Archive for September, 2009

Portsmouth, RI Runs on Its Own Power

Wednesday, September 30th, 2009

by Chris Menge

The Environmental Business Council’s wind energy committee held a meeting and site visit in Portsmouth, RI on September 22nd to hear about and see Portsmouth’s new 1.5 MW utility-scale wind turbine.  HMMH’s Director of Clean Energy, Steve Barrett, organized the meeting as chair of the EBC’s wind energy committee.  The presentation and site visit, attended by 12 to 15 interested parties, was hosted by Gary Gump, who led the effort to get the turbine permitted and built, as chairman of Portsmouth’s Sustainable Energy Subcommittee.

Gary gave an enthusiastic and very informative presentation, which included many details of the economic, legal, logistic, permitting, and construction aspects of the new wind turbine.  The goal of the project was to produce approximately three-fourths of the power required by the town of over 17,000 residents to run its municipal buildings, including the schools. 

The Portsmouth Sustainable Energy Subcommittee started working on the potential use of wind power in 2004.  First, they needed to ensure that a wind turbine would be an economic asset to the town, so they performed an extensive feasibility study that looked at all aspects of the project.

One challenging and critical aspect to making the project economically viable was that Rhode Island law had to be changed to allow for increased municipal net metering.  This change permitted the utility to give credit for power generated by the turbine at up to ten town electric meters, rather the five previously allowed. 

A large enough town-owned site was also needed, with nearby power lines.  Fortunately, Portsmouth High School had sufficient land, not too far from their tennis courts and athletic fields.

At the athletic fields

At the athletic fields

Once the project was deemed feasible, the committee then asked the citizens to vote to approve the project, which they did with a clear majority.  In April 2008, the town signed a contract with AAER of Canada to build the turbine, which was turned over to the town in March 2009.  The turbine has been in operation since then.

The site is very near Route 24, so the large turbine, which is 336 ft high at its highest, is very easily seen by passing motorists.  Our group was able to walk right up to the base of the turbine while it was running, and to go inside the base (Gary had the key) to see the power transfer units and some control systems.

Portsmouth turbine

Portsmouth turbine

Base of the turbine

Base of the turbine

The unit is self-contained and controlled, but it has two monitoring stations, one at the town hall, and one at the fire department.  The fire department controller can also start and stop the turbine, in case of emergencies.  As we saw during Gary’s demonstration at the town hall, these monitoring stations provide a great deal of data on the operation of the turbine, including wind speed and direction, momentary and historical power output, and direction it is pointing, to name a few.

The turbine was turning and generating power during our entire visit.  I was impressed at how quiet this utility-scale turbine seemed, since I’ve done noise studies for wind farms and read much about how some people are affected by the noise.  I did hear the “swish-swish” sound when I was close, but I couldn’t hear it if I was more than about 100 ft away from the turbine.  One advantage of this location was the presence of traffic noise from Route 24, a four-lane divided highway.  Traffic noise has a similar sound character to the turbine noise, so it masks the turbine sound quite effectively.

The Town of Portsmouth Sustainable Energy Subcommittee maintains a Website detailing the project and providing many facts and photographs.  The finacial bottom line that Gary gave us is that the turbine is expected to generate between $450,000 and $500,000 in income annually.  The expenses and debt service will be about $250,000 annually, so the net revenue to the town is expected to be approximately $200,000 per year.  As hoped, this represents about three-fourths of the town’s energy costs.

Congratulations to Gary and the Subcommittee for a very successful sustainable energy project!  And thanks for a terrific presenation and site visit!

Moon Power: HMMH Moves Into a New and Exciting Field

Friday, September 18th, 2009

by Steve Barrett

Tides are the rising and falling of Earth’s ocean surface caused by gravitational forces of the moon and sun.  The rising and falling is most dramatic twice each month when the Sun, Earth, and Moon align in space, revealed to skygrazers as either a full or new moon.

Moon Phases Diagram

Moon Phases Diagram:

Tides are also more pronounced at the poles than at the equator, and in jagged and irregular coastlines than straight coasts.

Bay of Fundy at high and low tide, taken by Samuel Wantman in 1972

Bay of Fundy at high and low tide, taken by Samuel Wantman in 1972

People have used the power of the Earth to do work for centuries.  River water and the wind driving grist mills provide the most familiar examples.  The power of the tides has been more difficult to harness primarily due to the vastness of the ocean.  Recent advances in technology are making the conversion of tidal currents to electricity possible.

HMMH is currently working with the Town of Edgartown, Massachusetts to investigate the opportunity of extracting tidal current energy from the Muskegat Channel – located between Martha’s Vineyard and Nantucket – to provide power to the Town’s residents.

For a view of the study area, see:

A 2005 report by the Electric Power Research Institute (EPRI) on tidal energy resources identified Muskegat Channel as the best tidal energy site in Massachusetts.  Because Muskegat Channel is within 3 miles of land and therefore in the legal boundaries of Edgartown, the Town decided to claim the right to evaluate the resource for energy development.  In March of 2007, it was granted a Preliminary Permit from the Federal Energy Regulatory Commission (FERC), giving it exclusive development rights.  Since that time, the Town has been working with researchers at the University of Massachusetts at Dartmouth’s School for Marine Science and Technology to more accurately measure and map the current velocity in Muskegat Channel to confirm the power of the resource and its capacity to generate electricity.  These data, reported in July of 2009, confirmed that the power of the currents (measured in knots per second) was even better than that predicted in the 2005 EPRI Report.  With this fundamental puzzle piece now placed, the next step is to prepare a project concept, undertake baseline environmental data collection, and conduct analyses of potential impacts from the project.

In anticipation of this next phase, Edgartown asked HMMH if it would lead a proposal team to bid on a solicitation from the US Department of Energy’s (DOE) Advanced Power Program to fund baseline environmental data collection and environmental impact analysis.  In early June, HMMH submitted its proposal titled “Environmental Effects of Sediment Transport Alteration and Impacts on Protected Species: Edgartown Tidal Energy Project.”  On September 3rd, DOE awarded grant funds to HMMH to implement the research.

HMMH’s proposal is based on the installation of a 1.5 MW pilot stage tidal energy project.  The study will consider each of the two prevailing tidal energy technologies that could be used:

  1. horizontal open bladed turbines mounted on monopoles
  2. horizontal helical turbines that float from moorings
Helical Turbine

Helical Turbine

A graphic illustration of an open-bladed turbine can be viewed at:

Projects for each of the two technologies have been demonstrated on the East Coast of the U.S.  In the East River in New York City, Verdant Power has deployed two horizontal bladed turbines and presently has an application before FERC for a larger pilot project.  Ocean Renewable Power Company (ORPC) has deployed a one-third scale model of a helical turbine in the western passage near Eastport, Maine and is currently building a full-scale model to be deployed this winter.

For the Muskegat Channel Environmental Study, the DOE is funding Woods Hole Oceanographic Institution and UMASS-Dartmouth to conduct baseline data collection to characterize the oceanographic processes and benthic habitat in Muskegat Channel, which will be used to develop a site-specific computer model for predicting changes in sediment dispersion caused by the pilot tidal project.  The model will be run for both types of technologies for comparison.  The Provincetown Center for Coastal Studies will be collecting all of the available existing information on marine protected species occurring in Muskegat Channel and assessing the potential impacts of the two tidal technologies on those species based on known behaviors and habitat preferences.  HMMH, acting as the Town of Edgartown’s consultant, will manage and direct all research activities, interact with regulatory agencies and the public, and facilitate all project reporting.  The studies will be completed over a two year period.