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Module 03 · Pre-build analysis

Energy Management

An 8,760-hour dispatch sizes PV and storage against the Farm32 demand curve, then tests how design and operating levers shift reliability. The reference design — 480 kWp PV with a 600 kWh LFP battery on a synchronized 18 h photoperiod — meets 82 % of annual load on-site.

Step 1 · Diagnostics

How the current design performs

Annual PV generation (830 MWh) exceeds annual load (695 MWh), but the shortfall is concentrated in winter when storage cannot bridge consecutive low-irradiance nights. Two questions matter for the business case: when does the deficit land, and how deep does it go?

Annual load

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MWh / yr

PV generation

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MWh / yr

Self-sufficiency

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% of load met

Shortfall hours

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hr / yr (—%)

Deepest deficit

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kW (single hour)

Longest dark streak

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consecutive hours

Monthly failure profile

When in the year does the system fall short? Winter (December–February) dominates.

Worst week — hourly energy flows

The 7-day window with the most unmet kWh. Battery state-of-charge (right axis, dotted) drains during long cloudy stretches and cannot recover.

Mean daily energy curve

Average kW across all 365 days. PV peak (midday) versus load peak (photoperiod) drives the storage requirement.

Hourly shortfall heatmap

365 days × 24 hours. Dark red = the highest unmet kW.

Where the deficit lives. 45 % of unmet energy lands in November–February — the four months with the deepest single-month deficits. December alone carries 16 MWh of unmet energy. Annual PV (830 MWh) exceeds annual load (695 MWh); the constraint is seasonal storage, not nameplate capacity.

Step 2 · Design sensitivity

Which levers close the gap?

Six configurations on the modelled Farm32 load curve. Capital levers change hardware (PV size, battery size); operational levers change how the facility is run (photoperiod, seasonal pauses).

Scenario comparison

Shortfall hours per year (lower is better). Bars sorted by self-sufficiency. The current design is shown for reference.

Full scenario table

PV size, battery size, load modifier, and resulting reliability for each alternative.

Scenario	PV (kWp)	Battery (kWh)	Load (MWh/yr)	Self-suf (%)	Shortfall (h/yr)	Deepest deficit (kW)

Design space — when does shortfall reach zero?

Each row is a battery size, each column a PV size. Annual shortfall hours decrease toward the upper-right. The current Farm32 design (480 kWp, 600 kWh) is marked. Use this to read off the capital lever required for any reliability target.

Energy Management Brief — A business summary of the diagnostics, scenarios, and recommended next steps. Plain language, no methodology appendix.

Download brief (PDF)

Assumptions & limitations

PV model

pvlib PVWatts at 30° south-facing tilt, 14% system losses, hourly POA irradiance & cell temperature from the Module-01 TMYx file. No tracking; mono-Si modules at 200 W/m².

Battery model

LFP chemistry, 92% round-trip efficiency, 90% depth-of-discharge, 150 kW power cap (independent of energy). Self-discharge negligible at hourly resolution.

Dispatch logic

Greedy hourly priority: PV serves load first; surplus charges the battery; deficit draws from the battery; residual is recorded as shortfall. No grid export, no curtailment penalty.

Design sweep

240–2,000 kWp × 200–3,600 kWh battery — 72 combinations, full 8,760 h re-run each. The zero-shortfall contour line is overlaid on the heatmap.

Load source

EnergyPlus 8,760-h simulation on the Farm32 facility (16.46 kWh/kg-FW). Includes LED canopy (70 %), chiller via COP 3.7 (21 %), and aux loads (9 %). Dehumidification overhead, post-harvest, and standby loads sit outside the EnergyPlus envelope and are not included in this dispatch.

Outputs handed downstream

Output	Goes to	How it is used
Sized PV (kWp) + battery (kWh)	Module 04 — Environmental Impact	Capital-goods stage: PV module + inverter + battery bill of materials
Grid import / export (MWh/yr)	Module 04 — Environmental Impact	Operational energy stage (PEFCR §5.3) — grid mix EF
Hourly dispatch baseline	Operate	Real-time deviation against measured PV + battery output
Selected scenario configuration	Operate · Module 04	Design freeze: PV size, battery size, photoperiod, and seasonal operating rule