Why install a Battery Storage system?
Batteries have a long lifetime and the cost savings over the life of the system can make economic sense for some homeowners and businesses. The increased ability to use renewable energy is an attractive bonus. Homeowners & Businesses can potentially reduce costs using battery storage in the following ways:
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Maximising Solar PV production
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The average cost of a Solar PV installation means that solar energy is typically inexpensive compared to purchasing electricity from the grid.
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Batteries enable Homeowners and Businesses to self-consume more Solar PV by storing energy for when solar is not available.
Application
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Most economical for Homeowners and small to medium energy users.
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Requires surplus Solar PV generating capacity.
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Suitable for Homeowners and Businesses interested in increasing the proportion of energy they consume from renewable sources.
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Time-of-use tariffs
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Batteries can be used to exploit the different cost of energy at different times of day.
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Energy can be sourced from solar PV or from the grid during off-peak tariff periods and consumed during peak tariff periods.
Application
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Most effective when the peak tariff rate is high.
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Larger energy users may find Time of-use tariffs ineffective because they are charged much less for energy than smaller energy users.
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Reducing capacity charges (Business only)
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Businesses that pay capacity charges can use batteries to limit the maximum power capacity used in a billing period.
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This technique limits the network component of charges which are calculated on peak power usage.
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Application
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Only suitable for businesses on applicable tariffs: typically larger energy users with predictable loads.
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Good knowledge of power usage is required for the system to be effective.
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Power for battery charging can be sourced from the grid, solar or otherwise.
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Most economical when high power usage occurs for short durations.
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What about battery life expectancy versus warranty?
Currently we are not aware of a single testing methodology that is used by all battery manufacturers to establish the performance and life cycling of their products. Predicting the life expectancy of batteries is likely to be inaccurate and inconsistent between different manufacturers.
Most batteries in the market today offer a warranty of up to 10 years. Within this 10-year period, some batteries offer warranties with 3650 cycles, (one cycle per day), while other batteries have warranties of 8000 cycles or more (if used for more than one cycle per day). Batteries designed for high numbers of cycles could potentially last longer than the 10-year warranty period when cycled only once per day. Professional advice is required for these assessments.
Does a solar PV system need batteries?
If the solar PV system is connected to the National Grid then technically your system will not need batteries as any excess energy can be sold to and fed into the grid under the Smart Export Guarantee (SEG). However more and more system owners are choosing to add battery storage to their solar PV system, increasing the self consumption from their PV system (how much they use of what the solar PV system generates) but more importantly reducing their overall house/site consumption and reliance on the grid. Even with battery storage the average household will still sell some excess energy to the grid and receive the SEG payment, assuming the system has been installed by an approved MSC or equivalent installation company. Added to this some energy suppliers now offer dynamic energy tariffs meaning you can also charge your battery storage during low rates and sometime even free. This is very useful in the winter/leaner solar PV production months as you can charge the batteries at lower rates and discharge at higher rates. The key to note with this is selecting the right energy management system that's user friendly with everything at your fingertips.
Batteries can also be integrated into hybrid grid tie / battery systems as a backup, protecting against mains power cuts.