A greener St. John + a greener (and more resilient) St. John villa

A greener St. John + a greener (and more resilient) St. John villa

The Powerwall lit up and charging
our st John villa portable generator after irmaIt’s been nearly 6 months since hurricanes Irma re nightnd Maria blew through the Caribbean. We’ve seen the emaoliage return faster than imagined, displaced islanders return, as well as visitors come back to their favorite little rock to enjoy themselves for a few days or weeks. For the first 4 months, it was work work work and a whole lot of 5-gallon fuel can filling. We’ve come to know the smell of gasoline on your skin as a kind of 2017 island cologne.
When Carrie and I bought and took over management of Great Expectations from Chuck and Kristin, the insurance adjustment was getting underway and the first obvious big picture project was replacing the 40+ photovoltaic and 3 solar hot water panels lost or destroyed in the storms.

Pre-power restoration of Hot Water

New solar Hot water panels on our St. John villa by Island Solar VIEven before the 2017 hurricanes, the villa used little to no electricity for domestic hot water (shower, sinks, etc). Since the sun doesn’t care about WAPA (Virgin Islands Water And Power Authority) and the BBC folks were busy rebuilding the island grid, we hired Dan Boyd of Island Solar VI to order and install 3 new hot water panels and plumb them right back into our domestic water system. The hot water from these panels circulates from the roof to the utility rooms via a small DC pump that has its own mini solar photovoltaic panel – no power is needed. The hot water heats the water in two electric domestic hot water tanks, and if the sun happens to be hidden for long periods or a lot of hot water is needed (early morning showers), the electric heater kicks in. Big thanks to Island Solar VI for making this happen, in the middle of a multi-hurricane zone, and helping us not only get hot water but also lower future energy bills. As I’ve started saying regularly – Dan’s the Man!
Once we had a portable generator big enough to power the water pumps & lights, we were able to get cold and hot water as needed, and keep the beer cold without standing in line for a bag of ice – again, just as long as we kept filling those gas cans.

Pre-Storm Electricity from Solar

Great Expectations had 52 photovoltaic (PV) and 3 Solar Hot Water panels before the hurricanes. The 52 x ~200W PV panels (10.4kW) were wired directly into each building/bedroom’s sub panel, providing power for lights, appliances, etc, and feeding back to the grid when power generation exceeded villa demand. This excess power lowered the monthly electric bill by about 30-40% over the past few years. The solar hot water probably saved another 3-5% on the WAPA bill since the hot water heaters didn’t need to use electricity to heat hot water every day for guests. With plenty of sun and high energy costs, implementing solar on a villa in St. John is a no-brainer.
St John villa Great Expectations power usage sample 2017

Pre-and post-storms backup power plans

Irma ripped off or tossed neighbors’ roof tiles into more than ⅔ of the panels. While some of them remained and could send power into the villa after Irma and Maria, it was only about 2000W worth of power at any one time during a sunny day, enough to run some lights and a fridge, but not water purification or pumping, pool pumps, or anything else.
Great Expectations had a medium-sized portable generator in a small wood shed, locked and chained down, near the power monument before the storm. When I arrived on island between Irma and Maria, the first thing I saw was a smashed wood box and cut chain: someone had ‘borrowed’ the villa generator. It was disappointing, but kind of understandable. I hope someone on island made good use of it after their home was destroyed.
That generator was under 7000W. Enough to run the lights, 2 refrigerators, and water filtration and pumps. Not enough to operate the rest of the villa for guests.
Six weeks after Maria, we got our hands on a new 6500W portable generator and our property maintenance man, Erickson, connected it to the existing transfer switch. We shut off breakers to the AC units, hot water heaters, and the pool pumps (large draw items) and ran the villa with 5 gallons of gas every 14-18 hours for months while FEMA staff stayed in Great Expectations during the recovery phase. September, October, November, and December found me and Erickson taking more than a dozen trips to the gas station (when there was gas to be had).

Taking Good and Making it Better

Until fairly recently, the only way to capture energy, store it, control its usage, AND monitor it ‘in the cloud’ was through a hodgepodge of hardware, switches, and software.  From what I’ve researched, it wasn’t that easy and the pieces are bulky and not made/supported by a single manufacturer.

Tesla logoEnter Tesla

We’ve all heard stories about how Tesla Powerwalls and solar PV panels are powering an island in the Pacific. I remember multiple conversations in September after Irma and Maria that would end with “why don’t we just gang together and buy a couple hundred Tesla Powerwalls?” There are quite a few companies in the US and British Virgin Islands combining solar and battery storage. There a couple of companies that sell and install Tesla Powerwalls. We chose Pro Solar with their USVI location on St. Thomas. One of their consultants, John Helgesson, was available and punctual – not a typical island one-two combo, especially after 2 hurricanes. He brought his ladder, climbed up on all 4 roofs, inspected the existing railings and solar panels, and answered my questions about design, costs, and lead times.

Retrofit or Redo?

First, we had to decide if it was worth it to move the solar connectivity from individual building sub panels.
Option 1: Work within existing wiring setup

If we were to leave the existing wiring setup, then the solar control would be lost to the demand of the buildings. On a typical day, there might be sometimes where the villa usage is less than solar output, and the Powerwalls would be charged from the solar panels. But most of the time, the batteries would be charged by the most-expensive WAPA incoming feed.
Solar diagram of existing solar hook up to Tesla Powerwalls on our St. John Villa

Option 2: Plan for the long term
On the other hand, if we were to home-run each building’s solar arrays to the location where WAPA came in and the batteries were installed, then we could control where each leg of power comes and goes. We would have to trench across some of the property. It would take more wire and conduit, but the end result would be complete control of the entire system: Solar, Powerwalls, WAPA, and even a future generator 4th leg.
connecting st. John villa solar power directly into Tesla Powerwall after hurricane irma
Guess which option we chose? Option 2 was $2500 more worth of labor, wiring, pipe, and trenching for the best possible setup for next month, next hurricane season, and the next decade!

The Install

Then came the install day: John, Zach, Marcel, and a whole bunch of other guys came in green shirts and started unboxing panels, rails, piping, and electrical equipment.

A ProSolar crew cleaned up the existing rails, removed defunct micro inverters, installed new rails, and then tested and repurposed the old 200W panels to a single array on the roof of building #1.  They then installed 3 new sets of panels on buildings 1, 2 and 3 with the 300w panels and new IQ6 micro inverters.
Before and After solar PV fixes from ProSolar on Great Expectations St. John Villa by ProSolar
Great Expectations is now setup with 12kW solar system tied to a gateway that connects the villa electrical system with the Tesla Powerwalls and WAPA.

Satellite Internet, Solar Hot Water, and Solar Photovoltaic on the Guest House

Cloud Monitoring

Oh, and our temporary to long-term satellite internet and WiFi mesh network from Hughes Net and Pirate IT provides the internet connectivity to send and receive data from the Tesla gateway and the solar panel map monitor, all the way back to a website and mobile app!

The Results

The installation was completed and registered at about 4pm on Friday February 16th. It was cloudy and raining. So I changed the Powerwalls to only act as backup power, rather than partially power the villa as well. I wanted to get them charged up to 100% as soon as possible. We got back to Great Expectations after dark and the Powerwall was 28% charged. The geek in me wanted to disconnect from WAPA and see how long she’d run the pumps, fridges, and new LED lights. But I didn’t.
The next morning was switch-over day with guests coming in. The cleaning crew showed up, the sun shone down, and before 3p were had not only fully charged the Powerwall, but had also powered the villa AND sent a couple of kWhr back to WAPA!
MyEnlighten web app for solar panel monitoring on St. John

ProSolar utilizes the EnPhase web app to display the new solar arrays along with power production

Other than a massive use of air conditioning, we may see grid-free nights in some cases, and much less draw from the grid during heavy-use days.

The Powerwall lit up and chargingConclusions

  • We should have taken down the solar panels before the storm. We will next time.
  • Generators are great, but for short term outages when guests need power for only a few hours, they are a short-sighted burden, that seems cheap, but is expensive in time and energy (and gas).
    • During long-term outages, schlepping 5 gallon gas cans for weeks and months sucks. There’s nothing enjoyable about it, except maybe the friends you make while waiting in line for your ration of go juice.
  • On a sunny rock, where you only get a credit against usage on your power bill for sending power back to the grid, high capacity storage and solar are the only way to go.
  • Island Solar VI and ProSolar are two professional outfits. (Heck, Dan Boyd came out to meet me at the villa a week after Maria! His house on Lovango was destroyed and he was on island helping people!) The ProSolar guys at one point had 4 trucks and 11 people onsite for the PV/Tesla install. They reviewed possible setups in detail. They explained how things work and how they don’t. They made an organized mess and cleaned it all up. They did it in days, not weeks or months.
We’d do it again. In a heartbeat.
We have added a massive value to future guests in the form of silent backup power to the villa for hours or days, if not weeks. We’re using solar to charge the batteries AND power the villa during the day. The Powerwalls send stored solar power back to the villa at night when the sun is down!
We’ve made our St. John villa stronger, more resilient, less expensive to maintain, and ‘greener.’ Long term, it equates to better for the environment (if everyone used less power a fossil fuel power plant). It is less expensive to power and gives us less reliance on grid power. Seamless always-on power for guests and us alike.
We’re already budgeting for another 20-40 solar panels AND 2-3 more Powerwalls. After a few months of data collection and some math, we may be able to be essentially off-grid in the near future AND have daily recharging of a villa-wide battery backup that doesn’t hum you to an angry sleep most nights during an extended power outage.

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