Parks and grounds staff have moved to using a Cardley Wave Mid Series system on the islands, which are 110 miles north of mainland Scotland.
In making its decision, the council noted that in future the use of glyphosate and other chemical weedkillers could be outlawed. The islands also see more than 250 days of rain each year, making pesticide-spraying a difficult proposition.
The Cardley Wave system launched in the UK early in 2015, offering a way to kill weeds without using any chemicals. Aberdeen City Council was the first UK local authority to purchase a machine outright after a trial period and many more councils, contractors and utility companies have followed their lead.
William Spence, executive manager of environmental services for Shetland Islands Council, said: "The environmental advantages are that we are not using chemicals in any form thus reducing the risk of contaminating waterways and effects on pets and wildlife."
Algae and moss on paved areas around the main streets are also being removed by the machine. Spence commented: "We also hope this will reduce slips and falls due to algae and moss, making all our paved area and lane areas safer for the public. We are also benefiting from the machine being dual purpose so we are able to power wash at the same time as we have been weeding. That is reducing time by not having to revisit the area."
The islands are exposed to the weather elements more so than other parts of the country, previously limiting the use of traditional chemical controls, but the new system can be used in wind and rain, increasing productivity.
Unlike chemical spraying, there are no mandatory training to operate the unit, meaning Spence may in future be able to let members of the community help battle weeds using the machine.