The Tennessee Valley Authority, the nation's largest buyer of coal and uranium, warned in a report today that giant energy companies have continued to corner fuel markets, resulting in diminished energy supplies and higher prices.

"The lifeblood of the country is in the hands of a few people who have more power than the government," TVA Chairman S. David Freeman said as the agency released its second report in two years claiming that the price of coal and uranium -- and thus, indirectly, the price of much of the nation's electricity -- is set by an oligopoly of giant energy conglomerates that control the price and production of several different fuels.

Freeman said the agency knows from experience in producing both fuels from its own reserves that "the prices are higher than the cost of production plus a reasonable profit."

The agency claimed it has documented a "startling" additional concentration in the energy field in the past 18 months, with oil-related firms taking over six coal producers and attempting to take over seven firms engaged in coal and uranium production.

Chairman Freeman, a recent Carter appointee, refused to blame the growing "antitrust problem" on less-than-aggressive antitrust enforcement by the Carter administration.

But the former Carter energy adviser urged the president to make energy company divestiture a top priority in the energy message he will deliver next Thursday.

TVA said that since 1973 the price of coal has risen from $5 a ton to $25, the price of uranium has increased from $9 a pound to over $40, and that it has been forced to more than double its residential electric rates and triple its industrial rates partly as a result of "monopoly pricing."

The agency took issue with a Justice Department study that showed less congolomerate domination of the coal market than TVA claimed. TVA said that only the Appalachian coal market is currently competitive and "preventive action" is needed "before the fire gets started thers."

TVA antitrust attorney William Mason said the Justice Department study had defined the national coal markets too broadly. He wrote in the agency's report that data used by the department and the Federal Trade Commission (both charged with antitrust enforcement) to determine concentration in coal reserve ownership "is fraught with shortcomings -- lacking accuracy, completeness, uniformity, and any measure of coal recoverability."

Meanwhile, in Washington, D.C., Assistant Attorney General for Antitrust John Shenefield defended his department's study od the coal industry, indicating that an FTC report and other studies agreed with Justice's findings that "there was not a scintilla of evidence indicating that there were anticompetitive practices in the coal industry."

Shenefield has testified at congresional committees that coal is a matter of concern, but called it a "utility regulatory problem." There had been allegations that utility companies were getting around regulations designed to keep energy costs down and limit their profits by inflating their costs as charged to them by their affiliated coal companies.

"Nobody disagrees with the TVA's efforts to combat anticompetitive practices," Shenefield said, "and where we see that we will bring suits." But he stressed that such problems can be handled by existing statutes.

An FTC staff official disagreed with Shenefield, and said "there is a need for more legislation in this area. We are investigating a number of mergers involving energy companies, and the basic problem is that under existing criteria, as interpreted by the courts, we are having a difficult time finding them anticompetitive."

He added, however, that the FTC has been unable to prove that energy prices are now artificially high.

The official said that the FTC study supporting the Justice Department findings of a competitive coal industry was done by the agency's Bureau of Economics and has since come under attack by the FTC's Bureau of Competition, which allegest that there is too much concentration in the energy industry.

In November 19778 TVA filed antitrust suits against 13 foreign and domestic uranium producers, claiming they had conspired to eliminate competition in the world uranium market by fixing prices and setting conditions of sale. Five foreign firms have ignored the suit to date. It has been combined in U.S. District Court in Chicago with a similar Westinghouse Corp. suit.

TVA general counsel Herbert Sanger said today that TVA, unlike Justice and the FTC, has limited power to investigate energy company mergers. He recommended that the antitrust laws be beefed up to "prevent energy company formation and growth by acquisition."

The TVA report noted that 65 percent of all the electricity in the United States is produced from coal and uranium. Freeman said this means that individual consumers ar "helpless" in trying to hold down the price of electricity, "except in being able to influence their representatives" tosupport additional antitrust legislation.