Switch energy now chart to watts, format values to W, kW etc (#28555)

* Switch energy now chart to watts

* Add kW

* Scale formatted value based on powers of 1000

1000 W -> 1 kW
W → kW → MW → GW → TW

* Explainers

* Use 3 dp for kW+ and 0 for W

* Add non-integer test

src/data/energy.ts

@@ -1363,9 +1363,9 @@ export const calculateSolarConsumedGauge = (
 };
 
 /**
- * Get current power value from entity state, normalized to kW
+ * Get current power value from entity state, normalized to watts (W)
  * @param stateObj - The entity state object to get power value from
- * @returns Power value in kW, or 0 if entity not found or invalid
+ * @returns Power value in W (watts), or undefined if entity not found or invalid
  */
 export const getPowerFromState = (stateObj: HassEntity): number | undefined => {
   if (!stateObj) {
@@ -1376,22 +1376,54 @@ export const getPowerFromState = (stateObj: HassEntity): number | undefined => {
     return undefined;
   }
 
-  // Normalize to kW based on unit of measurement (case-sensitive)
+  // Normalize to watts (W) based on unit of measurement (case-sensitive)
   // Supported units: GW, kW, MW, mW, TW, W
   const unit = stateObj.attributes.unit_of_measurement;
   switch (unit) {
     case "W":
-      return value / 1000;
-    case "mW":
-      return value / 1000000;
-    case "MW":
+      return value;
+    case "kW":
       return value * 1000;
+    case "mW":
+      return value / 1000;
+    case "MW":
+      return value * 1_000_000;
     case "GW":
-      return value * 1000000;
+      return value * 1_000_000_000;
     case "TW":
-      return value * 1000000000;
+      return value * 1_000_000_000_000;
     default:
-      // Assume kW if no unit or unit is kW
+      // Assume value is in watts (W) if no unit or an unsupported unit is provided
       return value;
   }
 };
+
+/**
+ * Format power value in watts (W) to a short string with the appropriate unit
+ * @param hass - The HomeAssistant instance
+ * @param powerWatts - The power value in watts (W)
+ * @returns A string with the formatted power value and unit
+ */
+export const formatPowerShort = (
+  hass: HomeAssistant,
+  powerWatts: number
+): string => {
+  const units = ["W", "kW", "MW", "GW", "TW"];
+  let unitIndex = 0;
+  let value = powerWatts;
+
+  // Scale the unit to the appropriate power of 1000
+  while (Math.abs(value) >= 1000 && unitIndex < units.length - 1) {
+    value /= 1000;
+    unitIndex++;
+  }
+
+  return (
+    formatNumber(value, hass.locale, {
+      // For watts, show no decimals. For kW and above, always show 3 decimals.
+      maximumFractionDigits: units[unitIndex] === "W" ? 0 : 3,
+    }) +
+    " " +
+    units[unitIndex]
+  );
+};

src/panels/lovelace/cards/energy/hui-power-sankey-card.ts

@@ -7,6 +7,7 @@ import "../../../../components/ha-card";
 import "../../../../components/ha-svg-icon";
 import type { EnergyData, EnergyPreferences } from "../../../../data/energy";
 import {
+  formatPowerShort,
   getEnergyDataCollection,
   getPowerFromState,
 } from "../../../../data/energy";
@@ -17,7 +18,6 @@ import type { PowerSankeyCardConfig } from "../types";
 import "../../../../components/chart/ha-sankey-chart";
 import type { Link, Node } from "../../../../components/chart/ha-sankey-chart";
 import { getGraphColorByIndex } from "../../../../common/color/colors";
-import { formatNumber } from "../../../../common/number/format_number";
 import { getEntityContext } from "../../../../common/entity/context/get_entity_context";
 import { MobileAwareMixin } from "../../../../mixins/mobile-aware-mixin";
 
@@ -26,8 +26,8 @@ const DEFAULT_CONFIG: Partial<PowerSankeyCardConfig> = {
   group_by_area: true,
 };
 
-// Minimum power threshold in kW to display a device node
-const MIN_POWER_THRESHOLD = 0.01;
+// Minimum power threshold in watts (W) to display a device node
+const MIN_POWER_THRESHOLD = 10;
 
 interface PowerData {
   solar: number;
@@ -472,8 +472,8 @@ class HuiPowerSankeyCard
 
   private _valueFormatter = (value: number) =>
     `<div style="direction:ltr; display: inline;">
-      ${formatNumber(value, this.hass.locale, value < 0.1 ? { maximumFractionDigits: 3 } : undefined)}
-      kW</div>`;
+      ${formatPowerShort(this.hass, value)}
+    </div>`;
 
   /**
    * Compute real-time power data from current entity states.
@@ -719,14 +719,15 @@ class HuiPowerSankeyCard
   }
 
   /**
-   * Get current power value from entity state, normalized to kW
+   * Get current power value from entity state, normalized to watts (W)
    * @param entityId - The entity ID to get power value from
-   * @returns Power value in kW, or 0 if entity not found or invalid
+   * @returns Power value in W, or 0 if entity not found or invalid
    */
   private _getCurrentPower(entityId: string): number {
     // Track this entity for state change detection
     this._entities.add(entityId);
 
+    // getPowerFromState returns power in W
     return getPowerFromState(this.hass.states[entityId]) ?? 0;
   }
 

src/panels/lovelace/cards/energy/hui-power-sources-graph-card.ts

@@ -210,9 +210,14 @@ export class HuiPowerSourcesGraphCard
         const { positive, negative } = this._processData(
           statIds[key].stats.map((id: string) => {
             const stats = energyData.stats[id] ?? [];
-            const currentState = getPowerFromState(this.hass.states[id]);
-            if (currentState !== undefined) {
-              stats.push({ start: now, end: now, mean: currentState });
+            const currentStateWatts = getPowerFromState(this.hass.states[id]);
+            if (currentStateWatts !== undefined) {
+              // getPowerFromState returns power in W; convert to kW for this graph
+              stats.push({
+                start: now,
+                end: now,
+                mean: currentStateWatts / 1000,
+              });
             }
             return stats;
           })

test/data/energy.test.ts

@@ -12,6 +12,7 @@ import {
   computeConsumptionSingle,
   formatConsumptionShort,
   calculateSolarConsumedGauge,
+  formatPowerShort,
 } from "../../src/data/energy";
 import type { HomeAssistant } from "../../src/types";
 
@@ -171,6 +172,17 @@ describe("Energy Short Format Test", () => {
       "151 MWh"
     );
   });
+  it("Power Short Format", () => {
+    assert.strictEqual(formatPowerShort(hass, 0), "0 W");
+    assert.strictEqual(formatPowerShort(hass, 10), "10 W");
+    assert.strictEqual(formatPowerShort(hass, 12.2), "12 W");
+    assert.strictEqual(formatPowerShort(hass, 999), "999 W");
+    assert.strictEqual(formatPowerShort(hass, 1000), "1 kW");
+    assert.strictEqual(formatPowerShort(hass, 1234), "1.234 kW");
+    assert.strictEqual(formatPowerShort(hass, 10_500), "10.5 kW");
+    assert.strictEqual(formatPowerShort(hass, 1_500_000), "1.5 MW");
+    assert.strictEqual(formatPowerShort(hass, -1500), "-1.5 kW");
+  });
 });
 
 describe("Energy Usage Calculation Tests", () => {