Batteries are widely known in the industry as commercially unviable at current costs. However there are some situations where installing Solar PV with a battery bank is the best economic option available. Firstly its worth looking at some of the main ways solar batteries create value.
- Self consumption during non-solar periods
Perhaps the most obvious way in which a battery could be utilised is by charging the battery during the daytime while solar panels generate surplus energy and discharging during the night time. Typically self-consumption in this method alone is not sufficient to merit the investment of Solar Batteries at current pricing. Best cases for self consumption will cycle daily to maximise utilisation during the useful life lifetime of a battery.
- Lowering peak demand
Lowering demand charges presents some challenges for Solar PV systems. Batteries can provide greater assurance that daily peaks won’t be as high. Demand charges can represent up to 50% of a commercial power bill so this is a significant benefit to investment of solar batteries. To calculate the savings you can expect, a granular understanding of your energy consumption (30 minute interval data) and a good understanding of your electrical retailers demand tariffs is required.
- Arbitrage between retail prices
A battery bank can help manage the fluctuation in retail prices through-out the day. At its simplest, the opportunity would be to charge the batteries in off-peak periods and discharge the batteries during the peak periods. In some cases the difference in c/kWh can be over 30c so this can create significant value if your energy profile suits. Similarly larger energy organisations are exploring opportunities to leverage battery solutions at scale to sell electricity on the National Energy Market (NEM) as critical times. In the future, peer to peer energy trading platforms will allow residents and businesses to do the same.
- Coverage During Blackouts
Power critical businesses stand to lose large amounts of money from lost business during unexpected blackouts. Depending on the reliability of the grid in your area, a battery solution as a backup power source can provide great value by enabling business continuity. Largely batteries contend with diesel generators in this space which are expensive upfront and to run – however offer greater longevity if the blackout lasts a longer than the battery capacity.
- Avoiding power supply upgrades
Grid infrastructure can be very expensive. In some cases businesses who require a lot of power will need to pay for a sub-station or large transformer to be added to the network to enable them to draw the required quantity of power. In most cases Solar Power with batteries is a cheaper and preferable solution and can be either tied in with the existing transformer or designed as an off-grid solution.
Importantly the above applications of solar batteries are not mutually exclusive. Meaning to assess the potential of solar batteries you need to analyse all other feasible opportunities in conjunction. Similarly the product specific attributes such as rate of degradation, round-trip efficiency and effective depth of discharge must be factored in to examine the performance over the expected lifetime.