Culper

Masterplan

7. Performance

Unit N+1 on every fleet we sized. Dry most of the year. Remaining PE studies are in §7.5.

27 of 31 design checks pass. Failures and out-of-scope items are listed below.

7.1Reliability and redundancy

Unit N+1 on every fleet we sized. Availability target 0.995. Each island is 0.997 internally, so the chance all 3 are up at once is 0.991. Expected IT on a given hour is 349.3 MW. Losing one section drops you to 233.6 MW, not to zero. That is still not Uptime Tier III.

99.70%One island up99.10%All 3 islands up
Figure 7.1. One island versus the whole campus.

Three numbers, three questions. Probability all 3 sections are up at once: 0.9910. Expected IT available on any given hour: 349 MW, which is 99.7% of contracted. SLA target we will sign: 0.995. The first falls as the campus grows and the second does not, because losing one section of 3 costs 33% of IT rather than the campus. Sign against the second, disclose the first.

Uptime Institute Tier III requires concurrently maintainable paths. Split islands without closed ties are not that. We do not claim Tier III or Tier IV. A tenant SLA that copies those words will be false until the sections are tied or ringed.

N+1 at the block. 3 independent 34.5 kV sections at 117 MW IT each: losing one drops 33% of IT, not the campus. No closed ties, so Uptime Tier III is not claimed. Independent sections, each internally N+1 at 0.997 working. Industry block figure, not a parts list, and not a Markov model. A real RBD needs component MTBF from the switchgear and PCU vendors.

7.2Code compliance status

Conductor ampaciOvercurrent protInterrupting ratVoltage drop to Voltage drop upsPCU loadingTransformer loadN-1 transformer N-1 PCU transferN-1 mechanical tN-1 house transfFirm generation N-1 turbine tripStorage covers aIslanded dynamicN-1 collector buMomentary dutyFirst-cycle dutyProtection coordArc flashCollector incomeSpecified MV feeSpecified LV maiSpecified PCU inSpecified PCU ouSpecified MV intSpecified LV intSpecified PCU inTransformer procPCU procurementPulse-smoothing
Green passed. Amber out of scope. Red is an action (buy the gear).
ResultCheckDetail
FAILStorage covers all three duties140 MW / 75 MWh specified against 175.2 MW / 13.0 MWh required: 175.2 MW GPU transient, a 34.5 MW unit trip, and a 20 min bridge
SCOPEIslanded dynamicsthe studies above are first-cycle and steady-state. What they do not cover is machine decrement over the following seconds, inverter fault behaviour under its own control law, and transient stability after a trip, which on an island is where protection actually gets decided
ACTIONTransformer procurement0 in stock · 160 of 160 to order at 40 weeks
ACTIONPCU procurement0 in stock · 372 of 372 to order at 40 weeks

Failures exist because we refused to mark islanded dynamics as passed, and because procurement is not an electrical pass. Interrupting, arc-flash (worst 17.8 cal/cm² at LVBUS-HOUSE-001), voltage drop, and N-1 transfers passed on the island estimator (26.5 kA MV / 87.1 kA LV). pandapower IEC 60909 on the same section: 28.6 kA ikss (+7.9% vs the closed-form island estimate), peak 72.3 kA. Catalog 63 kA still clears. A PE still stamps ETAP before the turbine PO.

Code checks C01–C26

IDRuleClsStatusFinding
C01Transformer loading within nameplate less headroom
NEC 220; manufacturer
CICalculated
pass
worst 3,710 kVA of 3,750 kVA (99%)
C02Bus and busway loading
UL 891/1558; IEC 61439
CICalculated
pass
worst 92.8% on C-MECH-BRANCH-0001 (1 x 4000 A busway)
C03Interrupting rating ≥ available fault
NEC 110.9
PSCalculated
pass
26.5 kA collector · 87.1 kA LV bus · 5.3 kA PCU-limited · 6 of 18 machines on the worst of 3 collector section(s) at 0.16 pu plus 46.6667 MW of grid-forming inverter; subtransient, decaying within cycles
C04Series-rating policy
NEC 110.9; UL
PSSelected
n/a
Radial plant; listed series combinations are not used.
C05Continuous load 125%
NEC 210.20(A); 215.2(A)(1)
CICalculated
pass
every low-voltage trip sits at or below conductor ampacity
C06Ampacity after derating
NEC 310.15, 310.16
CICalculated
pass
worst 92.8% on C-MECH-BRANCH-0001 (1 x 4000 A busway)
C07Voltage drop
practice 3%/5%
CICalculated
pass
1.46% PCU to rack against a 3% limit
C08Ground-fault protection of equipment
NEC 230.95; 215.10
PSSelected
n/a
415Y/240, not 480Y/277 ≥1,000 A service GFPE trigger.
C09Working space
NEC 110.26
PSPending
must_ask
NEC 110.26 clearances are a layout PE check, not this compile.
C10Selective coordination
NEC 700/701/708; IEEE 242
NDCalculated
pass
5 adjacent device pairs, every one selective by at least its coordinating interval (0.1 s low voltage, 0.25 s medium)
C11Redundancy N-1 invariant
IEEE 3002.x
CICalculated
pass
3 reserve unit picks up 3,710 kVA through 2 x 3200 A busway
C12Spare excluded from capacity
practice
CICalculated
pass
Checked 3 transformer classes. Installed counts exceed required on every one, so the reserve unit is genuinely spare and is not carrying load: 137 installed vs 134 required at 3750 kVA, 17 installed vs 14 required at 3750 kVA, 6 installed vs 3 required at 3750 kVA
C13Zone and facility reconciliation
practice
CICalculated
pass
3 zones sum to 350 MW against a 350 MW target (gap 0). Facility 372.74 MW equals PCU input plus mechanical plus house to 0.004 MW.
C14Single-point-of-failure scan (2N)
IEEE 3002.x
PSSelected
n/a
Unit N+1, not 2N. Sections are independent, not dual-path.
C15Phase balance
practice
CICalculated
pass
Three-phase NVIDIA power shelves. Aggregate rack imbalance is unpublished.
C16Transformer inrush vs upstream trip
IEEE 242
NDEstimate
scope
the studies above are first-cycle and steady-state. What they do not cover is machine decrement over the following seconds, inverter fault behaviour under its own control law, and transient stability after a trip, which on an island is where protection actually gets decided
C17Cable short-circuit withstand
ICEA; IEEE 242
PSCalculated
pass
low voltage 89.5 kA X/R-adjusted against 100 kA · medium voltage 40.3 kA against a 1.6 x 31.5 = 50.4 kA close-and-latch capability
C18Arc-flash incident energy
IEEE 1584-2018
NDCalculated
pass
worst 17.8 cal/cm2 at LVBUS-HOUSE-001, PPE category 3, boundary 7.3 m, cleared in 0.05 s by C-SECONDARY-0155
C19DC bipolar balance
OCP Diablo 400
CISelected
n/a
800 VDC path deferred (Alternative D).
C20DC ground-fault detection
IEEE 946
PSSelected
n/a
800 VDC path deferred (Alternative D).
C21DC arc-fault detection
OCP
NDSelected
n/a
800 VDC path deferred (Alternative D).
C22DC isolation monitoring
IEC; IEEE 946
PSSelected
n/a
800 VDC path deferred (Alternative D).
C23DC-rated interruption
UL/IEC emerging
PSSelected
n/a
800 VDC path deferred (Alternative D).
C24BESS separation and limits
UL 9540; NFPA 855
PSfail
fail
140 MW / 75 MWh specified against 175.2 MW / 13.0 MWh required: 175.2 MW GPU transient, a 34.5 MW unit trip, and a 20 min bridge
C25Occupancy consistency
IBC F-1/S-1
PSCalculated
pass
IBC F-1/S-1 selected for halls. Not a sealed occupancy study.
C26Ground-grid touch and step
IEEE 80 with IEEE 81 ρs
PSCalculated
pass
IEEE 80 screen: ρ=100.0 Ω·m, Rg=0.058 Ω, island GPR 553.0 V vs Etouch 595.0 V. Wenner still required to seal.

Codes: NEC 2023 through TAS 2012. King County will not be the electrical AHJ; TDLR will.

7.3Efficiency: what can be guaranteed

00.51ITMechanicalElectrical pathDesign PUEIT: 1Mechanical: 1.02Electrical path: 0.05Design PUE: 1.06PUE contribution
Figure 7.2. Design PUE as IT plus mechanical plus the electrical path.
  • PUE 1.064 Calculated from the cooling mix. Offer a design PUE of 1.26 with a 0.1 annual deadband. 2024 at this fence: 4.3110.1 °F, ~110.1 °F 0.4%-class cooling design. Do not write 1.064 into a lease.
  • Mechanical PUE 1.0179 Calculated from 52,608 hourly pairs: fans 7 GWh/yr and pumps 49 GWh/yr, 6.3 MW average. The electrical half is the conversion and distribution stack. Total PUE is the product.
  • WUE 0.0467 L/kWh Calculated from 116 AF/yr over 357 adiabatic hours. Do not put this in a contract before pump tests.
  • Path efficiency 95.6% Calculated PCU 97% times residual transformer and distribution. 800 VDC would claim more; it is Alternative D.
  • CUE 0.586 kgCO2/kWh-IT Estimate heat-rate × EPA NG EF. About 1,528,071 tCO2/yr. No methane leakage, no Scope 3, no 24/7 CFE.

7.4Environmental performance

Emissions follow the turbine fleet. First power at 158.5 MW gross sits under the 360 MW TCEQ standard-permit ceiling. The campus at 422.7 MW gross does not, so case-by-case NSR is on the Phase 2 critical path. At 1,528,071 tCO2/yr the campus is 20.4× the 75,000 tpy PSD greenhouse-gas trigger, which makes Title V and PSD/GHG BACT mandatory rather than a contingency. CUE is a heat-rate sketch (0.586 kgCO2/kWh-IT), not a vendor curve. Noise at the fence is modeled: Buy the silencers (~$15M, inside the owned-generation line). Then 50 dBA night is met at ~396 m, inside the gen-island setback. Skip them and the 50 dBA contour jumps to ~1 km and starts eating the pad. OEM octave-band Lw (NEMA TR-1 / ISO 3744) and one 30-day baseline at the fence. Replaces this ±5 dB. Water: MAG 49 AF/yr is ~30.4 gpm, enough for camp domestic and fire but not for 116.1 AF/yr dry-plant demand (~72 gpm). Chemistry is gypsum (TDS thousands). Dry cooling is not optional; the remaining water is an import / GCD-variance / brackish-RO question, not a well-count question. Construction SWPPP under TXR150000.

ReceptorkmdBA, no extra silencerdBA, with OEM silencers
Pad edge / CR-117 (working)
Closest public road and fence. Night criterion 50 dBA (WHO / typical rural insurer), Texas has no statute.
0.464.949.9
Workforce camp
2.5 mi east of perimeter. Sleeping crews. 45 dBA night inside tents/cabins after façade.
434.719.7
Guthrie (county seat)
USGS populated place. Not a noise-sensitive city; still the named town.
19-20.6-35.6

7.5Studies still required before construction

StudyCostLeadBlocks
Test wells + 72-hr pumps + TDS/chemistry
Hydrogeologist
$150–300k8–12 weeksWell permits, RO, WUE language
Geotech borings + karst geophysics + IEEE 81 resistivity
Terracon / Collier class
$250–450k8–12 weeksFoundations, C26 ground grid
ALTA/NSPS 2021 + Schedule B
Texas RPLS
$80–150k8–16 weeksTitle insurance, Ω_build legal, plats
Mineral runsheet + SUAs
Landman + O&G counsel
$40–90k + negotiation6–12 weeksLOI / surface-use close
Phase I ESA (ASTM E2247-23 rural)
Environmental
$25–45k4–6 weeksLender; Phase II on two RRC locations
H&H 2D (5/25/100-yr) + AJD
Civil hydrology PE
$120–220k12–20 weeksFFE, detention, 404
IPaC + habitat assessment; cultural / THC
USFWS/archaeologist
$40–120k8–16 weeksFederal nexus filings
Islanded protection & stability
Power-systems PE
$180–350k12–20 weeksRelay settings, turbine procurement
WETT informal screening (POI fault, headroom)
WETT / ERCOT SSWG
screening fee + NDA8–16 weeksSealed short-circuit; Phase 3 filing
ISO 9613-2 noise + FM wind/hail envelope
Acoustics / insurer engineer
$30–70k6–10 weeksSetbacks, roof spec
First studiesWells, borings, ALTA, minerals, H&H, IPaC. Protection study before turbine purchase. WETT screening as soon as the NDA is available.