At the Houston Rodeo, NRG Energy will be offering patrons the ability to rent portable chargers for their cellular and mobile devices.

Each portable charger costs only $2.99 per day to rent

In an FAQ, NRG says that the "Portable Power stations" (chargers) are only available as rentals at this time. "However, NRG Energy is in the process of developing a charger with even better capabilities than the chargers available at the Houston Livestock Show and Rodeo! We want you to have the best of the best."

NRG is incenting customers to show off the devices. Customers have a chance to win a $500 Visa gift card by posting a photo of the customer with the NRG Portable Power charger, or of the customer next to an NRG Portable Power station, on Instagram or Twitter

The chargers work with all Apple iPhones and Android, Windows, and Blackberry phones that use Micro-USB charging plugs

Check out nrgstation.com