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Power Supply & Delivery Infrastructure The Cape & Islands grid is relatively simple. Local homes, businesses, and communities are strung together by power lines. These high- and low-voltage wires, together with other utility equipment, deliver electricity to consumers. Nantucket and Martha's Vineyard are tethered to Cape Cod by underground and undersea transmission cables. Overhead transmission lines cross the Cape Cod Canal and link the regional grid to a network spanning all of New England and, for that matter, the rest of North America: This complex, interconnected system, which serves Mexico, the United States, and Canada, has been called the largest machine in the world. The Canal Generating Plant feeds electricity into the Cape & Islands grid at a substation in Bourne. Other small, dispersed generating systems supply electricity to local consumers, including a growing number of renewable energy installations. When the Canal Plant is operating, output exceeding the amount demanded on Cape Cod, Martha's Vineyard, and Nantucket is exported across the canal and injected into the New England grid. Otherwise, electricity generated elsewhere is imported to the region. Click on the links below for more detailed information: Supply Portfolio Supply Portfolio The Canal plant's total capacity is 1100 MW, far exceeding electricity demand within Cape & Islands communities. It includes two units and an undeveloped site for a third unit. Unit 1 is fueled by oil, and it is designed for continuous, full-capacity (baseload) operation. Unit 2 is designed to operate over a wide range of loads. It was retrofit in 1996 to combust oil or natural gas, but to date the cleaner and more expensive fuel has been used only sparingly. Over the past couple years, the plant itself has operated sparingly due to the high cost of oil. Other small generating systems are located in Cape & Islands communities, but the amount they deliver to the grid is negligible when considered in light of the region's overall demand. Many of these distributed energy solutions are sized to serve on-site needs or sited to deliver backup power in the event of an outage. Examples include the following:
Generating facilities on Cape Cod, Martha's Vineyard, and Nantucket contribute to electricity supply portfolios spanning various geographic scales. Click on the links below for more detailed information on the local implications of these portfolios: NationalAccording to the U.S. Energy Information Administration, coal-fired power plants accounted for 52% of total electricity generation in the United States in 2003. Nuclear plants produced 21%, natural-gas-fired plants 16%, hydroelectric facilities 7%, oil-fired plants 2%, and geothermal and "other" sources 1% each.
There are two key local implications of the U.S. supply portfolio, both relating to national reliance on coal:
New England
A more detailed table of 2003 contributions by individual fuel sources is provided in the table, Sources of Electricity in New England in 2003. The most important trend in the six-state region's supply portfolio is displayed in the bar chart below. Reliance on natural gas is steadily increasing. This has significant economic consequences for all local electricity consumers and for residents, businesses, and other organizations that rely on natural gas for heating, cooking, manufacturing, and other uses. Higher electricity and fuel prices are a major concern, on their own and because they have ripple effects: Consumers end up paying more for other products and services.
Periodic fuel shortages leading to price spikes, rolling blackouts, and gas service cutoffs represent another key concern - and not just a theoretical one. During a January 2004 cold snap, some power plants in New England stopped operating because no gas was available, while others shut down because plant owners could reap higher profits by selling (rather than burning) their fuel. The shortfall in generating capacity led ISO New England to issue a warning about possible rolling blackouts. The fuel shortage caused some Cape Cod residents and businesses to lose gas service. Massachusetts In April 2002, the Massachusetts Division of Energy Resources promulgated the RPS (225 CMR 14.00) under authority granted by the Electric Utility Restructuring Act of 1997. Since 2003, retail suppliers operating within the state - including distribution companies such as NStar and National Grid as well as municipal aggregators such as Cape Light Compact - have been required to purchase a certain amount of "generation attributes" from renewable energy facilities that meet criteria established by the RPS. Generation attributes are environmental and other non-monetary characteristics associated with electricity production. In the New England marketplace, these attributes are tracked by the New England Power Pool's Generation Information System (NEPOOL-GIS). For each megawatt-hour of electricity, NEPOOL-GIS creates an electronic certificate that describes when and where the power was produced; the fuel source used; the facility's RPS eligibility; the amount and type of certain pollutant emissions; and other characteristics. Electricity suppliers may sell their certificates to retail suppliers or other market participants, separate and apart from the actual electricity they generate. RPS-qualified facilities thus generate green electrons as well as renewable energy certificates (RECs). In 2007, retail suppliers are required to secure RECs equivalent to at least 3% of their annual sales within the state. This percentage increases by 0.5% annually through 2009, when it reaches 4%; thereafter, it is scheduled to increase by 1% annually. These RPS requirements, similar standards in other states, and additional provisions of the state's Electric Utility Restructuring Act are beginning to expand the role of renewables in the electricity supply portfolio of Massachusetts and the entire New England marketplace. RPS requirements have two important local implications:
Southeastern Massachusetts The area's supply portfolio, though more heavily weighted toward fossil fuels than that in the rest of New England, does include a mix of fuels. For example, SEMA facilities ranging in capacity from 75 to 200 MW rely on coal, fuel oil, natural gas, and jet fuel. The three major power plants in SEMA include the following:
The proximity of these large facilities to the Cape & Islands region has important implications for local environments and populations.
The Brayton Point plant is the single largest source of air pollution in New England. Data from the U.S. Environmental Protection Agency (EPA) indicate that the facility emitted more than 70 million pounds of SO2 and more than 21 million pounds of nitrogen oxides (NOx) in 2003. According to the U.S. EPA's Toxics Release Inventory, the plant's four smokestacks released 180 pounds of mercury and more than 1 million pounds of other toxic substances in 2001. Prevailing winds carry these airborne contaminants toward local communities. The Pilgrim plant generates electricity without producing SO2, NOx, or mercury. It is the exceptional event, rather than routine operation, that poses risks to the Cape & Islands region: A release of radioactive material from the plant, though unlikely, is possible. The U.S. Nuclear Regulatory Commission (NRC) defines two zones around each nuclear power plant. In the "emergency management zone" (EMZ), which covers an area about 10 miles in radius, the primary concern is direct exposure to and inhalation of airborne radioactive contaminants. In the "ingestion zone" (IZ), about 50 miles in radius, the primary concern is ingestion of contaminated food and water. (See Fact Sheet on Emergency Planning and Preparedness at Nuclear Power Plants from NRC.) Portions of the town of Bourne fall within the Pilgrim plant's EMZ, and many more local communities lie within its IZ. If an accident or attack results in a radioactive release, emergency plans would go into effect. The Sagamore Bridge would be closed to control access to the EMZ, and responses by Bourne and other towns would include alarms, sheltering, and evacuation, as appropriate. In addition, these towns, along with others within the IZ, would be required to alert residents, test locally grown foods and local water supplies, stop the distribution of contaminated food and water, relocate livestock, and control access, as appropriate. Communities with potassium iodide (KI) stockpiles would distribute these pills to reduce the risk of thyroid cancer in individuals exposed to radiation. This compound helps prevent the thyroid gland from absorbing radioactive iodine, one of several isotopes that could be present in a radioactive release. A Massachusetts law passed in 2002 requires the state to provide KI to communities in the Cape & Islands region that elect to stockpile thyroid-blocking agents. For the Canal plant, some economic, environmental, and social effects on local communities are itemized here. Last updated 09.19.07. |
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