How to define the number of solar panels for off-grid installation?
Off-grid solar power is a system that uses photovoltaic panels to generate electricity without the use of utility infrastructure.
It uses photovoltaic panels in conjunction with battery storage, charge controllers, and inverters in order to generate energy and maintain itself.
An off-grid system built with solar panels is a great option to be energy independent and save from utility bills. Until recently, the high cost of batteries and inverters made it prohibitively expensive for most people living off-grid.
But this has changed with technology advancements lowering prices dramatically making it more accessible for everyone.
However, the decision to live fully committed to solar power should not be taken lightly. In this article, we'll discuss how many solar panels would you need if you wanted to go completely off-grid.
There are important considerations to know when deciding the number of panels your off-grid system should have.
Important Considerations
Do you live in your home year-round?
If you're not a full-time resident, solar panels may be too expensive of an investment to make.
Going off-grid doesn't mean buying solar panels only. It also means investing in batteries or generators to store and efficiently use energy when needed later in the day.
In addition to this, installation and maintenance costs building a fully functional off-grid solar power system can cost thousands depending on how much electricity your property demands.
Going off-grid has its conveniences but it is not wise to do so on vacation homes that are used infrequently.
As a rule of thumb, the residential property you live in less than 4 months a year doesn’t deserve an off-grid installation.
Even if your solar investment seems to finally offer the ROI you plan to achieve, the long wait before getting there can be truly discouraging for many.
What is my average annual energy load?
One of the easiest ways to know your energy needs is by looking at your electricity bills. You can get a very good sense of how much power you're using on an annual basis.
It always makes sense if you can average the last five years of usage. By looking at last year’s usage may mislead you maybe because an abnormally cold or hot season required you to use more energy.
It's worth contacting your utility provider if you don't have bills for the last five years. Request a record of your usage history from the company.
If they are unable to assist, request baseline comparisons to determine what the average energy consumption is in homes similar to yours.
If you intend to build a house, you can use online calculators to estimate the energy consumption of your proposed structure. However, I'm not sure if these calculators can be used by everyone without assistance.
Again, using the baseline building comparison information from the utility company to find the energy use of other buildings similar to the one you want to build.
The best way to know your home's annual energy load is by getting it assessed. This can be done with a qualified assessor or through an online service that requires you to provide details about the property and its occupants as well as some of their habits, such as the number of people in each room at different times during the day/night, sleeping patterns (number hours they sleep), pets living there, kitchen use vs bathroom usage, etc.
Is my property will be Grid Connected or Off the Grid Solar Project?
A home solar array that is connected to the grid may look very different from one that is not. If your solar system is grid-connected, a solar utility company will have input, but if it is off the grid, there will be none.
Amongst the most common ways to live off the grid is to use a solar power generator with backup batteries.
The batteries will charge during the day while the sun is up and discharge at night when the sun sets and no more energy is generated. Both of these system designs have advantages.
To ensure that you always have power, you should typically oversize an off-grid solar system to account for extended periods of low sunlight. A smaller system is fine with grid-connected systems because the grid is always there to compensate for any shortcomings of the solar system.
As solar cell prices fall, it becomes more cost-effective to install larger systems to meet the entire demand of the home.
Do I plan to utilize net metering initiatives?
Because the sun does not shine constantly, it is only natural that you will need to rely on your solar utility company for energy.
Fortunately, many states have a policy known as net metering, which allows homeowners who produce more electricity than they use during daylight hours during some months of the year to export excess electricity back into their grid for other customers' consumption when needed at night or on cloudy days.
When you have solar power installed, the utility credits your electric bill for every kilowatt-hour of energy that is stored and exported.
This means when a sunny day comes to town with high demand from other communities in need of electricity, you get compensated by putting excess capacity into the grid.
In states where net metering solar laws do not exist, exported solar may only be valued at the wholesale rate rather than the regular resale rate.
Net metering solar to the grid also functions as a type of “battery” without the need to purchase one, which can be quite costly. States that have net metering laws usually have the solar power infrastructure in place to accommodate energy flowing both in and out of a home.
What number and capacity equipment will I choose?
Although there are many solar PV tools available for designing solar systems for your house, they can be costly, as can hiring someone to do that for you.
Instead, you can perform some simple calculations to determine the size of your solar system needed to meet your entire home's electricity consumption. First, you must determine the wattage of solar panels that will be installed on your house.
Some free solar PV tools can show you popular wattages as well as estimated prices. When planning your solar panel system, you should be able to find a free solar calculator online.
You will quickly find that higher wattage and more powerful solar panels are costlier, which will increase the overall cost of the solar system project but could prove to be worthwhile in the long run.
Energy Production Calculation
Calculating the number of panels and their capacity you can use online calculators. However, choose the ones which are simpler, and ask you the minimum input.
There are solar calculators that require the input of all household appliances from microwave to router in order to give an estimate.
These are seeming to be more effective but will do nothing other than making the calculation more complicated.
In fact, I always recommend reviewing your old energy consumption habits unless you don’t invest in a new property.
Even if you have invested in a new home, you can always contact your utility company to get an estimation of the baseline energy use of other properties similar to yours.
Here are a few examples that should inspire you on how simple a home solar energy consumption should be.
Let’s say you have a 365-watt solar panel. Next, let's assume that it gets around 8 hours of sunlight on your rooftop each day.
A 365-watt panel that receives 8 hours of direct sunlight per day can generate nearly 3 kilowatt-hours per day. When multiplied by 365 days a year, this translates to the average energy production of approximately 1,095 kilowatt-hours per year.
Next, we'll look at the average usage of a single-family home. According to the most recent estimates, an average home consumes just under 11,000 kilowatt-hours per year.
So, if we divide our total consumption by the projected output of one solar panel, we can see that ten solar panels of this size will be enough to power the house.. Ten solar panels at 365 watts each result in a 3.65 kilowatt on- or off-grid solar system.
As it is very obvious, solar panels use sunlight to generate electricity. The amount of energy solar panels produced depends on factors like the weather, location, and orientation to sunlight.
While solar energy is a promising alternative to traditional power, it does come with some losses.
It's important that you account for this by slightly oversizing your system and running during peak sunlight hours in order to make sure the PV system can meet your needs.
Size of the battery bank
A common misconception about off-grid systems is that it does not matter how efficiently they are converting and storing electricity from your panels into batteries for use throughout daylight hours.
But this couldn't be further from the truth. Having efficient equipment will save energy costs by increasing its lifespan while reducing maintenance time since less wear and tear means fewer replacement parts needed down the road.
After determining the electrical needs of an average day, you must translate that into a battery bank capacity. The appropriate amount is determined by all of these factors:
The efficiency of the inverter
In order to produce the most energy while maintaining high levels of efficiency, off-grid solar systems need a power inverter.
It converts DC electricity from your panels into AC current which is more compatible with modern appliances and devices that require this form of electrical input.
The first thing to consider when selecting batteries for an off-grid solar power system is whether or not your chosen inverter will work well with that type of battery.
This includes things like voltage requirements (some may need 12 volts while some require 24), as well as total capacity size in kW hours needed by the house load requirement.
It's important to keep these factors in mind because you want both options, electricity production from panels and storage capability from batteries working at their best levels all day long.
How long does the battery bank last?
Off-grid solar systems are almost always equipped with battery backups. But if you want to be able to get the most out of your system, it's important that you have enough storage capacity and know what kind of batteries will work best for your needs.
You will need a sturdy battery bank that can provide power for days at a time. You'll need to be able to function without electricity, and it's crucial you have enough juice stored on hand so nothing goes wrong when there are problems with your solar system.
The operating temperature and voltage of the batteries
Here is why it’s important to consider the operating temperature and voltage of batteries when sizing them for off-grid applications.
When you're trying to decide on which type of battery will work best in your remote location, there are three main factors that should be considered.
Operating Temperature: The higher the operating temperature is allowed by a given battery design, generally speaking, the less energy capacity can fit into one individual unit.
Voltage: A lower voltage means more charging cycles possible before needing replacement however this also increases amperage while decreasing watt-hours (Wh) per cell size.
Lifespan/Shelf Life Required by Customer Requirements: It's worth noting whether or not customers need short-term storage capabilities such as keeping their device up for 4 years without needing a replacement.
The batteries we carry offer both high capacity to store electricity generated by photovoltaic panels as well as lower temperatures than their competitors so that they have less risk of catching fire when stored outside unattended during winter months (or even summer).
How much you want to rely on the batteries for energy?
Off-grid solar systems are reliant on batteries to a certain extent. The degree of reliance depends entirely on the size and type of battery as well as your home’s energy needs.
Some people may not want to rely too much on batteries, but others might need that backup power in case their system creates problems or things go wrong more than it is unexpected.
