amount of the pollutant they can emit. US EPA gathers the data and tabulates the
emissions from each plant. The latest, 2013, ARP, and CAIR emission reductions are
as follows [67]:
1. CAIR and ARP Annual SO 2 Emissions: 3.2 million tons (69% below 2005)
2. CAIR and ARP Annual NO x Emissions: 1.7 million tons (53% below 2005)
3. CAIR Ozone Season NO x Emissions: 470,000 tons (41% 2005)
4. Ambient particulate sulfate concentrations have decreased since the ARP was
implemented, with average concentrations decreasing by 60 to 65% in observed
regions from 1989–1991 to 2011–2013
5. The Northeast and Mid-Atlantic have showed the greatest improvement with an
overall 64% reduction in wet sulfate deposition from 1989–1991 to 2011–2013
8.7 Acid Rain Allowances
The Acid Rain Program uses a market-based approach to control sulfur dioxide
emissions from power plants. Under the current system, known as a “cap and trade”
system, it limits, or caps, sulfur dioxide emissions by issuing a fixed number of
allowances and allowing only one ton of SO 2 to be emitted per allowance. The total
number of allowances is distributed by US EPA each year. Each power plant that
was operating during the years from 1985 to 1987 is assigned a number of allowances based on their emissions of sulfur dioxide during that period. Each power plant
must hold one allowance for each ton of SO 2 they emit. At the end of the year, these
facilities must surrender a number of allowances equal to the number of tons of SO 2
they emitted during the year. If they emit more SO 2 than they have allowances, they
must buy additional allowances. Conversely, if they can further reduce their emissions, they can sell their excess allowances. Some allowances were withheld by US
EPA and are made available through an annual auction. By limiting the number of
allowances, US EPA can limit the amount of SO 2 the power plants release.
The Acid Rain Program was implemented in two phases. During Phase I
(1995–2000), 11 units at five New England Stations were allocated a total of
167,779 allowances. During Phase II (starting in 2000), 27 facilities (about
80 units) in New England received a total of 273,150 allowances. The number per
unit was reduced during Phase II, so the total amount of SO 2 was also reduced. The
five units in Phase I received only 91,136 allowances per year in Phase II [68].
New units, which were not operating in 1987, are not assigned allowances. They
must obtain the necessary allowances from other units or buy them.
In 1995, US EPA issued about 8.7 million allowances to Phase I units. If all were
used, this would have resulted in a 2.2-million-ton reduction from the 1980 level.
Actual emissions in 1995 were 5.3 million tons. That means that in 1995, SO 2 was
reduced by 5.6 million tons. Of the 3.4 million unused allowances in that year, about
36,000 were sold or donated to private individuals or environmental groups and
“retired.” This effectively lowered the cap for SO 2 emissions for that year. The other
allowances were held either by brokerage firms or by the utilities themselves.
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293
emissions from each plant. The latest, 2013, ARP, and CAIR emission reductions are
as follows [67]:
1. CAIR and ARP Annual SO 2 Emissions: 3.2 million tons (69% below 2005)
2. CAIR and ARP Annual NO x Emissions: 1.7 million tons (53% below 2005)
3. CAIR Ozone Season NO x Emissions: 470,000 tons (41% 2005)
4. Ambient particulate sulfate concentrations have decreased since the ARP was
implemented, with average concentrations decreasing by 60 to 65% in observed
regions from 1989–1991 to 2011–2013
5. The Northeast and Mid-Atlantic have showed the greatest improvement with an
overall 64% reduction in wet sulfate deposition from 1989–1991 to 2011–2013
8.7 Acid Rain Allowances
The Acid Rain Program uses a market-based approach to control sulfur dioxide
emissions from power plants. Under the current system, known as a “cap and trade”
system, it limits, or caps, sulfur dioxide emissions by issuing a fixed number of
allowances and allowing only one ton of SO 2 to be emitted per allowance. The total
number of allowances is distributed by US EPA each year. Each power plant that
was operating during the years from 1985 to 1987 is assigned a number of allowances based on their emissions of sulfur dioxide during that period. Each power plant
must hold one allowance for each ton of SO 2 they emit. At the end of the year, these
facilities must surrender a number of allowances equal to the number of tons of SO 2
they emitted during the year. If they emit more SO 2 than they have allowances, they
must buy additional allowances. Conversely, if they can further reduce their emissions, they can sell their excess allowances. Some allowances were withheld by US
EPA and are made available through an annual auction. By limiting the number of
allowances, US EPA can limit the amount of SO 2 the power plants release.
The Acid Rain Program was implemented in two phases. During Phase I
(1995–2000), 11 units at five New England Stations were allocated a total of
167,779 allowances. During Phase II (starting in 2000), 27 facilities (about
80 units) in New England received a total of 273,150 allowances. The number per
unit was reduced during Phase II, so the total amount of SO 2 was also reduced. The
five units in Phase I received only 91,136 allowances per year in Phase II [68].
New units, which were not operating in 1987, are not assigned allowances. They
must obtain the necessary allowances from other units or buy them.
In 1995, US EPA issued about 8.7 million allowances to Phase I units. If all were
used, this would have resulted in a 2.2-million-ton reduction from the 1980 level.
Actual emissions in 1995 were 5.3 million tons. That means that in 1995, SO 2 was
reduced by 5.6 million tons. Of the 3.4 million unused allowances in that year, about
36,000 were sold or donated to private individuals or environmental groups and
“retired.” This effectively lowered the cap for SO 2 emissions for that year. The other
allowances were held either by brokerage firms or by the utilities themselves.
7 Lake Restoration
293