Battery storage systems
Store electrical energy in batteries for reuse later. After the sun has gone in the evening stored power can be recovered and delivered to supply the demand. If you have sufficient PV output during the day it may be worth installing a larger capacity battery.
There are two basically different types, DC coupled and AC coupled:-
- DC coupling basically uses a battery and via your existing inverter supplies you with electricity when the export has ceased and you start importing from the grid. Using your solar saved energy to supply the load when the PV stops generating - eg. at dusk or during the day when the sun goes behind a cloud.. Prices start from around £2500 installed.
- AC coupling uses a battery and is independent of your PV system and does the same as the DC coupled, but in addition has the future possibility of running as a backup should the grid fail. Prices start at around £2500 for self use storage installed
Storage with backup capability will add a considerable amount depending on the length of time (battery capacity) you might need to rely on for your own supply.
Battery technology is changing and typical storage batteries are Lithium Ion, (expensive but small), Lead acid AGM (cheapest but old technology and bulky) Aquion salt technology (new, expensive and bulky but recyclable).
Following the Government’s review of the Feed in Tariff, the payment rate has dropped considerably so its important to use as much of your own generated energy as possible. Some people will think it’s all over, there is no money in it anymore, but the reality is everybody needs energy.
The customer profile will change from one who is looking for a return on investment on their money, to one looking to secure their future energy and reduce their outgoings in the future.
Traditional financial models calculate financial return based on the FiT and the projected price increases, but how do we know what will happen to the price? For energy the most financially secure, and reliable way, is to have your own energy generation. This can be Solar PV, solar thermal, wind or hydro power.
With all the current publicity about possible government cuts many people will think there is no point in installing a renewable system now, but with all the uncertainties and the latest technology offerings, there has never been a better time to invest in generating your own energy.
With a 4kw PV system producing about 3,500 kWh a year, a typical summer day produces much more energy than you need but to meet the demand in December and January would need a much larger PV array.
What if you had storage? This could be storage into batteries or storage by dumping the excess into heating water. Either of these techniques makes more use of your own generated energy and can reduce peak demands on the grid, and even better save your daytime generated energy for your own use in the evening. All these are ways of storing your own generated energy for reuse later.
Currently using your own energy saves, depending on your tariff, around 15p/kWh, over 10p more than the current Feed in Tariff rate, so using your own energy is a reliable, secure, and predictable investment for the future.