Include solar export credit in the TOU cost breakdown

Previously only showed import cost by tariff period; now also shows the
feed-in/export credit components alongside it, plus a net (usage cost
minus export credit) total.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/api/usage.py

@@ -125,8 +125,9 @@ def usage_summary(days: str = Query("30")) -> dict:
 @router.get("/tou_breakdown")
 def tou_breakdown(days: str = Query("1")) -> dict:
     """Cost breakdown by the current plan's own usage components (e.g. Peak /
-    Off-Peak / Shoulder), so you can see where your spend is actually
-    landing rather than just the headline total."""
+    Off-Peak / Shoulder) and feed-in components (solar export credit), so
+    you can see where your spend -- and your credit -- is actually landing
+    rather than just the headline total."""
     end = datetime.now(timezone.utc)
     with get_session() as session:
         start = _resolve_start(session, days, end)
@@ -137,16 +138,28 @@ def tou_breakdown(days: str = Query("1")) -> dict:
 
     readings = [IntervalReading(ts=row.ts, import_kwh=row.import_kwh, export_kwh=row.export_kwh) for row in rows]
     result = evaluate(current_plan, readings)
-    components = [
+    usage_components = [
         {"label": c.label, "kwh": round(c.kwh, 2), "cost_dollars": round(c.cost_dollars, 2)}
         for c in result.usage_breakdown
         if c.kwh > 1e-9
     ]
+    # feed_in_breakdown's cost_dollars is already negative (a credit), same
+    # sign convention the plan comparison table uses.
+    feed_in_components = [
+        {"label": c.label, "kwh": round(c.kwh, 2), "cost_dollars": round(c.cost_dollars, 2)}
+        for c in result.feed_in_breakdown
+        if c.kwh > 1e-9
+    ]
+    total_usage_cost = round(sum(c["cost_dollars"] for c in usage_components), 2)
+    total_feed_in_credit = round(sum(c["cost_dollars"] for c in feed_in_components), 2)
     return {
         "available": True,
         "days_with_data": result.days_with_data,
-        "components": sorted(components, key=lambda c: c["cost_dollars"], reverse=True),
-        "total_usage_cost_dollars": round(sum(c["cost_dollars"] for c in components), 2),
+        "usage_components": sorted(usage_components, key=lambda c: c["cost_dollars"], reverse=True),
+        "feed_in_components": sorted(feed_in_components, key=lambda c: c["cost_dollars"]),
+        "total_usage_cost_dollars": total_usage_cost,
+        "total_feed_in_credit_dollars": total_feed_in_credit,
+        "net_usage_and_export_dollars": round(total_usage_cost + total_feed_in_credit, 2),
     }
 
 

app/static/css/style.css

@@ -202,7 +202,9 @@ form.settings-form label.p-day-label input {
   border-radius: 5px;
   overflow: hidden;
 }
-.tou-bar-fill { height: 100%; background: var(--accent); border-radius: 5px; }
+.tou-bar-fill { height: 100%; border-radius: 5px; }
+.tou-bar-fill-cost { background: var(--accent); }
+.tou-bar-fill-credit { background: var(--good); }
 .tou-bar-amount { width: 130px; flex-shrink: 0; text-align: right; }
 
 .pill-toggle { display: inline-flex; border: 1px solid var(--border); border-radius: 6px; overflow: hidden; }

app/web/templates/dashboard.html

@@ -262,21 +262,43 @@ async function loadDashboard(days) {
   });
 }
 
+function touBarRows(components, maxAbsCost, fillClass) {
+  return components.map(c => `
+    <div class="tou-bar-row">
+      <div class="tou-bar-label">${c.label}</div>
+      <div class="tou-bar-track"><div class="tou-bar-fill ${fillClass}" style="width:${Math.max(2, 100 * Math.abs(c.cost_dollars) / maxAbsCost)}%;"></div></div>
+      <div class="tou-bar-amount">${c.cost_dollars < 0 ? '-' : ''}$${Math.abs(c.cost_dollars).toFixed(2)} &middot; ${c.kwh.toFixed(1)} kWh</div>
+    </div>
+  `).join('');
+}
+
 async function loadTouBreakdown(days) {
   const body = document.getElementById('tou-breakdown-body');
   const data = await fetch(`/api/usage/tou_breakdown?days=${days}`).then(r => r.json());
-  if (!data.available || !data.components.length) {
+  if (!data.available || (!data.usage_components.length && !data.feed_in_components.length)) {
     body.innerHTML = '<div class="muted">No usage cost data yet for this period.</div>';
     return;
   }
-  const maxCost = Math.max(...data.components.map(c => c.cost_dollars), 0.01);
-  body.innerHTML = data.components.map(c => `
-    <div class="tou-bar-row">
-      <div class="tou-bar-label">${c.label}</div>
-      <div class="tou-bar-track"><div class="tou-bar-fill" style="width:${Math.max(2, 100 * c.cost_dollars / maxCost)}%;"></div></div>
-      <div class="tou-bar-amount">$${c.cost_dollars.toFixed(2)} &middot; ${c.kwh.toFixed(1)} kWh</div>
-    </div>
-  `).join('') + `<div class="muted" style="margin-top:0.6rem;">Total usage cost: $${data.total_usage_cost_dollars.toFixed(2)} over ${data.days_with_data} day(s) &mdash; excludes supply charge and feed-in credit.</div>`;
+  const maxAbsCost = Math.max(
+    ...data.usage_components.map(c => Math.abs(c.cost_dollars)),
+    ...data.feed_in_components.map(c => Math.abs(c.cost_dollars)),
+    0.01
+  );
+
+  const usageHtml = data.usage_components.length
+    ? `<div class="muted" style="margin-top:0.5rem;">Usage cost</div>${touBarRows(data.usage_components, maxAbsCost, 'tou-bar-fill-cost')}`
+    : '';
+  const feedInHtml = data.feed_in_components.length
+    ? `<div class="muted" style="margin-top:0.75rem;">Solar export credit</div>${touBarRows(data.feed_in_components, maxAbsCost, 'tou-bar-fill-credit')}`
+    : '';
+
+  const net = data.net_usage_and_export_dollars;
+  body.innerHTML = usageHtml + feedInHtml + `
+    <div class="muted" style="margin-top:0.6rem;">
+      Usage cost $${data.total_usage_cost_dollars.toFixed(2)} &minus; export credit $${Math.abs(data.total_feed_in_credit_dollars).toFixed(2)}
+      = <strong class="${net >= 0 ? 'savings-negative' : 'savings-positive'}">${net >= 0 ? '$' : '-$'}${Math.abs(net).toFixed(2)}</strong> net
+      over ${data.days_with_data} day(s) &mdash; excludes supply charge.
+    </div>`;
 }
 
 const touToggle = document.getElementById('tou-range-toggle');