Banking Permits: Economic Efficiency and Distributional Effects

Most analyses of the Kyoto flexibility mechanisms focus on the cost effectiveness of “where” flexibility (e.g. by showing that mitigation costs are lower in a global permit market than in regional markets or in permit markets confined to Annex 1 countries). Less attention has been devoted to “when” flexibility, i.e. to the benefits of allowing emission permit traders to bank their permits for future use. In the model presented in this paper, banking of carbon allowances in a global permit market is fully endogenised, i.e. agents may decide to bank permits by taking into account their present and future needs and the present and future decisions of all the other agents. It is therefore possible to identify under what conditions traders find it optimal to bank permits, when banking is socially optimal, and what are the implications for present and future permit prices. We can also explain why the equilibrium rate of growth of permit prices is likely to be larger than the equilibrium interest rate. Most importantly, this paper analyses the efficiency and distributional consequences of allowing markets to optimally allocate emission permits across regions and over time. The welfare and distributional effects of an optimal intertemporal emission trading scheme are assessed for different initial allocation rules. Finally, the impact of banking on carbon emissions, technological progress, and optimal investment decisions is quantified and the incentives that banking provides to accelerate technological innovation and diffusion are also discussed. Among the many results, we show that not only does banking reduce abatement costs, but it also increases the amount of GHG emissions abated in the short-term. It should therefore belong to all emission trading schemes under construction.emission trading, banking

The WITCH Model. Structure, Baseline, Solutions

WITCH – World Induced Technical Change Hybrid – is a regionally disaggregated hard-link hybrid global model with a neoclassical optimal growth structure (top-down) and a detailed energy input component (bottom-up). The model endogenously accounts for technological change, both through learning curves that affect the prices of new vintages of capital and through R&D investments. The model features the main economic and environmental policies in each world region as the outcome of a dynamic game. WITCH belongs to the class of Integrated Assessment Models as it possesses a climate module that feeds climate changes back into the economy. Although the model’s main features are discussed elsewhere (Bosetti et al., 2006), here we provide a more thorough discussion of the model’s structure and baseline projections, to describe the model in greater detail. We report detailed information on the evolution of energy demand, technology and CO2 emissions. We also explain the procedure used to calibrate the model parameters. This report is therefore meant to provide effective support to those who intending to use the WITCH model or interpret its results.Climate Policy, Hybrid Modelling, Integrated Assessment, Technological Change

International Energy R&D Spillovers and the Economics of Greenhouse Gas Atmospheric Stabilization

This paper explores how international knowledge flows affect the dynamics of the domestic R&D sector and the main economic and environmental variables. The analysis is performed using WITCH, a dynamic regional model of the world economy, in which energy technical change is endogenous. The focus is on disembodied energy R&D international spillovers. The knowledge pool from which regions draw foreign ideas differs between High Income and Low Income countries. Absorption capacity is also endogenous in the model. The basic questions are as follows. Do knowledge spillovers enhance energy technological innovation in different regions of the world? Does the speed of innovation increase? Or do free-riding incentives prevail and international spillovers crowd out domestic R&D efforts? What is the role of domestic absorption capacity and of policies designed to enhance it? The new specification of the WITCH model presented in this paper enables us to answer these questions. Our analysis shows that international knowledge spillovers tend to increase free-riding incentives and decrease the investments in energy R&D. We also analyze the implication of a policy mix in which climate policy is combined with a technology policy designed to enhance absorption capacity in developing countries. Significant positive impacts on the costs of stabilising GHG concentrations are singled out.Climate Policy, Energy R&D, International R&D Spillovers, Stabilization

Optimal Energy Investment and R&D Strategies to Stabilise Greenhouse Gas Atmospheric Concentrations

The stabilisation of GHG atmospheric concentrations at levels expected to prevent dangerous climate change has become an important, global, long-term objective. It is therefore crucial to identify a cost-effective way to achieve this objective. In this paper we use WITCH, a hybrid climate-energy-economy model, to obtain a quantitative assessment of some cost-effective strategies that stabilise CO2 concentrations at 550 or 450 ppm. In particular, this paper analyses the energy investment and R&D policies that optimally achieve these two GHG stabilisation targets (i.e. the future optimal energy mix consistent with the stabilisation of GHG atmospheric concentrations at 550 and 450 ppm). Given that the model accounts for interdependencies and spillovers across 12 regions of the world, optimal strategies are the outcome of a dynamic game through which inefficiency costs induced by global strategic interactions can be assessed. Therefore, our results are somehow different from previous analyses of GHG stabilisation policies, where a central planner or a single global economy are usually assumed. In particular, the effects of free-riding incentives in reducing emissions and in investing in R&D are taken into account. Technical change being endogenous in WITCH, this paper also provides an assessment of the implications of technological evolution in the energy sector of different stabilisation scenarios. Finally, this paper quantifies the net costs of stabilising GHG concentrations at different levels, for different allocations of permits and for different technological scenarios. In each case, the optimal long-term investment strategies for all available energy technologies are determined. The case of an unknown backstop energy technology is also analysed.climate policy, energy R&D, investments, stabilisation costs

International Energy R&D Spillovers and the Economics of Greenhouse Gas Atmospheric Stabilization

It is widely recognized that technological change has the potential to reduce GHG emissions without compromising economic growth; hence, any better understanding of the process of technological innovation is likely to increase our knowledge of mitigation possibilities and costs. This paper explores how international knowledge flows affect the dynamics of the domestic R&D sector and the main economic and environmental variables. The analysis is performed using WITCH, a dynamic regional model of the world economy, in which energy technical change is endogenous. The focus is on disembodied energy R&D international spillovers. The knowledge pool from which regions draw foreign ideas differs between High Income and Low Income countries. Absorption capacity is also endogenous in the model. The basic questions are as follows. Do knowledge spillovers enhance energy technological innovation in different regions of the world? Does the speed of innovation increase? Or do free-riding incentives prevail and international spillovers crowd out domestic R&D efforts? What is the role of domestic absorption capacity and of policies designed to enhance it? Do greenhouse gas stabilization costs drop in the presence of international technological spillovers? The new specification of the WITCH model presented in this paper enables us to answer these questions. Our analysis shows that international knowledge spillovers tend to increase free-riding incentives and decrease the investments in energy R&D. The strongest cuts in energy R&D investments are recorded among High Income countries, where international knowledge flows crowd out domestic R&D efforts. The overall domestic pool of knowledge, and thus total net GHG stabilization costs, remain largely unaffected. International spillovers, however, are also an important policy channel. We therefore analyze the implication of a policy mix in which climate policy is combined with a technology policy designed to enhance absorption capacity in developing countries. Significant positive impacts on the costs of stabilising GHG concentrations are singled out. Finally, a sensitivity analysis shows that High Income countries are more responsive than Low Income countries to changes in the parameters and thus suggests to focus additional empirical research efforts on the former.Climate Policy, Energy R&D, International R&D Spillovers, Stabilization

WITCH. A World Induced Technical Change Hybrid Model

The need for a better understanding of future energy scenarios, of their compatibility with the objective of stabilizing greenhouse gas concentrations, and of their links with climate policy, calls for the development of hybrid models. Hybrid because both the technological detail typical of Bottom Up (BU) models and the long run dynamics typical of Top Down (TD) models are crucially necessary. We present WITCH – World Induced Technical Change Hybrid model – a neoclassical optimal growth model (TD) with energy input detail (BU). The model endogenously accounts for technological progress, both through learning curves affecting prices of new vintages of capital and through R&D investments. In addition, the model captures the main economic interrelationships between world regions and is designed to analyze the optimal economic and environment policies in each world region as the outcome of a dynamic game. This paper provides a detailed description of the WITCH model, of its baseline, and of the model calibration procedure.Climate Policy, Hybrid Modelling, Integrated Assessment, Technological Change, Energy Mix.

Incentives and Stability of International Climate Coalitions: An Integrated Assessment

This paper analyses the incentives to participate in and the stability of international climate coalitions. Using the integrated assessment model WITCH, the analysis of coalitions’ profitability and stability is performed under alternative assumptions concerning the pure rate of time preference, the social welfare aggregator and the extent of climate damages. We focus on the profitability, stability, and “potential stability” of a number of coalitions which are “potentially effective” in reducing emissions. We find that only the grand coalition under a specific sets of assumptions finds it optimal to stabilise GHG concentration below 550 ppm CO2-eq. However, the grand coalition is found not to be stable, not even “potentially stable” even through an adequate set of transfers. However, there exist potentially stable coalitions, but of smaller size, which are also potentially environmentally effective. Depending on the assumptions made, they could achieve up to 600 ppm CO2-eq. More ambitious targets lead to the collapse of the coalition.Climate Policy, Climate Coalition, Game Theory, Free Riding

The incentives to participate in and the stability of international climate coalitions: a game theoretic approach using the WITCH Model

This paper uses WITCH, an integrated assessment model with a game-theoretic structure, to explore the prospects for, and the stability of broad coalitions to achieve ambitious climate change mitigation action. Only coalitions including all large emitting regions are found to be technically able to meet a concentration stabilisation target below 550 ppm CO2eq by 2100. Once the free-riding incentives of non-participants are taken into account, only a “grand coalition” including virtually all regions can be successful. This grand coalition is profitable as a whole, implying that all countries can gain from participation provided appropriate transfers are made across them. However, neither the grand coalition nor smaller but still environmentally significant coalitions appear to be stable. This is because the collective welfare surplus from cooperation is not found to be large enough for transfers to offset the free-riding incentives of all countries simultaneously. Some factors omitted from the analysis, which might improve coalition stability, include the co-benefits from mitigation action, the costless removal of fossil fuel subsidies, as well as alternative assumptions regarding countries’ bargaining behaviour.Climate policy; Climate coalition; Game theory; Free riding.