Analysis of carbon mitigation policies: feed-in tariffs, energy and carbon price interactions and competitive distortions on carbon markets

I study several policy instruments for carbon mitigation with a focus on subsidies for renewable energies, emission taxes and emission allowances. In Chapter 1, I analyze the optimal design and the welfare implications of two policies consisting of an emission tax for conventional fossil-fuel utilities combined with a subsidy for the producers of renewable energy equipment and an emission tax combined with a feed-in tariff for renewable electricity. In Chapter 2 I study the empirical interrelationships between European emission allowance prices and prices for electricity, hard coal and natural gas with an application to portfolio allocation. In Chapters 3 and 4, I discuss several policy-related issues of emissions trading, in particular the potential for market manipulations by firms holding a dominant position in the emission market, the output market or both, and competitive distortions and leakage due to unequal emission regulations across industries, sectors, regions, or countries

Subsidies for Renewable Energies in the Presence of Learning Effects and Market Power

We study the impact of learning by doing, learning spill-overs, and imperfect competition in a model with two types of electricity producers, an oligopolistic sector of polluting fossil-fuel utilities and a competitive fringe of non-polluting generators of electricity from renewable energy sources (RES-E). Furthermore we consider an upstream industry of RES-E equipment producers engaged in learning by doing. We show that a first-best policy requires two instruments, a tax in the fossil-fuel sector and an output subsidy for RES-E equipment producers. We then study second-best-optimal feed-in tariffs that are paid to the generators of RES-E. By means of simulations we calculate the welfare loss of a second-best-optimal feed-in-tariff policy and analyze how market structure impacts on second-best-optimal feed-in tariffsfeed-in tariffs; environmental subsidies; learning by doing; spill-overs; market structure

Comparison of susceptibility weighted imaging and TOF-angiography for the detection of Thrombi in acute stroke.

BACKGROUND AND PURPOSE: Time-of-flight (TOF) angiography detects embolic occlusion of arteries in patients with acute ischemic stroke due to the absence of blood flow in the occluded vessel. In contrast, susceptibility weighted imaging (SWI) directly enables intravascular clot visualization due to hypointense susceptibility vessel signs (SVS) in the occluded vessel. The aim of this study was to compare the diagnostic accuracy of both methods to determine vessel occlusion in patients with acute stroke. METHODS: 94 patients were included who presented with clinical symptoms for acute stroke and displayed a delay on the time-to-peak perfusion map in the territory of the anterior (ACA), middle (M1, M1/M2, M2/M3) or posterior (PCA) cerebral artery. The frequency of SVS on SWI and vessel occlusion or stenosis on TOF-angiography was compared using the McNemar-Test. RESULTS: 87 of 94 patients displayed a clearly definable SVS on SWI. In 72 patients the SVS was associated with occlusion or stenosis on TOF-angiography. Fifteen patients exclusively displayed SVS on SWI (14 M2/M3, 1 M1), whereas no patient revealed exclusively occlusion or stenosis on TOF-angiography. Sensitivity for detection of embolic occlusion within major vessel segments (M1, M1/M2, ACA, and PCA) did not show any significant difference between both techniques (97% for SWI versus 96% for TOF-angiography) while the sensitivity for detection of embolic occlusion within M2/M3 was significantly different (84% for SWI versus 39% for TOF-angiography, p<0.00012). CONCLUSIONS: SWI and TOF-angiography provide similar sensitivity for central thrombi while SWI is superior for the detection of peripheral thrombi in small arterial vessel segments

Patient with acute right-hemispheric-stroke.

<p>Time-to-peak perfusion map (A) displays impaired perfusion in the area of the right middle cerebral artery (MCA), while TOF-angiography demonstrates occlusion of the right MCA in the M1 segment (B). Typical appearance of a Susceptibility vessel sign (SVS) on SWI is shown in (C).</p

Patient characteristics.

<p>Patient characteristics.</p

Distribution of observed SVS on SWI and occlusion/stenosis on TOF images in patients with delayed perfusion.

<p>15 of 94 patients presented SVS on SWI without a corresponding occlusion or stenosis on TOF-angiography. In contrast, no patient presented an occlusion or stenosis on TOF-angiography without a corresponding SVS on SWI. Only 7 patients did not present any SVS at all.</p