The Root of the Behavior
Excess energy does not typically apply to separation anxiety but it does often contribute to paper chewing and other ways they attempt to relieve boredom. The obvious key here is to increase the amount of exercise they are receiving. This is extremely helpful toward your goals here but it is not the only measure you can take. Make sure your dog has some toys they can play with while you are not around. Supplying them an area of the house with those toys, their favorite blanket, and a place for them to lay their head down will help to reduce both their anxiety and boredom. Many dog owners simply use their kennel for this area, and often dogs respond well to it. Yet there are some dogs that chew paper, not out of boredom or anxiety, but simply as a bad habit. Compulsive chewing is common in canines and can often be observed in puppies that are teething. Puppies that chew to reduce the pain of teething will often grow compulsive chewing habits that you need to break at a later date.
Encouraging the Behavior
Leave them with the chew toy while you are gone so in case they need to chew on something for one reason or another, then they will have the toy during that time. The goal here is to reduce their compulsive chewing and eventually put the toy away for good. This slower process combined with toys they can play with and other measures to reduce anxiety should work in most cases. Unfortunately, while they are puppies, supplying them with something to chew on is sometimes necessary for the teething process.
Other Solutions and Considerations
Chewing on something from time to time can be good for your dogs health, so removing the compulsive chewing should not be done entirely. Supplying them with a bone from time to time helps keep their teeth clean and healthy.