Preheat grill to medium heat for direct cooking.

Scrub potatoes thoroughly with a brush; pat dry. Cut potatoes lengthwise into wedges. In a medium bowl, combine butter, olive oil, garlic, salt, ground chipotle chile pepper and lime zest. Toss potatoes in chipotle-butter mix.

Line grill rack with a piece of foil sprayed with nonstick cooking spray. Using a for, prick foil in several places. place potato fries on foil. Grill for 40 min or until tender, turning occasionally.