Luminous WISE-selected Obscured, Unobscured, and Red Quasars in Stripe 82

We present a spectroscopically complete sample of 147 infrared-color-selected active galactic nuclei (AGNs) down to a 22 μm flux limit of 20 mJy over the ~270 deg^2 of the Sloan Digital Sky Survey Stripe 82 region. Most of these sources are in the QSO luminosity regime (L_(bol) ≳ 10^(12) L⊙) and are found out to z ≃ 3. We classify the AGNs into three types, finding 57 blue, unobscured Type-1 (broad-lined) sources; 69 obscured, Type-2 (narrow-lined) sources; and 21 moderately reddened Type-1 sources (broad-lined and E(B − V) > 0.25). We study a subset of this sample in X-rays and analyze their obscuration to find that our spectroscopic classifications are in broad agreement with low, moderate, and large amounts of absorption for Type-1, red Type-1, and Type-2 AGNs, respectively. We also investigate how their X-ray luminosities correlate with other known bolometric luminosity indicators such as [O III] line luminosity (L_([O III])) and infrared luminosity (L_(6μm)). While the X-ray correlation with L_([O III]) is consistent with previous findings, the most infrared-luminous sources appear to deviate from established relations such that they are either underluminous in X-rays or overluminous in the infrared. Finally, we examine the luminosity function evolution of our sample, and by AGN type, in combination with the complementary, infrared-selected, AGN sample of Lacy et al. (2013), spanning over two orders of magnitude in luminosity. We find that the two obscured populations evolve differently, with reddened Type-1 AGNs dominating the obscured AGN fraction (~30%) for L_(5μm) > 10^(45) erg s^(−1), while the fraction of Type-2 AGNs with L_(5μm) < 10^(45) erg s^(−1) rises sharply from 40% to 80% of the overall AGN population

A Techno-economic Analysis of Distributed Energy Resources versus Wholesale Electricity Purchases for Fuel Decarbonized Heavy Duty Vehicles

Electric and hydrogen vehicles can help decarbonize heavy duty vehicles (HDV). Few studies examine how to meet energy requirements of decarbonized HDVs, and all assume electricity will come from centralized systems. However, decarbonized HDVs could significantly increase energy demands in areas with limited transmission access, potentially favoring deployment of distributed energy resources (DERs). In this paper, we develop an optimization-based techno-economic model that minimizes costs of meetingHDV energy demands by optimizing investments in and operations of DERs, investments in transmission interconnections, and wholesale electricity purchases. We apply it to a modeled U.S. dataset of electric HDV charging demands to quantify the deployment and value potential of three DERs - solar, batteries, and nuclear small modular reactors (SMRs) in the year 2040. For fleets of 100% electric HDVs to 60% electric and 40% hydrogen HDVs, DERs are deployed at 78% to 95% of all charging stations and meet between 24% to 30% of total HDV energy demand. Investments in DERs reduce annual costs by $647 million to$1.9 billion across all stations, while individual stations can save $20 million to over$100 million annually. SMRs make up over 99% of total deployed DER capacity, indicating significant potential for SMR deployment in this emerging market. Widespread DER deployment is robust to capital cost uncertainty in SMRs and transmission lines, wholesale electricity prices, and other factors.Master of ScienceSchool for Environment and SustainabilityUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/174106/1/Lovdal_Larson_Thesis.pd