132 research outputs found
Untersuchungen zur Integration der fluktuierenden Windenergie in das System der Elektroenergieversorgung
Die Arbeit systematisiert Herausforderungen und beschreibt Lösungsansätze zur Integration der fluktuierenden Windenergie in das System der Elektroenergieversorgung Europas. Dazu werden u.a. Optimierungsmodelle zur Standortauswahl von Windenergieanlagen und darauf aufbauend zur Quantifizierung des weiträumigen Ausgleichseffekts der Windenergie auf Basis meteorologischer Daten vorgestellt. Die Windenergie kann demnach einen maßgeblichen Beitrag zur Bereitstellung elektrischer Energie leisten
Estimating missing data in hierarchical space-time series with a short temporal extent
A challenging problem exists in the estimation of missing space-time data where the time series are
relatively short, and the space series belong to a spatial hierarchy. An example is provided by the
population estimates for regions belonging to the NUTS hierarchy which are available from the
EUROSTAT data portal. The table demo_r_gind3 provides estimates of the population of
NUTS0/1/2/3 regions at the 1st January 2000…2012 inclusive. Inspection of the table reveals that
estimates are missing for 2000-2003 for two of the five NUTS3 regions in the NUTS2 region of
Liège. There are other instances of missing data at NUTS3 where there are data for the corresponding
higher level NUTS regions. The EUROSTAT table demo_r_d2jan provides estimates of the
population on the 1st January for a longer time period, 1990…2012 inclusive, but these are only to
NUTS2. Again, there is missing data. The question then arises as to whether it is possible to estimate
the missing series. The NUTS2 values act as a constraint on the NUTS3 values – the total population
of the NUTS3 regions should equal those of the corresponding NUTS2 regions. However, the relative
shortness of the available series is a challenge if conventional methods of time series analysis are
adopted. Furthermore, the imposition of the spatial constraints is both a check as well as a challenge
- …