This heatmap visualizes the average share of renewable energy production (as a percentage of total generation) across ten European areas from 2000 to 2020. Using d3.csv to load the data, it maps years along the x-axis and areas along the y-axis, coloring each 30-pixel cell with d3.interpolateRgb.gamma to encode share values. On hover, each cell reveals its exact percentage via a text label. The chart is rendered as an SVG with d3.axisBottom and d3.axisLeft for the axes.