Energy mix

Abstract: In recent years, Carbon Capture and Storage (Sequestration) (CCS) has been proposed as a potential method to allow the continued use of fossil-fuelled power stations whilst preventing emissions of CO2 from reaching the atmosphere. Gas, coal (and biomass)-fired power stations can respond to changes in demand more readily than many other sources of electricity production, hence the importance of retaining them as an option in the energy mix. Here, we review the leading CO2 capture technologies, available in the short and long term, and their technological maturity, before discussing CO2 transport and storage. Current pilot plants and demonstrations are highlighted, as is the importance of optimising the CCS system as a whole. Other topics briefly discussed include the viability of both the capture of CO2 from the air and CO2 reutilisation as climate change mitigation strategies. Finally, we discuss the economic and legal aspects of CCS.

Abstract: A long-term hydrogen-based scenario of the global energy system is described in qualitative and quantitative terms here, illustrating the key role of hydrogen in a long-term transition toward a clean and sustainable energy future. In an affluent, low-population-growth, equity and sustainability-oriented B1-H2 world, hydrogen technologies experience substantial but plausible performance and costs improvements and are able to diffuse extensively. Corresponding production and distribution infrastructures emerge. The global hydrogen production system, initially fossil based, progressively shifts toward renewable sources. Fuel cells and other hydrogen-using technologies play a major role in a substantial transformation toward a more flexible, less vulnerable, distributed energy system which meets energy needs in a cleaner, more efficient and cost-effective way. This profound structural transformation of the global energy system brings substantial improvements in energy intensity and security of supply and results in an accelerated decarbonization of the energy mix, with subsequent relatively low climate impacts. Such energy-system path might still not be sufficient to protect against the risk of high climate sensitivities, but hydrogen-based technologies emerge as flexible options for the energy system and, thus, would be prime candidates for a risk management strategy against an uncertain climate future.

Abstract: Photovoltaic (PV) energy has grown at an average annual rate of 60% in the last five years, surpassing one third of the cumulative wind energy installed capacity, and is quickly becoming an important part of the energy mix in some regions and power systems. This has been driven by a reduction in the cost of PV modules. This growth has also triggered the evolution of classic PV power converters from conventional singlephase grid-tied inverters to more complex topologies to increase efficiency, power extraction from the modules, and reliability without impacting the cost. This article presents an overview of the existing PV energy conversion systems, addressing the system configuration of different PV plants and the PV converter topologies that have found practical applications for grid-connected systems. In addition, the recent research and emerging PV converter technology are discussed, highlighting their possible advantages compared with the present technology. Solar PV energy conversion systems have had a huge growth from an accumulative total power equal to approximately 1.2 GW in 1992 to 136 GW in 2013 (36 GW during 2013) [1]. This phenomenon has been possible because of several factors all working together to push the PV energy to cope with one important position today (and potentially a fundamental position in the near future). Among these factors are the cost reduction and increase in efficiency of the PV modules, the search for alternative clean energy sources (not based on fossil fuels), increased environmental awareness, and favorable political regulations from local governments (establishing feed-in tariffs designed to accelerate investment in renewable energy technologies). It has become usual to see PV systems installed on the roofs of houses or PV farms next to the roads in the countryside. Grid-connected PV systems account for more than 99% of the PV installed capacity compared to

Abstract: The fundamental challenge of the 21st century that mankind has to face is definitely energy supply, its storage and conversion in a way that necessarily protects the environment. For 250 years, the tremendous development of humanity has been founded on the harnessing of fossil fuels (coal, crude oil then natural gas) as primary energy due to their high energy density values and the easiness of access. However, this global pattern of energy supply and use is unsustainable. Global warming and finite fossil-fuel supplies call for a radical change in the energy mix to favour renewable energy sources. Without being exhaustive, we tackle in this article the tricky energy question and associated environmental issues as personally perceived. The eminent role of electric energy produced from decarbonized sources in a future sustainable economy is particularly highlighted as well as the issues of its needed storage. The possible and foreseen hindrances of electrochemical energy storage devices, focusing on the lithium-ion technology, are presented in parallel with the possible pathways to make such a technology greener in synergy with the rise of a biomass-based industry.

Abstract: Increasing demand for energy worldwide, driven largely by the developing world, coupled with the tremendous hidden costs associated with traditional energy sources necessitates an unprecedented fraction of the future global energy mix come from sustainable, renewable sources. The potential solar energy resource dwarfs that of all other renewable sources combined, yet only two photovoltaic technologies are known to have the potential to be scaled up to make dramatic impact on the overall energy mix: silicon and organic photovoltaics. In this paper, we present the long-term sustainability advantages of organics when compared to silicon and other photovoltaic technologies in terms of energy payback time and global warming potential while also discussing the outlook for transitional applications of organic solar cells.