PJM Data Center Study → Question 4

When Do Data Centers Leave the Grid?

Self-generation is already cheaper than grid power. Gas CCGT at $65/MWh is 36% below PJM's $102/MWh retail rate. But the cheap option is dirty, and the clean options barely pencil out. The regulatory structure determines whether departure helps or hurts everyone else.

Question 4

Self-Generation Cost Comparison

Q3 calculated what grid power costs with DC infrastructure investment. Q4 compares that to the cost of data centers generating their own power — using real transaction data from SEC filings, utility contracts, and industry benchmarks.

Levelized Cost of Self-Generation vs. PJM Grid Rate ($102/MWh)
$65
Gas CCGT (/MWh)
$80
Hybrid or Gas CT
$95
Nuclear PPA / Solar+Storage
$135
SMR (New Build)
Finding
Every option except SMRs already beats grid power. But the margins tell the real story: gas saves 36%, nuclear PPAs save only 7%. The cheap option doesn't meet carbon commitments. The clean options barely pencil out.

Sources: GridLab 2025 Gas Turbine Cost Report, Amazon-Talen SEC 8-K filing (~$85-95/MWh implied), Lazard LCOE v18, Meta El Paso $473M/366MW actual, Level Ten Energy PJM PPA data Q4 2024.

Grid Impact

Grid-Connected vs. Behind-the-Meter

The economics of self-generation are clear. But the regulatory structure determines whether DC departure improves or degrades grid reliability for everyone else. We modeled four self-generation scenarios at 30 GW of data center load.

Reliability Impact at 30 GW DC — by Self-Generation Structure
Scenario Hours Unserved Net Grid Effect
No self-gen (DC on grid only) 109 hrs +30 GW load, +0 GW gen
Grid-connected PPA (new gen) 0 hrs +30 GW load, +30 GW gen
BTM with new generation 0 hrs 0 net (both off-grid)
BTM taking existing nuclear 105 hrs −5 GW nuclear from grid

The regulatory structure matters more than the economics. Grid-connected PPAs (like the restructured Amazon-Talen deal) add new generation to the grid — everyone benefits. Behind-the-meter deals that take existing nuclear off the grid (like the original co-location attempt FERC denied twice) remove firm generation — everyone else pays the price. Same deal structure, opposite outcomes.

Hours Unserved by Scenario Across DC Load Levels

Model: hourly dispatch simulation with PJM capacity mix. Grid-connected PPAs add generation to system; BTM new gen removes both load and gen; BTM existing nuclear removes firm capacity without removing load.

Death Spiral

Do All Data Centers Eventually Leave?

We modeled the feedback loop: if grid rates exceed the cost of self-generation plus a reliability premium, rational DCs leave. Fixed costs spread over fewer customers. Rates rise. More leave.

Death Spiral Equilibrium — Starting DC Load vs. Final Grid-Connected DC
Finding
At 15, 30, and 50 GW starting loads, every data center leaves — equilibrium is zero DCs on grid. At 75 GW, 50 GW leave and 25 GW remain (one-third stays because the rate pressure rebalances before full departure). Either way, self-generation was already cheaper before the spiral started. The "tipping point" question is largely moot; the economics had already tipped.

But it's not catastrophic for residential rates. PJM's fixed costs spread across 815 TWh of non-DC load. Even if all DCs leave, residential rates rise modestly — a few percent from stranded infrastructure. The real cost is stranded infrastructure: CCGT plants built to serve data centers that become underutilized when those customers self-generate.

Model: iterative equilibrium — DCs depart when grid rate exceeds self-gen threshold ($65/MWh + reliability premium). Fixed costs redistributed each iteration until stable.

Reality Check

Why Are DCs Still on the Grid?

If self-generation is already cheaper, why haven't data centers left? The economics favor departure, but the barriers are real — especially for clean options.

  • — The cheap option is dirty. Gas CCGT at $65/MWh saves 36%, but Amazon, Microsoft, Google, and Meta all have carbon-neutral commitments. They can't build gas plants without reputational damage.
  • — The clean options barely pencil out. Nuclear PPAs at $95/MWh save only 7% — not enough margin to justify the complexity, especially with 2% annual escalators (Amazon-Talen deal).
  • — Interconnection and permitting take years. FERC denied the original Amazon-Talen co-location deal twice before it was restructured as a grid-connected PPA.
  • — Capital allocation. Meta's El Paso gas project cost $473M for 366 MW. That's capital diverted from core operations.
  • — Grid connection provides backup insurance. Dominion's new GS-5 rate class (25+ MW customers, 14-year contracts) is designed to keep DCs connected with standby power guarantees.
  • — FERC rules are still being written. The regulatory framework for large-scale co-location and behind-the-meter generation is actively being contested.

Gas self-gen is easy but dirty. Clean self-gen is expensive but mandatory for corporate commitments. That tension keeps data centers on the grid — for now. When clean options get cheaper, they'll leave.

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