diff --git a/frontend/src/assets/locales/en/fuelSupply.json b/frontend/src/assets/locales/en/fuelSupply.json
index 93c75760b..92ed0968f 100644
--- a/frontend/src/assets/locales/en/fuelSupply.json
+++ b/frontend/src/assets/locales/en/fuelSupply.json
@@ -15,7 +15,7 @@
     "fuelSupplyId": "Fuel supply ID",
     "fuelType": "Fuel type",
     "fuelTypeOther": "Fuel type other",
-    "fuelCategory": "Fuel category",
+    "fuelCategoryId": "Fuel category",
     "endUse": "End use",
     "provisionOfTheActId": "Determining carbon intensity",
     "fuelCode": "Fuel code",
diff --git a/frontend/src/views/FuelSupplies/AddEditFuelSupplies.jsx b/frontend/src/views/FuelSupplies/AddEditFuelSupplies.jsx
index 9d3ae3134..2c3c90356 100644
--- a/frontend/src/views/FuelSupplies/AddEditFuelSupplies.jsx
+++ b/frontend/src/views/FuelSupplies/AddEditFuelSupplies.jsx
@@ -7,7 +7,7 @@ import {
   useGetFuelSupplies,
   useSaveFuelSupply
 } from '@/hooks/useFuelSupply'
-import { isArrayEmpty } from '@/utils/formatters'
+import { isArrayEmpty, cleanEmptyStringValues } from '@/utils/formatters'
 import BCTypography from '@/components/BCTypography'
 import Grid2 from '@mui/material/Unstable_Grid2/Grid2'
 import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
@@ -161,10 +161,12 @@ export const AddEditFuelSupplies = () => {
             (item) => item.fuelCategory
           )
 
-          params.node.setDataValue(
-            'fuelCategory',
-            fuelCategoryOptions[0] ?? null
-          )
+          // Set to null if multiple options, otherwise use first item
+          const categoryValue = fuelCategoryOptions.length === 1
+            ? fuelCategoryOptions[0]
+            : null
+
+          params.node.setDataValue('fuelCategory', categoryValue)
         }
       }
     },
@@ -199,7 +201,9 @@ export const AddEditFuelSupplies = () => {
         severity: 'pending'
       })
 
-      let updatedData = params.node.data
+      // clean up any null or empty string values
+      let updatedData = cleanEmptyStringValues(params.node.data)
+
       if (updatedData.fuelType === 'Other') {
         updatedData.ciOfFuel = DEFAULT_CI_FUEL[updatedData.fuelCategory]
       }
diff --git a/frontend/src/views/FuelSupplies/FuelSupplySummary.jsx b/frontend/src/views/FuelSupplies/FuelSupplySummary.jsx
index 6944b0383..b9808f1ad 100644
--- a/frontend/src/views/FuelSupplies/FuelSupplySummary.jsx
+++ b/frontend/src/views/FuelSupplies/FuelSupplySummary.jsx
@@ -66,7 +66,7 @@ export const FuelSupplySummary = ({ data, status }) => {
         valueGetter: (params) => params.data.fuelType?.fuelType
       },
       {
-        headerName: t('fuelSupply:fuelSupplyColLabels.fuelCategory'),
+        headerName: t('fuelSupply:fuelSupplyColLabels.fuelCategoryId'),
         field: 'fuelCategory',
         valueGetter: (params) => params.data.fuelCategory?.category
       },
diff --git a/frontend/src/views/FuelSupplies/_schema.jsx b/frontend/src/views/FuelSupplies/_schema.jsx
index 5939d074b..ba1b52df9 100644
--- a/frontend/src/views/FuelSupplies/_schema.jsx
+++ b/frontend/src/views/FuelSupplies/_schema.jsx
@@ -98,6 +98,7 @@ export const fuelSupplyColDefs = (optionsData, errors, warnings) => [
         params.data.fuelTypeId = fuelType?.fuelTypeId
         params.data.fuelTypeOther = null
         params.data.fuelCategory = null
+        params.data.fuelCategoryId = null
         params.data.endUseId = null
         params.data.endUseType = null
         params.data.eer = null
@@ -147,7 +148,7 @@ export const fuelSupplyColDefs = (optionsData, errors, warnings) => [
   {
     field: 'fuelCategory',
     headerComponent: RequiredHeader,
-    headerName: i18n.t('fuelSupply:fuelSupplyColLabels.fuelCategory'),
+    headerName: i18n.t('fuelSupply:fuelSupplyColLabels.fuelCategoryId'),
     cellEditor: AutocompleteCellEditor,
     cellRenderer: (params) =>
       params.value ||
@@ -182,16 +183,7 @@ export const fuelSupplyColDefs = (optionsData, errors, warnings) => [
     },
     suppressKeyboardEvent,
     minWidth: 135,
-    valueGetter: (params) => {
-      const options = optionsData?.fuelTypes
-        ?.find((obj) => params.data.fuelType === obj.fuelType)
-        ?.fuelCategories.map((item) => item.fuelCategory)
-      if (options?.length === 1) {
-        return options[0]
-      } else {
-        return params.data.fuelCategory
-      }
-    },
+    valueGetter: (params) => params.data.fuelCategory,
     editable: (params) =>
       optionsData?.fuelTypes
         ?.find((obj) => params.data.fuelType === obj.fuelType)