The authors of bipartisan energy efficiency legislation introduced a dramatically scaled-back version of the bill July 30.

Sens. Jeanne Shaheen (D-N.H.) and Rob Portman (R-Ohio) have struck from the bill a title that would have established a program to finance commercial building efficiency improvements "due to late concerns raised."

That program, estimated by the Congressional Budget Office to cost $250 million, would have funded grants by the Energy Department for states to expand efficiency retrofit financing programs for private sector and commercial buildings.

The new version of the Energy Savings and Industrial Competitiveness Act of 2013 (S. 1392), is now estimated to cost $350 million over five years. That is less than the initial estimated cost of nearly $600 million. The new version replaces the previous version, S. 761.

Other changes to the legislation include the establishment of a grant program to train workers in energy-efficiency commercial building design and operation, and expanding the types of motors eligible for an energy efficiency rebate program, according to a summary of the bill.

Among the provisions that remain from the original bill are measures to increase energy conservation in the federal government, establish voluntary national model building codes, and increase energy efficiency in the manufacturing sector, including the creation of a "supply star" program to promote and increase efficiency in companies' supply chains.

Senate debate on the legislation, which may serve as a vehicle for amendments related to the Keystone XL pipeline, began Aug. 1, though no votes on amendments are expected until after the August congressional recess.

Other possible amendments include a measure planned by Sens. Joe Manchin (D-W.Va.) and John Hoeven (R-N.D.) that would block implementation of a requirement that federal buildings phase out fossil fuel use and a measure by John Barrasso (R-Wyo.) that would require the Obama administration to secure congressional approval for regulations to address climate change.

Shaheen and Portman have been trying to reach a deal with other lawmakers to limit amendments to the legislation, which would represent the first major energy bill on the Senate floor since 2007, but have so far been unsuccessful.

Shaheen said work on reaching such a deal would continue during the August break.