Are Targets for Renewable Portfolio Standards Too Low? The Impact of Market Structure on Energy Policy

In order to limit climate change from greenhouse gas emissions, governments have introduced renewable portfolio standards (RPS) to incentivise renewable energy production. While the response of industry to exogenous RPS targets has been addressed in the literature, setting RPS targets from a policymaker’s perspective has remained an open question. Using a bi-level model, we prove that the optimal RPS target for a perfectly competitive electricity industry is higher than that for a benchmark centrally planned one. Allowing for market power by the non-renewable energy sector within a deregulated industry lowers the RPS target vis-à-vis perfect competition. Moreover, to our surprise, social welfare under perfect competition with RPS is lower than that when the non-renewable energy sector exercises market power. In effect, by subsidising renewable energy and taxing the non-renewable sector, RPS represents an economic distortion that over-compensates damage from emissions. Thus, perfect competition with RPS results in “too much” renewable energy output, whereas the market power of the non-renewable energy sector mitigates this distortion, albeit at the cost of lower consumer surplus and higher emissions. Hence, ignoring the interaction between RPS requirements and the market structure could lead to sub-optimal RPS targets and substantial welfare losses

Tradable Performance-Based CO2 Emissions Standards: Walking on Thin Ice?

Climate policy, like climate change itself, is subject to debate. Partially due to the political deadlock in Washington, DC, US climate policy, historically, has been driven mainly by state or regional effort until the recently introduced federal Clean Power Plan (CPP). Instead of a traditional mass-based standard, the US CPP stipulates a state-specific performance-based CO2 emission standard and delegates considerable flexibility to the states in achieving the standard. Typically, there are two sets of policy tools available: a tradable performance-based and a mass-based permit program. We analyze these two related but distinct standards when they are subject to imperfect competition in the product and/or permit markets. Stylized models are developed to produce general conclusions. Detailed models that account for heterogenous technologies and the transmission network are developed to evaluate policy efficiency. Depending on the scenarios under consideration, the resulting problem could be either a complementarity problem or a Stackelberg leaderfollower game, which is implemented as a mathematical program with equilibrium constraints (MPEC). We overcome the nonconvexity of MPECs by reformulating them as mixed integer problems. We show that while the cross-subsidy inherent in the performance-based standard that might effectively reduce power prices, it could inflate energy demand, thereby rendering permits scarce. When the leader in a Stackelberg formulation has a relatively clean endowment under the performancebased standard, its ability to manipulate the electricity market as well as to lower permit prices might worsen the market outcomes compared to its mass-based counterpart. On the other hand, when the leader has a relatively dirty endowment, the "cross-subsidy" could be the dominant force leading to a higher social welfare compared to the mass-based program. This paper contributes to the current policy debates in regulating emissions from the US power sector and highlights different incentives created by the mass- and performance-based standards

Regulatory jurisdiction and policy coordination: A bi-level modeling approach for performance-based environmental policy

This study discusses important aspects of policy modeling based on a leader-follower game of policymakers. We specifically investigate non-cooperation between policymakers and the jurisdictional scope of regulation via bi-level programming. Performance-based environmental policy under the Clean Power Plan in the United States is chosen for our analysis. We argue that the cooperation of policymakers is welfare enhancing. Somewhat counterintuitively, full coordination among policymakers renders performance-based environmental policy redundant. We also find that distinct state-by-state regulation yields higher social welfare than broader regional regulation. This is because power producers can participate in a single power market even under state-by-state environmental regulation and arbitrage away the CO2 price differences by adjusting their generation across states. Numerical examples implemented for a stylized test network illustrate the theoretical findings

Oxidative stress contributes to cobalt oxide nanoparticles-induced cytotoxicity and DNA damage in human hepatocarcinoma cells.

BackgroundCobalt oxide nanoparticles (Co(3)O(4)NPs) are increasingly recognized for their utility in biological applications, magnetic resonance imaging, and drug delivery. However, little is known about the toxicity of Co(3)O(4)NPs in human cells.MethodsWe investigated the possible mechanisms of genotoxicity induced by Co(3)O(4)NPs in human hepatocarcinoma (HepG2) cells. Cell viability, reactive oxygen species (ROS), glutathione, thiobarbituric acid reactive substance, apoptosis, and DNA damage were assessed in HepG2 cells after Co(3)O(4)NPs and Co(2+) exposure.ResultsCo(3)O(4)NPs elicited a significant (P < 0.01) reduction in glutathione with a concomitant increase in lipid hydroperoxide, ROS generation, superoxide dismutase, and catalase activity after 24- and 48-hour exposure. Co(3)O(4)NPs had a mild cytotoxic effect in HepG2 cells; however, it induced ROS and oxidative stress, leading to DNA damage, a probable mechanism of genotoxicity. The comet assay showed a statistically significant (P < 0.01) dose- and time-related increase in DNA damage for Co(3)O(4)NPs, whereas Co(2+) induced less change than Co(3)O(4)NPs but significantly more than control.ConclusionOur results demonstrated that Co(3)O(4)NPs induced cytotoxicity and genotoxicity in HepG2 cells through ROS and oxidative stress

Economic and environmental consequences of market power in the South-East Europe regional electricity market

Market power in electricity and emission-permit markets in the South-East Europe Regional Electricity Market, which comprises both EU members subject to the EU Emissions Trading System (ETS) and non-EU members exempt from it, affects social welfare and carbon leakage. We examine its impact under three market settings: perfect competition (PC) and two leader-follower versions, in which a leader can exert market power in either the electricity market (S-T) or both the electricity and permit markets (S). Under PC, carbon leakage is equal to 11%-39% of ETS emission reduction depending on the cap stringency. Generally, in S-T, the leader's capacity withholding results in ETS emissions below and non-ETS emissions above PC levels. However, carbon leakage is lower vis-à-vis PC as the ETS emission reduction offsets the non-ETS emission increase. Finally, in S, the leader's propensity to lower the permit price increases ETS emissions and exacerbates carbon leakage compared to S-T

Hysteretic metal–ferroelectric– semiconductor capacitors based on PZT/ZnO heterostructures

Interfacing of ferroelectric and semiconductor materials provides a means of coupling unique properties associated with ferroelectric materials to high performance semiconductor devices. In this work we report the electronic properties of ferroelectric/ZnO heterostructures, where (Pb,Zr)TiO3 (PZT) is used as a prototypical ferroelectric oxide. Metal–PZT–metal structures demonstrate ferroelectric hysteresis with remanent polarization of 28 µC cm−2 and coercive field of 75 kV cm−1 for a loop of 15 V. The metal–PZT–ZnO capacitor structures demonstrate a characteristic metal–insulator–semiconductor capacitance–voltage (C–V) behaviour with a hysteretic memory window of approximately 4 V. The heterostructure C–V characteristics do not change significantly with varying frequency. Metal–PZT–ZnO capacitors are also used as part of a simple RLC circuit to demonstrate the ability to shift resonant frequency of the circuit with switching ferroelectric polarization.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58136/2/d7_8_003.pd