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In dieser Arbeit wurden mehrere Druckluftspeicher-Prozesse ermittelt, die durch Zuführung von Abwärme aus externen Quellen in der Lage sind, elektrischen Strom hocheffizient zu speichern und wieder bereitzustellen. Dabei sind vornehmlich Daten von Maschinen und Anlagenkomponenten verwendet worden, die aktuell am Markt verfügbar sind, so dass eine kurzfristige Umsetzung im Anlagenbau möglich ist. Als Ergebnis der Arbeit wird gezeigt, dass auch ohne Sondermaschinen die Speicherung und Bereitstellung von elektrischem Strom mit Druckluftspeichern bei guten bis sehr guten Effizienzwerten möglich ist. Dazu können heute ungenutzte Abwärmemengen, vorzugsweise bei hoher Temperatur, aus vielerorts verfügbaren externen Quellen in diesen auf dem AACAES (Advanced Adiabatic Compressed Air Energy Storage) basierenden Prozessen genutzt werden.
In this paper, we conduct a pan-European efficiency analysis to investigate the performance of European railways with a particular focus on economies of vertical integration. We test the hypothesis that integrated railways realize economies of scope and, thus, produce railway services with a higher level of efficiency. To determine whether joint or separate production is more efficient, we apply a Data Envelopment Analysis super-efficiency bootstrapping model which relates the efficiency for integrated production to a reference set consisting of separated firms which use a different production technology. We find that for a majority of European railways economies of scope exist.
In the course of railway reforms at the end of the last century, European national governments, as well the EU Commission, decided to open markets and to separate railway networks from train operations. Vertically integrated railway companies argue that such a separation of infrastructure and operations would diminish the advantages of vertical integration and would therefore not be suitable to raise economic welfare. In this paper, we conduct a pan-European analysis to investigate the performance of European railways with a particular focus on economies of scope associated with vertical integration. We test the hypothesis that integrated railways realize economies of joint production and, thus, produce railway services on a higher level of e±ciency. To determine whether joint or separate production is more e±cient we apply an innovative Data Envelopment Analysis super-e±ciency bootstrapping model which relates the e±ciency for integrated production to a virtual reference set consisting of the separated production technology and which is applicable to other network industries as energy and telecommunication as well. Our ¯ndings are that for a majority of European Railway companies economies of scope exist.