Power Advantage is a mod for Minecraft that provides a simple API for adding power systems (such as steam power) to Minecraft. By itself, Power Advantage adds some handy item conveyor machines (which don't need power) that help you sort items and can transfer items upwards (unlike hoppers) and some machines for collecting, storing, and dispensing water/lava/liquids. Add-on mods that use the Power Advantage API (e.g. Steam Advantage) add additional forms of power.
Talk to the dev on Discord: here
Note: Power Advantage now requires Java 8 or later. If you are using Java 6 or 7, please update to the latest Java SE version at java.oracle.com
License and Mod Packs
Power Advantage and Steam Advantage are licensed on the LGPL-3 open-source license. You may use the Power Advantage, Steam Advantage, and Electric Advantage mods in your modpacks without asking for permission. You may even use the code from these mods in your own mods, so long as you provide a link to the original Power Advantage source code. I really do encourage you to try using the Power Advantage API to make your own mods.
The unobfuscated API .jar files and code documentation (javadocs) are available on the GitHub project page under Releases (click Source in the navigation bar to go to the GitHub, and then click on Releases).