Powell is a C4 classified cyclist. She is a member of the Vikings Cycling Club ACT, and is coached by Sian Mulholland and Glenn Doney. Powell initially began cycling to improve her fitness for hockey and golf. After the hockey accident, she found that she could still participate in cycling, so she took the sport more seriously. She made her Australian national team debut at the 2009 Para-cycling Road World Championships and has since won 6 world championships. Sue has been named Champion of Champions at four consecutive Australian Paracycling Track Championships as well as three times Female Paracyclist of the Year. At the 2012 London Paralympics, she won a gold medal in the Women's Individual Pursuit C4, setting a new world record in the process, and a silver medal in the Women's Time Trial C4. Competing at the 2013 Para-cycling Road World Championships in Baie-Comeau, Canada, she won two bronze medals in the Women's Individual Time Trial C4 and Women's Road Race C4.At the 2014 UCI Para-cycling Track World Championships in Aguascalientes, Mexico, she won a gold medal in the Women's 3 km Individual Pursuit C4, a bronze medal in the Women's Time Trial C4 and finished fourth in the Women's C1-5 Scratch Race. Competing at the 2014 UCI Para-cycling Road World Championships in Greenville, South Carolina, Powell won two medals - silver medal in the Women's Road Race C4 and bronze medal in the Women's Time Trial C4. Powell repeated her 2014 results at the 2015 UCI Para-cycling Track World Championships in Appledorn, Netherlands by winning the gold medal in the Women's 3 km Individual Pursuit C4 and a bronze medal in the Women's Time Trial C4. At the 2015 UCI Para-cycling Road World Championships in Nottwil, Switzerland, she won the silver medal in the Women's Road Race C4 and finished fourth in the Women's Time Trial Race C4. The following year she finished second to Shawn Morelli in the Women's 3 km Individual Pursuit C4 at the 2016 UCI Para-cycling Track World Championships in Montichiari, Italy. Powell broke her sea-level personal best time twice in the competition. In May 2016 she was selected in the Australian team for the 2016 Rio Paralympics. At the 2016 Rio Paralympics, Powell won the silver medal in the Women's 3 km Individual Pursuit C4. It was Australia's first medal of the games. She followed the silver medal with a bronze medal in the Women's Road Time Trial C4. Powell's other results were eight in the Women's 500 m Time Trial C4-5 and ninth in the Women's Road Race C4-5. Since 2011, she has had a scholarship with the ACT Academy of Sport.