SYDNEY, May 21 (Reuters) - Australia faces the risk of power shortages because of delays in installing transmission lines tied to wind and solar farms, the energy market operator said on Tuesday, posing a challenge to the country's energy transition plans.

In an updated outlook for the electricity market, the Australian Energy Market Operator (AEMO) said the delay in commissioning dates for EnergyConnect, a 900 km (559 miles) transmission line to connect grids across three states, as well as the mothballing and retirement of gas and diesel power generators in South Australia could impact the power grid.

WHY IT'S IMPORTANT

Australia's power industry is struggling to meet the government's target for 82% renewable power by 2030 from around 40% now due to challenges in expanding transmission networks to handle new renewable projects located far from demand centres.

Compared to last year's outlook, the AEMO report said reliability risks have increased in New South Wales and Victoria, the two biggest power consuming states, from 2024-25 to 2027-28, and in South Australia in 2026-27.

KEY QUOTE

"While new generation and storage capacity continues to increase, project development and commissioning delays are impacting reliability throughout the horizon," AEMO CEO Daniel Westerman said.

Westerman said AEMO would bid for backup supplies to support Victoria and New South Wales to avoid supply gaps next summer, which usually begins in December in the southern hemisphere.

CONTEXT

Several Australian farmers are refusing to let high-voltage overhead power lines cross their land, which threatens plans to boost renewable generation and cut emissions.

To avoid supply shortages, about 10,000 km (6,200 miles) of new and upgraded transmission line is required, the operator said in a report in December.

(Reporting by Renju Jose in Sydney; Editing by Christian Schmollinger)