The U.S. Environmental Protection Agency is implementing a program of
SO2 emission allowance trading as part of the Acid Rain Program author
ized by the Clean Air Act Amendments of 1990. Electric utilities may u
se allowance trading as part of their compliance strategy to meet SO2
emission reduction requirements, which begin in 1995. In the interest
of a free market in emission credits, some utilities began trading in
1992. A strict but essential requirement for continuous-emissions moni
toring was developed to support the trading program. This program is b
eing widely watched and will be evaluated as part of an effort to dete
rmine if market concepts can be successfully extended to other environ
mental issues. One such issue is greenhouse gas emissions and their li
nk with global warming and climate change. This paper focuses on the e
arly lessons learned, issues, and challenges involved in going from a
domestic electric utility SO2 emissions trading program to inter-indus
try, inter-gas and international as well as national emissions trading
and offsets programs. Prominent among these issues are CO2 allowance
allocations, equity, emissions monitoring, enforcement, and cost-effec
tiveness.