Fig. 9From: A comparison of clustering methods for the spatial reduction of renewable electricity optimisation models of EuropeNormalised mapping of optimal power flows according to equation (11) with the estimated flows of the low resolution model \({\hat{f}}_{(c,d),t}\) on the x-axis and the aggregated flows on the y-axis. The first row shows results on the \(60\%\), the second row on the \(100\%\) reduction target. Instead of presenting the raw data, we plot a two dimensional histogram and outline the \(95\%\) and \(85\%\) percentiles of the corresponding probability density function (PDF) using contour plots. The black line depicts the origin (perfect correlation), the dashed one a line with the slope of the bivariate correlation coefficient \(\rho\). \(\alpha\) is the angle between the two linesBack to article page