diff --git a/Classes/Driver/AmazonS3Driver.php b/Classes/Driver/AmazonS3Driver.php
index dd64c757..0fa35790 100644
--- a/Classes/Driver/AmazonS3Driver.php
+++ b/Classes/Driver/AmazonS3Driver.php
@@ -226,7 +226,8 @@ public function processConfiguration()
      */
     public function initialize()
     {
-        $this->initializeBaseUrl()
+        $this->loadSettings()
+            ->initializeBaseUrl()
             ->initializeBaseFolder()
             ->initializeSettings()
             ->initializeClient();
@@ -1060,6 +1061,32 @@ public function streamFile(string $identifier, array $properties): ResponseInter
      ******************** Protected Helpers **********************
      *************************************************************/
 
+    /**
+     * Load extension configuration and load additional storage configuration
+     *
+     * Record-based storage configuration can be overridden by defining
+     * $GLOBALS['TYPO3_CONF_VARS']['EXTENSIONS']['aus_driver_amazon_s3']['storage']
+     * or
+     * $GLOBALS['TYPO3_CONF_VARS']['EXTENSIONS']['aus_driver_amazon_s3']['storage_X']
+     * (where X is the UID of the storage record)
+     * in config/system/additional.php.
+     * This makes it possible to use environment variable based storage configuration.
+     */
+    protected function loadSettings(): self
+    {
+        self::$settings = GeneralUtility::makeInstance(ExtensionConfiguration::class)->get(self::EXTENSION_KEY);
+
+        //allow overriding storage configuration from AdditionalConfiguration.php
+        if (isset(self::$settings['storage'])) {
+            $this->configuration = array_merge($this->configuration, self::$settings['storage']);
+        }
+        if (isset(self::$settings['storage_' . $this->storageUid])) {
+            $this->configuration = array_merge($this->configuration, self::$settings['storage_' . $this->storageUid]);
+        }
+
+        return $this;
+    }
+
     /**
      * initializeBaseUrl
      *
@@ -1113,16 +1140,13 @@ protected function initializeBaseFolder(): self
      */
     protected function initializeSettings()
     {
-        if (self::$settings === null) {
-            self::$settings = GeneralUtility::makeInstance(ExtensionConfiguration::class)->get(self::EXTENSION_KEY);
-
-            if (!isset(self::$settings['doNotLoadAmazonLib']) || !self::$settings['doNotLoadAmazonLib']) {
-                self::loadExternalClasses();
-            }
-            if ($this->compatibilityService->isFrontend() && (!isset(self::$settings['dnsPrefetch']) || self::$settings['dnsPrefetch'])) {
-                $GLOBALS['TSFE']->additionalHeaderData['ausDriverAmazonS3_dnsPrefetch'] = '<link rel="dns-prefetch" href="' . $this->baseUrl . '">';
-            }
+        if (!isset(self::$settings['doNotLoadAmazonLib']) || !self::$settings['doNotLoadAmazonLib']) {
+            self::loadExternalClasses();
         }
+        if ($this->compatibilityService->isFrontend() && (!isset(self::$settings['dnsPrefetch']) || self::$settings['dnsPrefetch'])) {
+            $GLOBALS['TSFE']->additionalHeaderData['ausDriverAmazonS3_dnsPrefetch'] = '<link rel="dns-prefetch" href="' . $this->baseUrl . '">';
+        }
+
         return $this;
     }