The concept of Solar PV battery storage is to save and store your unused Solar energy that you have produced through the day to use later when your Solar PV panels have stopped producing energy.
Without battery storage this energy would have made its way back to the grid and you would have received either zero if you’re on the feed in tariff or pennies from the SEG (smart export guarantee). This is of course completely counterintuitive – we install Solar Panels to see a return on our investment. Why then is it that so many people with Solar PV are failing to acknowledge the important of a battery storage system.
If you are on the feed in tariff you are already being paid for exporting 50% of what you generate regardless if you export it or not. Back when the feed in tariff was available to new customers there was no way of measuring the export so the agreement was 50% of what was generated was the assumed amount that would be exported.
The best part about this is that if the 50% amount isn’t exported and it is used or stored instead, it won’t affect your feed in tariff or the amount of money you receive in quarterly payments.
Battery storage is available in a selection of sizes from various manufacturers and below is a few examples:
Pylontech 2.4kWh / 3.5kWh / 4.8kWh
Growatt 3.3kWh / 6.5kWh
These batteries use Lithium ion phosphate technology (aka Lipo) and have a depth of discharge from 90% to 100% depending on the brand.
Battery storage upgrades are common place with rising energy costs as for each kWh you store, you won’t need to buy from the grid when you come to use it. If your energy price is 35 pence per kWh and you use 6kWh of energy from your batteries then you have saved £2.10.
If you take this a step further and assume you use this amount of energy each day after your panels have stopped producing then the maths is simple; £2.10 multiplied by 365 days gives you a total of £766.50 annually so a system wouldn’t take that long to start saving you a lot of money each year.
The thought of sending your energy back to the grid for pennies or free is enough for some people to warrant upgrading to battery storage especially when buying it back is so ridiculously expensive now!
The other advantage of battery storage is that you can charge from the grid on a cheaper overnight tariff.
If you can remember the old economy 7 tariff then the newer tariffs are similar albeit with less hours normally.
Octopus energy is currently offering overnight rates between 12:30am and 4.30am for less than 8 pence per kWh!
Batteries can be programmed using the inverter software to charge during this period thus saving more money, this is especially useful in winter when generation is significantly less through the day and early mornings. Waking up to a 50% charged battery could be just the boost you need to see you through your morning routine before the sun comes around and wakes up your Solar Panels.
Slowly i’m sure you’re starting to see that a battery storage system most definitely is worth it.
‘I already have Solar Panels though, can I still purchase a Battery Storage System?‘
Retrofitting battery storage technology can be done in 2 different ways.
The first way is an AC coupled inverter. These inverters are completely separate to your existing system and are basically a smart battery charger. They are installed with a ct that clamps around your main incoming supply and this tells the inverter to start charging when it sees your energy going back to the grid. Newer more complex models also come with monitoring software that allows you to view what your production and consumption rates are which is perfect if you like to see detailed figures and what your Solar array is actually producing.
The second option is to replace your current string inverter with a hybrid type. A hybrid inverter will carry out both functions that a string inverter and an ac coupled inverter would normally do but all inside one clever little unit. Online monitoring is available and the unit will take up much less space than fitting a second inverter.
A lot of companies seem to be offering a “Free Health Check”. I would advise that you should be careful of these potential scams. It usually involves a sales rep on commission from a sales company coming to your home and pressing a few buttons on your inverter with next to no knowledge or qualifications in Solar PV to then tell you that your system is only working at 35% efficiency. If you have seen a noticeable drop in your generation meter readings then you may have a problem if not they are just trying to sell you a battery storage system at a usually overinflated price.
The majority of battery storage systems come with a 10 year manufacturer warranty and the inverters are similar. A decent reputable brand of inverter will require an installer code which stops dangerous diy installations as you need this code to set up the inverter including monitoring and most importantly your warranty!
So the question remains – is solar battery storage worth considering?
If you look at the savings that can be made then most definitely! The most important thing is being savvy with your energy usage. Turning 10 appliances on at the same time will pull far more than the inverter/batteries can supply so clever usage will save you the most money.
A better storage system can increase your self consumption rate up to 85%! This means that if you are producing 3000kWh a year then it has the ability to increase your self consumption to 2550kWh whereas a typical self consumption rate without batteries is in the region of 25%!
Spectra Solar is fully qualified to complete these kinds of installs and has the necessary qualifications to sign these jobs off with building control and the national grid by completing a g98 or g99 form on your behalf.
If you are interested in battery storage or have questions about the installation of batteries for your Solar Pv system then please contact the office on 0800 772 3361 and speak to one of our expert team!