The plan to introduce a carbon pricing scheme in Australia has focused attention on the future relevance and necessity of using other policy instruments to reduce carbon emissions. Significant reports, including the Wilkins Review and reports by the Productivity Commission, have argued using the standard neoclassical economics framework that once a carbon price is established, it should be (almost) the only instrument needed to tackle climate change mitigation in Australia. With a small number of exceptions for complementary instruments to address some market failures, the use of other climate policy instruments, it is argued, will result only in unnecessary duplication and potential distortions. The aim of this article is to show that there are, in fact, a significant number of rationales for implementing several climate policy instruments in combination with a carbon price, and we should not be too quick to dismiss certain climate policy instrument combinations.

Anaerobic digestion systems can reduce greenhouse gas emissions while turning waste products into energy. Past U.S. economic research on anaerobic digesters has studied dairy farms, but limited economic information is available on anaerobic digestion systems for swine. Net present values (NPVs) were calculated for biodigesters and covered lagoons under different coproduct and policy scenarios. With no government intervention, covered lagoons are more promising for swine operations than more capital-intensive biodigesters. As there is interest in subsidizing anaerobic digestion systems, subsidies equal to a $38/t social cost of carbon would provide positive NPVs.

U.S. states have led the federal government in instituting policies aimed at promoting renewable energy. Nearly all research on renewable portfolio standards (RPSs) has treated RPS adoption as a binary choice. Given the substantial variation in the renewable energy goals established by RPSs, we propose a new measure of RPS ambition that accounts for the amount of additional renewable energy production needed to reach the RPS goal and the number of years allotted to reach the standard. By measuring RPS policy with more precision, our analysis demonstrates that many factors found to affect whether a state will adopt an RPS do not exert a similar effect on the policy’s ambitiousness. Most notably, our analysis demonstrates that Democratic control of the state legislature is the most consequential factor in determining the ambitiousness of state RPS policies.