First and foremost, all items currently in your inventory are unaffected, and you will not lose anything that you have. However, a new energy (Battery) limit has been introduced that will all you to only have 15 of each kind of Battery (+1, +2, or +3 energy) in your inventory at once. Again, if you have more than this number, you will not lose these items, but you will also be unable to add anymore to your inventory until the number drops back down below 15.
So much for a never-ending supply of energy. Zynga says that this previous stockpiling issue has negatively impacted the game's balance, and that they would like users to be strategic with their energy use, just as they encourage strategy with building new businesses or expanding your land. It's possible that this limit might change in the future, based on user feedback, so if you'd like to share yours, make sure to give it to Zynga in the appropriate thread.
What do you think of this new change? Will this make the game more fair for users that didn't have enough friends available to send them mass amounts of energy, or should users be able to accumulate as many energy points as possible? Let us know in the comments.