The role of large-scale energy storage design and dispatch in the power grid: A study of very high grid penetration of variable renewable resources

We present a result of hourly simulation performed using hourly load data and the corresponding simulated output of wind and solar technologies distributed throughout the state of California. We examined how we could achieve very high-energy penetration from intermittent renewable system into the electricity grid. This study shows that the maximum threshold for the storage need is significantly less than the daily average demand. In the present study, we found that the approximate network energy storage is of the order of 186. GW. h/22. GW (approximately 22% of the average daily demands of California). Allowing energy dumping was shown to increase storage use, and by that way, increases grid penetration and reduces the required backup conventional capacity requirements. Using the 186. GW. h/22. GW storage and at 20% total energy loss, grid penetration was increased to approximately 85% of the annual demand of the year while also reducing the conventional backup capacity requirement to 35. GW. This capacity was sufficient to supply the year round hourly demand, including 59 GW peak demand, plus a distribution loss of about 5.3%. We conclude that designing an efficient and least cost grid may require the capability to capture diverse physical and operational policy scenarios of the future grid. © 2014 Elsevier Ltd

First Principles LCGO Calculation of the Magneto-optical Properties of Nickel and Iron

We report a first principles, self-consistent, all electron, linear combination of Gaussian orbitals (LCGO) calculation of a comprehensive collection of magneto-optical properties of nickel and iron based on density functional theory. Among the many magneto-optical effects, we have studied the equatorial Kerr effect for absorption in the optical as well as soft X-ray region, where it is called X-ray magnetic linear dichroism (X-MLD). In the optical region the effect is of the order of 2\% while in the X-ray region it is of the order of 1\% for the incident angles considered. In addition, the polar Kerr effect, X-ray magnetic circular dichroism (X-MCD) and total X-ray absorption at the L$_{2,3}$ edges, soft X-ray Faraday effect at the L$_{2,3}$ edges have also been calculated. Our results are in good agreement with experiments and other first principles methods that have been used to calculate some of these properties.Comment: 22 pages RevTex. 8 figures submitted separately as a uuencoded, compressed tar fil

Distributed Resources Shift Paradigms on Power System Design, Planning, and Operation: An Application of the GAP Model

Power systems have evolved following a century-old paradigm of planning and operating a grid based on large central generation plants connected to load centers through a transmission grid and distribution lines with radial flows. This paradigm is being challenged by the development and diffusion of modular generation and storage technologies. We use a novel approach to assess the sequencing and pacing of centralized, distributed, and off-grid electrification strategies by developing and employing the grid and access planning (GAP) model. GAP is a capacity expansion model to jointly assess operation and investment in utility-scale generation, transmission, distribution, and demand-side resources. This paper conceptually studies the investment and operation decisions for a power system with and without distributed resources. Contrary to the current practice, we find hybrid systems that pair grid connections with distributed energy resources (DERs) are the preferred mode of electricity supply for greenfield expansion under conservative reductions in photovoltaic panel (PV) and energy storage prices. We also find that when distributed PV and storage are employed in power system expansion, there are savings of 15%-20% mostly in capital deferment and reduced diesel use. Results show that enhanced financing mechanisms for DER PV and storage could enable 50%-60% of additional deployment and save 15 /MWh in system costs. These results have important implications to reform current utility business models in developed power systems and to guide the development of electrification strategies in underdeveloped grids

TTS protein orthologs as interspecific reproductive barriers in the solanaceae

TTS (transmitting tissue-specific) proteins are abundant in the extracellular matrix (ECM) of the transmitting tissue, which forms the pollen tube pathway in Nicotiana pistils. These arabinogalactan proteins stimulate pollen tube growth and are vital for optimal seed set. I have cloned and sequenced two putative orthologs, PiPRP1 and PaPRP1, which are expressed in the pistils of Petunia integrifolia and Petunia axillaris, respectively. Comparison of the domain architecture and cross-reactivity with anti-TTS protein antibodies confirm that the proteins encoded by these Petunia cDNA clones are orthologs of TTS proteins (TTSPs) from Nicotiana species. Using immunological detection methods, I have shown that TTSP orthologs are present in the pistils of three subfamilies within the Solanaceae: Nicotianoideae, Petunioideae, and Solanoideae. Surprisingly, the proteins were also detected in leaves and roots of P. integrifolia seedlings. I cloned the TTSP ortholog expressed in seedling leaves (PiPRP2) and found it to be nearly indistinguishable from PiPRP1, encoded by the pistil cDNA. Like the TTSPs from Nicotiana, PaPRP1, PiPRP1, and PiPRP2 are histidine-domain arabinogalactan proteins with a highly variable proline-rich domain containing KPP repeats that vary in number and location among solanaceous taxa. Multiple alignments were used to deduce the effect of natural selection on the conserved and hypervariable domains of this multidomain subfamily of arabinogalactan proteins. For each pairwise comparison, I deduced the Ka/Ks ratio, which expresses the nucleotide substitutions per synonymous site (Ks) and non-synonymous site (Ka) in the two sequences. My analysis indicates that the two hypervariable domains of these proteins have undergone positive selection (Ka / Ks \u3e 1), whereas the conserved domains are under purifying selection (Ka / Ks \u3c 1). The differential selective pressure on the protein domains suggests that the hypervariable domains are involved in species-specific interactions with an unidentified pollen tube partner, and the conserved domains have general functions that are invariant. I propose that sequence divergence in the hypervariable domain reinforces speciation by generating a post-pollination prezygotic breeding barrier between incipient species

The U(1)-Higgs Model: Critical Behaviour in the Confinig-Higgs region

We study numerically the critical properties of the U(1)-Higgs lattice model, with fixed Higgs modulus, in the region of small gauge coupling where the Higgs and Confining phases merge. We find evidence of a first order transition line that ends in a second order point. By means of a rotation in parameter space we introduce thermodynamic magnitudes and critical exponents in close resemblance with simple models that show analogous critical behaviour. The measured data allow us to fit the critical exponents finding values in agreement with the mean field prediction. The location of the critical point and the slope of the first order line are accurately given.Comment: 21 text pages. 12 postscript figures available on reques

Comment on "Breakdown of the Internet under Intentional Attack"

We obtain the exact position of the percolation threshold in intentionally damaged scale-free networks.Comment: 1 page, to appear in Phys. Rev. Let

Restoring human nature : constructive theological anthropologies engaging the psychological sciences

Over the past decade, a growing number of theologians and philosophers from a variety of sub disciplines have expressed an interest in the possibilities of a “science-engaged theology.” The specific projects that fall under this somewhat broad conceptual umbrella are rather diverse, but at its most basic, science-engaged theology is a form of inquiry that is deeply engaged with one or more of the sciences in the service of articulating, defending, or critiquing existing theological and philosophical frameworks. Some operating in this fertile domain even seek to construct entirely new theological (and occasionally, scientific) categories in light of the generative insights born from a robust interaction between the sciences and theology.Publisher PDFPeer reviewe

Penalized Orthogonal-Components Regression for Large p Small n Data

We propose a penalized orthogonal-components regression (POCRE) for large p small n data. Orthogonal components are sequentially constructed to maximize, upon standardization, their correlation to the response residuals. A new penalization framework, implemented via empirical Bayes thresholding, is presented to effectively identify sparse predictors of each component. POCRE is computationally efficient owing to its sequential construction of leading sparse principal components. In addition, such construction offers other properties such as grouping highly correlated predictors and allowing for collinear or nearly collinear predictors. With multivariate responses, POCRE can construct common components and thus build up latent-variable models for large p small n data.Comment: 12 page