diff --git a/src/main/java/com/interplug/qcast/biz/pwrGnrSimulation/PwrGnrSimService.java b/src/main/java/com/interplug/qcast/biz/pwrGnrSimulation/PwrGnrSimService.java
index 390d559d..c9272407 100644
--- a/src/main/java/com/interplug/qcast/biz/pwrGnrSimulation/PwrGnrSimService.java
+++ b/src/main/java/com/interplug/qcast/biz/pwrGnrSimulation/PwrGnrSimService.java
@@ -1506,7 +1506,7 @@ public class PwrGnrSimService {
         PwrGnrSimRoofResponse listItem = data.getRoofModuleList().get(i);
         sb.append("<tr>");
         sb.append("<td>" + StringUtils.defaultString(listItem.getRoofSurface()) + "</td>");
-        sb.append("<td>" + Optional.ofNullable(listItem.getSlopeAngle()).orElse("") + "</td>");
+        sb.append("<td>" + StringUtils.defaultString(listItem.getSlopeAngle()) + "</td>");
         sb.append("<td>" + StringUtils.defaultString(listItem.getAzimuth()) + "</td>");
         sb.append("<td>" + StringUtils.defaultString(listItem.getItemNo()) + "</td>");
         sb.append("<td>" + StringUtils.defaultString(listItem.getAmount()) + "</td>");