(Adds details on previous orders)
Sept 6 (Reuters) - Walmart Inc's Canadian unit said on Thursday it would buy 30 more of Tesla Inc's all-electric 18-wheeler semi-trucks as part of a plan to have 100 percent of its fleet use alternative power by 2028.
Walmart in November ordered five Tesla semis for its fleet in the United States and ten for Canada.
The world's biggest retailer was among the first companies to order Tesla's big rig, which the electric vehicle maker unveiled in November and said it expected to put into production by 2019.
United Parcel Service Inc said in December it would buy 125 Tesla semis, while PepsiCo Inc reserved 100 of the vehicle. J.B. Hunt Transport Services Inc, Anheuser-Busch InBev NV and Germany-based Deutsche Post AG's DHL have also placed orders.
Tesla says its trucks will have some semi-automonomous driving features, similar to its electric cars, and will have a range of 500 miles.
Walmart Canada said 20 Tesla semis will be used to support its fleet base in Mississauga, Ontario, while the remaining 20 will be moved to Surrey, British Columbia. (Reporting by Uday Sampath in Bengaluru; Editing by Sriraj Kalluvila and Maju Samuel)