A Unit Commitment and Economic Dispatch Model of the GB Electricity Market – Formulation and Application to Hydro Pumped Storage

We present a well calibrated unit commitment and economic dispatch model of the GB electricity market and applied it to the economic analysis of the four existing hydro pumped storage (PS) stations in GB. We found that with more wind on the system PS arbitrage revenue increases: with every percentage point (p.p) increase in wind capacity the total PS arbitrage profit increases by 0.21 p.p.. However, under a range of wind capacity, the PS’ modelled revenue from price arbitrage is not enough to cover their ongoing fixed costs. Analysing the 2015-18 GB balancing and ancillary services data suggests that PS stations were not active in managing transmission constraints and in fact about 60% of constraint payments went to gas-fired units. However, the PS stations are active in provision of ancillary services such as fast reserve, response and other reserve services with a combined market share of at least 30% in 2018. Stacking up the modelled revenue from price arbitrage with the 2018 balancing and ancillary services revenues against the ongoing fixed costs suggests that the four existing PS stations are profitable. Most of the revenue comes from balancing and ancillary services markets – about 75% – whereas only 25% comes from price arbitrage. However, the revenues will not be enough to cover capex and opex of a new 600 MW PS station. The gap in financing will have to come from balancing and ancillary services market opportunities and less so from purely price arbitrage. Finally, we found that the marginal contribution of most of the existing PS stations to gas and coal plant profitability is negative, while from the system point of view, PS stations do contribute to minimizing the total operating cost

The Cost of Improving Gas Supply Security in the Baltic States

The Baltic States (Estonia, Latvia and Lithuania) are three amongst the smallest gas markets in Europe. They import all the gas they consume from Russia, with whom they have difficult political relationships. A disruption of their supply from Russia, whatever the cause, would have severe consequences as a large share of their peak winter consumption could not be replaced by alternative gas or other fuels. The three governments want to invest in improving gas supply security and the European Commission pushes in the same direction. But what should they do? We present an assessment of the cost of various national and regional options – dual-fuel for heat plants and CHPs; strategic gas storage; strategic LNG terminals – to increase gas supply security. The cost is calculated over thirty years for different scenarios of supply disruptions. Uncertainty in commodity prices and interest rates is taken into account through Monte Carlo simulations. We draw the policy conclusions, taking into account the regional political context

Market power and long-term gas contracts: the case of Gazprom in Central and Eastern European Gas Markets

We explore a major European competition decision, the 2012-18 Gazprom case, using a global gas market simulation model. We find that access to LNG markets alone is insufficient to counterbalance Gazprom’s strategic behaviour; central and eastern Europe (CEE) needs to be well interconnected with bidirectional flow capability. ‘Swap deals’ created by the decision facilitate CEE market integration, while limiting Gazprom’s potential market power. Such deals may increase the diversity of contracted gas and number of market players, but do not improve physical supply diversity. In the next five years, swap deals could marginally impact negatively the utilization of strategic assets in CEE, but since Gazprom’s commitments expire by mid-2026, utilization of these strategic assets may fall considerably, especially if Gazprom withholds supplies. As an unintended consequence, CEE markets may disintegrate from the rest of Europe. Avoiding such outcomes will require further gas market reforms, particularly, market design for gas transportation

A Portfolio approach to wind and solar deployment in Australia

We develop a new framework that can be used to analyse interactions between solar and wind generation using a Mean-Variance Portfolio Theory (MPT) framework. We use this framework to understand the role of electricity transmission integrating a high shar

Challenges to the Future of European Single Market in Natural Gas

Recent gas price dynamics in Europe shows convergence to the extent that locational price differentials approached transport tariffs and hence arbitrage was largely saturated – it is a sign of a well-functioning pan-European gas wholesale market. We employ a transaction cost economics framework to understand how we got to where we are in terms of the evolution of the gas industry structure in Europe and its institutional setup. The move towards a single market in gas, which is still ongoing, has allowed European gas consumers to benefit from transparently set, market-based wholesale prices as well as from increased market competition between suppliers. However, as the gas market in Europe matures and with the increased penetration of renewable energy generation in the electricity sector as well as overall decarbonization of the energy sector in Europe, the gas market and its current regulatory regime face a number of challenges. Addressing these challenges may require an update to the current market design and possibly drastic reforms to tariff setting in the gas transport market

The case of 100% electrification of domestic heat in Great Britain

Unlike power sector decarbonisation, there has been little progress made on heat, which is currently the biggest energy consumer in the UK, accounting for 45% of total energy consumption in 2019, and almost 40% of UK GHG emissions. Given the UK’s legally binding commitment to "Net-Zero" by 2050, decarbonising heat is becoming urgent and currently one of the main pathways involves its electrification. Here, we present a spatially-explicit optimisation model that investigates the implications of electrifying heat on the operation of the power sector. Using hourly historical gas demand data, we conclude that the domestic peak heat demand is almost 50% lower than widely-cited values. A 100% electrification pathway can be achieved with only a 1.3-fold increase in generation capacity compared to a power-only decarbonisation scenario, but only, by leveraging the role of thermal energy storage technologies without which a further 40% increase would be needed

Can wholesale electricity prices support “subsidy-free” generation investment in Europe?

Using a Pan-European electricity dispatch model we find that with higher variable renewable energy (VRE) production wholesale power prices may no longer serve as a long-run signal for generation investment in 2025. If wind and solar are to be self-financing by 2025 under the current European market design, they would need to be operating in circumstances which combine lower capital cost with higher fossil fuel and/or carbon prices. In the absence of these conditions, long term subsidy mechanisms would need to continue in order to meet European renewable electricity targets. More VRE production will exacerbate the ‘missing money’ problem for conventional generation. Thus, closures of unprofitable fossil fuel generation would sharpen and increase energy-only prices but would put more pressure on ancillary services markets to support system stability. Thus, the question of the need for a market redesign to let the market guide investments in both renewables and conventional generation would seem to remain

Cryo-Electron Tomography Elucidates the Molecular Architecture of Treponema pallidum, the Syphilis Spirochete

Cryo-electron tomography (CET) was used to examine the native cellular organization of Treponema pallidum, the syphilis spirochete. T. pallidum cells appeared to form flat waves, did not contain an outer coat and, except for bulges over the basal bodies and widening in the vicinity of flagellar filaments, displayed a uniform periplasmic space. Although the outer membrane (OM) generally was smooth in contour, OM extrusions and blebs frequently were observed, highlighting the structure’s fluidity and lack of attachment to underlying periplasmic constituents. Cytoplasmic filaments converged from their attachment points opposite the basal bodies to form arrays that ran roughly parallel to the flagellar filaments along the inner surface of the cytoplasmic membrane (CM). Motile treponemes stably attached to rabbit epithelial cells predominantly via their tips. CET revealed that T. pallidum cell ends have a complex morphology and assume at least four distinct morphotypes. Images of dividing treponemes and organisms shedding cell envelope-derived blebs provided evidence for the spirochete’s complex membrane biology. In the regions without flagellar filaments, peptidoglycan (PG) was visualized as a thin layer that divided the periplasmic space into zones of higher and lower electron densities adjacent to the CM and OM, respectively. Flagellar filaments were observed overlying the PG layer, while image modeling placed the PG-basal body contact site in the vicinity of the stator–P-collar junction. Bioinformatics and homology modeling indicated that the MotB proteins of T. pallidum, Treponema denticola, and Borrelia burgdorferi have membrane topologies and PG binding sites highly similar to those of their well-characterized Escherichia coli and Helicobacter pylori orthologs. Collectively, our results help to clarify fundamental differences in cell envelope ultrastructure between spirochetes and gram-negative bacteria. They also confirm that PG stabilizes the flagellar motor and enable us to propose that in most spirochetes motility results from rotation of the flagellar filaments against the PG

Human fibroblast and stem cell resource from the Dominantly Inherited Alzheimer Network

BACKGROUND: Mutations in amyloid precursor protein (APP), presenilin 1 (PSEN1) and presenilin 2 (PSEN2) cause autosomal dominant forms of Alzheimer disease (ADAD). More than 280 pathogenic mutations have been reported in APP, PSEN1, and PSEN2. However, understanding of the basic biological mechanisms that drive the disease are limited. The Dominantly Inherited Alzheimer Network (DIAN) is an international observational study of APP, PSEN1, and PSEN2 mutation carriers with the goal of determining the sequence of changes in presymptomatic mutation carriers who are destined to develop Alzheimer disease. RESULTS: We generated a library of 98 dermal fibroblast lines from 42 ADAD families enrolled in DIAN. We have reprogrammed a subset of the DIAN fibroblast lines into patient-specific induced pluripotent stem cell (iPSC) lines. These cells were thoroughly characterized for pluripotency markers. CONCLUSIONS: This library represents a comprehensive resource that can be used for disease modeling and the development of novel therapeutics

Atomistic nucleation sites of Pt nanoparticles on N-doped carbon nanotubes

[[abstract]]The atomistic nucleation sites of Pt nanoparticles (Pt NPs) on N-doped carbon nanotubes (N-CNTs) were investigated using C and N K-edge and Pt L3-edge X-ray absorption near-edge structure (XANES)/extended X-ray absorption fine structure (EXAFS) spectroscopy. Transmission electron microscopy and XANES/EXAFS results revealed that the self-organized Pt NPs on N-CNTs are uniformly distributed because of the relatively high binding energies of the adsorbed Pt atoms at the imperfect sites. During the atomistic nucleation process of Pt NPs on N-CNTs, stable Pt–C and Pt–N bonds are presumably formed, and charge transfer occurs at the surface/interface of the N-CNTs. The findings in this study were consistent with density functional theory calculations performed using cluster models for the undoped, substitutional-N-doped and pyridine-like-N-doped CNTs.[[journaltype]]國外[[incitationindex]]SCI[[booktype]]紙本[[countrycodes]]GB