When Congress passed the energy bill last year, there was widespread relief that the U.S. finally had turned a corner. Although the new law isn't apt to cut consumption much, it was a symbolic commitment to a national energy policy. At last there was an overall framework for U.S. initiatives.

Now, barely three months later, the nation is facing its biggest uncertainty over energy since the days after the 1973 oil embargo. The political turmoil in Iran -- and the steeper-than-expected oil-price hike by the Organization of Petroleum Exporting Countries -- have shattered the once-favorable outlook.

Plans to lift government price controls over curde oil and gasoline early this spring have been dealt a new setback. And suddenly, policy makers have begun hinting that the nation may have to resort to rationing if the situation doesn't stabilize soon.

The cloud-shrouded picture stems primarily from the Iranian oil workers' strikes. The unrest has slashed that country's daily crude oil production from 6 million barrels a day -- about one-fifth of the oil cartel's total output levels -- to practically zero, in the space of a few weeks.

While the Energy Department estimates that the U.S. can go on as long as six months or so before feeling any pinch from the cuts, private experts aren't as sanguine. Data Resources Inc., a private consulting firm, figures that the impact could be felt as early as April 1. After that, it's downhill -- fast.

But the Iranian situation isn't the only element in the energy picture for 1979. Prices, which moderated in 1978 after a big surge during the previous year, are expected to speed up sharply again in 1979. Consumption -- mainly because of the coming recession -- will remain flat. And imports will rise.

There are these predictions:

PRICES: DIR's forecast predicts that overall energy prices will rise 13.3 percent this year -- compared with 4.8 per cent in 1978 -- primarily because of last year's natural gas deregulation bill and the expected phasing out of crudeoil price controls beginning next May.

Of this, more than 5 1/2 percentage points stems from expected decontrol of oil prices, 2.7 percentage-points from higher electric utility bills, 2 percentage points from higher gas prices and 1 percentage point from increased coal costs. The OPEC price rises will add another 1 1/2 percentage points.

Ronald M. Whitfield, chief of DRI's energy-forecasting team, lists these changes in government regulations as major factors behind this year's price boosts: The new natural gas bill, eliminating the two-tier price system; oil price decontrol; new strip-mining regulations; and more clean-air rules.

CONSUMPTION: Mostly because of the coming economic slowdown, overall energy consumption is expected to remain relatively flat this year, rising by a scant 0.6 percent, following increases of 3.4 and 3 1/2 percent in the two previous years.

Despite world wide grousing about the huge -- and, to foreigners, seemingly uncontrollable -- U.S. energy appetite, consumption in this country has been tapering off steadily in the face of constantly rising prices ever since the 1973 embargo. If the recession runs deeper, intake could slow even more.

IMPORTS: In large part because of the OPEC price rise, the dollar volume of U.S. imports of foreign-produced petroleum is likely to rise moderately -- perhaps to 8.4 million barrels a day in 1979, up from 8.34 million barrels last year, according to DRI.

Nevertheless, the overall U.S. trade deficit still is expected to shrink visibly, and the "current account" -- the closely watched measure that includes not only trade but tourism, investment flows and military sales as well -- is expected to approach near-balance.

(The OPEC price hike, wiile larger than expected, still isn't likely to be that crippling, at least according to most forecasters. While technically the rise totals a scary 14 1/2 percent between now and next October, it actually amounts to 10 percent for the year -- close to the 6 percent forecast earlier.)

SUPPLIES: Apart from the Iranian oil situation, the rest of the energy supply outlook here looks relatively good: In the wake of last year's natural gas legislation, there's surfeit of gas in this country, at least for the moment, and coal supplies are expected to hold their won through 1979.

The impact of all this on U.S. energy policy is to throw what had been a set of reasonably clear commitments into a sea of confusion. Before the latest OPEC price rise and the Iranian shutdowns, Carter had one distinct energy goal for 1979 -- to begin pushing domestic prices toward the world market prices.

But now, however, with inflation and the larger-that-expected OPEC price boost making price-raising so difficult politically, Carter is said to be seeking administrative alternatives to outright decontrol -- by revamping existing regulations.

Moreover, while supplies are reasonably plentiful now, policy makers have raised the possibility that the administration also may have to move simultaneously to rationing if the Iranian cutbacks continue. Energy Secretary Janes R. Schlesinger mentioned the prospect a few weeks ago.