Storage is taking off, but installers who want to keep customers happy will appreciate the benefits of a well-designed solution against an off-the-shelf system, writes Clean Energy Council general manager installation integrity Sandy Atkins.

At the Clean Energy Council we have recently noticed an increase in consumer complaints regarding solar power with accompanying storage units.

Although most of these have related to issues with off-grid systems, the same principles apply for storage which is connected to the grid. The Clean Energy Council splits each of the main accreditation types (grid-connect and stand-alone) into two key categories: design and install. While it’s possible an individual can be accredited in both of these disciplines, the two categories are distinct and require different skills.

What we are seeing is the supersizing of solar PV arrays with very little battery storage. For example, we might see 20kW of PV installed with 15kWh of usable storage (at C100) for a customer who has an average demand of 20kWh per day. The standard AS/NZS 4509.2 Stand-alone Power Systems Design has a section dedicated to battery sizing (section 3.4.7 for those who don’t know it off the top of their head).

What the consumer is finding in practice when they use these systems is that the batteries fill up quickly and they don’t use much electricity during the day. Evening is the peak use time, when people are showering, cooking dinner, watching television with their families and the like. But because the energy is being drawn out of the battery so quickly during these periods, it ends up operating more like a 10kWh unit at the C10 rate.

The frustrating thing about this situation is that a diesel generator is often required to get people through until the sun comes up. And although we are talking about a stand-alone power system in this example, if you replace “generator” with “the grid”, you can probably get an idea of what can go wrong here.

As you can understand, the consumer experience with solar and storage will not be a very good one if the generator is running every night.

One size doesn’t suit all systems

The common issue identified by the CEC’s investigations is that the issue at the root of this problem seems to be the purchase of “off the shelf” inverter and storage kits. These are kits where manufacturers sell pre-made systems with set amounts of storage. These are becoming very common in the on-grid storage market but they are also finding their way more and more into the stand-alone power system market.

Please don’t get me wrong in regards to these “off the shelf” systems. They can be great for meeting the needs of the customer and providing a very professional solution. But ultimately it is the accredited designer’s responsibility to ensure that they both understand the customer’s needs and the design limitations of these systems.

Energy storage is a new concept for most people. But it is also important to recognise that industry integrity can be a painstaking thing to build, which is particularly vulnerable if people begin to have bad experiences when the market is still very young.

This is the case with the storage industry right now, and every poorly-designed system risks eroding the community’s opinion of one of the most promising energy technologies of our time. It is imperative that the job is done right.

If you want help, just ask

If you don’t want to design systems yourself, that’s fine. There are others who can help. It doesn’t matter if it is a simple PV system or a complex energy storage system: the Clean Energy Council requires these systems to be designed by someone with a CEC Design Accreditation.

We have a list of accredited people who have “design only” accreditation. These people do not install systems but are completely focused to designing systems. So if you need some assistance in this area, please don’t hesitate to get in touch. We can help to hook you up with someone who can do the job right, and make sure the storage unit that is installed is the right size for the people who need it.