Many people assume you need batteries for solar to be viable. In some cases a battery is required, while in other cases it would be a waste of resources. Lets break down when you should or shouldn't store your energy.
Do you need battery storage for your home?
In most situations NO! If you have a grid connection and don't suffer regular power outages, you have no need to install energy storage at your home. The grid is there for a reason, you might as well utilize it to get the best economic payback from your solar power system. Installing a battery almost never makes economic sense, it is more of a "want" than a "need" in most cases.
Our typical grid-tie system feeds excess power to the grid for a credit and pulls back power in the evenings or when the array isn't exposed to sunlight. Essentially you should think of the grid as your battery. You charge it up with credits during the day and draw power out of it at night for your cost of electricity. It is almost always less expensive to use the grid as your home battery than to install your own localized energy storage. You might as well let the taxpayer foot the bill for your storage and stick to the grid for the vast majority of grid-tied solar power systems.
OK, so when do you need batteries?
Batteries a great additional feature for your home if you anticipate frequent power outages. Knowing the timespan of the outage you expect can keep your costs down. The battery required to store enough energy to run your home for 3hrs is considerably less than the battery required to run your home for days.
In short, batteries are absolutely required when you have no grid connection. RV's, cabins and even full homes can be made to function flawlessly without any grid connection when the solar power system is sized appropriately and the energy storage is maximised.
What if you want to go off-grid?
In order to go fully off grid, a few things must happen in order for the system to work.
The solar array must be LARGE. Like, really large. In the middle of winter you will only be getting 5hrs of sunlight per day to generate enough electricity to power your home for 24hrs. But it gets worse, you could go up to 2 weeks without sunlight, do you want a solar array that can generate 2 weeks of energy in 5hrs? Ya I do too, but its not very practical.
Now that you have a massive solar array, you will need batteries to store that energy. Do you want enough batteries to power your home for 2 weeks without generation? Maybe, but the cost of so much battery power is very high - most customers opt for a generator backup. Our off-grid customers with generators typically only run their generators for a few days a year, making the tradeoff worthwhile for the comfort.
Watch your energy usage! A lot of money can be saved in your off-grid setup by keeping an eye on your usage and sizing your system accordingly. Designing the building with efficiency in mind is key to keeping initial costs and long term expenses as low as possible on your off-grid home, cabin or other building.
Off-grid systems are an amazing feat of technology that allows you to live as comfortable as you like anywhere on the planet. You should expect much higher financial costs for this type of a system but costs will still be less in the long run than a generator.
Another option is to have your home designed for off-grid use, but with a grid connection. This is a more environment friendly alternative as the excess energy created by your array can be exported to power your neighbors homes, rather than being discarded after your batteries are topped up. Lets see how that works out!
Can you go off-grid on the grid?
Heck yeah you can! You can have the best of both worlds, utilizing a smaller battery with a smaller solar array saves huge over a full off-grid design, while allowing for backup grid connection during those cloudy weeks in the winter. You can also sell your excess energy to the grid while consuming the majority of your solar generated electricity on site.
This type of setup uses the battery to provide power in the evenings and during outages while exporting additional electricity to the grid and importing energy whenever the battery has been depleted. It acts more as a backup energy system than it does as a full off-grid as some laws in Alberta currently limit the quantity of energy that can be exported. You can decide when to run your home off-grid and when to connect the grid, or let the system handle those decisions automatically to maximize your economic payback.
What battery chemistry should you get?
That depends on multiple factors such as:
Where do you plan to put the battery/batteries?
How much space is available?
How much $ do you want to spend?
How many charge/discharge cycles do you expect?
How often do you want to replace your battery system?
Flooded lead acid batteries (5-7 year lifespan)
These are the least expensive batteries making them a favourite for homes, cabins and commercial applications. They operate great in cold weather making storage more simple as they don't have to occupy heated space. They do have some downsides though. They require frequent maintenance, they must be oriented upright to ventilate and they can only be discharged to 50% without drastically reducing battery lifespan. Nevertheless these are the most commonly used battery setups as their cold weather performance and price point are unmatched.
Absorbent Glass Mat batteries (3-5 year lifespan)
These are very similar to flooded lead acid batteries except the electrolytes have been suspended in fibreglass mats making them a dry storage type that can be stored in any orientation. They have similar characteristics to flooded lead acid; however require zero maintenance and don't vent any toxic gases. Unfortunately they are more expensive and have a shorter lifespan than flooded lead acid batteries.
LiFePO Batteries (10+ year lifespan)
LiFePO batteries are a dry battery storage solution with many advantages for solar power systems. They have a discharge of 100% without reducing the lifespan of the battery. Most of these batteries come with a 10 year warranty and are stable and non-toxic. These advantages do come with some disadvantages unfortunately. The downsides to LiFePO batteries is mostly the cost and location requirements. Most manufacturers require these batteries to be stored at 20C or higher, so they will have to be installed in a heated space. They also include lithium which means they can't be installed in the dwelling unit. Typically these must be installed in permanently heated garages or a permanently heated enclosure outside of the home.
Li-Ion Batteries (10+ year lifespan)
Li-Ion is another dry battery storage solution very similar to LiFePO batteries. They also offer 100% discharge and a 10+ year lifespan with a 10 year warranty in most circumstances. They are less expensive than LiFePO batteries but still considerably more expensive than Flooded lead acid or absorbent glass mat batteries. The advantages are usually worth the additional price when used every day such as an off-grid home, but might not be as worthwhile for backup power applications or vacation properties.
Won't somebody please think of the environment?
Any type of resource extraction is harmful to the planet. This is because removing these raw materials can result in soil degradation, water shortages, biodiversity loss, damage to ecosystem functions and an increase in global warming. But when we think of extraction, we think of fossil fuels like coal and gas. Unfortunately, battery materials fall under the same umbrella, despite paving the way for an electric future.. Lithium can be described as the non-renewable mineral that makes renewable energy possible.
While solar panels typically reach net zero in their second year of operation (having produced more clean energy than was used for production), it is much more difficult to calculate a batteries net zero crossover.
We like to be realistic at E-2, and we acknowledge issues with Lithium and other battery resource extraction. These issues are not strictly locked in the renewable sector, oil and gas and most other resource extraction has similar problems. We as a company strive to ensure our suppliers are utilizing ethical resource extraction techniques that do not require child or other slave labour to produce.
Once the lithium is extracted, manufactured and transported the carbon cycle ends. This is not comparable to fossil fuels where after the resources have been extracted, manufactured and transported, they will then be burned in to our atmosphere, warming the planet and polluting the air we breath.
Changing our energy production to renewable technologies is not a 100% solution to save the planet. Renewable technology still requires resources and materials that must be extracted from the earth. The point is to keep upgrading our quality of life, while reducing our environmental impact and eventually stopping all carbon emissions to avert extinction.
If you have any questions about which energy storage system is best for you, send us a message or book your consultation with our energy experts today.
Cheers! ~Spencer