Solar Power

The New Carlisle Solar Challenge is Launched!

CarlisleSolarThe Carlisle Solar Challenge is a community solar campaign sponsored by the Carlisle Energy Task Force with support from the Town of Carlisle.  The objective of the Carlisle Solar Challenge is to make it easier and more affordable for Carlisle residents to adopt and own residential solar energy systems. Our goal is to double the amount of residential solar from about 70 solar systems today to more than 140 home solar systems by the end of 2015.  Request a Free Home Solar Evaluation Continue reading

The Little Town That Did

Flash back to the May 3rd edition of the Carlisle Mosquito and its Green Corner submission, The Little Town That Could. That article announced Carlisle’s selection to participate in the state-wide Solarize Mass program. This article is its “bookend” counterpart to share the results of how well we actually did.

Solarize Mass backgrounder

Solarize Mass was developed and sponsored by the Massachusetts Clean Energy Center (MassCEC) and the Massachusetts Department of Energy Resources (DOER) with the express mission of increasing the awareness and adoption of solar energy systems throughout the state. Having just completed its third yearly cycle, Solarize Mass has helped overcome the complexities and cost barriers that have traditionally plagued the solar energy market, and in doing so has enabled the addition of more than 1,250 new solar energy systems within 31 Massachusetts cities and towns. The electric energy produced by those solar systems will reduce the state’s greenhouse gas emissions by more than 140,000 tons of CO2 during their operational lifespan.

How well did Carlisle do?

Carlisle was one of ten communities participating in this round of Solarize Mass. I’m pleased to report that 54 Carlisle households took advantage of the program’s attractive pricing and are now en route to solarizing their homes. The town will be adding more than 380 kilowatts of new solar electric capacity to its preexisting 160 kilowatts (i.e., more than a 235% increase), which will reduce Carlisle’s greenhouse gas emissions by an additional 5,700 tons of CO2 over a 25-year period.

Carlisle’s performance in Solarize Mass substantially exceeded the goals and expectations we had envisioned at the outset of the program, which is a testament to the environmental consciousness of our community. With 200 households expressing interest in solar energy—and 54 actually contracting for a system—Carlisle’s solar interest “conversion rate” of 27% led all ten participating communities. Similarly, Carlisle also led all ten communities in the percentage of homes receiving a solar site assessment that went on to contract for a solar system (an impressive 43% of the 127 Carlisle homes that were assessed procured a solar system versus a program-wide average of just 32%).

What’s next for solar in Carlisle?

Despite the town’s excellent level of solar adoption during Solarize Mass, we actually had far more homeowner interest in solarizing than suitable sites to do so. Solar energy systems need to be installed in locations that receive a sufficient number of hours per day of uninterrupted (and unshaded) sun exposure to make their investment financially practicable. We all love our large, wooded lots, but frequently they don’t present an ideal set of ingredients for solarizing.

Given the sizable unfulfilled level of interest in solarizing in Carlisle, the Energy Task Force has already begun considering additional approaches to reduce the town’s dependence and reliance on electric power generated from fossil fuels. One of the options we will be investigating includes installing more solar systems on town-owned buildings (e.g., town hall, fire station, cranberry bog house, adding to the existing school solar system, etc.). Installing a community “solar garden” in town may also be a viable option. The town of Harvard is leading the way as the first city or town in the state to launch such a community resource, serving as a model for other communities (see

In the meantime, if you have any questions or suggestions regarding solar energy in Carlisle, you can continue to reach out to Solarizing in Carlisle isn’t ending with the conclusion of Solarize Mass!

Solarize Mass Deadline Extended to October 31st!

Solarize Mass Program Extension

Greetings everyone. There’s nothing quite like a looming deadline to get people’s attention focused, and last week was no exception here in Carlisle. Carlisle homeowners signed on for almost 50 kW of new solar capacity last week as the September 30th Solarize Mass deadline grew closer. But those of you who have been in private communication with me recently know that I’ve been anticipating that MassCEC would end up extending the program through the month of October, and the official decision to do just that was publicly announced on September 25th. You can read MassCEC’s press release on the Solarize Mass program extension here:

As indicated in the press release, this round of Solarize Mass will be extended through October 31st in order to allow homeowners who are already engaged in the consideration of a solar solution through the program (such as most of you) more time to evaluate their options and make an informed decision in a less hurried manner. As I’ve reported previously, we’ve seen a substantial uptick in new solar interest among Carlisleans since the end of August, and I know from personal experience that getting an assessment, evaluating a proposal (or multiple proposals), making a go/no-go decision, researching and figuring out financing options, determining whether or not to undertake re-roofing and/or tree removal, etc. can take a chunk of time. So for those of you who have been feeling rushed by the September 30th deadline, now there’s a bit more breathing room for you to make the decisions that are right for you. Continue reading

Computing the ROI of a Solar Energy System

Whether or not to acquire a solar photovoltaic (PV) energy system can be a tough decision for many people. Finances and economics tend to dominate the overall decision process. But thanks to a variety of both first-year and ongoing incentives, most solar PV energy systems are able to produce annual returns on investment of 10%-20%, along with complete payback of your net upfront expenses within five to seven years.

But how are those figures actually computed, and how do you know what set of system options and assumptions yield the greatest long-term benefits for you? Read this (somewhat longish) posting to find out: Computing the ROI of a Solar Energy System.

High Performance Solar Panels: Extra Oomph for Your Solar System

When you acquire a solar photovoltaic (PV) system, the price you pay is generally based on the combined power capacity of the solar panels in the system (expressed in watts or kilowatts), whereas the financial value you derive from the system stems from the electric energy that it generates over time (expressed in kilowatt-hours). For a brief tutorial on power vs. energy, click here.

The electric energy delivered by a solar system is mostly governed by its rated power capacity, but it’s also fairly dependent on external efficiency-related factors such as the degree of shading that the system experiences, as well as the tilt angle and azimuth of the roof on which it’s installed. As a general rule, it makes prudent financial sense to acquire a solar system with as much power as you can afford (or that your roof will accommodate). That will serve to minimize the duration of your payback period while maximizing your return on investment.

But how much power is enough, and how much is too much? A simple rule of thumb applicable to solar PV energy systems is that each watt of power capacity will generate between 1.0 and 1.2 kilowatt-hours per year of electric energy (depending on the efficiency-related factors mentioned above). That means that a 5 kilowatt solar system (the average size across Massachusetts) will generally produce between 5,000 and 6,000 kilowatt-hours per year of electricity, depending on its efficiency. Continue reading

Momentum Builds for Solar Power!

The momentum of interest in our solarize program continues to build. Here are some statistics through the end of July: Solarize-Chelmsford-Carlisle(Web)

  • Number of Carlisle residences expressing potential interest in a solar energy solution: 86
  • Number of solar site assessments performed in Carlisle: 47
  • Number of solar proposals submitted to Carlisle residences: 33
  • Number of signed Carlisle contracts: 5
  • Total solar capacity under contract: 36.5 kW
  • Average system size: 7.3 kW
  • Current Solarize Mass tier level: 2

The total contracted solar capacity that we achieve by the end of the program in September (combined with that of Chelmsford) will determine the price per watt that every participant in the program will pay for SolarFlair’s base solar PV package. solarflairlogo

Tier Level Contracted Capacity Price per Watt
Tier 1 1-25 kW $3.69
Tier 2 25-50 kW $3.59
Tier 3 50-100 kW $3.49
Tier 4 100-200 kW $3.34
Tier 5 >200 kW $3.14

If you are considering a solar solution for your home—but have not yet scheduled a solar site assessment—you should do so soon in order to beat the last-minute rush.  If you have any questions or need information please feel free to contact me at

Rich Kane, Solar Coach

Power vs. Energy for Solar PV Systems

Most technology disciplines have their own lingo and terminology. The solar photovoltaic (PV) industry is certainly no different in that regard, but a lot of its lingo happens to be rooted in the electrical industry.

A solar panel’s sole mission in life is to convert sunlight into electricity, but knowing how that’s technically performed within the solar panel isn’t really something that the typical homeowner needs to master. What is important, however, is your ability to understand how much electricity a solar panel produces, and how that relates to the electricity usage within your home.

Click here to help you decipher some of the most common electrical terminology pertaining to solar PV systems so that you’ll be better equipped to consider and evaluate whether a solar PV system is right for you, as well as what kind (and size) of system might best meet your needs.

Free Air Conditioning

Been running your air conditioner a bit recently? If so, it’s likely that your NSTAR meter has been whirring around like the warp engine in the Starship Enterprise. Why not slow that meter down—way down—by relying on a plentiful, inexpensive, and environmentally conscious way to fuel the cool breezes in your home?

According to NSTAR statistics, the average home in Carlisle uses approximately 50% more electricity during the “dog day” summer months than it does during late spring and early fall. That’s over 400 kilowatt-hours (kWh) per month of additional electricity consumption for the average Carlisle home, largely attributable to air conditioner usage. With summertime NSTAR rates now exceeding 17 cents per kWh, that’s about $70 per month tacked onto your electric bill for air conditioning alone.

With a solar photovoltaic (PV) energy system, the additional electricity that your home consumes for air conditioning can be nicely offset by the additional PV production achieved during these wonderful sunny summertime days of early sunrises and late sunsets. Your total annual air conditioning usage can likely be accommodated by the production of less than two solar panels alone. With an average-sized Carlisle solar PV system consisting of about 30 solar panels, there would still be plenty of additional solar PV production capacity available to power your “everyday” items like heating, lighting, refrigeration, entertainment, communications, and well water.

With Carlisle’s current participation in the Solarize Mass program, there’s never been a better time to go solar. There are now less than three months left to take advantage of Solarize Mass pricing. Don’t wait for the September rush to the finish line. Sign up today for a free, no-obligation site assessment and begin learning more about how and why a solar energy system can be such a worthwhile addition to your home. See additional information about Solarize Mass posted to the Solar Power section of this Green Carlisle website, or contact for more details.

Meet Your Installer Night a Great Success!

On Thursday evening, June 20th, a hearty contingent of more than 40 Carlisleans braved calm and balmy pre-solstice weather conditions to attend the Solarize Mass Meet Your Installer Night held in the Clark Room at Town Hall. During this event attendees listened intently to presentations from representatives of both the Massachusetts Clean Energy Center and SolarFlair Energy detailing the ways in which the Solarize Mass program provides such a great opportunity for Carlisle residents to avail themselves of the many advantages of solar photovoltaic energy systems. A lively and interactive Q&A period followed the formal presentations.

Meet Your Solar Installer NightIf any of you would like to review what was presented during Meet Your Installer Night, the presentations may be accessed via the links below.

MassCEC presentation:

SolarFlair presentation:




Thanks again to all attendees who came to last week’s meeting. If any of you would like to initiate or continue a discussion regarding a solar PV system for your home, your Solarize Carlisle team will be available to speak with you at two locations on Saturday at Old Home Day. Please contact for any further details related to solar PV systems and/or the Solarize Mass program.

Net-Metering 101

There are numerous financial and environmental reasons why homeowners acquire solar PV systems. From a financial perspective, a compelling motivator that’s applicable to all solar systems (whether you purchase or lease) is the prospect of reducing—and in some cases even eliminating—your public utility electric bill. It’s estimated that about a third of the homes in the US are potentially capable of generating most of the electricity they consume within a year with a rooftop solar energy system.

net meterGazinta Minus Gazouta

With solar energy, you have unrestricted access to the electricity your system generates while it’s being generated. At times when your solar system produces more electricity than you’re using, it feeds the excess into the electric utility grid, and your electric meter actually runs in reverse. When you’re consuming more electricity than your system is currently producing, you get as much of the remainder as you need from your utility just like you do today. Over the course of your billing cycle, you only end up paying for the net electricity you consume from the grid (i.e., over and above what your solar system produces). That’s where the term “net-metering” comes from.

Net-Metering Practicalities

Residential solar PV systems are generally sized to generate somewhat fewer kilowatt-hours (kWh) on an annual basis than their homes actually consume annually. That’s the most common end-user scenario, and means that credits generated during high solar production periods will be “depleted” during low solar production periods (i.e., most Carlisle homeowners with solar systems will still end up paying some amount of money to NSTAR on an annual basis).

During NSTAR billing periods in which your solar PV system generates more power than your home consumes (i.e., the NSTAR meter reading at the end of the billing cycle is less than it was at the start of the billing cycle), NSTAR will apply a net-metering credit to your bill based on the net number of kilowatt-hours deposited back into the grid. The current rate for those credits is $0.166 per kWh (generation + delivery), but that will fluctuate over time (mostly an upward trend). Net-metering credits will accumulate during billing periods where production is higher than consumption (e.g., summer months); conversely, the credits will get depleted during billing periods in which consumption exceeds production (e.g., winter months).

The bottom line is that NSTAR will not send a check to you each month for your net-metering credit. The credits will just get carried forward on your NSTAR bills until they’re depleted during lower production periods later in the year.

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