Wind Vs. Solar Power

If you're comparing a small-scale wind power system vs. a grid-tied photovoltaic system, there are a number of factors to consider.

Small scale wind, in general, is a more challenging application in Maine because it requires both 1) a really good wind site, and 2) a turbine site that is at least 30' higher than nearby obstructions (i.e. trees). Very few locations in Maine meet these requirements, see the solar insolation vs. wind map comparison chart to see this visually.

These restrictions aside, small scale wind is making a comeback thanks to modern technology that resolves limitations and mistakes made with earlier generations. One of the champions of the revival of small scale wind is local Maine-based manufacturer Pika Energy. Pika Energy offers a unique wind-solar hybrid inverter that allows you to combine multiple renewable technologies to power your home.

Questions about wind vs. solar? Contact us. We'd love to help.


Combo of Solar and Wind Give Greene Homeowner Energy Independence

February 18th, 2014

Greene ME Solar power suniva array

The split-axis solar array for Jim Weston in Greene, ME. Uses all-black American made Suniva solar modules

After an initial horror story with an early wind turbine, Jim Weston of Greene has settled on the perfect renewable combination: a new generation Pika Energy wind turbine and a solar electric array installed by ReVision Energy.

Jim first installed his Raum turbine in the mid-2000s, when “wind was hot” in Maine. Unfortunately, the Raum turbine rarely lived up to advertised production figures and in 2012, the turbine failed completely. By that time both the original installer and Raum Energy were out of business, and Jim was left wondering what to do with a 100 foot tower installed on his wide-open property in Greene – an excellent place to capture wind, if the right technology was employed.

ReVision Energy has heard similar stories from other owners of small scale wind turbines, and so when we met Jim at the Common Ground Fair in 2012 we understood his skepticism that solar would work as advertised. However, in the years since Jim had last looked at solar, costs had dropped by more than 50%, and no longer required batteries, making solar a much more cost-effective investment than it had been in years past.

ReVision Energy sent our seasoned solar design expert Will Kessler to evaluate Jim’s home, which had ample shade-free area on his roof, but a tricky configuration because part of the roof faced southeast and other part southwest. Kessler designed a split-array, with modules on both parts of Jim’s roof. The system utilizes Enphase microinverters so that performance would remain at peak capacity despite the differences in angle and azimuth between the two arrays.

Since the installation, Jim has reported that the solar array has performed “just as promised” and had almost an entire year without electric bills, only exhausting his solar credits during the challenging solar month of December, 2013.

A Local Company Revives Wind

Pika Wind Turbine in Greene, MaineWhile happy with his solar array, Jim wanted to do something with his 100 foot tower and thought that the wind resource blowing across his property might still be the right way. When Jim started looking into wind again, he found that a Westbrook-based startup, Pika Energy, was re-inventing the small wind turbine market with a new generation of turbines that addressed shortcomings of the older technology.

Pika Energy, led by co-founders Ben Polito and Joshua Kaufman, recently moved into a 4,300 sq. ft. manufacturing facility in Westbrook where the 10-person-and-growing company is transitioning from an R&D operation into a scale manufacturer of leading-edge wind technology. In addition to innovations with their T701 Wind Turbine, Pika also has a unique inverter product which allows a home to have a ‘micro grid’ featuring both solar and wind production on the same system. The system is accessible via smartphone and web portal and offers a robust amount of technical data for both the homeowner (for education) and Pika’s engineers (for troubleshooting). While focused on growing its manufacturing operation in Maine, Pika is building a national network of trained dealers to sell and install Pika wind-solar hybrid systems.

Pika’s T701 turbine has several advantages over prior units, including better overheat protection, more robust stopping mechanisms, and a vastly superior alternator which is built by hand in their state-of-the-art facility. The turbines are subjected to strenuous performance tests where they are subject to extreme heat, cold, and wind pressure to ensure that they perform as expected in adverse weather and over time.

Jim commissioned Pika to install one of their turbines at his property, which was excellent fit due to proper siting of the existing tower. Even advanced technology will fail when not installed in the correct place, and wind turbines work best when installed on a tower at least 30′ higher than surrounding objects with open space to the prevailing direction of the wind.

Jim reports that the Pika team worked smoothly in the installation of the turbine, and so far he is impressed with its performance compared to his older turbine. “Though the old one was rated at a higher output, I think the Pika turbine will provide much more actual electricity,” he says, “Plus it’s a lot quieter. It’s less than 30 feet from our home and we can hardly hear it.”

Even more importantly, the combination of solar and wind finally allows Jim to have the renewable energy synergy he’s dreamed of since retirement. “I’m really pleased with where we are now,” he says, “The byproduct of not having oil under our soil is war. The wind and the sun – we have plenty of these and they are in abundant supply. It makes me feel a lot better about my impact on the planet.”

Take Virtual Tour of Pika’s Wind Turbine Manufacturing Plant in Maine

Manufacturing Innovation at Pika Energy from Pika Energy.



Bangor Daily News Cautions Against Small Scale Wind Energy

April 5th, 2010

In today’s Bangor Daily News, an article titled
Small-scale windmills generate mixed reviews” documents the unimpressive results that some Mainers have received from residential windmill installations.

In the article, as well as in the particularly lively comments section, there is a lot of discussion about site and design being key to a successful wind installation. We agree, and add this: very few areas have the potential to be a successful and economically viable site for wind.

Wind Vs. Solar:

Solar vs Wind Resources
A National Renewable Energy Lab map of solar resources (top) and wind resources (bottom) of the United States.

While most of the state of Maine is rated as a “poor” wind resource, all of Maine receives 4 or more kWhr/day of harvestable sunshine.

Maine’s Limited Wind Resources

A glance at Maine’s 50-Meter Wind Resource Map shows that most of the state of Maine is a poor or marginal wind resource.

A US-DOE wind map confirms this, by showing most of the state of Maine being in “Zone 2″ for wind, meaning roughly 10mph wind speeds under ideal conditions at 33 feet – barely the minimum speed require to turn most wind turbines.

Even if your home sits in a windy spot, you need to account for trees, neighboring homes, hills, etc., not to mention the building code challenges and aesthetics of erecting a windmill.

Compare this to solar, which is basically ubiquitous. Provided you have a clear space that receives sunlight from 9AM – 3PM, you can enjoy the benefits of a solar electric or solar hot water system.

And unlike wind, if your site is initially too shady, you can add to your solar resource just by doing some tree work!

Wind Vs. Solar: The Fine Print

An average small-scale windmill costs about $15,000, prior to any rebates and incentives. This windmill, if we go by the optimistic specifications provided by the manufacturer, will produce 4,800 kWh a year.

For roughly the same cost, we could install a 3KW grid-tied solar installation. Using real-world data (the PVWATTS tool for Maine’s solar insolation), we estimate that the solar array will produce 3,840 kWh a year of electricity.

So, why not choose wind and get an extra 1000 kWh/year?

The reality is: very rarely will wind live up to its expectations.

From the Bangor Daily News article cited above:

While wind may be the fastest-growing electric energy source, home windmills aren’t for everyone, according to Richard Hill, professor emeritus of mechanical engineering at the University of Maine.

“If you have a great deal of money, and you hate the public utility and if you think you live in a windy place, you’ll be very disappointed when you put up a windmill,” Hill said recently. “You may, however, be justified because you’re interested in principle.”

… his windmill hasn’t delivered more than 100 kilowatt-hours a month, although it was advertised as capable of generating 400 kilowatts-hours a month. “I can tell you it doesn’t generate anywhere near that,” he said. Arnold has found that the wind must blow at least 8 mph to get his windmill going.

We also got this testimonial from some Shelter Institute graduates who installed their own wind system as well as solar power:

I think the main lesson we have learned (and would like to pass along to others) is that PV panels (solar panels) are much more cost effective as a means of autonomous energy production than wind, unless the wind site is very unique …

We did our own informal wind survey and felt fairly confident we’d get at least 1 kWh of production daily in the winter months (but only when the prevailing winds shifted to northerlies), and we’ve met that.

However, many people we’ve spoken to have mistakenly used turbine specs rather than an integrated formula for wind speed and time to calculate what they will generate, only to be disappointed in the small amount of energy they actually are able to produce.

The bottom line? Dollar-per-dollar, a solar system will outperform a wind system in nearly all real-world applications.

Reliable Sun Energy

GO Logic Passive Solar Home - Belfast, Maine
This solar electric system will displace roughly 250,000 lbs of C02 over its expected 50-year lifespan!

A Word on Reliability

It’s also worth noting that the value of a long-term renewable energy is directly related to the reliability of that investment. Solar panels have no moving parts, are warranteed for 25 years, and are expected to last double that.

An average warranty for a wind power system, in contrast, is only five years.

The expected life of a wind mill, under the best of circumstances, is around 25 years, half that of a solar installation.

Over the life of the system, the solar array will generate roughly 200,000 kWh, nearly double that of the wind – should the wind system perform to optimistic specifications over an optimistic lifespan.

Reliability, Economics, and Aesthetics

While ultimately we want to encourage everyone to find their personal path off of oil, we also have a duty to ensure that we recommend reliable, economically smart choices for our customers – which is why ReVision chooses to recommend and install grid-tied solar electric and solar hot water systems, and not wind.

With superior life expectancy, more reliable performance, better aesthetics, and better rebates, solar is the clear choice for clean, renewable electricity.



Shelter Institute Grads Share Observations on Wind Vs. Solar Power

January 25th, 2010

Installing Wind Generator Maine
Wind energy works in certain regions of Maine, but most homeowners are better off with solar power
Photos courtesy of Blueberry

Last week, our friends at the Shelter Institute posted a report from two of their Small Housebuilding Class graduates.

James and Kim wrote about a small-scale wind project they have recently finished on one of the islands off of Friendship in Muscongus Bay, Maine.

Not only is their story fascinating and impressive, but they make some serious and thoughtful analysis of how wind compares to solar power as a renewable energy.

They remark that while their wind system is performing as expected, for most people they think solar is a better option:

I think the main lesson we have learned (and would like to pass along to others) is that PV panels (solar panels) are much more cost effective as a means of autonomous energy production than wind, unless the wind site is very unique … We did our own informal wind survey and felt fairly confident we’d get at least 1 kWh of production daily in the winter months (but only when the prevailing winds shifted to northerlies), and we’ve met that. However, many people we’ve spoken to have mistakenly used turbine specs rather than an integrated formula for wind speed and time to calculate what they will generate, only to be disappointed in the small amount of energy they actually are able to produce.

… So, for the biggest green generation bang, we recommend solar panels. Compared to wind, the sun is ubiquitous. Our situation is unique in that we know we’ll get wind when the sun isn’t out in the winter, so the wind project fills in a gap in our ability to generate power year round, and we have no other means of getting non-fossil power out here. An alternative would have been to double our solar PV bank and add batteries to our current 2,000 pound battery bank, storing excess energy on sunny days for those days when we have wind without sun.

We have to agree – while wind energy has great potential under the right circumstances, most homes are built on poor sites for wind while solar power is available anywhere the sun shines.

If you’re curious as to whether your home or business has potential for harvesting solar energy, ReVision offers a free solar site evaluation.

A complete write-up of their experience with both wind and solar is up on the Shelter Institute blog – there are also some great photos on Picasa.

We want to thank the Shelter Institute again for sharing this inspiring story!



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Cape Elizabeth, Maine - Solar Hot Water

We love getting hot water from the sun. The installation looks fine on our old farm house.

This summer we had 13 people living, showering, cooking and doing laundry here and the furnace didn't go on even once. Hooray!

Red and Louise Sullivan
Two Lights Rd., Cape Elizabeth

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