The citizens lobby Common Cause sued Presdient Carter and the Department of Energy yesterday for their alleged failure to come up with plans for energy conservation within the federal government.

In one of three separate lawsuits filed in the U.S. District Court, Common Cause contended that both the DOE and the Office of Management and Budget are required by the Energy Policy and Conservation Act of 1975 to develop a 10-year plan for energy conservation in all buildings owned by the federal government.

Common Cause alleged that the plan, if implemented, would reduce energy consumpton in federal buildings by at least 31 million barrels of oil a year for an annual saving of more than $900 million.

Another of the lawsuits filed yesterday by Common Cause contends that neither Carter nor the Office of Federal Procurement Policy has met terms of the Energy Conservation Act which call for mandatory energy-saving standards for government procurement policy and decisions.

Finally, Common Cause alleged in a third lawsuit that federal law requires the DOE to consult with other government agencies to promote "maximum possible energy conservation measures." Common Cause contended that the government has failed to come up with such standards to restrict energy consumption for federal transportation, which accounts for more than half of the energy consumed by the federl government.

Rules proposed by the DOE in February didn't consider mandatory conservation standards for federal transportation, leaving it up to the agencies to set up procedures for reducing energy use in that area, Commnon Cause alleged.

The lawsuits ask the court to order the president and the agencies to implement the various energy conservation plans.