18.8 kW Solar + Battery in Key Biscayne, FL

A 18.8 kW rooftop solar and battery system designed, permitted, and installed by Sprightful for Key Biscayne homeowners. Energized August 2021.

System size

18.8kW

54 modules

Battery

40.5kWh

Powerwall 3

Permit → energize

180days

121d in permitting

Sprightful Solar 18.8 kW solar + battery system installed on a home in Key Biscayne, Florida

18.8 kW rooftop array in Key Biscayne, FL · 54 modules · s-5! clamps on standing seam metal.

At a glance

Project ledger

CountyMiami-Dade County

Permitting authorityKey Biscayne

EnergizedAugust 2021

Permit → energize180 days

System size18.8 kW

Modules54 panels

InverterSE 10000H

BatteryPowerwall 3 (40.5 kWh)

Annual production (est.)28,200 kWh

30-yr lifetime savings (est.)$201,244

Hardware

What was installed, and why.

Modules — 54× panels
MSE345SX5T. Sized to cover the home's 12-month baseline load with a minor buffer for future electrification.
Inverter — SE 10000H
Grid-tied inverter equipment converts rooftop production for home loads and FPL net metering.
Battery — Powerwall 3
40.5 kWh usable. Whole-home backup through grid outages, and time-of-use shifting when utility peak tariffs apply.
Racking — mounting system
S-5! clamps on standing seam metal

Equipment diagram showing the Key Biscayne solar system hardware and utility connection

Project timeline

How the Key Biscayne project moved from contract to meter.

A dated view of the work: contract, permitting, on-site installation, utility handoff, and any later expansion or battery phases.

Start

Project begins

March 1, 2021Day 0

Milestone

Permits submitted to city

Day 42

Install

Installation begins

August 11, 2021Day 163

Install

Installation completed

Day 166

Milestone

FPL replaces meter

August 28, 2021Day 180

Total span

180 days contract to energized

vs. Florida average

~324 days · ~44% faster

Project notes

About the project

This Key Biscayne family wanted more than just a lower FPL bill — they wanted resilience. Living on a barrier island means hurricane season is a yearly reality, and a standard grid-tied array wouldn't keep the lights on when the wind picks up. Sprightful designed a 54-panel, 18.8 kW rooftop system paired with two Tesla Powerwall 3 batteries and an expansion pack, giving the home roughly 40.5 kWh of usable backup — enough to ride out most outages without anyone missing a beat.

Because the home has a standing-seam metal roof, our crew used S-5! V-clamp attachments — no roof penetrations, no leaks, and a cleaner finished look than traditional L-feet. The whole install wrapped in four days (Aug 11–14, 2021), and the system has been producing their own power ever since.

Why it matters

A 30-year financial and environmental decision.

These aren't projections pulled from thin air. FRCC eGRID emissions data, current FPL residential tariff, and modeled production under South Florida irradiance (~1,500 kWh/kW/yr).

28,200

kWh produced annually (estimated)

$201,244

30-year savings vs. staying on grid-only power

332tons

CO₂ offset over lifetime — equivalent to ~5,533 trees planted

Cumulative savings vs. grid-only30-year horizon

Good-faith estimates using FRCC eGRID emissions data, current FPL tariff, and Aurora-modeled production. Actual results vary with shading, weather, and future rate changes.

“Sprightful did a great job and I am very happy I chose them. They were helpful every step of the way. The system they installed has been operating for a few months now and it is working as expected. Our energy bills have plummeted. I worked with Andrea, Jeff and Pablo — and all of them were a pleasure to work with.
The one negative I would say is that the job took longer than expected due to (i) holdups from my municipality's permitting department and (ii) I think Sprightful outsources some of the engineering work and this was a big bottleneck at the beginning.
That said, Sprightful delivered a great system, they were a pleasure to work with and they did it for a very competitive price (and never tried to gouge me like some of their competitors). I highly recommend them.”

Key Biscayne homeowner·Energysage review

Nearby Sprightful installs.

Each AHJ has its own quirks — permit fees, setback rules, wind-load calcs. Here are similar projects we've run through the same county offices, close to Key Biscayne.

Miami, FL

FAQ

Solar in Key Biscayne, FL.

How long does the solar permit process take in Key Biscayne?

Key Biscayne took 121 days from submittal to approval on this project. Typical range we've seen is 2–8 weeks depending on whether the roof assembly requires a secondary wind-load review.

What size solar system is typical for a Key Biscayne home?

Most Key Biscayne homeowners land between 8–16 kW — sized to offset 90–100% of their FPL bill. This project is 18.8 kW, on the larger end.

Does my HOA need to approve it?

Florida's Solar Rights Act (§163.04) prevents HOAs from outright banning rooftop solar. They can make reasonable aesthetic requests — we handle the HOA submittal directly and have a 100% approval rate to date.

What rebates and incentives are available in Miami-Dade County?

The 30% federal Investment Tax Credit (ITC) is the primary incentive — Florida has no state-level solar rebate. There's also no property tax increase for the added home value (Florida exemption), and no sales tax on the equipment.

Solar in Key Biscayne? Start with your roof.

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