Solar power is America’s fastest growing electricity source, and the total installed capacity in the country surpassed 100 gigawatts during the first months of 2021. Solar panels become even more useful when combined with battery systems – their electricity can be used at any time, and not only when there is sunshine available. Batteries can also be used for backup power, something that is not possible with solar panels alone.
A key advantage of a solar battery system is not requiring any external fuel inputs, while diesel must be delivered by truck, and natural gas must be provided as a utility service. Also, backup generators fired by fossil fuels don’t perform any functions when the building operates normally, while a solar power system is constantly reducing your electricity bills.
The US offers a federal tax credit for solar power systems, which is currently set at 26% until the end of 2022. However, the tax credit also covers solar powered battery systems, as long as they meet the following condition:
- Residential battery systems: Getting 100% of their charge from solar panels.
- Business battery systems: Getting at least 75% of their charge from solar panels.
A solar power system with batteries also operates with zero emissions, while diesel generators and gas microturbines release greenhouse gases when being used.
Combining UPS Units and Inverters
Since UPS units are more expensive, it does not make sense to size them for hours of operation with no power supply. A smarter approach is having a short-term UPS capacity, providing time for a larger inverter + battery system to take over the load.
- An inverter with energy storage can be used as a direct power source for less critical loads such as lighting and ventilation.
- UPS loads can remain connected during an extended blackout, and you can simply recharge the UPS batteries with the inverter output.
Note that energy efficiency measures let you operate longer with backup power. For example, if you replace fluorescent lights with equivalent LED products that consume 50% less energy, they can last twice as long with backup power.
The best configuration changes depending on the loads present in your building. For example, an office with plenty of computers and communication equipment generally needs a large UPS. On the other hand, a storage area that only uses ventilation and lighting can use a conventional inverter with no problem. With a professional assessment of your installations and equipment, you can determine the optimal configuration.