 MW front-of-meter power purchase agreement, a structure that does not require FERC approval.
The Talen-Amazon restructureThe largest attempted BTM arrangement in PJM history was rejected and restructured to front-of-meter. Treat it as the governing precedent. The myth The reality BTM netting still works for large loads because the rules technically permit it. BTM rules were built for small loads. FERC has signaled that large BTM does not reflect grid and upgrade costs and is closing that door. A co-located generator serving most of my load means I avoid transmission charges on the rest. PJM's Tariff requires NITS on a gross demand basis for co-located loads, not net. If my net withdrawal is near zero, my ancillary services bill is near zero. Regulation service and black start service are assessed on gross demand even at zero net withdrawals. Reliability obligations are boilerplate. PJM has previewed a Two-Strike regime; first violation triggers a 120 days operational pause, second violation terminates the transmission service contract. - 04 The trap Talen-Amazon: the precedent that governs every large BTM structure
In April 2025, FERC upheld its rejection of a behind-the-meter arrangement between Talen Energy and Amazon Web Services at the Susquehanna nuclear plant. Utility companies argued the arrangement would unjustifiably shift transmission costs to other PJM customers. By June 2025, the parties had restructured to a 1,920 MW front-of-meter power purchase agreement, a structure that does not require FERC approval.
The Talen-Amazon restructureThe largest attempted BTM arrangement in PJM history was rejected and restructured to front-of-meter. Treat it as the governing precedent. The myth The reality BTM netting still works for large loads because the rules technically permit it. BTM rules were built for small loads. FERC has signaled that large BTM does not reflect grid and upgrade costs and is closing that door. A co-located generator serving most of my load means I avoid transmission charges on the rest. PJM's Tariff requires NITS on a gross demand basis for co-located loads, not net. If my net withdrawal is near zero, my ancillary services bill is near zero. Regulation service and black start service are assessed on gross demand even at zero net withdrawals. Reliability obligations are boilerplate. PJM has previewed a Two-Strike regime; first violation triggers a 120 days operational pause, second violation terminates the transmission service contract. FERC's April 2026 order approved four interconnection mechanics for co-located data center loads. All four rely on existing PJM and FERC tariff mechanics rather than new constructs, a deliberate choice to reduce legal exposure and accelerate adoption. The interconnection mechanic (how the load connects) and the tariff product (what service the load receives) are two separate decisions.
Available capacitySub-full-capacity interconnection service
Co-locate with an existing host generator and interconnect at less than the host's full capacity, using interconnection rights the generator does not need.Queue positionAcceleration at Decision Points I and II
Advance ahead of the standard queue at defined checkpoints. Requires demonstration that no significant network upgrades are triggered and readiness milestones are met.Study timingProvisional Interconnection Service (PIS)
Interim interconnection services provided during the full study, giving developers a bridge to early operations.Pre-studied capacitySurplus Interconnection Service (SIS)
Use of unused capacity at an already-studied generator's interconnection point without triggering a new full study. The most commercially interesting mechanic for existing generator owners.Choose one, or islandThe three tariff products
PJM must revise its tariff within 60 days of the order to require an eligible customer taking transmission service on behalf of a co-located load to take one of three products, or otherwise island from PJM entirely.
Tariff product What you get What you accept NITS firm contract demand Firm transmission service consistent with most aspects of NITS Cannot exceed contracted demand; penalty for excess withdrawals Interim non-firm (bridge) Early energization at NITS rate, including ancillary and black start; no generation capacity charge Curtailment under system emergency conditions Non-firm contract demand Lowest cost, available at more interconnection points Curtailment based on real-time grid conditions FERC's April 2026 order approved four interconnection mechanics for co-located data center loads. All four rely on existing PJM and FERC tariff mechanics rather than new constructs, a deliberate choice to reduce legal exposure and accelerate adoption. The interconnection mechanic (how the load connects) and the tariff product (what service the load receives) are two separate decisions.
Available capacitySub-full-capacity interconnection service
Co-locate with an existing host generator and interconnect at less than the host's full capacity, using interconnection rights the generator does not need.Queue positionAcceleration at Decision Points I and II
Advance ahead of the standard queue at defined checkpoints. Requires demonstration that no significant network upgrades are triggered and readiness milestones are met.Study timingProvisional Interconnection Service (PIS)
Interim interconnection services provided during the full study, giving developers a bridge to early operations.Pre-studied capacitySurplus Interconnection Service (SIS)
Use of unused capacity at an already-studied generator's interconnection point without triggering a new full study. The most commercially interesting mechanic for existing generator owners.Choose one, or islandThe three tariff products
PJM must revise its tariff within 60 days of the order to require an eligible customer taking transmission service on behalf of a co-located load to take one of three products, or otherwise island from PJM entirely.
Tariff product What you get What you accept NITS firm contract demand Firm transmission service consistent with most aspects of NITS Cannot exceed contracted demand; penalty for excess withdrawals Interim non-firm (bridge) Early energization at NITS rate, including ancillary and black start; no generation capacity charge Curtailment under system emergency conditions Non-firm contract demand Lowest cost, available at more interconnection points Curtailment based on real-time grid conditions - Decision matrix
When co-location is worth pursuing, and when it is not
✓ Pursue co-location- You need power well before your standard interconnection queue position clears
- A host generator with unused interconnection rights sits in your target geography
- Your load can absorb curtailment on the residual portion, or you can layer firm service
- You have counsel who understands the April 2026 order and the Two-Strike enforcement regime
- Your pro forma prices gross demand charges for regulation and black start, not net
✗ Do not force it- Your financial model depends on BTM netting to hit its return threshold
- The deal is structured around Point of Change in Ownership language FERC rejected
- You cannot operationally tolerate curtailment and have not budgeted for firm service
- Full islanding is unacceptable and you assumed grid backup would be cheap
- Your team treats reliability obligations as boilerplate rather than binding
Questions for your morning huddle- Has our project modeled curtailment frequency under the non-firm tariff product during peak conditions, and does that model account for compound outage risk when the onsite generator and grid supply fail at the same time?
- Are we pricing gross demand charges for regulation service and black start on our residual grid draw, including in hours where net withdrawal approaches zero?
- If our deal was structured around behind-the-meter configuration with grid backup, has legal confirmed the structure survives the April 2026 FERC order and the Talen-Amazon precedent?
- If we are evaluating a host generator with unused interconnection rights, a retiring coal plant or a derated nuclear unit, have we had a serious conversation about Surplus Interconnection Service as the interconnection mechanic?
The one thing to rememberThe regulatory middle ground of large-scale BTM with grid backup is precisely what FERC is eliminating. The remaining binary is real: accept the co-location framework with its mechanics, gross demand charges and reliability enforcement, or commit to true islanding with no grid backup at all.
Before your next design review, pull the pro forma and confirm the residual grid charges are calculated on gross demand for regulation and black start, not net. If they are not, rebuild the model and re-test the project's return threshold against the corrected number.
Know if the numbers actually pencil out before you sign anything.
A written second opinion on the project in front of you, whether that is a rate change, new equipment, or a renewable installation.
- 01A short call, to figure out quickly whether we can actually be helpful. If we can't, we'll say so on the spot.
- 02We pull the data, your bills, your rate structure, vendor proposals, project specs.
- 03You get the verdict in writing: whether the payback will materialize, and the opportunities or risks nobody has raised.
Get a Blueprint at blueprint.tac-nrg.com Free for Indiana-based operations spending five figures or more a month on electricity. No obligation. You keep the write-up either way. - The one thing to remember
The regulatory middle ground of large-scale BTM with grid backup is precisely what FERC is eliminating. The remaining binary is real: accept the co-location framework with its mechanics, gross demand charges and reliability enforcement, or commit to true islanding with no grid backup at all.
Before your next design review, pull the pro forma and confirm the residual grid charges are calculated on gross demand for regulation and black start, not net. If they are not, rebuild the model and re-test the project's return threshold against the corrected number.
The Energy Decision BlueprintKnow if the numbers actually pencil out before you sign anything.
A written second opinion on the project in front of you, whether that is a rate change, new equipment, or a renewable installation.
- 01A short call, to figure out quickly whether we can actually be helpful. If we can't, we'll say so on the spot.
- 02We pull the data, your bills, your rate structure, vendor proposals, project specs.
- 03You get the verdict in writing: whether the payback will materialize, and the opportunities or risks nobody has raised.
Get a Blueprint at blueprint.tac-nrg.com Free for Indiana-based operations spending five figures or more a month on electricity. No obligation. You keep the write-up either way.- Behind-the-Meter (BTM)
- An arrangement where the generator sits on the customer's side of the utility meter and serves the load through a private line without an interconnection agreement.
- Co-location (BYOG)
- A generation facility sited adjacent to a large load that interconnects directly to the bulk power grid, serving the load contractually through a PPA with power flowing through the meter.
- Front-of-Meter (FTM)
- A system located on the utility side of the meter, supplying the grid through conventional generation and transmission service.
- NITS
- Network Integration Transmission Service. PJM's firm transmission product committing PJM to serve a customer's full load at any and all times.
- Gross vs. net demand
- Gross demand charges apply to the total load regardless of onsite generation offset. Net demand nets onsite generation against load first. PJM now requires gross for co-located loads.
- Surplus Interconnection Service (SIS)
- A mechanic allowing use of unused capacity at an already-studied generator's interconnection point without triggering a new full interconnection study.
- Provisional Service (PIS)
- Interim interconnection service provided during the full study, giving developers a bridge to early operations.
- Two-Strike Rule
- A previewed PJM reliability regime: a first load-shedding or generator-tripping violation triggers an operational pause; a second violation terminates the transmission service contract.
- Islanding
- Operating a load fully disconnected from the utility transmission system, served solely by onsite generation with no grid backup.