D3 Multiple Area Chart

<!DOCTYPE html>
<svg width="960" height="500"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>

var svg = d3.select("svg"),
  margin = {top: 20, right: 20, bottom: 30, left: 50},
  width = +svg.attr("width") - margin.left - margin.right,
  height = +svg.attr("height") - margin.top - margin.bottom,
  g = svg.append("g").attr("transform", "translate(" + margin.left + "," + margin.top + ")");

var parseDate = d3.timeParse("%Y/%m/%d %H:%M");

var color = d3.scaleOrdinal()
  .domain(["PVkW", "TBLkW"])
  .range(["rgba(249, 208, 87, 0.7)", "rgba(54, 174, 175, 0.65)"]);

var x = d3.scaleTime().range([0, width]),
  y = d3.scaleLinear().range([height, 0]),
  z = color;

var area = d3.area()
  .curve(d3.curveMonotoneX)
  .x(function(d) { return x(d.date); })
  .y0(y(0))
  .y1(function(d) { return y(d.kW); });

d3.csv("kW_zoomed.csv", type, function(error, data) {
  if (error) throw error;

x.domain(d3.extent(data, function(d) { return d.date; }));
  y.domain([
    0,
    d3.max(sources, function(c) { return d3.max(c.values, function(d) { return d.kW; }); })
  ]);
  z.domain(sources.map(function(c) { return c.id; }));

g.append("g")
      .attr("class", "axis axis--x")
      .attr("transform", "translate(0," + height + ")")
      .call(d3.axisBottom(x));

g.append("g")
      .attr("class", "axis axis--y")
      .call(d3.axisLeft(y))
    .append("text")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", "0.71em")
      .attr("fill", "#000")
      .text("Power, kW");

var source = g.selectAll(".area")
      .data(sources)
      .enter().append("g")
      .attr("class", function(d) { return `area ${d.id}`; })

source.append("path")
       .attr("d", function(d) { console.log(area(d.values)); return area(d.values); })
       .style("fill", function(d) { return z(d.id); });
});

function type(d, _, columns) {
  d.date = parseDate(d.date);
  for (var i = 1, n = columns.length, c; i < n; ++i) d[c = columns[i]] = +d[c];
  return d;
}

</script>
  </body>
  </html>

https://d3js.org/d3.v4.min.js