Clean Power

Solar Power for Construction Sites: Sizing, Cost, and ROI Calculator

Portable and modular photovoltaics can slash diesel runtime, reduce complaints about noise and fumes, and keep critical loads online—especially during daylight shifts. This guide shows how to size solar for construction site operations, estimate costs, and run payback with a built-in ROI tool. You’ll also get a downloadable kWh sizing sheet to build your load model in minutes.

Jump to Sizing → Open ROI Calculator Download kWh Sizing Sheet

What’s inside

• Why solar for construction site operations now
• Map your loads: work lights, tools, office, pumps
• PV/battery/inverter sizing (with example)
• Hybrid strategy: solar + diesel done right
• What it costs (illustrative ranges)
• ROI calculator: inputs → payback, NPV, LCOE
• Download the kWh sizing sheet (.csv)
• Deployment tips: theft, dust, weather & safety
• FAQ

Why solar for construction site operations

Construction sites run on power: lighting, IT, pumps, fans, small tools, surveillance, and sometimes EV chargers for compact equipment. Diesel generators are flexible—but fuel, transport, noise, and maintenance add up. Modular solar for construction site setups (trailers, skids, containers) reduce run-hours and fuel by offloading daytime energy to PV. Benefits include:

• Lower OPEX: kWh from sunshine is free; you pay only for hardware and modest O&M.
• Less noise & fumes: easier permitting and happier neighbors.
• Resilience: critical loads keep running when the gen set is down for service.
• Scalable: add panels/batteries as the site grows.
• Data: IoT controllers expose real-time usage so you right-size the generator.

Map your loads before you buy a single panel

Categorize loads so your solar and battery cover the right energy at the right time:

Continuous (base) loads

Routers and modems, site security cameras, small servers, access control, telemetry, charging trays for hand tools.

Daily schedule loads

LED work lights, office laptops/monitors, fans or spot coolers, water pumps, small electric heaters, printers.

Intermittent/high-surge loads

Saws, grinders, mixers, compact welders, pressure washers, sump pumps starting surge.

Tip: Put a plug-in energy meter on the site office and a clamp meter on the lighting circuit for one week. Your PV model will be 10× more accurate with real numbers.

Sizing solar for construction site operations

Step 1 — Estimate daily energy (kWh/day)

For each load, calculate: Energy (Wh) = Watts × Hours/day × Duty Cycle × Quantity. Sum them and divide by 1000 for kWh/day.

Step 2 — Size PV array (kW-DC)

First approximate the effective production hours (peak sun hours, PSH). Many locations fall between 4–6 PSH. Include system efficiency (wiring, controller, temperature) ~70–80%.

PV size (kW) ≈ Daily kWh ÷ (PSH × Efficiency)

Example: If your site needs 25 kWh/day, PSH=5, efficiency=0.75 → PV ≈ 25 ÷ (5×0.75) ≈ 6.7 kW.

Step 3 — Battery storage (kWh)

Decide how much night/backup coverage you want. For a day-shift site, 6–10 hours of base load is common.

Battery (kWh usable) ≈ Night kW load × Hours × 1.25 (losses)

If base load is 1.2 kW for 8 hours → 1.2×8×1.25 ≈ 12 kWh usable. With 80% DoD cells, nameplate ≈ 15 kWh.

Step 4 — Inverter/charger (kW) and surge

Size inverter for peak simultaneous power and high-surge tools. Many sites pair a 5–10 kW inverter with a diesel set that handles occasional extreme surges.

Step 5 — Allow for expansion

Choose racking/trailer space for 25–50% more modules, if the project grows.

Rule of thumb: If tools dominate daytime loads, aim for solar to cover base + scheduled loads, and keep the generator for peak-surge windows (hybrid mode).

Hybrid strategy: solar + diesel

• Daytime: PV serves loads and charges batteries; generator off.
• Evening: batteries run base loads; auto-start the generator only if SOC drops below a threshold or a surge exceeds inverter capacity.
• Oversizing risk: too much PV with too little storage wastes production unless you can shift loads (e.g., pump water midday).
• Undersizing risk: if PV is tiny, the generator still runs all day—little ROI.

What it costs (illustrative ranges)

Prices vary by country, supply chain, and spec. The ranges below are illustrative to help frame budgets.

Item	Typical Size	Illustrative Cost*	Notes
PV modules (portable/rigged)	5–15 kW	$700–$1,200 per kW	Racks, wiring, combiner included or separate
Battery pack (LFP)	10–40 kWh	$350–$650 per kWh	Cabinetized or containerized
Hybrid inverter/charger	5–15 kW	$800–$3,500 each	Stackable for 3-phase/large sites
All-in mobile “solar trailer”	5–20 kW PV / 10–60 kWh batt.	$25,000–$125,000+	Plug-and-play, rapid redeploy

*Illustrative only. Obtain quotes for your site, currency, and specifications.

ROI Calculator — Solar for Construction Site

Adjust the inputs to match your jobsite. The calculator compares a diesel-only baseline with a solar-hybrid system that offsets daytime energy.

Region/Currency United States (USD) United Arab Emirates (AED) Diesel price (per liter) Generator fuel rate (liters/kWh) Gen O&M (per kWh)

Site energy need (kWh/day) PV size (kW-DC) Peak sun hours (PSH) System efficiency (0–1)

Total solar CAPEX O&M (% of CAPEX/year) Workdays per year Analysis period (years) Discount rate (%)

Results

Diesel baseline cost per kWh

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PV energy per day

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Annual fuel+O&M savings

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Simple payback

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NPV (analysis period)

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Solar LCOE (approx)

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Assumes PV offsets diesel consumption up to site daily kWh; savings reduce if PV > load or if curtailment occurs. Use workdays/yr to reflect weekend/holiday schedules.

Download: kWh Sizing Sheet (.csv)

Build your load model quickly—enter each load, quantity, watts, hours, and duty cycle. The sheet totals daily energy in Wh. You can import it into Google Sheets or Excel.

Download kWh Sizing Sheet

• Pre-filled with common site loads (work lights, office, pumps, tools)
• Add your own loads and tweak hours/duty cycles
• Use totals to set PV size and battery hours

Deployment tips: theft, dust, weather & safety

• Security: bolt racks to ballast; add tamper alarms and GPS on trailers. Position inside perimeter CCTV.
• Dust & cleaning: construction dust reduces output. Plan quick brush/air-blow daily; deep clean weekly.
• Cabling: use UV-rated cable; protect runs from traffic; label breakers clearly.
• Weather: select tilt and ballast for site wind; secure during storms. In hot climates, allow airflow under modules.
• Safety: lockout/tagout on inverters; train crew on emergency shutoff; keep clearances around gear.
• Load shifting: schedule pumps, charging trays, and mixing to midday when solar is strongest.

FAQ — Solar for Construction Site

How large should my PV be?

Start with daily kWh. Divide by (PSH × 0.7–0.8). If you’re running heavy tools, prioritize covering base and scheduled loads; keep the generator for surge windows.

Do I always need batteries?

For daylight-only sites with steady loads, you can run PV-direct with a hybrid inverter and minimal storage. Most sites still add batteries for evening base load and gen-free quiet hours.

Can solar run welders and big saws?

High-surge/continuous heavy tools are usually left to the gen set. Solar knocks out background loads and charging to cut diesel hours dramatically.

What about moving the system between sites?

Pick trailer or skid systems with quick-disconnect combiner boxes, labeled cables, and forklift pockets. Design for 2-person redeploy in under a day.

Final word

Well-sized solar for construction site projects deliver fast fuel savings, quiet operations, and cleaner air. Model your loads, start with base + scheduled consumption, and let the generator handle peaks. Use the ROI tool and the kWh sheet to dial in your design before you buy.

Disclaimer: This guide is educational—always consult qualified electricians, engineers, and your local permitting authority. Costs and availability vary by market.