Solar energy production has grown rapidly and exponentially over the last several years, providing residential and commercial buildings with a renewable, clean, and sustainable source of electricity. We caught up with Solaris owner Suzan Elichaa to learn more about the options available to Mainers who want to utilize this technology in their homes.
SG: What is photovoltaic energy and how does it differ from other solar energy solutions?
SE: Photovoltaic (PV) systems take the sun’s radiant energy and turn it into electricity. Historically in Maine solar thermal hot water systems were most popular, but with the price drops in solar electric photovoltaic modules over the last few years this has reversed.
SG: What are the solar PV options available to residential customers today?
SE: The majority of solar PV customers choose to remain tied to the utility power grid to avoid the cost and maintenance associated with batteries. With grid tied systems, CMP becomes your battery. So when you create more electricity than you use, you receive a credit (in your CMP account) that you draw from when your solar PV system is not making electricity such as at night or when there is little sunlight. Because CMP will provide electricity to meet the needs that your PV system may not you can start small and expand as your needs or budget allows.
SG: Are there some solar products that are a particularly good fit for Maine homes?
SE: PV is a great product for Maine. Most solar systems rely on the sun’s radiant energy, not heat, and we actually get a good amount of sun. Compared to an “ideal” solar state like Arizona, in Maine we need about 30% more modules. Our cooler temperatures actually help us since PV output decreases as temperatures rise. Plus we get enough rain to keep the modules clean. Micro-inverters give better winter/snow performance than standard string inverters. When PV is combined with an air source heat pump it makes the ideal way to have the sun’s free energy heat your house.
How has solar PV technology changed in recent years?
SE: The actual PV technology that is most commonly used has not changed much. What has changed is a much lower module cost and increased module output. Compared to 5 years ago, per watt prices are down over 50%. Another exciting change is micro-inverters. Traditionally you had one large string inverter that took the module’s DC power and converted it to AC that you use in your home. With micro-inverters, you have a small inverter at each module. So you do not need to worry about “outgrowing” the inverter size if you expand. And you can mix today’s 250 watt modules with 170 watt modules from 5 years ago. Partial shading is less of a problem with today’s technology and you get outstanding module by module performance data. You can even watch your system performance via the web or your smart phone. Over 90% of the installs we do take advantage of micro-inverters.
If you decide to use a traditional string inverter, SMA just released a game-changing unit. With all grid tied systems, when the CMP line fails the inverter shuts down. This prevents your solar power from feeding into the grid and can cause further problems or harm a line worker. The new SMA emergency power inverter disconnects then takes the power from your solar array to activate a built in outlet. On sunny day this may be enough to run your boiler or frig for a bit and keep your cell and computer charged.
SG: What kind of payback period are you seeing today?
SE: We buy our cars and homes because we know that making monthly lease payments costs us more in the long run. Electric power is no different. You can make a monthly payment to CMP or you can make a capital investment and generate your own energy. With the reasonable financing available today, in many cases you will pay less than you would if you buy your energy monthly.
Payback is a loaded word; there are so many ways to look at it. The wonderful, unique, valuable point is that with solar there is a payback. No matter which car, oven, or boiler you buy it will never start paying you back. With solar you can reduce or eliminate your electric bill. In most cases, after about 10 years your savings offset the initial capital investment. Since electric rates are bound to rise it may even be sooner. Then for the next 30 years or more the money you would have given to the electric company can go to fund your kids college, retirement, or for enjoyment. Quality PV has a 25 year warranty and a 40+ year lifespan. That’s a lot of years of free electricity.
SG: If a homeowner is interested in incorporating solar PV technology into his or her home, how do you recommend they get started?
SE: The first step is to make sure you are using electricity efficiency. Borrow a kilo-watt meter at the library to help find “phantom loads” such as VCR, computer monitors, printers, etc, and put them on power strips. Check the electric draw of appliances and replace them if necessary. This is much less expensive than buying more PV modules.
We will then review your annual kilo watt hour usage (available on your CMP bill) to determine how big of a solar array you need and come to your house to do a site survey to determine the best location for a solar PV installation.
SG: Is there anything else you’d like us to know?
SE: We would love to see solar on every home, but in reality there are often other projects that should be accomplished first. This may be weatherization, a boiler upgrade, and these days air source heat pump for space heating are a great idea for the vast majority of homes. A home energy assessment or audit is a great place to start.
