Forge 1.12.2 2657

java.lang.NullPointerException: Initializing game
at de.ellpeck.actuallyadditions.mod.items.base.ItemEnergy$EnergyCapabilityProvider.getCapability(ItemEnergy.java:230)
at de.ellpeck.actuallyadditions.mod.items.base.ItemEnergy$EnergyCapabilityProvider.hasCapability(ItemEnergy.java:222)
at net.minecraftforge.common.capabilities.CapabilityDispatcher.hasCapability(CapabilityDispatcher.java:94)
at net.minecraft.item.ItemStack.hasCapability(ItemStack.java:1162)
at de.ellpeck.actuallyadditions.mod.items.base.ItemEnergy.func_150895_a(ItemEnergy.java:77)
at net.minecraft.client.Minecraft.func_193986_ar(Minecraft.java:586)
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:528)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:377)
at net.minecraft.client.main.Main.main(SourceFile:123)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

A detailed walkthrough of the error, its code path and all known details is as follows:

-- Head --
Thread: Client thread
Stacktrace:
at de.ellpeck.actuallyadditions.mod.items.base.ItemEnergy$EnergyCapabilityProvider.getCapability(ItemEnergy.java:230)
at de.ellpeck.actuallyadditions.mod.items.base.ItemEnergy$EnergyCapabilityProvider.hasCapability(ItemEnergy.java:222)
at net.minecraftforge.common.capabilities.CapabilityDispatcher.hasCapability(CapabilityDispatcher.java:94)
at net.minecraft.item.ItemStack.hasCapability(ItemStack.java:1162)
at de.ellpeck.actuallyadditions.mod.items.base.ItemEnergy.func_150895_a(ItemEnergy.java:77)
at net.minecraft.client.Minecraft.func_193986_ar(Minecraft.java:586)
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:528)

-- Initialization --
Details:
Stacktrace:
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:377)
at net.minecraft.client.main.Main.main(SourceFile:123)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

duplicate of #1068 and #1069 - don't use forge 2657

What is the highest forge it works with

I'm not sure, just through I'd try be helpful with marking it as duplicate. I'd try a version below though