You asked (1) which gases besides carbon dioxide (CO₂) are high global warming potential gases, (2) to what extent they are emitted in Connecticut, (3) how they are emitted, and (4) what steps Connecticut, other states, and the private sector have taken to reduce them.

SUMMARY

There are five greenhouse gases (GHG) or groups of gases besides CO₂: (1) methane, (2) nitrous oxide, (3) hydrofluorocarbons (HFCs), (4) perfluorocarbons (PFCs), and (5) sulfur hexafluoride (SF₆). According to the state Department of Environmental Protection (DEP), CO₂ accounted for 91% of the state's GHG emissions in 2000, followed by methane (4%), and nitrous oxide (3. 3%). HFCs, PFCs and SF₆ together accounted for about 1. 7% of the state's GHG emissions.

Sources of methane include oil and gas transmission and distribution, livestock, landfills, and waste combustion and decomposition. Nitrous oxide is emitted from agricultural sources and chemical and fuel combustion. Industrial sources produce HFCs, PFCs and SF₆.

The state's Climate Change Action Plan sets out a number of steps to reduce GHGs. Although most of the initiatives are meant to reduce CO₂ emissions, the state also seeks to reduce methane emissions by designating methane-to-energy sources as a renewable energy source, and reduce nitrous oxide emissions by reducing fertilizer use. It is seeking to reduce HFCs, PFCs and SF₆ by improving appliance efficiency and minimizing leaks. Other states and the private sector have embarked on a number of programs aimed at these GHGs, which we describe below.

Much of the information below is from the Connecticut Greenhouse Gas Inventory, 1990-2000, published in 2003. DEP is now updating this information, as well as collecting additional data. The revised data should be available later this year.

GREENHOUSE GASES

A GHG absorbs and re-emits infrared radiation, warming the earth's surface and contributing to climate change. The Kyoto Protocol, an agreement under which many industrialized countries agreed to reduce their GHG emissions, identifies six GHGs. (The U. S. has not ratified the Kyoto Protocol). In 2000, CO_2, which occurs both naturally and when fossil fuels and wood are burned, accounted for 83% of total U. S. GHG emissions by weight. Other GHGs listed in the protocol include (1) methane and (2) nitrous oxide, which occur both naturally and as the result of human activity (“anthropogenic”), and three GHGs not found in nature: (3) hydrofluorocarbons (HFCs), (4) perfluorocarbons (PFCs) and (5) sulfur hexafluoride (SF₆).

Table I, below, identifies the primary anthropogenic sources of these non-CO₂ GHGs. (Other gases that affect global warming are not considered in this report. These include water vapor, ozone, carbon monoxide, sulfur dioxide, and nitrogen oxides. )

Table I: Man-Made Sources of Non-CO₂ Greenhouse Gases

*Also occur naturally.

GLOBAL WARMING POTENTIAL

Because different gases have different lifetimes and varying heat-trapping abilities, scientists use Global Warming Potential (GWP) to compare their global warming impacts to that of CO₂. The GWP compares each gas to CO₂ based on (1) its relative ability to absorb heat, and (2) how fast it leaves the atmosphere. The values are set by the Intergovernmental Panel on Climate Change, which periodically revises them. The GWPs in Table II indicate relative GWPs for a 100-year period. Thus, one ton of HFC-23 has the same global warming impact over 100 years as 12,000 tons of CO_2. More information on GWPs is available on this U. S. Department of Energy website.

Table II: GHG Global Warming Potential (GWPs)

* refrigerant and fire extinguishing agent

** aluminum smelting byproduct

CONNECTICUT SOURCES OF NON-CO₂ GHGS

GHG emissions are measured in terms of million metric tons of carbon dioxide equivalent, or MMTCO₂E. According to the Connecticut Greenhouse Gas Inventory, 1990-2000, Connecticut emitted 44 MMTCO₂E of GHG in 1990, and 48 MMTCO₂E in 2000. In 2000, CO₂ accounted for 91% of state GHG emissions, followed by methane (4%), and nitrous oxide (3. 3%). HFCs, PFCs, and SF6 together accounted for about 1. 7% of state GHG emissions. CO₂ represents a greater proportion of Connecticut's GHG then it does in the nation as a whole because the state has a relatively small agricultural sector, and does not have sources that produce significant amounts of methane, such as coal mines and oil and gas production.

Methane

Methane is emitted during oil and gas production, storage, transportation, and distribution. In Connecticut, emissions occur from chronic leaks, accidents, and other sources as the gas is transmitted throughout the state and distributed to end users. According to DEP, emissions of methane from natural gas transmission and distribution systems accounted for approximately one percent of all GHG emissions in Connecticut during the 1990s. According to the Inventory report, several of the major gas transmission companies serving New England are working with EPA to reduce these emissions. Methane and CO₂ also are emitted from decomposing organic matter in landfills in approximately equal amounts by volume. Some landfills flare (burn off) recovered landfill gas, which converts the methane portion to CO2. Since methane has a global warming potential value of 23, compared to one for CO2, flaring reduces net GHG emissions from landfills.

Nitrous Oxide

Nitrous oxide is produced at the high temperatures found in waste combustors by the combination of nitrogen (both nitrogen contained in the waste and nitrogen gas in the air) and oxygen in the air. GHG emissions (both CO₂ and nitrous oxide) from municipal solid waste disposal – including both landfilling and waste combustion – accounted for roughly six to eight percent of Connecticut's annual GHG emissions in the 1990s, and declined by nearly 10 percent from approximately 3. 5 MMTCO2E in 1990 to 3. 16 MMTCO2E in 2000.

Industrial GHGs

HFCs and PFCs. Industrial production processes accounted for about 0. 7 percent of Connecticut's annual GHG emissions in the early 1990s, rising to nearly 2 percent by 2000. This contribution came mainly from HFCs, PFCs, and SF₆. While these substances account for a relatively small share of state emissions, their contribution is noteworthy because it grew from 0. 3 to 0. 84 MMTCO2E in the 1990s, as HFCs and some PFCs replaced ozone-depleting substances, such as CFCs. Emissions from these substitutes rose from negligible levels in 1990 to approximately 0. 7 MMTCO2E in 2000.

PFCs emitted during semiconductor manufacturing accounted for a small fraction of Connecticut's GHG emissions throughout the decade. However, DEP states that these emissions are likely to rise in the coming decades, driven by a growing demand for semiconductors. The World Semiconductor Council has pledged to reduce PFC emissions from chip manufacture at least 10 percent below 1995 levels by 2010.

SF_6. This substance is primarily used as an electrical insulator in electrical transmission and distribution equipment. Connecticut's SF₆ emissions decreased from approximately 0. 3 MMTCO2E to 0. 1 MMTCO2E between 1990 and 2000, reflecting national efforts by the electric power industry to control leaks in response to SF₆ price increases and concerns about its environmental impact. According to the GHG inventory, several Connecticut electric utility companies are participating in a voluntary partnership with EPA to reduce SF₆ emissions and establish SF₆ emissions reduction goals.

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CONNECTICUT CLIMATE CHANGE ACTION PLAN RECOMMENDATIONS

The 2005 Connecticut Climate Change Action Plan, prepared by the Governor's Committee on Climate Change, made specific recommendations to reduce non-CO₂ GHGs. In February, 2006, the steering committee tracked the progress made in the previous year. The following information comes from the plan and the follow-up 2006 report, Taking Action in Connecticut to Address Climate Change: Progress Made in 2005.

Methane Reduction

The plan recommended (1) supporting landfill-to-gas energy projects to capture and use methane as a fuel, rather than release it to the air, and (2) increasing recycling and source reduction, thereby reducing the amount of methane emissions associated with producing new materials.

The 2006 progress report notes that state law (CGS § 16-245a) requires that a percentage of electricity generation come from clean energy. Under the law, electric suppliers and distribution companies must obtain 3. 5% of their energy from “Class I” sources in 2007, increasing gradually to 7% in 2010. Methane gas from landfills is included among the Class I sources.

Nitrous Oxide Reduction

A portion of nitrogen applied to the soil as fertilizer is emitted as nitrous oxide. Reducing the amount of fertilizer therefore can reduce these emissions. The Climate Change Action Plan's goal is to reduce non-farm fertilizer use by 7. 5% in 2010 and by 15% in 2020.

The 2006 progress report notes several initiatives to reduce fertilizer use (and thus nitrous oxide emissions) on non-farm land. The Connecticut Northeast Organic Farmers Association promotes organic land care practices and trains lawn care professionals. DEP and the association are to pilot organic land care practices on a school or recreational field in one municipality. Milford and Cheshire are taking part in a voluntary program to reduce the use of pesticides and chemical fertilizers on residential lawns.

HFC, CFC and SF₆ Reduction

To reduce these GHGs, the plan recommends (1) setting minimum efficiency levels for appliances, which would reduce HFC and CFC emissions by reducing leaks from refrigerators, freezers, and air conditioners; (2) encouraging consumers to replace old appliances with newer, more efficient ones; and (3) identifying measures to reduce high GWP gases.

ACTIONS TAKEN BY OTHER STATES

States have implemented various measures to reduce non-CO₂ GHGs, ranging from buying old air conditioners in New York to heating a high school in Missouri with methane from a nearby landfill. More information on the programs below and other programs can be found on this Pew Center on Global Climate Change web site.

Indiana

Indiana has an Industrial Energy Efficiency Fund, which provides loans to industries seeking to acquire energy and material-efficient manufacturing equipment. Proposed projects must result in measurable energy savings and contribute to the state's long term economic development. The amount of money awarded varies from year to year.

Missouri

Pattonville High School in Maryland Heights, Missouri, burns free methane from a nearby landfill instead of natural gas to fuel its boilers. Project officials estimate the methane gas reserves will provide the school with at least 40 years of fuel.

New Hampshire

The New Hampshire Building Energy Conservation Initiative analyzes state buildings for energy saving opportunities, retrofits, and upgrades. It also seeks to create local jobs and provides a public example of good energy management.

New York

The New York State Energy Research and Development Authority has implemented the Keep Cool Air Conditioner Bounty Program to reduce the number of inefficient air conditioners used in that state. Multi-family building owners and management companies receive $ 75 per air conditioner when they turn in old ones and replace them with Energy Star-marked air conditioners. (Energy Star is a federal government backed program to encourage energy efficiency). The old air conditioners are recycled.

North Carolina

The North Carolina State University Animal and Poultry Waste Management Center is evaluating several technologies to enable farms to reduce methane emissions by using waste methane to generate energy.

Wisconsin

A pilot manure-to-energy system began in 2001 at one of the state's largest dairy farms. Until recently, nearly 60,000 gallons of manure a day was discharged into lagoons and used as fertilizer. The anaerobic digestion system produces biogas, which fuels a pair of engines that drive two 375-kilowatt generators. Similar programs are taking place in other states, including Vermont.

ACTIONS TAKEN BY THE STATE'S PRIVATE SECTOR

The following programs target primarily CO₂, but may also include non-CO₂ GHGs.

Several Connecticut companies take part in the U. S. Environmental Protection Agency's “climate leader” program. These companies develop long-term strategies to reduce GHGs and inventory their emissions.

Among the companies taking part are United Technologies (UTC), Frito-Lay; the Hartford; Pfizer; Unilever; and General Electric. According to the Connecticut Climate Change web site, for example, UTC has reduced its GHG emissions by 15% since 1997, largely through improvements in energy efficiency.

United Illuminating has hosted events at which consumers can trade in highly inefficient halogen torchiere bulbs for more efficient fluorescent bulbs. Besides being cheaper to operate than halogen bulbs, another advantage of the switch is that air conditioners do not have to work as hard to cool indoor air heated by fluorescent bulbs.

According to “A Climate of Innovation: Northeast Business Action to Reduce Greenhouse Gases,” prepared in 2004 by the World Resources Institute, Bristol Myers Squibb Co. built a combined heat and power plant at its Wallingford plant that uses natural gas as a fuel and burns oil as a backup. The unit eliminates the need for an additional boiler and has allowed staff to redesign plant utilities to achieve optimal efficiency. According to the report, the project has reduced GHG emissions by 20% from the amount the plant would have otherwise consumed.

In October 2005, DEP, the Insurance Department, and the state treasurer co-sponsored a climate change “summit” of insurance industry executives and state regulators. It was the first in a series of workshops planned for the state's insurance and financial services companies. More information on these and other programs is available on this Connecticut Climate Change web site.

OTHER PRIVATE SECTOR PROGRAMS

According to “A Climate of Innovation: Northeast Business Action to Reduce Greenhouse Gases” the following companies are among those that have been active in reducing GHGs.

Con Edison

Since 1993 Con Ed has reduced its methane emissions by more than 47,000 metric tons, helping save the company about $ 5 million in leakage costs. Con Ed also helped fund the design, development and assembly of a new technology to capture natural gas in pipelines that are being repaired. Maintenance crews remove the gas from the section of pipeline being repaired and feed it into the active part of the line, thus preventing the gas' release into the atmosphere.

Pfizer

Pfizer developed a computer technology to track its GHG emissions, and find possible emission reduction projects. It has identified more than 600 energy savings projects at all levels of the company.

Staples

Staples has used money it saved from implementing energy efficiencies to buy renewable power. In 2003 Staples increased its renewable power use from less than 2% of its annual electricity consumption to an industry leading 10%.

Johnson & Johnson

In 2003, Johnson & Johnson completed one of the largest purchases of renewable energy certificates by a U. S. corporation, buying more than 162,000 megawatt-hours over a three year period.

MORE INFORMATION

More information on these and other private sector programs can found on the web site listed above, and at Cool Solutions to Global Warming.

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