Wednesday 22 February 2017

Making the most of your excess Solar PV generation

Its been a while since I have written a post, though I see I have a whole load of half completed drafts. Things have been busy over the last few months!

Just this week I have put together this editorial for a regional magazine, The Landsman, and thought it would be a good idea to reproduce here as solar storage has changed dramatically since just last year, with far better batteries available at really good prices that mean Li-Ion is now leading the way over Lead Acid on performance and cost!

If you’re an owner of solar PV panels, you will already be aware of the benefits that are brought simply by daylight. Lower power bills and free to use electricity count as main drivers of course, along with Feed in Tariff payments meaning you receive a payment simply for generating your own power.

One of the small drawbacks of this seemingly utopian system is that a proportion of this generated power will be exported straight out onto the grid without any benefit to you but add some technology and this could change. There are devices available that can be retro fitted to grab power before it gets exported allowing you to store it for later use.

The budget version is just one of the many power diversion devices on the market. A reliable unit is the Solar iBoost, costing around £400, which keeps a check on that excess PV power and sends it to the immersion heater in your hot water cylinder to store as hot water. Great if you have a hot water cylinder to use, if not, maybe look at battery storage?

Until a few years ago, Solar battery technology was still based on traditional lead/acid, like a car battery. This was mainly due to economics as compact lithium based batteries were still really expensive, but they do offer a 10-15 year lifespan and require no maintenance.

This situation has now changed, and since Tesla’s introduction of the cumbersomely large Lithium Ion battery a year or so ago, other manufacturers such as LG, Victron and SolaX are now producing more compact storage devices, ideal for installation inside your home. Based on the same concept as hot water diversion, battery storage systems divert the excess power to be exported into a set of batteries. A controller keeps that power securely stored away until your house needs to draw power off the grid, then releases if back for you to use. In an ideal situation, with a good balance between battery and solar array size, you should see a dramatic reduction in the amount of electricity you purchase.
Most are easy to fit, and can be easily accommodated in your house and integrated with your existing Solar PV system. Some models also provide you with a backup power socket to keep you supplied with 230v power if in the case of a power cut - handy for rurally situated people.

Though the concept of payback is not used in the battery storage world, we have recently seen what may be the first of many energy price increases, so it does spur us to consider ways of keeping electricity bills as low as possible. You’ll find that good quality systems start at around £4,000 installed and will provide you with either online or in home monitoring too. For more information speak to Chris Rudge on or visit