Calculating the scale elasticity in DEA models.

In economics scale properties of a production function is charcterised by the value of the scale elasticity. In the field of efficiency studies this is also a valid approach for the frontier production function. It has no good meaning to talk about scale properties of inefficient observations. In the DEA literature a qualitative characterisation is most common. The contribution of the paper is to apply the concept of scale elasticity from multi output production theory in economics to the piecewise linear frontier production function, and to develop formulas for calculating values of the scale elasticity for radial projections of inefficient observations. Illustrations also on real data are provided, showing the differences between scale elasticity values for the input- and output oriented projections and the range of values for efficient observations.Scale elasticity; DEA, production theory; Farrell efficiency measures

Dynamics of Technical Efficiency and Productivity Change under Central Planning: The Romanian Cement Industry 1966-1989

This paper investigates the time-path of efficiency and productivity change in the case of the Romanian cement industry 1966-1989. The analysis is based on different specifications of stochastic frontier models. The efficiency scores and the time paths of efficiency and technical change are found to vary substantially among models. The most important feature of the Romanian cement industry before the revolution in 1989 is a slow rate of productivity progress, and a corresponding catch up in the level of productive efficiency.Productivity change; productive efficiency; stochastic frontiers; time-varying efficiency; panel data; cement industry; Romania;

Renewable Energy Expansion and the Value of Balance Regulation Power

To achieve a stable and reliable electricity supply, efficient provision of reserve capacity or, more generally, ancillary services is crucial. Because of the expansion of wind power with random variation in supply, and expected environmental restrictions in hydropower operation causing reductions in regulated hydropower capacity, the balancing power and system reliability issues have become topical in Scandinavia. Moreover, there seems to be a wide-spread opinion that increase in wind-power generation will lead to increased demand for regulating power, much higher prices for reserves and a much higher value of regulated hydro power. Thus, this chapter deals with the value of balance regulation power, or electricity reserves, in the Nordic electricity market, and we will address the issue of the future value of electricity reserves, hydro capacity in particular, that could be used either for energy production or to balance power production, and more generally discuss the value of balancing power in the Nordic electricity system. In the first, theoretical, part of this study we will apply a simple dynamic electricity generation model, involving hydropower, thermal power and wind power to derive the value of the water in a dam of a hydropower plant. In the second, more empirically oriented, part we will address a number of issues related to balance regulation and the value of balancing power with focus on the Nordic electricity market and against the background of an expanding generation capacity of intermittent renewable electricity, especially wind power

Skatt i retur

Godkänd; 2009; 20090529 (roblund)</p

Inventering av fuktproblem i täta hus

Fuktproblem har inventerats i elva småhus i Luleå under våren 1979. Husen är byggda under 1977 och 1978 enligt de skärpta regler beträffande värmeisolering och täthet som infördes 1977.  De vanligaste fuktproblemen är kondens och isbildning på fönster och dörrar samt drag vid ytterdörrar och hörn. Orsakerna till problemen analyseras och möjliga åtgärder diskutera