Wednesday, September 28, 2011

Lempster Wind Farm

Approaching the Wind Farm

Yesterday, the Energy Safari course went to Lempster Wind Farm in Lempster, NH. We went on a lovely sunny day, which would have been great for the solar farm visit last week. Unfortunately, we went to the solar farm in the rain, and the wind farm on a clear, sunny day with almost no wind!

Bob Hargraves did an excellent blog post on our visit at the Energy Safari site. I am just adding my impressions.

The picture above shows the entrance to the wind facility. (If you enlarge it, you can see one of the turbines.) Unlike the solar farm, which is just a short walk from a few houses, with no locked gate, the wind facility is more heavily protected. There are moving parts overhead (it's all a hard-hat area) and people are not allowed to wander around it by themselves.

Several landowners still live within the wind farm boundaries, and I assume they can do as they choose about hard hats. (They probably signed something about liability. I am just guessing.) We were tourists, and we were well guided. Ed Cherian was the construction manager for the project, and he was our knowledgeable, patient and gracious host.

I admit I am rather fond of the photo on the right. We are standing at the base of one wind turbine, looking over at another wind turbine, and in between is a solar array to run a private communications tower.

Inside the Turbine Building

We had a great time and lots of access at the wind facility. At the left, you can see that they allowed us inside the turbine building. There's a readout there of the power production for the turbine. "Our turbine" went from negative production to positive production while we were there, as the wind picked up. Readout below.


However, I did find it frustrating that the owners would not tell us the price at which they sold their power. They don't have to tell us, I know. They are a private company, and have every right to their trade secrets. Bigger companies, like Hydro Quebec, also do not share that information. We don't have any right to have that information.

However, we are the "energy safari" course and it just makes it harder to assess the success of the first wind project in New Hampshire. In contrast, the solar farm sells their power according to the Vermont SPEED program. The solar farm people were quite straightforward about their production and prices.


It was a beautiful sunny day, and we had an excellent visit. We were allowed to see everything, everything was explained to us, and many aspects of the site were very impressive. For example, Iberdrola is very careful about safety. Everything is done from within the tower, or on the nacelle. Nobody is ever up there on scaffolding. If they need to work outside, like lowering a damaged rotor, they hire a crane. When the facility was under construction, they had helicopter landing pads in place to take any injured workers to the hospital. (The pads were not needed or used.)

The wind turbine base is sunk with 40 foot bolts into solid bedrock. The turbine itself is bolted to the concrete base. The bolts are covered with black plastic because otherwise they tend to collect minerals and salt, and therefore they attract moose. There's a lot of wildlife around the windfarm.

Factoid time: Why are wind turbines white or light grey? It's an FAA rule for pilot safety.

Jolly Group

I will finish with the obligatory picture of the jolly group! For a more complete assessment of the visit, please go to Bob Hargraves excellent write-up. We are grateful to Iberdrola Renewables for the opportunity to visit their facility. Out on a hillside on a sunny autumn day in New Hampshire! It hardly gets better than this!

All pictures are my own. Click on any picture to enlarge it.


Paul Lindsey said...

The owners may not be required to tell you what they sold their power for, but they are required to tell the FERC on a quarterly basis!

Go to and select a quarter. I chose Q2, Apr-Jun 2011. Then select the name of the power company. I guessed "Lempster" and bingo, "Lempster Wind, LLC"

Downloading and opening the data file, there are two internal files. The "contracts.xls" file is supposed to show the contract details: the length of the contract, to whom, the rate, etc. For some reason, the rate column shows "0", but the contract with PSC of NH started on 01/02/2008 and goes to 01/02/2023, 15 yrs.

The other file, "transactions.xls", shows the reported power amount and cost per MWh for each reporting period. In this case, Lempster Wind reported in monthly increments, with the "transaction_quantity" in MWh and price of $52.5 per MWh. For the 91 day period, Lempster produced 17,201.07 MWh. Since it is rated at 24 MW, that gives a cf of 32.8% over that 3 month period.

I've seen other wind farms report on an hourly basis, typically because the contract pays a different rate for different MWh per hour. In those cases, the spreadsheet gets confusing, because there are multiple lines for a single hourly period. I have also seen a wind farm make a single line entry for the entire qtr (i.e. 04/01/2011 to 07/01/2011) because the rate was fixed. Lempster could have done this.

Looking at the Q1 report for Lempster, it appears rate that Lempster is paid may change month to month. In Jan 2011, Lempster recieved $54.05/MWh, but only $52.5/MWh in Feb and Mar 2011. During Q1, Lempster's cf was 35.8%.

Hope this helps. I just started delving into the FERC reports a couple of months ago.

Paul Lindsey said...

I tried to pull the FERC data on the Allearth renewables solar farm, but I need the corporate name of the solar farm owner. Also, if this solar farm is utility-owned, then there won't be an FERC report, because FERC reports are only required when power is sold from one entity to another.

Anonymous said...

Could someone please explain to me how a wind turbine can generate "negative" power? I interpret that to mean it's *using* power instead of producing it? How does a turbine "use" power? Lighting? That little monitoring computer? I can't imagine that lighting and an embedded computer would take more than maybe 100-200 watts of power?

Robert Hargraves said...


Besides payment for MWh, I believe there is also a payment for capacity -- the promise to produce power.

Meredith Angwin said...

Paul and Bob commented about the economics of the site. I especially appreciate Paul's comments on how to find out about economics! However, I know the employees are not allowed to share this information with us, so I didn't ask them any follow-up questions about money.

However, Jeff's comment about wind turbines using power was very interesting. People in the class also wanted to know why the use was so high (4 kilowatt in my picture, 9 kilowatt in Bob's picture on his blog). So, I asked Ed Cherian, who was our guide at Lempster. He was kind enough to answer. It is a longish answer so I will use another comment block for it.

Meredith Angwin said...

Here is Ed's answer:

Hi Meredith -

4 to 9 kilowatts may not be as much as you think. A typical household electric water heater is rated at 4500 watts. A dishwasher can burn 2,000 watts.

Other draws for a wind turbine besides lights, computer, and FAA beacon may include Blades Pitch Components Hydraulic Pump Motor, Fans, Gearbox Pump Motor, Heaters, PLC Systems: Hub, Nacelle, Base Cabinet, and Yaw Drive Motors.

So, at the time we were there, that was the net negative load (it was fluctuating constantly depending on the very light winds - was positive part of the time). If nothing but lights and computer are running, the draw would be less. There was some turbine movement into the shifting wind while we were there, so the main draw was likely the yaw drive motors.

I'm glad you enjoyed the visit. We enjoy showing off NH's first wind farm!


Anonymous said...

Parasitic energy can be as much as 10 to 20 percent of the output of the turbine.

I monitored the Bolton Vally Ski Resort 100 kW wind turbine on cold days last winter and its power output is significantly less than would be read from its performance curve.

It is all explained in this article