Printed on paper containing at least 50% wastepaper, including 10% post consumer waste.iii PrefaceThis report has been produced by Intertek APTECH for the National Renewable Energy Laboratory (NREL) and Western Electricity Coordinating Council (WECC) to support their renewable integration studies.This report provides a detailed review of the most up to date data available on power plant cycling costs. Increasing variable renewable generation on the electric grid has resulted in increased cycling of conventional fossil generation. Previous studies by NREL and WECC have corroborated this fact and the purpose of Intertek APTECH's task was to provide generic lower bound power plant cycling costs to be used in production cost simulations. The inclusion of these costs in production cost simulations would result in accounting for some of the increased costs (system aggregate) and reduced reliability of conventional generation due to cycling.The results of this report are only indicative of generic lower bound costs of cycling conventional fossil generation power plants. The primary objective of this report is to increase awareness of power plant cycling cost, the use of these costs in renewable integration studies and to stimulate debate between policymakers, system dispatchers, plant personnel and power utilities. About Intertek APTECHIntertek APTECH is in Intertek's Industry and Assurance Division and is an internationallyknown engineering consulting firm specializing in performance optimization of equipment and the prediction and extension of the remaining useful life of piping, boilers, turbines, and associated utility equipment, structures, industrial equipment, and materials.Intertek APTECH has been examining the cycling damage to power plant components for over two decades and has pioneered the development of numerous condition assessment methods for power plant equipment. They have been working closely with several clients with increasing renewable resources to assess the integration cost impacts on conventional generation. iv Executive SummaryCompetition and increasing penetration of variable renewable generation are having a farreaching impact on the operation of conventional fossil generation. For many utilities and plant operators, plant operations and maintenance (O&M) expenditures are the one cost area that is currently rising at a rate faster than inflation. To stay competitive, utilities need to better understand the underlying nature of their plant O&M costs, and take measures to use this knowledge to their advantage. A major root cause of this increase in O&M cost for many fossil units is unit cycling. Power plant operators and utilities have been forced to cycle aging fossil units that were originally designed for base load operation.Cycling refers to the operation of electric generating units at varying load levels, including on/off, load following, and minimum load operation, in response to changes in system load requirements. Every time a power plant is turned off and on, the boiler, steam lines, ...

In the present paper we report the effect of graphene oxide (GO) doping on the structural and superconducting properties of MgB 2 . Bulk polycrystalline samples have been synthesized via a solid state reaction route with compositions MgB 2 + x wt% of GO (x = 0, 1, 2, 3, 5, 7 and 10) by sintering at ∼850 • C in a reducing atmosphere of Ar/H 2 (9:1). The x-ray diffraction results confirm the formation of the MgB 2 phase in all samples, together with traces of a MgO impurity phase. The XRD data results also show substitution of carbon for boron, but in the present case the actual amount of carbon substituting for boron is very small as compared to other carbon sources. A substantial improvement in the critical current density, J c (H), has been observed in the entire magnetic field range (0-8 T) for samples x = 1, 2 and 3 as compared to the undoped sample. In addition to J c (H), marginal improvements in the upper critical field (H c2 ) and the irreversibility field (H irr ) have been observed for the doped samples x = 1, 2 and 3 with respect to pristine MgB 2 . Furthermore, a curious result of the present investigation is that there is no change in the superconducting transition temperature (T c ) up to a doping level of 10 wt%. The possible mechanisms of flux pinning and correlations between the observed superconducting properties and structural characteristics of the samples have been described and discussed in this paper.

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