Editing Pieee (section)

===Chemical Storage===
 
====Ammonia-based energy storage for concentrating solar power====
*'''Authors:''' Keith Lovegrove (Australian National University, Australia), John Pye (Australian National University, Australia), Greg Burgess (Australian National University, Australia), Rebecca Dunn (Australian National University, Australia)
*'''Contact email:''' keith.lovegrove@anu.edu.au
*'''Scope:''' Concentrating solar power uses mirrors to concentrate solar radiation to a hot focus. One method of storing this energy is based on the reversible dissociation of ammonia. In this storage system, a fixed inventory of ammonia passes alternately between energy-storing (solar dissociation) and energy-releasing (synthesis) reactors. Coupled with a Rankine power cycle, the energy-releasing reaction can be used to produce dispatchable power for the grid. At 20 MPa and 20<sup>o</sup>C, the enthalpy of reaction is 66.8 kJ/mol. The main advantage of an ammonia-based storage system is that energy is stored in chemical bonds, rather than heat. Therefore energy can be transported around a gigawatt-sized solar field with no heat losses from steam or oil lines. In addition, an ammonia-based storage system can leverage the substantial industrial experience of the ammonia industry.

====The importance of the seasonal variation in demand and supply in a renewable energy system====
*'''Authors:''' Alvin O. Converse (Dartmouth College, USA)
*'''Contact email:''' alvin.o.converse@dartmouth.edu
*'''Scope:''' As energy systems become more completely dependent on renewable sources, seasonal variations in supply and demand will require massive seasonal energy stores and/or long distance energy transportation systems.  This will favor the use of hydrogen over electricity because of the lower cost of gas storage and pipeline transport compared to batteries and transmission lines.
 
====Hydrogen generation technologies from water electrolysis: Present and future of high-pressure electrolyzers====
*'''Authors:''' Alfredo Ursúa (University of Navarra, Spain), Pablo Sanchis (University of Navarra, Spain)
*'''Contact email:''' pablo.sanchis@unavarra.es
*'''Scope:''' This paper describes the water electrolysis technology to produce clean hydrogen in a renewable energy-based grid. First, basic concepts concerning thermodynamics and electrochemistry of water electrolysis, with special attention to the influence of the temperature and pressure on the process, are explained both from a theoretical and practical point of view. Then, the two main types of electrolyzers, alkaline and PEM, are described and compared. After that, the technology used in atmospheric and pressurized electrolyzers is exposed and evaluated, and their strengths, weaknesses and trends for the coming years are analyzed. Commercial units of the different technologies offered by manufacturers are included in the analysis.
 
====The hydrogen-fueled internal combustion engine====
*'''Authors:'''  Sebastian Verhelst (Ghent University, Belgium)
*'''Contact email:''' sebastian.verhelst@ugent.be
*'''Scope:''' Use of hydrogen as an energy carrier for transport applications is mostly associated with fuel cells. However, an internal combustion engine converted to or designed for hydrogen, can attain high power output, high efficiency and ultra low emissions, at a cost currently far below that of fuel cells. More importantly, because of the possibility of bi-fuel operation, the hydrogen engine can act as an accelerator for building up a hydrogen infrastructure. This article presents the current state and future prospects for hydrogen engines.
 
====Energy storage and supply from sustainable organic fuel made with CO<sub>2</sub> and water in a solar powered process====
*'''Authors:''' R. Pearson (Lotus Engineering, UK), P. Edwards (University of Oxford, UK), M. D. Eisaman (PARC, USA), Karl A. Littau (PARC, USA), Leon di Marco (FSK Tech., UK)          
*'''Contact email:''' leon.dimarco@btinternet.com
*'''Scope:''' Massive long-term energy storage using CSP generated sustainable organic fuels, which can be used for conventionally powered transportation, as part of a large-scale atmospheric CO<sub>2</sub> reduction strategy.