Glossary: M to O
A-C | D-F | G-I | J-L | M-O | P-R | S-U | V-Z
M
Massachusetts Technology Collaborative (MTC): The Massachusetts Technology Collaborative is the state’s development agency for renewable energy and the innovation economy. MTC administers the Renewable Energy Trust and other funds and initiatives like the John Adams Innovation Initiative.
Mechanical energy: Mechanical energy refers to an object that is doing work by being in motion. Mechanical energy can be transformed into electrical energy or thermal energy. Examples include wind turbines and refrigerators, respectively.
Megawatt (MW): A standard unit of electrical power equal to 1,000 kilowatts, or 1 million watts. Like watts and kilowatts, the term “megawatt” is used as a standard measure of electric power plant generating capacity. It is most commonly used for large systems like wind turbines, biomass plants, and coal, natural gas, and nuclear plants.
Megawatt-hour (MWh): 1 megawatt acting over a period of 1 hour. One megawatt-hour is equal to 1,000 kilowatt-hours or 1 million watt-hours. The primary difference between a megawatt and a megawatt-hour is that “megawatt” measures the capacity of an electric generator and “megawatt-hour” measures the actual amount of electricity it produces over a certain period of time.
Methane gas: Methane is a common, naturally occurring and human-produced gas that can have serious climate change impacts when it is not captured. When captured, it can be used as a fuel. Methane produced by decomposition in landfills and through other human activities can be burned to produce energy for turbines and even fuel cells.
Municipal utility: Municipally owned utilities are owned and operated by the individual towns and cities they serve. These utilities are responsible for customer billing, wire, pole, and meter maintenance, connecting new customers, distribution of electricity, and restoring power after an outage. These utilities are not required to collect energy efficiency and renewable energy funding for use in public funds, but some have elected to establish their own energy efficiency funds and install clean energy in their local service areas.
N
Natural gas: Natural gas is a fossil fuel made of about 50% methane, a potent greenhouse gas. Like coal and oil, natural gas is a nonrenewable resource because it cannot be replenished on a human time scale. According to the U.S. EPA, natural gas power plants provide about 14 percent of the electricity produced in the United States, ranking third behind coal and nuclear power. In New England, its use is much higher, with about 40% of our electricity and the majority of our heating provided by natural gas.
New England Power Pool (NEPOOL): NEPOOL is a voluntary association of entities that are engaged in the electric power business in New England and is closely affiliated with the ISO-NE. The NEPOOL participants include utilities, power marketers, load aggregators, generation owners and end users.
Nitrogen oxides (NOx): Nitrogen oxides are byproducts of nitrous oxide from fossil fuel combustion. They are called criteria pollutants (along with carbon monoxide, sulfur dioxide, nonmethane volatile organic compounds, lead, and particulates). They contribute to acid rain, smog, and respiratory problems, and have an indirect impact on global climate change.
Nitrous oxides (N2O): Nitrous oxides are greenhouse gases. The natural sources and cycles of nitrous oxides are not as well understood as those of carbon dioxide and methane, but their primary natural source appears to be bacterial breakdown of chemicals in soil. Human activities that increase nitrous oxide levels in the atmosphere (and the corresponding risk of climate change) include fossil fuel burning, use of nitrogen-based fertilizers in farming, and emissions from industrial processes.
Nuclear energy: Nuclear energy relies on the splitting of uranium atoms in a process called fission, which generates heat for producing steam that then turns a turbine to produce electricity. While nuclear power plants do not emit air pollutants, nuclear wastes and abandoned uranium mines pose health risks from radiation for as long as 250,000 years if not contained properly.
O
Office of Commonwealth Development (OCD): The OCD oversees the state’s energy, environment, housing, and transportation agencies. It has a strong focus on maintaining the built and natural environment through various policies, programs and regulations including the Massachusetts Climate Action Plan.
Ohm: A measure of the electrical resistance of a material equal to the resistance of a circuit in which the potential difference of 1 volt produces a current of 1 ampere. Ohms are used by utilities and electrical engineers to measure the resistance of wires conducting electricity.
Oil: Oil, a liquid fossil fuel, is used in enormous quantities worldwide. Oil contains carbon, nitrogen, sulfur, mercury, lead, and arsenic, all of which are emitted when oil is burned to produce energy. Advancements have been made in producing cleaner-burning oil; however, its emissions are still significant. Oil is a nonrenewable resource, like coal and natural gas, and oil spills have caused severe damage to natural environments.
Ozone (O3): Ozone is a unique emission because it is not directly produced by human sources. Instead, it is created as a result of chemical reactions between human-produced emissions and other gases in the atmosphere. Ozone is also unique because it is considered beneficial in some places and detrimental in others. When ozone is in the earth's upper atmosphere it is considered good because it protects the earth from the sun's radiation. But when ozone is created in the lower atmosphere, it creates smog which can cause respiratory problems and damage to plant and animal life. In the lower atmosphere, ozone is typically created when volatile organic compounds (VOCs) or nitrogen oxides react with other atmospheric gases.