Xcel Energy this week begins installing more energy efficient LED fixtures in 90,000 company-owned streetlights in nearly 350 communities throughout the Twin Cities and in Minnesota.

The conversion from high-pressure sodium bulbs to what the utility said Tuesday brings economic, environmental and aesthetic benefits starts in the Osakis area in central Minnesota and is expected to take 2½ years to complete.

After first focusing its attention on northwestern and central Minnesota, Xcel will turn to the Twin Cities area starting about Nov. 1.

The suburbs will get theirs first, said Xcel Energy spokesman Matt Lindstrom. They are: Apple Valley, Arden Hills, Blaine, Bloomington, Brooklyn Center, Circle Pines, Eagan, Edina, Inver Grove Heights, Lauderdale, Lino Lakes, Mendota, Mendota Heights, New Brighton, New Hope, Richfield, Shoreview and South St. Paul. Minneapolis and St. Paul follow in 2017 and 2018.

The state's two largest cities together operate nearly 60,000 streetlights.

In preparation for installing LED fixtures, Xcel tested the technology in three pilot projects, with the one in West St. Paul being the largest. The upgrade of 537 streetlights in that suburb "showed a significant reduction in energy use," the utility said in its announcement Tuesday.

LED fixtures use 40 to 60 percent less electricity than cobra head-shaped HPS lights and have a longer life. That means less maintenance and fewer replacements. Once conversion is completed, communities can expect to save 4 to 7 percent annually on their street-lighting bills.

Wattage of the new fixtures range from 100 to 400.

Xcel Energy crews carry out the installation, and the utility pays for all costs associated with the retrofits, including removal and salvage of old lights and placement of the new fixtures.

Xcel's changeover in Minnesota is part of a broader LED conversion of a total of 300,000 streetlights in all eight states that Xcel serves. The switch is complete in North Dakota and Wisconsin, and underway in South Dakota, Michigan, Colorado, Texas and New Mexico.

For all the cost and energy-saving benefits, the whiter hue of LED lighting has drawn some criticism for being too harsh on people's vision when compared to the gold tint of older bulbs.

In June, the American Medical Association, which otherwise supports the conversions, warned against installing a common type of LED streetlight that is the preference of Xcel and many Minnesota governments. Its blue-filled white light can disrupt sleep patterns — similar to staring at a smartphone before bed — and generate more glare that temporarily impairs vision, the AMA said.

Lindstrom said Xcel is confident that its choice has "significantly lower glare for improved nighttime visibility and allows people to better discern color."