TransCanada asked on the Nebraska Public Power District to have transmission lines in place for the planned oil pipeline from Canada by the end of 2014.
NPPD Chief Operating Officer Tom Kent was quoted by the Columbus (Neb.) Telegram as saying the deadline was "wishful thinking" on TransCanada's part.
"We have a lot of work to do," he said.
Concerns over pipeline route plans through Nebraska's Sand Hills groundwater ecosystem forced TransCanada to redesign the planned Nebraska section. Kent said it would take at least a year to redevelop plans to accommodate the revised route.
Thousands of protesters descended on Washington last weekend to protest the pipeline. So-called tar sands oil, the type designated for Keystone XL, is considered by environmental groups too great of a risk to support the pipeline.
U.S. Rep. Fred Upton, R-Mich., chairman of the House Energy and Commerce Committee put the White House on the clock to approve the project, which needs U.S. federal approval because it would cross the U.S.-Canadian border.
"The Keystone XL pipeline is exactly the kind of private sector project America needs to strengthen our economy and create jobs," Upton said in a statement.