Like many other states, Oregon has begun to pursue climate policies to attempt to fill the gap created by the lack of effective climate policy at the Federal level. After adopting a variety of policies to address climate change and other environmental impacts from energy use, Oregon is now contemplating the adoption of a greenhouse gas (GHG) cap-and-trade system. However, interactions between policies can have important consequences for environmental and economic outcomes. Thus, as Oregon considers taking this step, reconsidering the efficacy of its other current climate policies may better position the state to achieve long-run emission reductions at sustainable economic costs.

California’s Greenhouse Gas (GHG) cap-and-trade program is a key element of the suite of policies the State has adopted to achieve its climate policy goals. The passage of AB 398 (California Global Warming Solutions Act of 2006: market-based compliance mechanisms) extended the use of the cap-and-trade program for the 2021-2030 period, while also specifying modifications of the program’s “cost containment” structure and directing CARB to “[e]valuate and address concerns related to overallocation in [ARB’s] determination of the allowances available for years 2021 to 2030.” The changes being considered by CARB will not only affect the program’s stringency, but also its performance by affecting the ability of the “cost containment” structure to mitigate allowance price volatility and the risk of suddenly escalating allowance prices. We address key design issues that were identified by the legislature in AB 398 and have been identified by CARB in its “Preliminary Concepts” white paper, including: (1) Price levels for the Price Ceiling and Price Containment Points; (2) Allocation of allowances between the auction budgets, Price Containment Points, and Price Ceiling; (3) “Overallocation” of GHG allowances; and (4) the program’s administrative and operational rules, such as procedures for distributing allowances to the market from the Price Ceiling or Price Containment Points, procedures for using allowances once distributed, and banking rules.

Many economists have long held that carbon pricing—either through a carbon tax or cap-and-trade—is the most cost-effective way to decarbonize energy systems, along with subsidies for basic research and development. Meanwhile, green innovation and industrial policies aimed at fostering low-carbon energy technologies have proliferated widely. Most of these predate direct carbon pricing. Low-carbon leaders such as California and the European Union (EU) have followed a distinct policy sequence that helps overcome some of the political challenges facing low-carbon policy by building economic interest groups in support of decarbonization and reducing the cost of technologies required for emissions reductions. However, while politically effective, this policy pathway faces significant challenges to environmental and cost effectiveness, including excess rent capture and lock-in. Here we discuss options for addressing these challenges under political constraints. As countries move toward deeper emissions cuts, combining and sequencing policies will prove critical to avoid environmental, economic, and political dead-ends in decarbonizing energy systems.

Pricing greenhouse gas emissions involves making trade-offs between consumption today and unknown damages in the (distant) future. The optimal carbon dioxide (CO2) price, thus, is based on society’s willingness to substitute consumption across time and across uncertain states of nature. Standard constant relative risk aversion preference specifications conflate the two. Moreover, they are inconsistent with observed asset valuations, based on a large body of work in macroeconomics and finance. This literature has developed a richer set of preferences that are more consistent with asset price behavior and separate risk across time and across states of nature. In this paper, we explore the implications of these richer preference specifications for the optimal CO2 price. We develop the EZ-Climate model, a simple discrete-time optimization model in which the representative agent has an Epstein-Zin preference specification, and in which uncertainty about the effect of CO2 emissions on global temperature and on eventual damages is gradually resolved over time. We embed a number of features including potential tail risk, exogenous and endogenous technological change, and backstop technologies. The EZ-Climate model suggests a high optimal carbon price today that is expected to decline over time as uncertainty about the damages is resolved. It also points to the importance of backstop technologies and to very large deadweight costs of delay. We decompose the optimal carbon price into two components: expected discounted damages and the risk premium. JEL code: D81, G11, Q54.

This article presents an overview of the design and performance of seven major emissions trading programs that have been implemented over the past 30 years and identifies a number of important lessons for future applications of this important environmental policy instrument. A brief discussion of several other proposed or implemented emissions trading programs is also included.

This paper introduces an approach for separately quantifying the contributions from renewables in decomposition analysis. So far, decomposition analyses of the drivers of national CO2 emissions have typically considered the combined energy mix as an explanatory factor without an explicit consideration or separation of renewables. As the cost of renewables continues to decrease, it becomes increasingly relevant to track their role in CO2 emission trends. Index decomposition analysis, in particular, provides a simple approach for doing so using publicly available data. We look to the U.S. as a case study, highlighting differences with the more detailed but also more complex structural decomposition analysis. Between 2007 and 2013, U.S. CO2 emissions decreased by around 10%—a decline not seen since the oil crisis of 1979. Prior analyses have identified the shale gas boom and the economic recession as the main explanatory factors. However, by decomposing the fuel mix effect, we conclude that renewables played an equally important role as natural gas in reducing CO2 emissions between 2007 and 2013: renewables decreased total emissions by 2.3–3.3%, roughly matching the 2.5–3.6% contribution from the shift to natural gas, compared with 0.6–1.5% for nuclear energy.