Installing solar panels will reduce your household’s annual energy bill. Solar panels could save you up to £1,190 every year – that’s nearly £30,000 over the lifespan of your panels.
Most solar panels in the UK come with a 20-25-year warranty, which is exceptionally long for any appliance or device. While solar panels are great during the day, they cannot generally produce power at night and will drop in efficiency when overcast.
To overcome this issue, you will need to invest in an inverter and solar panel battery storage. But what exactly is solar panel battery storage?
What Is Solar Panel Battery Storage?
Solar panel battery storage is the system that allows homeowners to capture the excess electricity generated during the daytime for use in the evening and sometimes throughout the night.
If you’re installing four 550-watt solar panels, they will generate 2200 watts at their peak, or 2.2 kilowatts. This is enough to run most home ovens. But if you’re not running an oven at this time when the panels are performing at their peak, the excess power generated is simply drained away via the earth outlet.
To ensure you capture and store this energy, you need a battery, or batteries, to stow away this potential power for later use.
Homeowners in the UK will mainly encounter three types of solar batteries to store power.
These batteries use the same energy storage material that your cellphone uses but of a higher quality. This is the current popular choice for several reasons, including:
- They store the most amount of energy per weight;
- They offer high efficiency, which means less energy is lost during charging and discharging;
- They have a longer lifespan compared to other options (10-15 years);
- And they allow for deep discharge (which means you can use more of them).
However, lithium-ion batteries are also more expensive, are not tolerant of extreme temperatures, and are highly combustible.
And when moving lithium-ion batteries, remember to handle them with care, as they can self-ignite if bumped hard.
Most Britons will know these types of batteries from their cars. They are designed to be recharged but can’t be as deeply discharged as lithium-ion. In layperson’s terms, you shouldn’t discharge the battery too much; otherwise, you’ll damage it.
However, lead-acid batteries are great for several reasons:
- They are affordable and significantly cheaper than lithium-ion batteries;
- Can tolerate more extreme temperatures;
- As a well-understood technology, they are very safe.
But even with these benefits, your lead-acid battery will offer you less energy density, be less efficient, and have a short lifespan.
The next option is a bit of both worlds.
Lithium Iron Phosphate (LiFePO4)
Also known as LFP, it is a type of lithium-ion battery with several advantages. These include:
- LiFePO4 batteries are safer than standard lithium-ion batteries due to their internal chemical structure not being as volatile;
- They have a longer lifespan compared to the usual lithium-ion battery, being able to last between 2,000 to 5,000 charge cycles compared to 500 to 1,000;
- Faster recharge rates;
- They operate at a wider temperature tolerance;
- And they offer deeper discharge tolerance.
While this sounds great, they are more expensive, offer lower energy density, and are not easily sourced in the UK.
Now that we’ve gone through the types of solar panel battery storage options, UK residents need to answer the following questions before purchasing.
Questions To Answer About Solar Panel Battery Storage
Before purchasing a solar panel battery storage solution for your home, you must compile a few energy consumption statistics.
First, you’ll want to check your average daily energy consumption. This figure will help you determine the size and capacity of the battery you need. To gather this information, you must track your energy usage for several days.
The second figure to gather is your home’s peak energy usage. This will be a reading when your home has high energy demands. Situations that will cause this increased demand for electricity are turning on your hot water boiler, air conditioners, and oven.
You want your batteries to be able to handle this peak demand.
And the third and last factor to consider is whether it will be future-proof.
Will you be expanding your household? Are you planning on purchasing an electric vehicle? These are situations where you want your batteries to perform at their best in the future.
To gauge whether your battery can handle these demands, you must understand the difference between kilowatt-hours (kWh) and kilowatts (kW).
- The kWh is the measurement of the amount of energy your battery can store. A 10kWh battery can power a typical home for about 4-5 hours (depending on your home’s energy requirements).
- The kW measures the power output of the battery. The higher the kW rating of the battery, the more power it can discharge at once. This is important for handling peak loads.
The next factor to consider is whether your batteries are compatible with your solar system. Mainly, do they integrate with your home’s inverter?
An inverter is a device that converts your solar panel’s DC (direct current) output into AC (alternating current). Your home’s plug points and devices can only use AC, so converting from DC is essential.
Now that we know what solar panel battery storage is, what types of solar batteries there are, and how should you select the right one for your home? You may be wondering…
Do Solar Panels Have Battery Storage?
No, solar panels do not have built-in battery storage. They only convert sunlight into electricity or DC.
For a straightforward breakdown of how solar panels produce power, they are made from silicon or other semiconductor materials. When exposed to the sun’s energy, the solar panels' internal material releases electrons, producing an electric charge.
As mentioned, solar panels only generate DC electricity. For your home to use this electricity, it needs to be converted by an inverter.
This AC electricity can be used by devices or appliances around the home or stored in your solar panel batteries.
Solar panels and batteries are different items in your home’s solar system. Now that we understand the difference, what are the pros and cons of storing energy?
Pros & Cons Of Storing Solar Panel Energy
As with everything in life, there are pros and cons to installing batteries to store your solar panels’ energy. But this is a list that’s overwhelmingly balanced in one direction. So, let’s look at the positives.
Pros For Storing Solar Panel Energy
The positives of having a solar panel battery solution include:
- Having energy independence, reducing your reliance on the grid, and being able to reduce your energy bills.
- Being able to be rest assured that you will have access to backup power.
- Reducing your home’s impact on the environment.
- And being able to apply for government incentive plans when they are introduced.
In some countries, you can sell electricity back into the grid, which could be an excellent method of tapping into an alternative income.
But as we said, there are some cons to storing solar panel energy.
Cons For Storing Solar Panel Energy
There are some downsides to purchasing batteries to store your solar panels’ energy, which include:
- Upfront costs are high.
- Your batteries will only have a limited capacity to store energy.
- Batteries need to be replaced every 10 to 15 years.
- Disposing of and creating batteries impacts the environment very badly.
- Solar panel energy storage needs loads of space as they are large.
- As mentioned, lithium-ion is combustible and incredibly hard to extinguish, so safety is a significant concern.
If you are concerned about the fire potential, ensure that your batteries are installed in a well-ventilated space and not obstructed by large items so you can be sure they are cool.
Now that we’ve addressed one major issue, how much are solar storage batteries in the UK?
How Much Are Storage Batteries?
It shouldn’t come as a surprise, but storage battery prices vary widely. Rough estimates around the battery capacity range are:
- 5kWh: £3,500 - £5,000
- 10kWh: £5,000 - £7,500
- 15kWh: £7,500 - £10,000
- 20kWh: £10,000 - £12,500
The different pricing is down to battery technology and brand reputation. Purchasing batteries will be the most expensive part of your solar system.
With the price of batteries being so high, would it be possible to purchase new ones in the future and integrate them into your system?
Can You Add Battery Storage To Existing Solar Panels?
Yes, you can add new batteries to your solar system’s storage solution. But before purchasing more batteries, check if your inverter can handle additional units.
Most modern inverters are ready to accommodate more batteries. The next item to check would be your solar panels' voltage and current outputs. You want to be sure that they match.
We’d recommend that homeowners with a restricted budget purchase solar panels and an inverter to supplement their home’s monthly energy bills.