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Solar Marina Calculator

Enter your marina's slip count, facilities, lighting type, and location — get system size, ITC+MACRS tax benefits, payback, and solar+battery vs. grid+propane comparison.

Marina facility details
slips
buildings
pumps
machines
$/mo
Solar system for your marina
125.0 kW system (313 × 400W panels) — 24% energy offset
Annual solar production182,500 kWh/yr
Annual electricity savings$24,090/yr
Additional LED upgrade savings$1,109/yr
Gross system cost$350,000
Federal ITC (30%)-$105,000
Year 1 MACRS depreciation tax savings-$26,775
Combined first-year tax benefit$131,775
Effective cost after tax benefits$218,225
Payback period9.1 yrs
25-year NPV (5% discount)$104,047
Resilience savings vs. propane generator$9,034/yr
Annual CO2 reduction35.2 tons/yr
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How to Use This Calculator

Enter your slip count and facility loads

Commercial marina solar sizing depends on the full facility load — not just slip count. Slip pedestals providing 30A or 50A power to liveaboards and large cruisers are the largest variable load. Enter each major load category: bathhouses (each with HVAC, hot water heating, and laundry), ship store (retail cooling, freezers, merchandise), fuel pump stations, and ice machines. The calculator estimates total facility kWh from these inputs, then sizes solar to offset the bill you enter.

Select your pier lighting type

High-pressure sodium (HPS) pier lighting uses 2.4× more electricity than LED equivalents. If you're currently on HPS, the calculator shows your additional savings from an LED upgrade — often $5,000-30,000/year for a 100-slip marina. LED pier lighting also improves light quality, reduces maintenance (longer lifespan), and qualifies for utility rebates in most states.

Coastal location and hurricane resilience

Select your location by peak sun hours (PSH). Coastal Southeast and Gulf Coast marinas (Florida, Gulf Coast, Carolinas) get 5.0-5.5 PSH — excellent solar production. Pacific Northwest marinas get 3.5 PSH — still economical given higher electricity rates. Hurricane resilience: a solar + battery system powers critical loads (security lights, communications, fuel pumps, bilge pump power for slips) for 2-3 days without grid — far more reliable than propane generators that may run dry post-storm.

The Formula

Facility Load Estimate (monthly kWh): Slips: slip count × 150 kWh/slip Bathhouses: count × 1,800 kWh each Ship store: 2,500 kWh (if present) Fuel pumps: count × 400 kWh each Ice machines: count × 720 kWh each Lighting: slips × 5 kWh (LED) or 12 kWh (HPS) Max System kW = (Slips × 100 sq ft) ÷ 80 sq ft/kW System kW = min(kW for full bill offset, Max kW) Annual kWh = System kW × PSH × 365 × 0.80 Offset % = Annual kWh ÷ Annual Usage × 100 Annual Savings = Annual Bill × Offset % Gross Cost = System kW × 1,000 × $2.80/W ITC = Gross Cost × 30% Year 1 MACRS Tax Savings = (Gross Cost − ITC×50%) × 24% × 25% Payback = Effective Cost ÷ Annual Savings

The structural roof area for marina solar is estimated at 100 sq ft of rooftop/canopy per slip — conservatively accounting for bathhouse roofs, ship store roof, and dock canopies. Larger marinas often have additional outbuildings that increase available area. For precise sizing, conduct a facility roof audit.

Example

Bayfront Marina — 100-slip facility, Gulf Coast

A 100-slip marina on the Gulf Coast has 2 bathhouses, a ship store, 2 fuel pumps, 3 ice machines, and HPS pier lighting. Monthly electricity bill: $8,500. They're evaluating solar with an LED pier lighting upgrade.

Slip count100 slips
Facilities2 bathhouses, ship store, 2 fuel pumps, 3 ice machines
LightingHPS (upgrade opportunity)
LocationGulf Coast (5.0 PSH)
Monthly bill$8,500/mo ($102,000/yr)

Result

System size~85 kW (213 × 400W panels)
Annual savings~$68,000/yr
LED upgrade additional savings~$8,500/yr
Gross cost$238,000
ITC (30%)-$71,400
Year 1 MACRS tax savings-$22,200
Effective cost$144,400
Payback~2.1 years

Gulf Coast marinas combine excellent solar production (5.0 PSH) with high electricity costs, creating outstanding economics. The LED upgrade adds $8,500/year in additional savings — a 10-year savings stack of $765,000 from solar + LED combined over the system lifetime.

FAQ

Yes — commercial marinas have multiple solar installation opportunities: bathhouse roofs, ship store roofs, fuel station canopies, and dock-end solar canopies. The main loads (slip pedestals, ice machines, bathhouse HVAC, lighting) are high and predictable. Coastal locations often have excellent solar resources despite proximity to water. The 30% ITC plus MACRS depreciation makes commercial marina solar economics comparable to other commercial installations.
A 100-slip marina with bathhouse, ship store, and ice machines typically uses 15,000-25,000 kWh/month. Slip pedestals are the largest variable load — liveaboards running air conditioning draw 20-30A continuously in summer months; boats charging batteries draw 5-15A overnight. Ice machines (400-500 lb/day capacity) run nearly continuously in summer. HVAC for bathhouses, fuel pump submersible motors, and dock lighting add significant base load.
Solar + battery storage is the optimal resilience solution for coastal marinas. A well-designed system can power critical loads — security lighting, communications, bilge pump power at slips (preventing boats from sinking during heavy rain), and fuel pumps — for 2-3 days without grid power. After a hurricane, fuel for boats departing or arriving for repairs becomes critical. A solar system that survived the storm (panels rated for 140+ mph winds with proper ballast) provides immediate value before grid restoration.
Most coastal states have Clean Marina programs: Florida Clean Marina, California Clean Boating, North Carolina Clean Marina, and others under the national Clean Marina Initiative. Certifications require documentation of environmental practices including energy reduction. Solar is a significant qualifying criterion that puts marinas on the fast track to certification. Certified marinas receive state marketing support, can display Clean Marina flags (recognized by boaters), and studies show certified marinas command 5-10% premium slip rates.
For coastal marinas in hurricane zones, solar+battery wins on economics and resilience. Propane generators cost $0.35-0.60/kWh to operate and require fuel deliveries that may be unavailable for days post-storm. Solar produces power at $0.06-0.09/kWh LCOE with zero fuel logistics. Battery storage costs have fallen 85% since 2015 — a 100 kWh battery system for critical marina loads now costs $40,000-80,000 with a 10-year warranty. The hybrid approach (solar+battery for base loads, propane generator for extended outages beyond battery capacity) provides the best of both worlds.

Related Calculators

⛰ Boat Solar Calculator
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🔋 Solar Battery Backup Calculator
Size battery storage for critical load backup and hurricane resilience.
💰 Solar Savings Calculator
Estimate annual electricity savings for any commercial solar system.
📌 Solar Tax Credit Calculator
Calculate your exact federal ITC for commercial marina systems.

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