Solar Service Home Solar Panels
Written by Lisa Walsh

Solar Energy During a Power Outage?

Not quite so cut and dry…

Solar Service ,Home Solar PanelsMost 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.

Written by Lisa Walsh

Solar Monitoring

Homeowners can see how their daily sunshine dollar is spent

Most homeowners who have invested a tidy 20 – 30K in a whole-house solar electric system want some idea of exactly how much, and when, their solar system is generating energy. This is true especially given the fact that most solar systems in Maryland, DC, Virginia and surrounding area are grid-tied. The solar electric system provides a large portion, though generally not ALL of a home’s electricity, with the balance coming from the traditional energy provider (BGE, PEPCO, etc.) during periods of high usage and/or low sunshine levels. So most customers still receive an electric bill, albeit greatly reduced. An online solar monitoring system keeps the homeowner plugged in to how much energy they are receiving from the sun versus their utility “back-up”.

The monitoring system is tied to the Inverter… (An inverter, by the way, converts DC power to usable AC power.)

SES often uses Enphase Microinverters in residential solar electric systems. This is our preferred monitoring system for a variety of reasons, including simplicity, cost-effectiveness, and customer support. With this system, each panel has its own inverter and associated monitoring. In contrast, solar systems that use only one inverter for the whole array do not have the ability to monitor performance of individual panels; just the entire as a whole. Microinverters, convert, quantify, and record the DC to AC energy conversion on each individual panel, independent of the other panels. These microinverters come with the Envoy Enlighten monitoring system. The homeowner simply clicks on a link from on their computer or Smartphone to see live readout of their current system power generation along with a robust record of historical data. Both the homeowner and system installer are notified when Enphase detects issues such as a panel or inverter failure (a rare occurrence), communication issues or shading (due to tree growth etc.), enabling a speedy remediation. Fortunately, true solar panel/inverter issues are few and far between, if at all, keeping the monitoring system employed at its optimum job: counting the rays of sunshine that power your home.