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Wind Energy Wind is the world's fastest growing source of energy. It is harnessed by tapping the kinetic energy of flowing air (wind) to create mechanical energy. Historically, this mechanical energy was used directly for grinding grain and other purposes; current technologies convert it into electricity for either on-site or off-site use.
Hundreds of windmills once dotted Cape & Islands landscapes. The mechanical energy supplied by the rotating paddles of these early machines pumped water, processed food, and powered saltworks and other early industries. Antique windmills and replicas may be seen today, evoking the region's historical reliance on this abundant resource. Wind energy's current renaissance is fueled by modern turbines. These high-technology machines transform the mechanical energy of rotating blades into zero-emissions electricity. Many countries - particularly in Europe - are developing wind resources to meet growing demands for power while reducing reliance on fossil fuels and meeting commitments to reduce greenhouse gas and pollutant emissions. Wind generating capacity in the United States has substantially increased over the last few years, but it still supplies only a small fraction of the country's overall needs. Cape Cod, Martha's Vineyard, and Nantucket are blessed with onshore and offshore wind energy resources that are among the best in the continental United States. Numerous wind projects have been proposed or are being considered by homeowners, institutions, businesses, and municipalities. A few small-scale turbines are up and running, but the first large-scale, land-based unit was installed at Massachusetts Maritime Academy in spring 2006. (See a video of the installation). This Vestas V47 660 KW wind turbine stands 242 feet tall and is currently the single largest source of green energy on the Cape and Islands. To learn more about the MMA wind turbine click here. Click on the links below for more information on wind energy in the Cape & Islands region. Issues and activities specific to municipal wind projects are described on this website's Community Wind page. Technology Overview
Today's wind turbines harness the kinetic energy of this flowing air and then transform mechanical energy into electricity - flowing electrons. Over the past 25 years, major advances in turbine technology have made this process ever more efficient, making wind energy a cost-competitive option for a growing number of applications. Most modern turbines include four primary components: the rotor and nacelle are located atop the tower, while electronics are distributed throughout this highly engineered system. The rotor includes a central hub and, in most cases, three lightweight blades that are also known as airfoils. The rotor spins as air flows over the blades, rotating faster as wind speeds increase. This spinning motion drives the shaft of an electric generator, which is typically located in the nacelle. The generator converts the rotational (mechanical) energy into electricity. Control systems and other electronics monitor, manage, and optimize system operations to maximize power generation under varying wind conditions. Electrical cables carry green electrons from the nacelle toward the base of the tower, where they are connected to a power delivery circuit via electronic devices of varying complexity. Wind turbines tap a locally available energy source to generate green electrons without depleting natural resources. The clear environmental advantages of wind power are complemented by numerous economic and social benefits. These benefits are listed at the right and characterized in more detail on MTC's Clean Energy website.
Wind energy can be used in diverse applications because systems may be sized to meet site-specific needs. Commercially available turbines range in rated capacity from 0.25 kW (little more than a small fan that generates rather than uses electricity) all the way up to 4.5 MW, a large and very visible machine. When operating at full power, the smallest and the largest wind generators can power a few light bulbs and thousands of homes, respectively. Wind turbines can be deployed individually, in small clusters, and in large-scale arrangements known as wind farms or wind parks. Three types of uses exist: Consumer-side (behind-the-meter) applications: The wind generation, typically one turbine, is located
on the customer's side of the electric meter. Electricity is used to meet on-site requirements, and excess electricity
may be fed to the power grid for sale and delivery to others. Turbines installed at Cape Cod Tech in Harwich and Upper
Cape Tech and the Massachusetts Maritime Academy in Bourne fit this description. Many local towns are pursuing this
type of installation, as are Cape Cod Community College, Woods Hole Research Center, and other organizations.
Off-grid applications: The wind generation is tied to a localized circuit that does not connect to the power grid. Electricity is used to meet on-site requirements. Off-grid applications often include solar photovoltaic and/or battery storage systems to supply electricity when the wind is not blowing. Wind turbines may also be classified by scale, with rated capacity increasing with rotor diameter and hub height. Present-day technology may be divided into three broad size ranges, briefly characterized below:
Community-scale wind projects may include one or a couple large turbines with rated capacity of about 1.5 MW or less. The actual power output of a turbine is generally much lower than rated capacity because the wind does not blow consistently. A capacity factor of 25 to 40% is typical. A turbine rated at 1 MW with a 30% capacity factor could produce anywhere from 0 to 1 MW on an instantaneous basis, but its annually averaged output would be 0.3 MW. The table shows the influence of capacity factor on actual output and on the number of homes served by an individual turbine (assuming an average home consumes about 6,000 kWh/yr).
The power available from wind is proportional to the cube of its speed, which means that twice as much wind produces eight times as much electricity. This relationship has three important implications: (1) at low wind speeds, little power can be generated; (2) even small increases in average speed correspond to a significant increase in the amount of electricity produced; and (3) there is much more energy available in locations with high wind velocities. Wind speed generally increases with fetch (the distance over which the wind blows), which explains why the best wind resources are generally located on plains, on ridges and mountaintops, and in coastal and offshore environments. Wind speed also generally increases with height, which explains why today's turbines are positioned atop tall towers. Other key siting considerations include
These site-specific factors can greatly influence the economics of a potential wind installation. A variety of other considerations also come into play, beyond the cost of the wind turbine itself and the ancillary components required to connect it to electrical loads or power delivery circuits. A few are listed below:
This map of average wind speeds at 100 m demonstrates the region's outstanding wind
resources. (Source: TrueWind Solutions/AWS Scientific)
Detailed wind resource maps for the Cape & Islands region are available. All of these maps are derived from work conducted by TrueWind Solutions and AWS Scientific under funding provided by MTC, Connecticut Clean Energy Fund, and Northeast Utilities Service Company. Maps of onshore and offshore wind resources, transmission lines, ocean depth, and other features for the Cape & Islands region, the state, and New England are available via the link below: More detailed maps of wind energy resources, open space, and other landscape features for Cape & Islands communities and other towns in Massachusetts are available from the MTC Community Wind Atlas. These maps facilitate initial analysis of siting possibilities for land-based wind projects in local communities. Site-specific wind resource data are available for several locations in the Cape & Islands region. These data were
collected by the Renewable Energy Research Laboratory at the University of Massachusetts with funding from the MTC
and the Massachusetts Department of Energy Resources. Click
here to access data characterizing the wind resource
in Nantucket Sound (Bishop & Clerks Lighthouse), Bourne, Eastham, Falmouth, Nantucket, Orleans, Yarmouth, and other
locations.
Local Projects Cape Cod: Detailed status information on municipal wind projects is available here; other wind energy development activities in local communities are listed below. Click here to submit updated information on these or other projects. Barnstable: Country Garden in Hyannis is moving forward with its effort to install a turbine to power the lights, fans, pumps, and other equipment used at this nursery. The machine would have a rotor diameter of about 32 feet and would be installed on a 120-ft tower. As of early February 2007, the project was moving through the local permitting process, and it had been granted approval by the Site Plan Review Committee. The initial feasibility study for this project was supported in part by Barnstable County Cape Cod Cooperative Extension. Cape Cod Community College plans to host a large-scale turbine to complement its green building and renewable energy education initiatives. Progress has been delayed significantly by flight path conflicts with Barnstable Municipal Airport. As of November 2006, the college is moving forward with plans to site a 600- to 750-kW machine on the western edge of its West Barnstable campus. Reports and visual simulations for the project are available here. As of February 2007, the town's planning board is in the process of creating a zoning ordinance to address siting and permitting issues for commercial and residential wind turbines. Bourne: The first modern, commercial-scale turbine on Cape Cod began operation in spring 2006 at Massachusetts Maritime Academy (MMA). The 660-kW turbine is cutting MMA's electricity bills while giving students hands-on experience with clean energy technology. In May 2006, a 10-kW machine was installed at Upper Cape Cod Regional Technical High School. An innovative, trebuchet-style tower designed by Clean Energy Design provides students with easy, tilt-down access for educational and maintenance purposes. A small, roof-mounted unit is up and running at someone's house on Spruce Drive. The town has created a bylaw to manage future installations. On the Massachusetts Military Reservation, the Air Force Center for Environmental Excellence is pursuing installation of a 660-kW machine to help power groundwater pumping and treatment facilities. The turbine's location is in the southwestern corner of the base; it is expected to be visible from Route 28 in Cataumet. Falmouth: At the Woods Hole Research Center, erecting a turbine at its award-winning high-performance building represents the final element in its strategy for achieving energy independence (click here for information). The project has been in the works for several years; as of February 2007, the center is attempting to finalize tower design and permitting issues. Woods Hole Oceanographic Institution is studying a two-turbine installation at its Quisset campus. Webb Research Corp. is looking to install a ~1.5-MW machine at its headquarters in Falmouth Technology Park. An MTC-funded feasibility study was completed in 2005, and work is continuing with support from MTC's Large On-Site Renewables Initiative. The project received approval from the Falmouth Historical Commission in August 2006, a determination by the Federal Aviation Administration is pending, and engineering plans are being prepared to support a permit application to the town. As of November 2006, the biggest obstacles to an economical installation appear to be current interconnection policies: The goal is to create a behind-the-meter project serving this company, as well as a neighboring company about 1100 ft away. Interconnection standards don't address a scenario in which a single generator is connected to meters serving different consumers, meaning that the fate of this large-scale installation may depend on a favorable decision by NStar, a clarification in interconnection requirements, or a policy change to allow "virtual" net metering. Harwich: Cape Cod's first grid-connected turbine, a 1.7-kW unit, began operation in June 2005 at Cape Cod Regional Technical High School. It was installed through a hands-on training session involving Cape & Islands Self-Reliance, Clean Energy Design, and other local organizations. In its initial 6 months of spinning, the turbine generated more than 1300 kWh, no pollution or greenhouse gases, lots of attention, and valuable learning opportunities. Nearby homeowners liked its looks so much they are pursuing the town's first residential installation under a new town bylaw. Depot Development LLC is seeking to install a 20-kW turbine at its facility in North Harwich, with a goal of having the first privately owned commercial wind project on the Cape. Sandwich: A Bishop Path homeowner looking for relief from skyrocketing electricity bills is attempting
to site two small turbines on 30-foot towers on one small lot, generating consternation from neighbors and concern
from renewable energy advocates interested in quality installations. The project has been delayed due to permitting
issues; as of February 2007, the town is working to develop a bylaw for residential wind projects.
Truro: The Highlands Center at the Cape Cod National Seashore is pursuing a wind project incorporating anywhere from one to three large-scale turbines. A 50-m meteorological tower installed on a former helipad in the southeast region of the Center is scheduled to begin monitoring wind conditions in spring 2006. Martha's Vineyard: Detailed status information on municipal wind projects is available here; other wind energy development activities in local communities and offshore environments are listed below. Click here to submit updated information on these or other projects. Oak Bluffs: A 2.5-kW turbine began spinning in October 2006 at the shop of Against the Grain Cabinetmakers. West Tisbury: South Mountain Co. installed a 10-kW turbine in fall 2004, the island's first grid-connected machine. This resource-conscious architecture and building company installed the turbine with the intent of meeting more than 50% of electricity needs at its shop. Nantucket: Status information on municipal wind projects is available here. Click here to submit updated information on other local projects. Offshore: Local, national, and global attention is riveted on the wind energy project proposed for Nantucket Sound, while a proposal advanced for Buzzards Bay in 2006 has attracted somewhat less notoriety. Several alternative offshore sites in the Cape & Islands region are being explored, some through regulatory review of the Cape Wind project. Others are being examined by developers and government agencies that all would like to evolve an organized process for capturing wind resources in near-shore and "over the horizon" environments. Baseline information relating to the Cape Wind project is available via the links below:
For information on the Buzzards Bay project, visit the following links:
Brief information is available here on the local sites in federal and state waters identified by Winergy LLC. The U.S. Minerals Management Service is heading up U.S. efforts to develop a framework for siting and permitting offshore energy projects in federal waters. In addition, MTC, in partnership with the U.S. Department of Energy, GE Wind, and others, is coordinating the Offshore Wind Collaborative (OWC). This group focuses on technical, political, economic, environmental, and societal barriers to the development of U.S. wind resources in deepwater and far-offshore environments, where energy levels are higher and aesthetic concerns are reduced or eliminated. The goal is to establish "over the horizon" wind farms in U.S. waters as a cost-competitive electricity supply option. Baseline Information Resources
Clean Energy Information: Wind Energy Last updated 8.29.08 |
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The Mass Maritime Academy wind turbine is currently the largest producer of
green energy on the Cape and Islands.
