11/15/2012

Our County goes Green

Hancock County, Maine, containing Bar Harbor and Lamoine just got a lot greener. According to census figures we have 23,300 households. Eighteen thousand, or 77% of those household’s electricity needs are now matched by the new 34 megawatt Bull Hill Wind Project just 30 miles away from SeaCat’s Rest, atop 600 foot Bull Hill. Of course, the power is fed into the grid so the power goes everywhere, but it still means Hancock County is now a significant energy producer. It only happens when the wind blows, but the engineers at First Wind have done their research and picked a site where there is dependable wind. The success of a wind site can be expressed as the capacity factor, the percentage of rated output that an array produces over time. It’s too soon to know Bull Hill’s, but another First Wind array in Maine, Mars Hill, has achieved 35% according to here.

The substation where voltage is matched to the grid.

On the fourteenth of November, 2012 I traveled to Bull Hill to see this project for myself. It’s a little remote and requires driving over gravel roads for a while, but the site is accessible to all and I recommend that everyone take a look. The land is owned by H. C. Haynes Inc, a timber company and leased to First Wind. Haynes has a policy of allowing access to its lands for recreational purposes, and so the extensive roads servicing the installation are available for visitors at any time. Standing under a 300 foot tower with slowly spinning 150 foot blades is an awesome experience.  Seeing nineteen of them spinning together is humbling. Actually, seeing all nineteen at once is not easy, since each tower is about 1500 feet away from its closest neighbor.

The blades above my head spun at about 12 RPM, a blade swishing by about every 2 seconds at 128 miles per hour at the tip.  I wanted to ask someone what the turbine’s output was at that speed and soon after I was speaking with a young First Wind worker at the facility’s substation who was kind enough to answer my questions. At 12 RPM he said, the generation was “at rated output” or about 1.8 megawatts. The wind was not that strong on the ground, about 12 MPH here at home, so I was surprised to hear that. The young man, who decided not to have his name mentioned, explained that the site is chosen after several years of monitoring wind speeds and that the model of the turbine is chosen to match the wind resource. The Vesta V100-1.8 MW is a model fitted to lower wind speed sites, reaching rated output at 27 miles per hour. I don’t think the wind was that strong even 300 feet up. At 15 miles per hour the output is 600 kilowatts.

Investment in a wind installation is not a casual affair. Not only does the local population have to be on board ($340,000 per year in taxes and community benefit payments helps), but the project needs to be near an existing power grid so that the overall project cost can be kept reasonable. And then the wind too. Being on top of a hill is a big help. There are other, windier sites in Hancock County, but many are close to the coast and off limits for aesthetic and political reasons. Finally, the young man reported that most people don’t realize that the new wind economy has already pumped a billion dollars into the Maine economy.

The Bull Hill project in some ways resembles a housing development in that there are winding streets and flattened build sites with good drainage and planted grass.  All the power from the turbines goes through buried conduits, so like a fancy development there are no wires overhead. Each turbine sends out its maximum 1.8 megawatt at 34,500 volts. It joins with the output of other turbines and heads to the substation, all underground. At the substation the collected power is boosted to 115,000 volts and joins the grid. The substation is staffed 24 hours a day and so the facility is an ongoing employer, keeping watch of the 19 turbines. I asked about the maintenance of the turbines, specifically if the three hundred foot climb was by ladder. The answer was yes, but there is a “power assist” which is basically a lifting cable clipped onto a harness which makes the climb a little less tiring. I would hate to get to the top and realize I forgot my wrench. Tasks at the top include greasing the gearbox, tightening bolts and checking power connections and output. I was hoping to get an invitation to the top but it was not to be. It’s probably a good thing, I’m not crazy about heights.

Wind power is still controversial. Some people hate the way turbines look and others object because they are supposed to kill bats and birds. Still others claim they are an unreliable and expensive source of power.  I like the way they look and hope the source proves to be viable. I am no expert when it comes to giving an intelligent assessment of this power source, but when I look at those big turbines I know there is wind energy being converted to electricity and I see no smoke. As someone who lives 15 feet above high tide, I need to make sure the Greenland ice sheet doesn’t melt, and it’s certain that humans producing CO2 are not helping. That’s my opinion!

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