Not quite so cut and dry…
Most of us who live here in Anne Arundel County appreciate our proximity to the Chesapeake Bay, changing seasons with spectacular Spring and Fall temperatures, and mature wooded areas. However, these pros quickly become cons during snowstorms, thunderstorms and Maryland’s annual hurricane season from late August through October when Hurricanes such as the infamous Isabelle and Sandy blast through our wooded, watery region, bringing floods, downed trees and – the clincher – power outages. If not for the threat of the power outage, we may sit back and enjoy a hurricane as a powerful force of nature, so long as our lights are on, heat or ac is blasting, and refrigerator’s chilling.
Hurricane Sandy caused around 300 thousand power outages here in Maryland, with an estimated 60 thousand in Anne Arundel County alone. It’s a no wonder that many prospective solar system owners – as well as existing solar system owners – want to know if a solar power system can power any of their appliances during a power outage, even if only while the sun shines. Unfortunately, it’s not that simple.
For both functional and safety reasons, there are several additional complexities to a “hybrid” PV system that connects to the grid but also provides backup power during a power outage. To start, during an outage you need to be able to safely isolate your “solar generator” from the grid to protect the line workers. You will also need energy storage (batteries) to balance solar energy supply and household demand. In most cases, you need an additional inverter to convert the batteries’ DC electricity back to AC electricity for your household. Lastly, most battery systems require some level of maintenance as well as replacement one or more times in the lifetime of the solar system. The bottom line is that unless you are willing to pay a nominal 30% premium for a solar system that includes the necessary batteries, transfer switches and additional inverter(s), you might be better served with a more traditional approach to backup power, like a gasoline or natural gas generator, and possibly just for critical loads.
Don’t get me wrong. Hybrid systems are growing in numbers and technology advancements, consumer demand, and smart grid capabilities all will help to drive down costs to make these systems more affordable in the future, ideally making our grid more stable with many distributed sources of energy. In the mean time, most solar installers can offer a hybrid (battery backup) or traditional generator back up options, so you can decide what suits you best.