diff --git a/.github/workflows/build-deploy-pudl.yml b/.github/workflows/build-deploy-pudl.yml
index 57ea623ddf..ea5e402205 100644
--- a/.github/workflows/build-deploy-pudl.yml
+++ b/.github/workflows/build-deploy-pudl.yml
@@ -33,13 +33,27 @@ jobs:
         uses: actions/checkout@v4
         with:
           ref: ${{ env.BUILD_REF }}
+          fetch-depth: 0
+
+      - name: Skip the build if no changes since the last successful nightly build.
+        if: ${{ (github.event_name == 'schedule') }}
+        run: |
+          CURRENT_COMMIT=$(git rev-parse HEAD)
+          NIGHTLY_COMMIT=$(git rev-parse origin/nightly)
+          if [[ "$CURRENT_COMMIT" == "$NIGHTLY_COMMIT" ]]; then
+            echo "::notice::No changes since last successful nightly build. Skipping."
+            echo "SKIP_BUILD=true" >> $GITHUB_ENV
+            exit 0
+          fi
 
       - name: Set action environment variables
+        if: ${{ env.SKIP_BUILD != 'true' }}
         run: |
           echo "NIGHTLY_TAG=nightly-$(date +%Y-%m-%d)" >> $GITHUB_ENV
           echo "BUILD_ID=$(date +%Y-%m-%d-%H%M)-$(git rev-parse --short HEAD)-${BUILD_REF}" >> $GITHUB_ENV
 
       - name: Show freshly set envvars
+        if: ${{ env.SKIP_BUILD != 'true' }}
         run: |
           echo "GCE_INSTANCE: $GCE_INSTANCE"
           echo "BUILD_REF: $BUILD_REF"
@@ -47,7 +61,7 @@ jobs:
           echo "BUILD_ID: $BUILD_ID"
 
       - name: Tag nightly build
-        if: ${{ (github.event_name == 'schedule') }}
+        if: ${{ (github.event_name == 'schedule') && (env.SKIP_BUILD != 'true') }}
         run: |
           git config user.email "pudl@catalyst.coop"
           git config user.name "pudlbot"
@@ -56,6 +70,7 @@ jobs:
 
       - name: Docker Metadata
         id: docker_metadata
+        if: ${{ env.SKIP_BUILD != 'true' }}
         uses: docker/metadata-action@v5
         with:
           images: catalystcoop/pudl-etl
@@ -66,16 +81,18 @@ jobs:
             type=ref,event=tag
 
       - name: Set up Docker Buildx
+        if: ${{ env.SKIP_BUILD != 'true' }}
         uses: docker/setup-buildx-action@v3
 
       - name: Login to DockerHub
-        if: github.event_name != 'pull_request'
+        if: ${{ (github.event_name != 'pull_request') && (env.SKIP_BUILD != 'true') }}
         uses: docker/login-action@v3
         with:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
       - name: Build image and push to Docker Hub
+        if: ${{ env.SKIP_BUILD != 'true' }}
         uses: docker/build-push-action@v5
         with:
           context: .
@@ -87,6 +104,7 @@ jobs:
           cache-to: type=gha,mode=max
 
       - id: "auth"
+        if: ${{ env.SKIP_BUILD != 'true' }}
         uses: "google-github-actions/auth@v2"
         with:
           workload_identity_provider: "projects/345950277072/locations/global/workloadIdentityPools/gh-actions-pool/providers/gh-actions-provider"
@@ -94,10 +112,12 @@ jobs:
 
       # Setup gcloud CLI
       - name: Set up Cloud SDK
+        if: ${{ env.SKIP_BUILD != 'true' }}
         uses: google-github-actions/setup-gcloud@v2
 
       # Deploy PUDL image to GCE
       - name: Deploy
+        if: ${{ env.SKIP_BUILD != 'true' }}
         env:
           DAGSTER_PG_PASSWORD: ${{ secrets.DAGSTER_PG_PASSWORD }}
           PUDL_OUTPUT_PATH: ${{ env.GCS_OUTPUT_BUCKET }}/${{ env.BUILD_ID }}
@@ -107,7 +127,7 @@ jobs:
             --metadata-from-file startup-script=./docker/vm_startup_script.sh
           gcloud compute instances update-container "$GCE_INSTANCE" \
             --zone "$GCE_INSTANCE_ZONE" \
-            --container-image "docker.io/catalystcoop/pudl-etl:${{ env.BUILD_REF}}" \
+            --container-image "docker.io/catalystcoop/pudl-etl:${{ env.BUILD_REF }}" \
             --container-command "micromamba" \
             --container-arg="run" \
             --container-arg="--prefix" \
@@ -117,7 +137,7 @@ jobs:
             --container-arg="bash" \
             --container-arg="./docker/gcp_pudl_etl.sh" \
             --container-env-file="./docker/.env" \
-            --container-env BUILD_REF=${{ env.BUILD_REF}} \
+            --container-env BUILD_REF=${{ env.BUILD_REF }} \
             --container-env BUILD_ID=${{ env.BUILD_ID }} \
             --container-env NIGHTLY_TAG=${{ env.NIGHTLY_TAG }} \
             --container-env GITHUB_ACTION_TRIGGER=${{ github.event_name }} \
@@ -140,6 +160,7 @@ jobs:
 
       # Start the VM
       - name: Start the deploy-pudl-vm
+        if: ${{ env.SKIP_BUILD != 'true' }}
         run: gcloud compute instances start "$GCE_INSTANCE" --zone="$GCE_INSTANCE_ZONE"
 
       - name: Post to a pudl-deployments channel
diff --git a/docker/gcp_pudl_etl.sh b/docker/gcp_pudl_etl.sh
index d3466eb055..f366d1bfd7 100644
--- a/docker/gcp_pudl_etl.sh
+++ b/docker/gcp_pudl_etl.sh
@@ -2,11 +2,6 @@
 # This script runs the entire ETL and validation tests in a docker container on a Google Compute Engine instance.
 # This script won't work locally because it needs adequate GCP permissions.
 
-# Set PUDL_GCS_OUTPUT *only* if it is currently unset
-: "${PUDL_GCS_OUTPUT:=gs://nightly-build-outputs.catalyst.coop/$BUILD_ID}"
-
-set -x
-
 function send_slack_msg() {
     curl -X POST -H "Content-type: application/json" -H "Authorization: Bearer ${SLACK_TOKEN}" https://slack.com/api/chat.postMessage --data "{\"channel\": \"C03FHB9N0PQ\", \"text\": \"$1\"}"
 }
@@ -57,38 +52,38 @@ function shutdown_vm() {
     curl -X POST -H "Content-Length: 0" -H "Authorization: Bearer ${ACCESS_TOKEN}" "https://compute.googleapis.com/compute/v1/projects/catalyst-cooperative-pudl/zones/$GCE_INSTANCE_ZONE/instances/$GCE_INSTANCE/stop"
 }
 
-function copy_outputs_to_gcs() {
-    echo "Copying outputs to GCP bucket $PUDL_GCS_OUTPUT"
-    gsutil -m cp -r "$PUDL_OUTPUT" "$PUDL_GCS_OUTPUT"
+function save_outputs_to_gcs() {
+    echo "Copying outputs to GCP bucket $PUDL_GCS_OUTPUT" && \
+    gsutil -m cp -r "$PUDL_OUTPUT" "$PUDL_GCS_OUTPUT" && \
     rm "$PUDL_OUTPUT/success"
 }
 
 function copy_outputs_to_distribution_bucket() {
     # Only attempt to update outputs if we have a real value of BUILD_REF
-    if [ -n "$BUILD_REF" ]; then
-        echo "Removing old $BUILD_REF outputs from GCP distributon bucket."
-        gsutil -m -u "$GCP_BILLING_PROJECT" rm -r "gs://pudl.catalyst.coop/$BUILD_REF"
-        echo "Copying outputs to GCP distribution bucket"
-        gsutil -m -u "$GCP_BILLING_PROJECT" cp -r "$PUDL_OUTPUT/*" "gs://pudl.catalyst.coop/$BUILD_REF"
-
-        echo "Removing old $BUILD_REF outputs from AWS distributon bucket."
-        aws s3 rm "s3://pudl.catalyst.coop/$BUILD_REF" --recursive
-        echo "Copying outputs to AWS distribution bucket"
+    # This avoids accidentally blowing away the whole bucket if it's not set.
+    if [[ -n "$BUILD_REF" ]]; then
+        echo "Removing old $BUILD_REF outputs from GCP distributon bucket." && \
+        gsutil -m -u "$GCP_BILLING_PROJECT" rm -r "gs://pudl.catalyst.coop/$BUILD_REF" && \
+        echo "Copying outputs to GCP distribution bucket" && \
+        gsutil -m -u "$GCP_BILLING_PROJECT" cp -r "$PUDL_OUTPUT/*" "gs://pudl.catalyst.coop/$BUILD_REF" && \
+        echo "Removing old $BUILD_REF outputs from AWS distributon bucket." && \
+        aws s3 rm "s3://pudl.catalyst.coop/$BUILD_REF" --recursive && \
+        echo "Copying outputs to AWS distribution bucket" && \
         aws s3 cp "$PUDL_OUTPUT/" "s3://pudl.catalyst.coop/$BUILD_REF" --recursive
     fi
 }
 
 function zenodo_data_release() {
-    echo "Creating a new PUDL data release on Zenodo."
-    ~/pudl/devtools/zenodo/zenodo_data_release.py --publish --env sandbox --source-dir "$PUDL_OUTPUT"
+    echo "Creating a new PUDL data release on Zenodo." && \
+    ~/pudl/devtools/zenodo/zenodo_data_release.py --publish --env "$1" --source-dir "$PUDL_OUTPUT"
 }
 
 function notify_slack() {
     # Notify pudl-builds slack channel of deployment status
-    if [ "$1" = "success" ]; then
+    if [[ "$1" == "success" ]]; then
         message=":large_green_circle: :sunglasses: :unicorn_face: :rainbow: The deployment succeeded!! :partygritty: :database_parrot: :blob-dance: :large_green_circle:\n\n "
         message+="<https://github.com/catalyst-cooperative/pudl/compare/main...${BUILD_REF}|Make a PR for \`${BUILD_REF}\` into \`main\`!>\n\n"
-    elif [ "$1" = "failure" ]; then
+    elif [[ "$1" == "failure" ]]; then
         message=":large_red_square: Oh bummer the deployment failed ::fiiiiine: :sob: :cry_spin:\n\n "
     else
         echo "Invalid deployment status"
@@ -100,50 +95,80 @@ function notify_slack() {
 }
 
 function update_nightly_branch() {
-    git config --unset http.https://github.com/.extraheader
-    git config user.email "pudl@catalyst.coop"
-    git config user.name "pudlbot"
-    git remote set-url origin "https://pudlbot:$PUDL_BOT_PAT@github.com/catalyst-cooperative/pudl.git"
-    echo "BOGUS: Updating nightly branch to point at $NIGHTLY_TAG."
-    git fetch origin nightly:nightly
-    git checkout nightly
-    git merge --ff-only "$NIGHTLY_TAG"
-    ETL_SUCCESS=${PIPESTATUS[0]}
-    git push -u origin
+    # When building the image, GHA adds an HTTP basic auth header in git
+    # config, which overrides the auth we set below. So we unset it.
+    git config --unset http.https://github.com/.extraheader && \
+    git config user.email "pudl@catalyst.coop" && \
+    git config user.name "pudlbot" && \
+    git remote set-url origin "https://pudlbot:$PUDL_BOT_PAT@github.com/catalyst-cooperative/pudl.git" && \
+    echo "Updating nightly branch to point at $NIGHTLY_TAG." && \
+    git fetch --force --tags origin "$NIGHTLY_TAG" && \
+    git fetch origin nightly:nightly && \
+    git checkout nightly && \
+    git show-ref -d nightly "$NIGHTLY_TAG" && \
+    git merge --ff-only "$NIGHTLY_TAG" && \
+    git push -u origin nightly
+}
+
+function clean_up_outputs_for_distribution() {
+    # Compress the SQLite DBs for easier distribution
+    gzip --verbose "$PUDL_OUTPUT"/*.sqlite && \
+    # Remove redundant multi-file EPA CEMS outputs prior to distribution
+    rm -rf "$PUDL_OUTPUT/core_epacems__hourly_emissions/" && \
+    rm -f "$PUDL_OUTPUT/metadata.yml"
 }
 
-# # Run ETL. Copy outputs to GCS and shutdown VM if ETL succeeds or fails
+########################################################################################
+# MAIN SCRIPT
+########################################################################################
+# Initialize our success variables so they all definitely have a value to check
+ETL_SUCCESS=0
+SAVE_OUTPUTS_SUCCESS=0
+UPDATE_NIGHTLY_SUCCESS=0
+DATASETTE_SUCCESS=0
+CLEAN_UP_OUTPUTS_SUCCESS=0
+DISTRIBUTION_BUCKET_SUCCESS=0
+ZENODO_SUCCESS=0
+
+# Set PUDL_GCS_OUTPUT *only* if it is currently unset
+: "${PUDL_GCS_OUTPUT:=gs://nightly-build-outputs.catalyst.coop/$BUILD_ID}"
+
+# Run ETL. Copy outputs to GCS and shutdown VM if ETL succeeds or fails
 # 2>&1 redirects stderr to stdout.
 run_pudl_etl 2>&1 | tee "$LOGFILE"
 ETL_SUCCESS=${PIPESTATUS[0]}
 
-copy_outputs_to_gcs
+save_outputs_to_gcs 2>&1 | tee -a "$LOGFILE"
+SAVE_OUTPUTS_SUCCESS=${PIPESTATUS[0]}
 
 # if pipeline is successful, distribute + publish datasette
 if [[ $ETL_SUCCESS == 0 ]]; then
-    # Deploy the updated data to datasette
-    if [ "$BUILD_REF" = "dev" ]; then
-        python ~/pudl/devtools/datasette/publish.py 2>&1 | tee -a "$LOGFILE"
-        ETL_SUCCESS=${PIPESTATUS[0]}
+    if [[ "$GITHUB_ACTION_TRIGGER" == "schedule" ]]; then
+        update_nightly_branch 2>&1 | tee -a "$LOGFILE"
+        UPDATE_NIGHTLY_SUCCESS=${PIPESTATUS[0]}
     fi
 
-    # Compress the SQLite DBs for easier distribution
-    # Remove redundant multi-file EPA CEMS outputs prior to distribution
-    gzip --verbose "$PUDL_OUTPUT"/*.sqlite && \
-    rm -rf "$PUDL_OUTPUT/core_epacems__hourly_emissions/" && \
-    rm -f "$PUDL_OUTPUT/metadata.yml"
-    ETL_SUCCESS=${PIPESTATUS[0]}
+    # Deploy the updated data to datasette if we're on dev
+    if [[ "$BUILD_REF" == "dev" ]]; then
+        python ~/pudl/devtools/datasette/publish.py 2>&1 | tee -a "$LOGFILE"
+        DATASETTE_SUCCESS=${PIPESTATUS[0]}
+    fi
 
-    # Dump outputs to s3 bucket if branch is dev or build was triggered by a tag
     # TODO: this behavior should be controlled by on/off switch here and this logic
-    # should be moved to the triggering github action. Having it here feels
-    # fragmented.
-    if [ "$GITHUB_ACTION_TRIGGER" = "push" ] || [ "$BUILD_REF" = "dev" ]; then
-        copy_outputs_to_distribution_bucket
-        ETL_SUCCESS=${PIPESTATUS[0]}
-        # TEMPORARY: this currently just makes a sandbox release, for testing:
-        zenodo_data_release 2>&1 | tee -a "$LOGFILE"
-        ETL_SUCCESS=${PIPESTATUS[0]}
+    # should be moved to the triggering github action. Having it here feels fragmented.
+    # Distribute outputs if branch is dev or the build was triggered by tag push
+    if [[ "$GITHUB_ACTION_TRIGGER" == "push" || "$BUILD_REF" == "dev" ]]; then
+        # Remove some cruft from the builds that we don't want to distribute
+        clean_up_outputs_for_distribution 2>&1 | tee -a "$LOGFILE"
+        CLEAN_UP_OUTPUTS_SUCCESS=${PIPESTATUS[0]}
+        # Copy cleaned up outputs to the S3 and GCS distribution buckets
+        copy_outputs_to_distribution_bucket | tee -a "$LOGFILE"
+        DISTRIBUTION_BUCKET_SUCCESS=${PIPESTATUS[0]}
+        # TODO: this currently just makes a sandbox release, for testing. Should be
+        # switched to production and only run on push of a version tag eventually.
+        # Push a data release to Zenodo for long term accessiblity
+        zenodo_data_release sandbox 2>&1 | tee -a "$LOGFILE"
+        ZENODO_SUCCESS=${PIPESTATUS[0]}
     fi
 fi
 
@@ -151,9 +176,14 @@ fi
 gsutil cp "$LOGFILE" "$PUDL_GCS_OUTPUT"
 
 # Notify slack about entire pipeline's success or failure;
-# PIPESTATUS[0] either refers to the failed ETL run or the last distribution
-# task that was run above
-if [[ $ETL_SUCCESS == 0 ]]; then
+if [[ $ETL_SUCCESS == 0 && \
+      $SAVE_OUTPUTS_SUCCESS == 0 && \
+      $UPDATE_NIGHTLY_SUCCESS == 0 && \
+      $DATASETTE_SUCCESS == 0 && \
+      $CLEAN_UP_OUTPUTS_SUCCESS == 0 && \
+      $DISTRIBUTION_BUCKET_SUCCESS == 0 && \
+      $ZENODO_SUCCESS == 0
+]]; then
     notify_slack "success"
 else
     notify_slack "failure"