PV-Wind Hybrid Systems for Swedish Locations

PV-Wind-Hybrid systems for stand-alone applications have the potential to be more cost efficient compared to PV-alone systems. The two energy sources can, to some extent, compensate each others minima. The combination of solar and wind should be especially favorable for locations at high latitudes such as Sweden with a very uneven distribution of solar radiation during the year. In this article PV-Wind-Hybrid systems have been studied for 11 locations in Sweden. These systems supply the household electricity for single family houses. The aim was to evaluate the system costs, the cost of energy generated by the PV-Wind-Hybrid systems, the effect of the load size and to what extent the combination of these two energy sources can reduce the costs compared to a PV-alone system. The study has been performed with the simulation tool HOMER developed by the National Renewable Energy Laboratory (NREL) for techno-economical feasibility studies of hybrid systems. The results from HOMER show that the net present costs (NPC) for a hybrid system designed for an annual load of 6000 kWh with a capacity shortage of 10% will vary between $48,000 and $87,000. Sizing the system for a load of 1800 kWh/year will give a NPC of $17,000 for the best and $33,000 for the worst location. PV-Wind-Hybrid systems are for all locations more cost effective compared to PV-alone systems. Using a Hybrid system is reducing the NPC for Borlänge by 36% and for Lund by 64%. The cost per kWh electricity varies between $1.4 for the worst location and $0.9 for the best location if a PV-Wind-Hybrid system is used.

Towards Presidential Rule in Ukraine : Hybrid Regime Dynamics under Semi-Presidentialism

This article sets out to analyse recent regime developments in Ukraine in relation to semi-presidentialism. The article asks: to what extent and in what ways theoretical arguments against semi-presidentialism (premier-presidential and president-parliamentary systems) are relevant for understanding the changing directions of the Ukrainian regime since the 1990s? The article also reviews the by now overwhelming evidence suggesting that President Yanukovych is turning Ukraine into a more authoritarian hybrid regime and raises the question to what extent the president-parliamentary system might serve this end. The article argues that both kinds of semi-presidentialism have, in different ways, exacerbated rather than mitigated institutional conflict and political stalemate. The return to the president-parliamentary system in 2010 – the constitutional arrangement with the most dismal record of democratisation – was a step in the wrong direction. The premier-presidential regime was by no means ideal, but it had at least two advantages. It weakened the presidential dominance and it explicitly anchored the survival of the government in parliament. The return to the 1996 constitution ties in well with the notion that President Viktor Yanukovych has embarked on an outright authoritarian path.