Fixes #172

src/main/java/techreborn/blocks/storage/BlockIDSU.java

@@ -4,7 +4,9 @@ import cpw.mods.fml.relauncher.Side;
 import cpw.mods.fml.relauncher.SideOnly;
 import net.minecraft.block.material.Material;
 import net.minecraft.client.renderer.texture.IIconRegister;
+import net.minecraft.entity.EntityLivingBase;
 import net.minecraft.entity.player.EntityPlayer;
+import net.minecraft.item.ItemStack;
 import net.minecraft.tileentity.TileEntity;
 import net.minecraft.util.IIcon;
 import net.minecraft.world.IBlockAccess;
@@ -67,4 +69,13 @@ public class BlockIDSU extends BlockMachineBase {
         return true;
     }
 
+    @Override
+    public void onBlockPlacedBy(World world, int x, int y, int z, EntityLivingBase player, ItemStack itemstack) {
+        super.onBlockPlacedBy(world, x, y, z, player, itemstack);
+        TileEntity tile = world.getTileEntity(x, y, z);
+        if (tile instanceof TileIDSU) {
+            ((TileIDSU) tile).ownerUdid = player.getUniqueID().toString();
+        }
+    }
+
 }

src/main/java/techreborn/tiles/idsu/IDSUManager.java

@@ -119,6 +119,9 @@ public class IDSUManager {
         }
 
         public IDSUValueSaveData getSaves(String udid) {
+            if(udid == null){
+                return null;
+            }
             if (idsuValues.containsKey(udid)) {
                 return idsuValues.get(udid);
             } else {

src/main/java/techreborn/tiles/idsu/TileIDSU.java

@@ -15,11 +15,17 @@ public class TileIDSU extends TilePowerAcceptor {
 
     @Override
     public double getEnergy() {
+        if(ownerUdid == null){
+            return 0;
+        }
         return IDSUManager.INSTANCE.getSaveDataForWorld(worldObj, ownerUdid).storedPower;
     }
 
     @Override
     public void setEnergy(double energy) {
+        if(ownerUdid == null){
+            return;
+        }
         IDSUManager.INSTANCE.getSaveDataForWorld(worldObj, ownerUdid).storedPower = energy;
     }
 
@@ -92,6 +98,9 @@ public class TileIDSU extends TilePowerAcceptor {
 
     public void writeToNBT(NBTTagCompound nbttagcompound) {
         super.writeToNBT(nbttagcompound);
+        if(this.ownerUdid == null){
+            return;
+        }
         nbttagcompound.setString("ownerUdid", this.ownerUdid);
     }