diff --git a/scripts/seed-electricity-prices.mjs b/scripts/seed-electricity-prices.mjs
index d8d63f6ab..707cc40a3 100644
--- a/scripts/seed-electricity-prices.mjs
+++ b/scripts/seed-electricity-prices.mjs
@@ -35,13 +35,13 @@ const ENTSO_E_REGIONS = [
   { region: 'SE', eic: '10Y1001A1001A46L', name: 'Sweden (Stockholm)' }, // SE3 bidding zone
 ];
 
-const EIA_REGIONS = [
-  { region: 'CISO',  name: 'California' },
-  { region: 'MISO',  name: 'Midwest' },
-  { region: 'PJM',   name: 'Mid-Atlantic' },
-  { region: 'NYISO', name: 'New York' },
-  { region: 'ERCO',  name: 'Texas (ERCOT)' },
-  { region: 'SPP',   name: 'Southwest' },
+export const EIA_REGIONS = [
+  { region: 'CISO',  respondent: 'CISO',  name: 'California' },
+  { region: 'MISO',  respondent: 'MISO',  name: 'Midwest' },
+  { region: 'PJM',   respondent: 'PJM',   name: 'Mid-Atlantic' },
+  { region: 'NYISO', respondent: 'NYIS',  name: 'New York' },
+  { region: 'ERCO',  respondent: 'ERCO',  name: 'Texas (ERCOT)' },
+  { region: 'SPP',   respondent: 'SWPP',  name: 'Southwest' },
 ];
 
 // ── Date helpers ─────────────────────────────────────────────────────────────
@@ -179,7 +179,7 @@ async function fetchEiaRegion(region, apiKey, today) {
   const dateStr = isoDate(today);
   const params = new URLSearchParams({
     'data[]': 'value',
-    'facets[respondent][]': region.region,
+    'facets[respondent][]': region.respondent,
     start: isoDate(new Date(Date.now() - 2 * 24 * 3600 * 1000)),
     end: dateStr,
     'sort[0][column]': 'period',
diff --git a/tests/electricity-prices-seed.test.mjs b/tests/electricity-prices-seed.test.mjs
index 9f2fcc5de..512ac412f 100644
--- a/tests/electricity-prices-seed.test.mjs
+++ b/tests/electricity-prices-seed.test.mjs
@@ -4,6 +4,7 @@ import assert from 'node:assert/strict';
 import {
   parseEntsoEPrice,
   buildElectricityIndex,
+  EIA_REGIONS,
   ELECTRICITY_INDEX_KEY,
   ELECTRICITY_KEY_PREFIX,
   ELECTRICITY_TTL_SECONDS,
@@ -127,3 +128,38 @@ describe('exported key constants', () => {
     );
   });
 });
+
+// ── EIA region/respondent mapping ────────────────────────────────────────────
+
+describe('EIA_REGIONS respondent codes', () => {
+  const EXPECTED = {
+    CISO: 'CISO',
+    MISO: 'MISO',
+    PJM: 'PJM',
+    NYISO: 'NYIS',
+    ERCO: 'ERCO',
+    SPP: 'SWPP',
+  };
+
+  it('every entry has distinct region and respondent fields', () => {
+    for (const entry of EIA_REGIONS) {
+      assert.ok(typeof entry.region === 'string' && entry.region.length > 0, `missing region`);
+      assert.ok(typeof entry.respondent === 'string' && entry.respondent.length > 0, `missing respondent for ${entry.region}`);
+    }
+  });
+
+  it('maps public region IDs to correct EIA respondent codes', () => {
+    for (const [region, respondent] of Object.entries(EXPECTED)) {
+      const entry = EIA_REGIONS.find((r) => r.region === region);
+      assert.ok(entry, `missing EIA_REGIONS entry for ${region}`);
+      assert.equal(entry.respondent, respondent, `${region} should use respondent ${respondent}, got ${entry.respondent}`);
+    }
+  });
+
+  it('covers all expected regions', () => {
+    const regions = EIA_REGIONS.map((r) => r.region);
+    for (const expected of Object.keys(EXPECTED)) {
+      assert.ok(regions.includes(expected), `EIA_REGIONS missing ${expected}`);
+    }
+  });
+});