http://ieeexplore.ieee.org TOC Alert for Publication# 5 2012 February 10 100 2 C1 C1 497 100 2 C2 C2 67 100 2 309 310 280 100 2 311 316 447 100 2 317 321 155 100 2 322 334 1093 100 2 335 347 1265 100 2 348 359 1319 100 2 360 390 4995 2 dish concentrator, as well as closed-loop storage demonstrations. An ongoing computational study deals with the performance of an ammonia receiver for a 489-m ² dish concentrator. The ammonia storage system could employ industry-standard ammonia synthesis converters for superheated steam production. A standard 1500 t/day ammonia synthesis reactor would suffice for a 10-MW_e baseload plant with 330 large 489-m² dishes. At this stage, an updated economic assessment of the system would be valuable.]]> 100 2 391 400 1304 100 2 401 409 1381 100 2 410 426 1833 2ICE). These characteristics also result in more flexibility in engine control strategies and thus more routes for engine optimization. This article describes the most characteristic features of H ₂ICEs, the current state of H ₂ICE research and demonstration, and the future prospects.]]> 100 2 427 439 1228 2 in the atmosphere leading to an anthropogenic influence on the Earth's climate. We highlight here that a versatile energy carrier can be produced by recycling CO₂ and combining it chemically with a substance of high chemical bond energy created from renewable energy. If CO₂ is taken from the atmosphere, a closed-loop production process for carbon-neutral fuels is possible providing an energy-dense and easily distributed storage medium for renewable energy. The rationale for reduced carbon or carbon-neutral energy carriers made from recycled CO₂ is described, focusing on, for transport applications, their manifestation as energy-dense carbonaceous liquid fuels. Techniques for the separation of CO₂ directly from the atmosphere are reviewed, and the challenges and advantages relative to flue-gas capture are discussed. Pathways for the production of carbonaceous fuels from CO₂ are discussed. An integrated system is proposed where renewable energy is stored in the form of synthetic methane in the gas grid for supply to the power generation and heat sectors while methanol and drop-in hydrocarbon fuels are supplied to the transport sector. The use of atmospheric CO₂ and water as feed stocks for renewable energy carriers raises the important prospect of alleviating a dependency on imported fossil energy with the associated large financial transfers. Their application in the transport sector yields a high-value end product. The synthesis and storage of carbon-neutral liquid fuels offers the possibility of decarbonizing transport without the paradigm shifts required by either electrification of the vehicle fleet or conversion to a hydrogen economy. They can be supplied either as dr- p-in hydrocarbon fuels for existing reciprocating and turbine-powered combustion engines or, at lower energetic cost and using simpler chemical plant, in the form of low-carbon-number alcohols which can be burned at high efficiency levels in optimized internal combustion engines. The suitability of these fuels for conventional engines enables the continued provision of globally compatible, affordable vehicles.]]> 100 2 440 460 1219 100 2 461 472 937 100 2 473 483 658 100 2 484 492 865 100 2 493 503 970 e Torresol Gemasolar power tower, featuring 15 h of molten-salt storage, having come online in Spain in May 2011. Advantages of the power tower storage system include the elimination of heat transfer oil and associated heat exchangers, a lower salt requirement, higher steam cycle efficiency, better compatibility with air cooling, improved winter performance, and simplified piping schemes. Near-term advances in molten-salt power tower technology include planned up-scaling, with SolarReserve due to begin constructing a 110-MW_e plant in Nevada by August 2011. Other advances include improvements to the thermal properties of molten salts and the development of storage solutions in a single tank. With these developments at hand, CSP will continue to provide dispatchable solar power, with the capacity to provide energy storage for 100% renewable electricity grids in sun-belt countries.]]> 100 2 504 515 2051 °C. Material parameters and storage performance have been validated in a 20-m³ test module with more than 23 months of operation between 200 ^°C and 400 ^°C and more than 370 thermal cycles. For an up-scaled concrete storage design with 1100-MWh capacity in a modular setup for a 50 MW_el parabolic trough power plant of the ANDASOL-type, about 50 000 m³ of concrete is required and the investment costs are approximately 38 million euro. The simulation of the annual electricity generation of a 50 MW_el parabolic trough power plant with a 1100-MWh concrete storage illustrates that such plants can operate in southern Europe delivering about 3500 full load hours annually; about 30% of this electricity would be generated by the storage system. This number will increase further, when improved operation strategies are applied. Approaches for further cost reduction using heat transfer structures with high thermal conductivity inside the concrete are analyzed, leading to a 60% reduction in the number of heat exchanger pipes required. For implementation of the structures, the storage is build up of precast concrete blocks.]]> 100 2 516 524 1433 100 2 525 538 2773 100 2 539 549 877 100 2 550 555 673 100 2 556 557 113 100 2 558 558 226 100 2 559 560 1564 100 2 C3 C3 422 100 2 C4 C4 470