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Before considering expensive battery storage for your Solar PV system – other options exist that can direct unused solar PV generation to electric vehicles, hot water and even heating.  In reality, battery storage is not for everyone.

Battery storage systems are currently being sold aggressively.  Unfortunately, for the consumer, they are not always economically viable and many will not see the return on investment.

The problem with battery storage systems is that it is difficult to model savings.  Everyone has different energy usage and different patterns of life. Many people will also see a significant change in energy use if they invest in an electric vehicle in the future (which completely changes any assumptions on current usage).

It is also important that any battery storage system ‘pays back’ its investment before the end of its warranty period.  We are hearing that many sales people are claiming that battery storage systems will operate beyond their warranty period which is a dubious claim. There are potentially insurance implications from continuing to use a battery storage system in a home which is out of warranty.

Aggressive sales pitches promoting battery storage systems are also failing to fully understand a clients actual energy use and opportunities for maximising onsite usage of Solar PV electricity produced by the solar system.  Energy ‘diverters’ like the iBoost and Myenergi ‘Eddi’ cost a fraction of the cost of battery storage systems.

These systems can effectively re-direct unused electricity to hot water or other heating applications.  These alternative options for diverting ‘unused’ solar generation (normally lost to the grid) can have a significant impact on energy bills by reducing oil or gas bills by heating using excess solar electricity without spending thousands on battery storage.

We are currently experimenting with the latest products to further maximise bill savings and usage of onsite generation.

Anyone installing a solar PV system can (and should) sign up for a Smart Export Guarantee (SEG).  This requires an electricity meter that can monitor ‘export’ and this reading is used to pay the home owner for any electricity generated by the solar system and exported to the grid.

The benefit of this electricity meter (that monitors actual ‘export’) is that it allows a home owner to monitor actual ‘export’ over a 12-month period (to account for summer and winter months).  This reading of exported electricity over a set period gives the home owner actual data to calculate if battery storage is financially viable.

The key question is ‘can the battery storage provide a return on investment over the warranty period of the battery storage system (normally around 10 years)?’ A caveat is that even with battery storage, a solar PV system will still export some electricity to the grid when the battery is full. This will also need to be factored in when doing the calculations.

Questions that should be considered include:

• Current energy consumption and patterns of energy consumption.
• Scope for using energy as it is generated from a solar PV system (pattern of life, occupancy and can energy use be adjusted to maximize benefit from solar PV production.
• Alternative scope for usage of unused solar PV without deploying battery storage using lower cost products (i.e. does the property have a hot-water tank allowing more cost effective hot water energy diverters to be used).
• The likely financial benefit of storing unused solar energy in battery storage for use later. A calculation based on anticipated (or measured) solar PV lost to the grid – that would be stored in battery storage (even with battery storage most PV systems will export when the battery is full and energy demand is below generation); compared against the likely earnings from any export payments (i.e.the smart export guarantee (SEG)). Are the bill savings of storing and using more solar energy (less the possible income from selling it to the grid without battery storage) likely to pay for the battery storage system within its warranty period?

There are people claiming that a solar PV system and battery storage systems have given them a significant saving in electricity bills.  The fact they installed Solar PV is likely the main reason for the bill savings.  The contribution of the battery storage system versus the investment cost (and payback) is another consideration.

Just installing a solar PV system alone will give a home owner potentially significant bill savings.  By adding a battery at the same time the Solar PV is installed – people cannot be certain that the additional benefits from the Battery Storage system will actually pay for the battery part of the system within the warranty period.

We are being called out to a lot of battery storage systems sold by other companies which are struggling to maintain charge and discharge cycles in the winter months; or are not performing financially.  Many homeowners are assuming there is a problem with the battery storage when the actual issue is their expectations which are unrealistic and based on mis-representation by the original installer / sales person.

We are seeing on social media that solar battery installers are making various claims about battery storage systems being financially viable when used to aggregate between night and day electricity rates.

This involves the home owner charging the battery at night (at a cheaper electricity rate) and then using this lower cost electricity during the day when the ‘day rate’ of bought electricity is higher.

We advise caution using this as a basis for any financial decision to buy battery storage.  Day and night rates / economy 7 rates may be withdrawn – the energy market is changing and some providers have already stopped offering new customers economy 7 or cheaper night rates.

By assessing real world data and actual case studies, we have some guidance on when battery storage becomes financially viable.  The key is understanding a homeowner’s pattern of life, electricity usage and exploring any other options for using unused solar electricity before it is lost to the grid.

Future electricity prices and changes to the cost of battery storage systems may change the viability of battery storage, but unless you have a large solar PV system, the financial model does not add up for most households.

It has come to our attention that several solar companies are contacting legacy system owners making various false claims. A common claim is that “the warranty for the solar PV system is no longer valid because the original installer has ceased trading”.  Following an ‘inspection’ (normally by a sales rep who has no electrical qualifications), the dubious recommendations include: “a new solar PV system because the existing system is unsafe”; or “the home owner would benefit from a battery storage system”.

This is concerning for the industry. In reality, industry governing bodies and competent persons schemes provide very little consumer protection.  It is important that consumers get a second opinion and do their own due diligence / research before committing to a substantial investment in battery storage. It should also be noted that if incorrectly designed and installed – battery storage can actually invalidate any legacy Feed-in-Tariff (FiT) payments.

Solar battery storage sales which mis-represent the financial benefits of battery storage may give consumers scope for recovering any payments (and the ability to write off any on-going liability) – especially if the product was sold on finance.  This will require legal advice, and this is likely to be one of the next big mis-selling issues.