diff --git a/src/main/java/gregtech/common/metatileentities/multi/electric/MetaTileEntityPowerSubstation.java b/src/main/java/gregtech/common/metatileentities/multi/electric/MetaTileEntityPowerSubstation.java
index c3fdd2b18b6..af4b6a7a0bd 100644
--- a/src/main/java/gregtech/common/metatileentities/multi/electric/MetaTileEntityPowerSubstation.java
+++ b/src/main/java/gregtech/common/metatileentities/multi/electric/MetaTileEntityPowerSubstation.java
@@ -587,8 +587,12 @@ public void registerBars(List<UnaryOperator<TemplateBarBuilder>> bars, PanelSync
         syncManager.syncValue("energy_capacity", energyCapacityValue);
 
         bars.add(b -> b.progress(() -> {
-            if (energyCapacityValue.getValue().equals(BigInteger.ZERO)) return 0;
-            return energyStoredValue.getValue().divide(energyCapacityValue.getValue()).doubleValue();
+            BigInteger capacity = energyCapacityValue.getValue();
+            BigInteger stored = energyStoredValue.getValue();
+            if (stored.equals(BigInteger.ZERO)) return 0;
+            double factor = capacity.divide(stored).doubleValue();
+            if (factor == 0) return 0;
+            return 1 / factor;
         })
                 .texture(GTGuiTextures.PROGRESS_BAR_MULTI_ENERGY_YELLOW)
                 .tooltipBuilder(t -> {
diff --git a/src/main/java/gregtech/mixins/mui2/BigIntAdapterMixin.java b/src/main/java/gregtech/mixins/mui2/BigIntAdapterMixin.java
new file mode 100644
index 00000000000..db374739b7d
--- /dev/null
+++ b/src/main/java/gregtech/mixins/mui2/BigIntAdapterMixin.java
@@ -0,0 +1,20 @@
+package gregtech.mixins.mui2;
+
+import net.minecraft.network.PacketBuffer;
+
+import io.netty.buffer.ByteBuf;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Redirect;
+
+// todo remove in next mui2 update
+@Mixin(targets = "com.cleanroommc.modularui.utils.serialization.ByteBufAdapters$3")
+public class BigIntAdapterMixin {
+
+    @Redirect(method = "serialize(Lnet/minecraft/network/PacketBuffer;Ljava/math/BigInteger;)V",
+              at = @At(value = "INVOKE",
+                       target = "Lnet/minecraft/network/PacketBuffer;writeBytes([B)Lio/netty/buffer/ByteBuf;"))
+    public ByteBuf fixIncorrectCall(PacketBuffer instance, byte[] bytes) {
+        return instance.writeByteArray(bytes);
+    }
+}
diff --git a/src/main/resources/mixins.gregtech.mui2.json b/src/main/resources/mixins.gregtech.mui2.json
index 72a083a3408..5299e07453a 100644
--- a/src/main/resources/mixins.gregtech.mui2.json
+++ b/src/main/resources/mixins.gregtech.mui2.json
@@ -8,6 +8,7 @@
     "maxShiftBy": 10
   },
   "mixins": [
+    "BigIntAdapterMixin",
     "TextWidgetMixin"
   ],
   "client": [