Local LLM infrastructure calculator

Find the useful delta between watts, tokens, and dollars.

Model a local 70B-class host, choose how it is powered, and compare the trade-off between immediate compute value, lifecycle cost, and energy independence.

Infrastructure model

Balance compute, power, and capital.

Compare documented local LLM hardware profiles across grid, hybrid grid-tied solar, and dedicated off-grid solar. The model prioritises 70B-class inference and reports both upfront and lifecycle TPS per dollar.

01 Hardware profile

Selected profile Dual RTX 3090 value node

VRAM
70B speed
Peak load
Hardware

02 Power selection

Standard grid Lowest infrastructure CapEx; all energy billed. Hybrid Grid-tied panels; no battery bank modeled. Off-grid solar Ground array, battery, pure sine inverter, and controls.

03 Operating option

StockDocumented baseline speed and power. Power limitLower peak draw for a small TPS trade-off. Smart batch4x aggregate throughput at the same peak draw. Power + batchPower-limited aggregate throughput.

04 Planning assumptions

Heavy inference / day

4 hrs

Server-room overhead

Grid energy price

$/kWh

Lifecycle

years

Hybrid load offset

Winter peak sun

hrs

Selected configuration

/

Overall CapEx

compute + power infrastructure.

Projected TPS

TPS / CapEx × 10k

Higher means more projected 70B throughput per upfront dollar.

3-year TCO

modeled grid energy over the selected lifecycle.

TPS / TCO × 10k

Lifecycle score including grid energy, but excluding maintenance and replacement.

Active energy intensity

Estimated watt-hours required to generate 1,000 tokens at sustained output.

Power build

Requirements based on the selected hardware.

Daily energy

Solar array

Battery bank

Inverter / supply

Grid energy / year

Grid OpEx / year

At , before demand charges or tariff escalation.

Power strategy comparison

Same hardware, different power architecture.

Power strategy	Power CapEx	Overall CapEx	Annual grid OpEx	3-year TCO	TPS / TCO × 10k
Standard grid
Hybrid grid-tied
Off-grid solar

Fit, pros, and risks

What this selection optimises, and what it gives up.

Hardware advantages

Hardware risks

Power advantages

Power risks

Documented equal-budget benchmark

Reinvesting power infrastructure into compute changes the winner.

These presets reproduce the three strategy examples in calculationInformation.md. Load one to continue adjusting its assumptions above.

Off-grid baseline 15 TPS

Pool: 2x RTX 3090
Upfront: $25,750
3-year TCO: $25,750
TPS / TCO × 10k: 5.82

Hybrid balance 35 TPS

Pool: 6x 3090 / 4 active
Upfront: $24,500
3-year TCO: $26,768
TPS / TCO × 10k: 13.07

Pure grid maximum 42 TPS

Pool: 6x RTX 3090 farm
Upfront: $19,000
3-year TCO: $22,801
TPS / TCO × 10k: 18.42

Planning model only. Hardware speeds, component costs, solar yield, and battery autonomy are estimates transcribed from calculationInformation.md, not supplier quotes or guaranteed benchmarks. Validate the final electrical design with a qualified installer and benchmark the intended model, quantisation, context length, and serving stack before purchase. Generator backup, maintenance, finance cost, hardware replacement, cooling installation, demand charges, and tariff escalation are not included.