Is a Small Wind Energy System Installation Right for My Property?

 

The Major Issues

 

Wind

 

The first question to be asked is whether the wind resources at your site are sufficient.  We know that in Jackson winds are blustery and wind speeds vary greatly with terrain. Maps of measured wind speeds for the White Mountain area are useless because of this highly variable nature.

 

However, for the record, here is the link to the federal governments rendition of the big picture – a survey of winds in the State of New Hampshire – and below is the map that you will find.

It would appear that wind power is superb along the ridges of the Presidential Range and marginal elsewhere.

 

As the small print says: Wind resource at a micro level can vary significantly; therefore, you should get a professional evaluation of your specific area of interest.

 

The web site, Firstlook 3Tier, provides a means of obtaining wind speed estimates for specific locations.  Below is a chart showing the speed range for a 20 meter tower located in the Tyrol area of Jackson. The speed range given is 7.2 - 12.4 mph.

 

The influence of tower height can be determined as the site provides estimates for 20, 50 and 80 meter heights:

                     Height (m)          Speed (mph)

                     20        7.20 – 12.4

                     50        10.3 – 15.3

                     80        11.9 – 17.0

Quadrupling the height of the tower yields a 50% increase in the estimated wind speed. This is in accordance with expectations that tower height has a critical influence on turbine performance.

 

Location should have a primary effect on wind speeds. The village district, at the lowest elevation in town would be expected to yield minimal average speeds while a property on the ridge line of Thorn, Middle and Tin Mountains would be expected to yield the highest average.

Results from the website for a 20m tower  are:

                                                     Location                   Speed (mph)

                                    Village District              7.2 – 12.3

                                    Tyrol                             7.2 – 12.4

                                    Presidential                   7.1 – 12.2

So it appears that although the website has a sophisticated interface, the data have no real geographic resolution.

 

A second web site, windNavigator, also provides wind speed data. On this site, speeds are reported as an average speed for selected tower heights. The height options are limited to relatively tall towers. Results are given below for an 80 meter tower.

 

                                                Location                         Speed (mph)

                                                Top of Thorn                  7.69

                                                Top of Middle                7.61

                                                Top of Tin                      8.25

                                                Tyrol                              7.69

                                                Village District               6.53 

                                                Dana Place                     8.16

Here the Village District result is a lower speed than the ridge lines, but not as much as one would expect. Also, note that the Dana Place location yields speeds almost as high as the mountain tops.

 

The bottom line would seem to be that these data bases cannot be expected to have sufficient resolution to establish a reliable indication of wind speed in our area. A metrological tower installation is the only source of reliable data at this time.

 

 

 

The US Department of Energy supports a web site for wind energy in which the importance (and difficulty) of evaluating the wind energy on a property is addressed. One interesting tidbit is entitled ÒObserve Vegetation FlaggingÓ.

 

Flagging—the effect of strong winds on area vegetation—can help determine area wind speeds. Trees, especially conifers or evergreens, can be permanently deformed by strong winds. See flagging illustration below for more information.

Now a lot of us have observed Classes IV – VII deformity in the Alpine Garden and other approaches to the tree line in the Whites, but this is not something observed by this writer here in Jackson. Interesting, but not very useful.

 

At least two sites in Jackson have anemometers that are monitored by the organization Weather Undergound. These anemometers are usually roof-top units, so do not provide quantitative information on which turbine performance can be assessed. But they do provide an indication of the nature of the winds here in Jackson.

 

Below is the chart for wind speeds recorded at the Dana Place (location code KNHJACKS3) for 2008.  Note that the blue dots are maximum gust speed and the amber-colored curve shows the average speed.  It looks like the average speed is less than 5 mph. And, as we all know, the gust speeds can be significant.

Dana Place anemometry – Year 2008

 

March is known as a windy month. Below is the chart for March 2008 at the Dana Place. The results are the same – average wind speed of less than 5 mph.

Dana Place Anemometry – March 2008

 

The second Jackson site listed by the Weather Underground shows slightly higher speeds, but the identity of the source is unknown. Does anyone in one of the higher locations in Jackson  have an anemometer  with a recording feature that can generate a computer file giving time-dependent wind speeds?  If so, and if you would be willing to share the data, please contact the Wind Turbine Subcommittee.

 

Lot Size

 

The second consideration is that  your building lot must be of sufficient size to site the tower. Southwest Windpower, a major supplier, states that siting a wind generator is extremely important to the performance of the machine. It is the difference between a machine that give you lots of energy and a garden sculpture. The ideal location for a wind turbine is 20 feet above any surrounding object within a 250 foot radius. This generally means your property should be at least one acre in size.

View Impact

 

Third, you want to make sure that the siting does not create a view impact issue for your neighbor or, in the case of the larger units, for the townspeople.

 

 

Lastly, you want to make sure that you abide by the guidelines of any agreements that you have entered into by virtue of deeded provisions/trestrictions in your neighborhood regarding towers or tall structures.

 

 

Additional Resources

 

On June 23, 2009 Chris Franchi of Renewable Energy Solutions gave a seminar at the Whitney Center on the issues related to wind power in Jackson. Click here to access highlights of the material presented.

 

The DOE Small Wind Energy ConsumerÕs Guide gives an overview of SWES installation issues.

 

*******

 

Based on the experience of Jacksonites who have looked into wind turbine installations, an independent assessment by a local contractor or consultant with experience with these systems is the best way to proceed.

Here is a list of such contractors/consultants. This is not an endorsement of any particular firm.

 

Chris Franchi, Renewable Energy Solutions, 2531 Chinook Trail, Wonaloncet, NH 03897  (603) 986-9244.

 

Green Alternative Energy, LLC, 41 Hemlock Drive, North Conway, NH 03860 (603) 356-4444.

 

Home

 

Updated July 23. 2009