AFTER FALLING steadily for five years, oil consumption in this country is going to rise again next winter. That forecast comes from the Energy Department's statisticians, and it is very likely to be correct. There's plenty of oil available at the moment. Prices are stable, and there's no immediate reason for anxiety. But when you consider the amount of grief that oil shortages have brought to this country and the world over the past decade, you will want at least to keep an eye on this turn in the trend.

Oil consumption reached its peak in this country in 1978, the year when the Iranian revolution began. In the chaos Iran suddenly stopped shipping oil, creating a worldwide shortage--gasoline lines began to appear in this country in May 1979--and prices shot upward again. At the time the trouble started Americans were using 18.8 million barrels of oil a day. This year consumption will be just over 15 million barrels a day.

About a third of that saving, incidentally, has been on the highway. The average car isn't being driven quite as far each week at it was five years ago, and, of course, fuel efficiency is up. For every eight gallons of gasoline that this country burned up five years ago, it is using about seven today.

Why do the Energy Department's technicians foresee a rise in oil demand next year? First of all, the economic recovery will increase the need for industrial fuel. Next, prices have been dropping a little. And then it's unlikely that there will be a repetition of the past winter's extraordinarily mild weather.

American imports are a particularly sensitive figure, and five years ago this country was importing 8 million barrels of oil a day. For the past year or so imports have been running hardly more than half that volume--saving the country, at present prices, some $40 billion a year. Much more important, that drop is a major contribution to keeping international oil markets slack and discouraging further price increases. In the first half of next year, according to the Energy Department's analysis, imports will be back up over 5 million barrels a day. That's not a dangerous increase in itself, but the pattern is beginning to move in the wrong direction.

While there's plenty of oil for sale this summer, it's always useful to keep it in mind that the oil markets sometimes swing around without warning. A revolution created the last crisis, and you can hardly say that the politics of the Persian Gulf has become more stable since then. The case for conservation remains as compelling as ever.