An Energy Department study of Government subsidies to the energy industry has concluded that the amounts involved are small and do not affect consumption much. But an evaluation by a prominent electricity analyst finds enormous subsidies for the nuclear industry, along with enormous costs incurred directly by the utilities.

The question of which energy forms the Government should support is drawing increased attention with the change of administrations. President Jimmy Carter won huge increases in Federal support for renewable energy resources and plans to replace oil with fuels derived from coal and other sources. As Presidents, Ronald Reagan and George Bush vigorously backed nuclear power. President-elect Bill Clinton and Vice President-elect Al Gore have talked about returning to renewable fuels and promoting natural gas and conservation. A Contrarian View

The Government study, released Wednesday, contradicts some conventional thinking about Washington's role in energy prices. It found, for example, that the oil industry, thought of as pampered with Government support, paid more in taxes than it got in benefits.

The study says a shift to conservation and use of renewable sources of energy, which the Clinton team advocates, has to a large extent already occurred.

The study, ordered by Congress last year, concludes that Government subsidies to the energy industry are equal to 1 to 3 percent of the value of all energy consumed, or $5 billion to $13 billion a year, depending on how a subsidy is defined.

The nation's total yearly energy bill is $475 billion, the study found.

"Contrary to what might be the popular impression, energy is not heavily subsidized," said Calvin A. Kent, administrator of the Energy Information Administration, an independent statistical agency within the Energy Department.

But the study did find that some energy sources, like gasohol and natural gas recovery from coal seams, existed only because of subsidies.

In contrast, a separate study to be released in a few days by Greenpeace, the environmental group, concludes that taxpayers have spent nearly $100 billion to promote nuclear power. The total, stated in 1990 dollars to account for inflation since the first expenditures in the early 1950's, said the subsidy amounted to 1.6 cents for every kilowatt-hour of electricity produced with nuclear power from 1968, when the first large plants began operating, until 1990. 'An Official Technology'

The Greenpeace study was written by Charles Komanoff, a New York-based electricity analyst who has been comparing the costs of competing sources for 20 years, and an associate, Cora Roelofs. It excludes benefits received from Washington by the nuclear industry like "the ideological support which crowned nuclear power an 'official technology' and won investor confidence."

The study puts the total cost of a nuclear kilowatt-hour at just over 10 cents. The figure includes $347 billion spent to build, fuel and operate reactors and to begin programs to tear them down when they retire. The utilities have spent $48 billion on indirect costs, including waste disposal and investments in plants that were canceled. Both numbers were stated in 1990 dollars.

In contrast to the 10-cent figure, which is a wholesale figure, the average cost of a kilowatt hour to all customers in the first eight months of this year was 6.6 cents, according to the Energy Department.

Mr. Komanoff said the investments in nuclear power had not been worthwhile, adding that they were a warning "to be more tolerant of teething costs for renewables and energy efficiency."

"I don't mean that I or anyone else wants to spend half a trillion dollars on solar energy or wind," he said. "But when you see eyebrows being raised because a couple of hundred million is going to photovoltaic solar cells or a wind farm, you have to put it in perspective."

The Government study also found a heavy subsidy for nuclear power but did not compare the figure with the cost per kilowatt hour. It found that for fiscal 1992, direct appropriations for nuclear power were $890 million for research and development and $9 million in regulatory costs borne by taxpayers.

But nuclear power also has benefits separate from Congressional appropriations: it enjoys a partial exemption from liability for reactor accidents, which the study valued at $3 billion a year in reduced insurance costs.

The sector getting the most help, through subsidized loans and Government sales at below-market prices, is electricity, at $1.8 billion, the study found. In contrast, it said the oil industry lost nearly $2.2 billion to the Government, when comparing the value of its tax breaks with the Federal excise taxes on fuel.

Dr. Kent said the study did not rank sectors of the energy industry by size of subsidy because many different assumptions went into the counting. But if subsidies were counted on the basis of quantity of energy produced compared with subsidies received, renewable sources, which include solar power, hydroelectricity, wood, wind and other technologies that do not consume fossil fuels, would get $847 million in the current fiscal year. This includes $244 million in research and development funds plus $540 million in tax exemptions and $63 million for help to low-income people.

The coal industry is subsidized with $1.1 billion, the study said, with the largest item being $551 million for research into cleaner ways to burn the fuel.

Taxpayers will spend $635 million this year to subsidize conservation, the department said. The natural gas industry gets $1.7 billion.