sectoral economic costs and benefits of ghg mitigation - IPCC

Energy Intensive Industries
column, the sector-specific carbon permit prices range from about $160 per ton carbon in the
electric utility sector to around $900 per ton carbon in the transportation sector. These results
reflect the greater ability to fuel-switch in the electric sector on the time horizon to 2010.
Table 4
Carbon Permit Prices in 2010 (1995 US$ per Ton Carbon)
Cases With Trade
With Proportional Cap
Case Price Sector Price
FT 307 AG 423
E/TRG 487 ELEC 157
E/H&AG 504 EINT 402
E/EINT 440 TRAN 881
E/ELEC 913 OIND 386
E/TRAN 452 H 228
The comparison in Table 3 also illustrates one of the major benefits of a trading system. Even
though initial reduction targets by sector might be established in a pattern not too far from
economic efficiency, changes in an economy over time will lead these targets to become more
and more inefficient. A trade system provides a mechanism that automatically adjusts to
economic change (as would a uniform carbon tax). But hard sector targets or technological
requirements are likely to create ever greater distortions, because it is extremely unlikely that
growth in different sectors will be identical or that emissions reduction opportunities will develop
equally across sectors.
The remaining cases all involve exemption of one or more sectors, and the cost penalties are
correlated with the relative quantities of emissions exempted. As shown in Table 3, the cost
penalty in 2010 from exemption of these sectors, relative to the case with full trading, ranges
from a low of 32% when energy intensive industries are left out (E/EINT) to a high of nearly
300% when electricity is omitted from the control regime (E/ELEC). And, similar to the NT
case, the cost penalty associated with each of these exemptions grows over the years to 2030.
The penalty rises over time because demand for products from exempted sectors grows as the
prices of their goods fall relative to the prices of other goods that do bear cost of emissions
reductions. Also, at the same time these exempted sectors switch to more carbon intensive fuels
whose prices have fallen because of the carbon constraint elsewhere in the U.S. economy (and in
other Annex B countries).
Sector Impacts
Another interesting question is whether these exemptions actually have their intended effect. We
are not able to explore this question in detail because, as discussed earlier, we are using a model
that presumes that all assets and labor are fully employed. In some policy circles there is concern
about stranded assets - those assets that would be retired prematurely because of an
environmental policy. The best way to avoid the severe economic loss that stranded assets might
involve is to introduce an economy-wide cap-and-trade system, so firms and households across
the economy could buy permits rather than retire capital early (Of course, a tight constraint
introduced with little lead-time will cause some capital to be retired prematurely in any case). To
analyze this circumstance would require a model where our exogenous depreciation rate was
replaced with an endogenous representation of the retirement decision. Similarly, to capture the
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