You can take and return e-bikes only at multimedia stations, without the need of any additional charges in your membership.
When you take an e-bike, the station will always give you bicycles with a battery percentage higher than 20%. If the battery runs out during your trip, the electric assistance will stop, but you can continue riding it as a regular bike.
Remember that the rights and responsibilities of riding electric bicycles are the same as those of conventional bicycles, so you must adhere to the city’s traffic regulations for non motorized vehicles.