Should you go off grid

What are the advantages and disadvantages of using an off-grid solar system to power your house in the Caribbean?

The Good Stuff

Reduced electricity bills

The solar system will pay for itself over time

Protection from power outages

If you live somewhere the power is out occasionally or often, the solar system will provide a backup system

Guaranteed power during hurricane outages

After Gonzalo, we had no power for seven days. Generators, while wonderful, are not a practical source of 24 hour for a number of days. The fuel cost mounts rapidly and it is not good for a generator to run continually. Most generators are rated for short use only.
Now, after a hurricane or even during, we will never be without power. If you factor in the cost of generator fuel, the solar system pays for itself quickly after a storm.

Protection for your equipment

The solar system is a big UPS. The utility can deliver low or high voltages to your home due to faults on the line. An off-grid solar system protects your house from this danger.

The Bad Stuff

Cost

An off-grid solar system large enough to power a modern home is not cheap. While the system will pay for itself over time, it requires a large initial investment. A grid tied system costs a lot less and pays back a lot faster, but does not provide power backup. It all depends on how much you value power backup.

Space

The equipment takes up space in your home. If you are lucky enough to have suitable space available, then this is not an issue but for a lot of people the space is a problem.

Lifestyle

Living with a finite power source means changing your routine. You probably will not be able to dry clothes at night, run your convection oven in the evening, or have air conditioning. If that's a problem for you, don't choose to go off the grid.

Batteries

Batteries, at least the ones we use now, have to be replaced. The lifespan depends a lot on the quality of battery and the way you treat it. If you discharge it heavily, forget to equalize, and you bought cheap car batteries, you will not get much life out of the battery. Heavy duty solar batteries will last a lot longer, but someday all batteries need to be replaced.

Da Mutter...a note from Solar Witch

Before you make the decision to go off grid make sure everyone in the household is pro-solar and ready to make some life style changes. In a family situation where parents are creating a new and exciting life and learning experience by all means, this way of living is great but if you have an older family member who has become set in their ways getting them to make even minor concessions can be difficult to impossible. Explaining that conserving power and making better choices on when you do things falls on deaf ears and usually leads to an angry episode.

We decided against better judgement to just go ahead and do it all and see how things went and we take a lot of heat for it. But we are trying it out with all the warts because we want to know if people will be able to do this and live with it. It's interesting to be sure.

Article of interest

and here's an interesting article about the future of battery backup for off grid solar.
http://www.usnews.com/news/articles/2015/04/29/new-tesla-battery-could-end-electricity-bills

The equipment - the technical stuff

The Set-up

In order to move a modern home off the grid, the system has to be able to support the power requirements without too much change to the lifestyle of the homeowners. In previous times, going solar meant washing clothes in a nearby stream, chopping logs for the wood burning water heater, and huddling together to watch the battery operated tv.
Times have changed. Solar Panel prices have dropped drastically and are now considered cheap, the inverters have become sophisticated control centers, and the batteries, well, they are still the same.
But change is coming; battery prices and options are expanding rapidly and it will not be long before the solar industry enjoys the same progress as the electric vehicle industry, in fact, as a direct result of that industry. Did we mention we have an EV? We purchased a Nissan Leaf in 2013, and love it. But that's another story.
In this article, I will detail how we achieved our off-grid status. There's a lot of good equipment on the market and lots of ways to get to the same objective, but this is how we did it. No approach is bad (unless it is actually bad), and the reader should research a lot and ask a lot of questions. Our system is a work in progress, in fact everything we are doing is a solar experiment, so you don't have to and we will post more updates as we develop this installation further.

Inverter

The center of any whole-house solar power based system is the inverter. We chose to use the Outback Radian 8kW GS8048A as it was large enough to supply all our power, had very sophisticated modes, and was part of a complete system. It's all stainless steel, so it's also beautiful.
The intriguing part of the Radian was the more sophisticated modes, namely Mini-Grid and Grid-Zero. Mini-Grid allows you to use your battery power until depleted to a configured level, then the inverters takes power from the grid to feed the loads, as well as charge the batteries. As we have very reliable sunshine, we decided we did not want the battery charge feature, so we set the charge rate to zero. We stay on grid until the solar charge controller raises the voltage to 54 volts, at which time all the loads revert to solar. While this means using some grid power, it makes the system very robust, ensuring that there is never a power outage due to low batteries. It also protects the batteries from deep discharge, which will damage them.
Grid-Zero is a new approach. Outback saw the potential for battery based systems to provide most of a home's power while using the grid for larger loads and cloudy days. The Grid-Zero mode mixes grid power with battery power, keeping both sources inline all the time and switching larger, short term loads to grid to prevent low battery voltage issues. By doing this a homeowner can utilize their full solar resource but have a smaller battery system. The idea is very clever and should have a large impact, particularly in countries where grid export is not allowed.
Outback have been making solid inverters for years, in fact we have been using an Outback VFX3648 to power our warehouse for years, and we weld and use power tools without any issue. The earlier models are very reliable and good value, but they lack some of the advanced features of the Radian, such as 240V output and the advanced configuration modes.
The Radian also comes with a GSLC, or Load Center, which contains the termination bars, shunts, and breakers to safely wire the system. I would not try installing the Radian without one.

MATE3

The control center of the system is the Outback MATE3. Previous Outback systems were controlled using the MATE display, which left a lot to be desired in terms of usability. But the MATE3 fixed all that.
The unit is networked, has a web interface, and controls the configuration of the inverter(s).

OpticsRE

An optional online monitoring and control site called OpticsRE allows for remote display of the system's performance and state, and allows the owner to make changes remotely. This site is new and has a few wrinkles but these are rapidly being solved. I love being able to view this graphic display of the system while it functions, and we have dedicated a tablet to display the site in our home.

Solar Panels

In truth, solar panels are solar panels. While we prefer Canadian Solar for our commercial grid tied work because of their reputation and warranty, for small off-grid systems the choice of panel is less of an issue. Solar panels have become a commodity item over the last few years due to the rise of the Chinese manufacturers. However, for off-grid systems, it is normally prefered to use 12V panels, just because you can string more of them together. Most solar charge controllers will allow a maximum voltage of 150V, and that limits you to three 24V panels in series. With 12V panels, you can string six together in series.
We got around this limitation by using Morningstar’s TriStar MPPT 600V charge controller (TS-MPPT-600V) which allowed us to move our previously grid tied 600V system to off-grid without rewiring.
Our rooftop is covered by a number of pieces of solar equipment. For the off-grid system, we have 20 BP3175 panels or 3,500 watts, a 175W polycrystalline solar panel made by BP (the oil company) while they cared about having clean air to breathe. We have had them for about seven years now, and they don't owe us anything. I recently seen 3,400 watts of power coming through the charge controller, so they are still putting out full power. If anyone tries to tell you solar panels only last five years, laugh and walk away.

Charge Controller

The charge controller, Morningstar’s TriStar MPPT 600V charge controller (TS-MPPT-600V) , converts the solar panel output to 48V DC and charges the batteries. The MPPT units use a complex algorithm to find the maximum power point and get the most power from the panels. A lesser unit, designated PWM, will produce about 20% less power and cannot convert the voltages in the same way. Our Morningstar unit came with an input disconnect and an output breaker, both very useful.
It is also connected to our network, of course, and so we can read the setting and values remotely.

Batteries

Ahh, batteries, how I hate you...

The weakest part of an off-grid solar system is the batteries. While the price of solar panels has dropped at an incredible rate, and the technology of solar systems has advanced in keeping with the panels, batteries are still the same clunky lead and acid mixtures they were in Edison's time. They have to be carefully tended, kept cool, kept warm, kept ventilated, and kept full, and the owner has to perform esoteric equalization rituals on a monthly basis, computing the State of Charge from the temperature compensated hydrometer readings.
But help is on the way. New technologies such as LiFePO4 and Aquion are on the horizon or are available, and over time trends will establish the new leaders in this technology. I expect that in five years we will not use a lot of Lead Acid batteries in solar systems.
For now, one must buckle up and learn to maintain our batteries.
We chose Trojan IND batteries, which are tough industrial batteries with long life times.

Battery Watering

Keeping the battery electrolyte levels where they should requires diligence. A watering system makes it a whole lot easier. We use and can recommend the Trojan Hydrolink system.

Battery Box

We chose to install the batteries in a box to keep them out of sight (as they are in the kitchen), and to keep the fumes from choking us. A battery box is one of those fun projects that I love to work on, so I made my own box. And it only took three five seven nine days two weeks to complete. An ideal box is tight, raised slightly off the floor, has a vented exhaust system, and will not be damaged by acid inside. We coated the insides with West System Epoxy, which should keep it safe from the fumes. The other surfaces were Polyurethane varnish.

Vent Fan

Most of the industry uses the Zephyr Vent fan as it is robust and works great. Read the instructions, do not glue the pipe.
We chose the 12V unit as we connected it to the Radian's Aux Connection in Vent Fan mode, which allows it to turn the fan on when the solar charge controller is charging the batteries. It does not need to run any other time.

Battery Monitor

Monitoring the battery properly requires a State Of Charge meter, and Outback kindly provides one. The FNDC integrates with the Load Center and monitors the battery current and voltage. It can tell how much power went into the battery and how much came out, and so computes the State Of Charge very accurately. It also has a handy-dandy AUX contact, more on that later.

Load Management

Raspberry Pi system

Once we get into the late evening, some of the loads drain our power unnecessarily. The biggest problem with solar is the length of time from 6 p.m., sundown, to 7 a.m., when thebatteries takes on the loads. The Radian has a programmable Aux contact that we connected to a three pole relay. The programming set points are voltage points, and so we allow the loads to function until the battery system needs to be protected, usually during the night. Then the contactor clicks off and disconnects a couple of non-vital loads, such as the wine fridge and small chest freezer.

Heavy loads

In our configuration, we have an abundance of solar power after the batteries are charged, typically after midday. In the Caribbean, there are very few days when the system does not fully charge.

Once charged, the solar power is largely wasted, as it cannot charge the batteries any more, and there is only the loads to use it. So we wanted to be able to use heavy load equipment for those times, but not allow them to drain our batteries.
The FNDC has it's own AUX contact that can switch up to 30V DC. I installed a 24V DC power supply and four 24V DC relays to switch loads. Programming the FNDC AUX contact is done through the MATE3 display under the Battery Monitor settings.
By using these settings, we can dry clothes in the electric dryer or charge the electric car without risk of depleting our batteries. The Load Management is set to turn off these heavy loads when the State of Charge is below 90%, or the voltage is less than 50V.
In the near future we will enhance the Load Manager with a Raspberry Pi based system (top right) to actively manage the loads. Watch this space!

Installation

Installing an off-grid solar is not a simple task if you want a polished, professional appearance, as well as a safe and reliable system. For most people, it's better to get someone like me to do it. But if you have reasonable electrical and mechanical skills, and a lot of tools, it's a great project.
Good luck with it.

On and Off

And so we begin the learning process of off grid solar. You have to be a little nuts and extremely dedicated to the discipline of working with a finite supply of that thing we have taken for granted since birth, electricity.

Now that the technical part of this process is complete for the moment it falls to me, meet the Solar Witch, to make sure that all that hard work and expense does not go to waste.

Bad Info

As long as the sun shines the solar witch flies.

Everybody has this idea that you can throw a couple of solar panels up on your roof and all your energy problems are solved. Actually it takes a lot of solar panels and no amount can take care of all of your needs unless you have sufficient battery back up to run your house during the night. Even then you have to be careful how much power you use and abuse. Used to be that leaving on a light or a fan or even that cell phone charger was no big deal. Well it isn't a big deal if you are willing to pay the price for the electricity it takes to run these appliances but if you are making your own power you really start paying attention to all those little things because they add up quick.

First things first.

There are some items in your house you simply must leave on all the time. Your refrigerator is very important. How about that pump when you need water. But what else…do you really need to have other things on all the time?

Examples might be your computer. Putting it to sleep is not turning it off. You walk out of a room and leave the light on and don't even think about it. The fan too. We think about that now.

Learning how to conserve is very important when you are responsible for making and storing your own power. But the up side is you have control over your power, it is a big responsibility but at the same time it makes you feel very powerful. 

Investigate

The first thing we did when we started making power was to look around the house and see what is using all of our energy. We have a washer and dryer and it is electric. Very bad for power. We have a big fridge and small fridge and a dishwasher. Numerous lights and fans and of course the water pump.

What about hot water you say. We solved that problem long ago with a solar hot water heater. Anybody in Anguilla that wants hot water and doesn't invest in a solar water heater just doesn't want hot water. It is completely off the grid and just makes hot water as long as the sun shines. We have had it for over 10 years and we have never been without.

We like finding ways to save energy and it is not just about the money.

Find out where your power is going

We have a nifty little device that tells us how much power a device uses. It is called a Kill A Watt, you plug it into your receptacle and then plug your device or appliance into it. The device gives you an accurate account of how much that thing uses in electric.

So now you know how much, what value does it have in the big solar picture. Once you know how much power your house uses you can figure out how many batteries you will need to get you through the night. During the day your solar system is humming away charging your batteries and also providing you with all the power you need to run stuff in your house.

Get a Kill A Watt http://www.amazon.com/P3-P4400-Electricity-Usage-Monitor/dp/B00009MDBU/ref=sr_1_1?s=electronics&ie=UTF8&qid=1430174061&sr=1-1&keywords=killawatt

Timing is everything

We have what I call the magic hours. These are the hours where your batteries are fully charged and now you are making a bunch of power that is just getting wasted. So figure out what to do with it.

Don't start before 11 or after 3 

Wash a load of clothes. Run the dishwasher. We make our own filtered water so I will make a big pot full of water to use for days. Bake bread. I have a restaurant style convection oven. It is great but it is 220 and uses power. During the magic hours, between noon and 3 PM, baking bread is a great idea. You can't do everything at once so you have to figure out which ones will work together. it's like a giant puzzle that can save you money.

Making a Schedule

After working with this system for a while I have finally realized that I must have a schedule of events. As an artist I just hate any sort of thing you might call a schedule but now I look at it as a way to get things done efficiently and it has given me a bit of discipline. Not a bad thing. If you miss a day or something comes up forgive yourself and move on. This stuff is not carved in stone, it is a learning exercise. I use google calendar that shows up on my computer and my phone. I share it with Chris. I now have a section for solar related jobs. It even sends me a reminder.

Terms to Know

Kill A Watt

From Wikipedia, the free encyclopedia

Prodigit Model 2000MU (UK version), shown in use and displaying a reading of 10 Watts being consumed by the appliance

The Kill A Watt (a pun on kilowatt) is an electricity usage monitor manufactured by P3 International. It has a large LCD display. It measures the energy used by appliances plugged directly into the meter, as opposed to in-home energy use displays, which display the energy used by an entire household. It displays voltage, current, true, reactive, and apparent power, power factor (for sinusoidal waveform), energy consumed in kWh and hours connected. Some models display estimated cos

From <http://en.wikipedia.org/wiki/Kill_A_Watt> 

Solar Witch

A solar witch is anyone that has the power to control energy using solar and their mind. 

Getting Started

The decision to go "off the grid" was not an easy one and we viewed our chances of success and satisfaction with much trepidation. 

First, it is a bit expensive to purchase all the items needed to create an off-grid system. It is not simply a bunch of solar panels, an inverter and some wiring. Off-grid systems require all of that, a lot more wire plus a huge bank of batteries, really giant batteries, and a place to keep them. It also needs a totally different and more complicated inverter system, data collectors, an exhaust system for the batteries and all sorts of computer stuff so your system will get along with all your other electrical sources such as the grid and a generator. 

Fortunately, we have a lot of experience with solar (the grid-tied kind), so we were already set up and running a very nice grid tied system at home. Much research was required to find the best components to move from the grid and become completely self-reliant. 

It doesn't happen overnight in Anguilla. You have to get the equipment to the island. That takes time, maybe six months or more.  But finally arrive it did, and Chris proceeded with the installation.

We have an unusual kitchen because the first floor of the house lacks that one extra block height to make it perfect for most humans. Fortunately we are not too tall so we don't bang our heads.
We chose a wall near double doors to the outdoors for plenty of circulation.
Next, Chris built a beautiful box to house the batteries. An exhaust pipe complete with relay driven exhaust fan was installed to pull the fumes out of the battery case during battery charging.
We installed a data recorder so we know what is going on all the time. Information is very important. 

Finally, it is all done, well not exactly finished but done enough so we can turn it on. 

Solar energy is an industry in flux. Everyday someone comes out with a new way to do things. It is a very exciting field to be involved with at the moment. 

Many months later, we are finally up and running smoothly and making enough power for our needs.

Now we start exploring ways to put more and more of the compound's load on the solar system. We have three buildings on property.The garage is home to the washer and electric dryer. In order to be able to safely use the dryer, we designed a load management system that only turns on the power to the garage when there is surplus. To date, we have all the load on the solar system except for the guest cottage.

Terms to understand

Power inverter or inverter...this is from Wikipedia.

A power inverter, or inverter, is an electronic device or circuitry that changes direct current (DC) to alternating current (AC).[1]

The input voltage, output voltage and frequency, and overall power handling depend on the design of the specific device or circuitry. The inverter does not produce any power; the power is provided by the DC source.

The Great Experiment

Going off the grid on Anguilla

Comet Solar Team

We are solar designers and installers in the Caribbean and our home base is on the island of Anguilla, a small island about an hours flight east of Puerto Rico.
We have sunshine on the island almost every day of the year. Sounds like a great place for solar right?

Not so much. 

The utility company here uses imported diesel fuel to power the island. For reasons that continually escape us, they fight the implementation of solar on the island as a means to reduce the cost of electricity and to use less fossil fuel, something most of the world agrees is a good thing to do. Our electricity cost is one of the highest in the world. Companies and home owners are drowning in the cost of running their business especially since we are in the tropics and it gets very hot  here for a good part of the year.

In the Beginning

When we started installing solar here we assumed since the govt. listed in their manifesto that solar would be welcome that it would be welcome. Well you know what they say about assuming. Although the solar systems are duty free (if they arrive as a complete solar system which does not exist), since no one is allowed to benefit from grid tied solar, and in fact are penalized if they happen to export to the gird, we can not recommend using solar in residential homes.
A business that operates during the day and uses air-conditioning can achieve substantial savings by installing solar as long as it does not exceed the amount the business uses. If they install too much and happen to export to the electricity grid they would be penalized by the utility company.
Since we are very serious about providing a safe and sensible system that is dependable and basically automatic we spend a lot of time investigating and experimenting with various products and systems in order to find the most logical way to solve an energy problem.
We have now installed many systems on Anguilla and in the Caribbean, mostly for businesses that can use all the power they create. We constantly have private home owners approaching us about a simple solution to a very complex problem, how to save on energy costs but avoid the penalties issued by the utility company.

We started looking 

The obvious choice these days is off grid solar. It will not work for many people, but since Anguilla is mostly single family dwellings with the kind of roof that might accommodate solar, it could work here.
So we decided to take on the experiment of a serious off grid system for our house.
How to begin? Well we know a lot already but most of it is about a grid tied system. That means that the electricity produced is connected to the electrical grid (power company) even if it is not exporting to that grid. It means there is no need for a power storage device. The electric is simply hooked directly into the breaker box and the power to directed to replace the grid power. Very simple and very clean.

Off grid is a whole different animal. 

It starts out the same, solar panels on the roof that create electricity. An inverter converts electric into the kind of power you need to run your household. But what about at night, no sun at night, that means no power. So you need a way to store power and at the moment, that mean batteries. They are costly and don't last forever. The world is waiting for the magic battery that will solve our storage problems. There are people out there working furiously trying to figure out how to do it but we couldn't wait, we wanted to do it now so we are stuck with the battery that is available.

The good news is it works! 

It is actually fabulous. Sun makes power, batteries are charged during the day, household is run during the day from the power being made and when the sun sinks into the west, we are charged up and ready to run through the night. It is great, it works and it is automatic. You don't even have to think about it.
Well that is not entirely true. You have to think about it a lot. Not about making power, you look up, the sun is shining, you smile because you know whatever you are using at that moment is being powered by that lovely sunshine. But you have to remember that the system is also charging those batteries that have given you power all night. So what can you do, what is the solution? You can get tons and tons of batteries, the more batteries, the more solar you need solar production it is not infinite, so much solar makes so much power. It can get very expensive.

Conservation

So, the one word that comes to mind when thinking about going off grid is conservation.
It is a good word. It means you are paying attention. It means you are not wasting. It means you know what's going on in your house and you are doing things like making sure the light goes out when you leave a room. Oh, turn that fan off too. Using air-conditioning, you might want to reconsider going off the grid. It uses way too much power.
How about that nice convection oven that you want to turn on at 7:00 PM to make dinner. Might be better to do that mid-day and use the power you are making wisely. So you say "I will use gas!" OK but you are still buying and using some sort of energy. Wouldn't it be nice if you made the decision to start conserving power like you conserve money because power is money. Any kind of power you use from wood to just paying your electric bill cost money or time and energy.
We paid for our grid tied solar in three years and then it started to work for us by paying us back the money we spent.
The one thing that is there every day, all day all year every year is the sun. If it wasn't there, we would not be here.

The other side of the coin.

When you go off grid, you never stop paying because you must replace those batteries. You are still saving money but wouldn't it be nice if everyone was able to put some solar on their house, reduce the cost of their electric and did not have to worry about charging those batteries and if they could use their convection oven or clothes dryer anytime they wanted? That is called compromise and it is usually the solution to most problems. The solution in this case is called grid tie and it means you can export your unused  solar created power back  into  the electricity grid in our case known as ANGLEC. You  get some payback for your exported power and you still have an electricity bill but it  is reduced in  size.People are not drowning in electricity costs and the utility is serving it customers. Sounds like a plan.

Terms to know

A grid-tied electrical system, also called tied to grid or grid tie system, is a semi-autonomous electrical generation or grid energy storage system which links to the mains to feed excess capacity back to the local mains electrical grid. When insufficient electricity is generated, or the batteries are not fully charged, electricity drawn from the mains grid can make up the shortfall.