Energy conservation programs in the industrialized countries faltered last year, reversing a three-year trend of lower rates of growth in energy demand since the Arab oil embargo.

International energy experts are concerned that the growth in energy use - which in the post-war era which has roughly paralleled the rate of economic growth - is once again on the rise.

Last year energy use in the 24-member Organization of Economic Cooperation and Development rose 6 per cent, compared with a 5 per cent economic growth rate. Between the 1973 embargo and the end of 1975, energy demand grew at a significantly lower rate than the industrialized countries' economies did.

"The energy conservation data we are receiving reveals a disquieting trend," says Samuel A. Van Vactor of the International Energy Agency.

Van Vactor, who monitors IEA members conservation programs, recently completed an independent analysis of 1976 conservation efforts. The results of his study show that with the exception of Japan, France and the U.K., most of the industrial countries' conservation results fell short of desired goals. Total energy demand in Japan and France, was slightly less last year than it was in 1973.

The U.S. had a more effective conservation program in 1976 than most of the industrialized countries, improving on relatively poor conservation results from the time of the embargo through the end of 1975, the study says.

One surprise, Van Vactor says is that "several of the countries thought of as conservation stars, namely Germany and Sweden, had disappointing results during 1976."

Sweden has frequently been cited by administration officials as a country which has been able to maintain a high level of economic prosperity despite low per capita energy use.

From 1973 to 1975 Sweden's total energy use rose only 4.2 per cent. As a result of the increase in last year's demand, however, Sweden's increase in energy consumption from 1973 through the end of 1976 increased by 8.8 per cent.

Germany, on the other hand is an example of an industrialized country which has relied heavily on the price mechanism, rather than government regulation, to boost conservation.

"Price rises alone are not enough to spur conservation, they must be linked with administration programs," Van Vactor says. He attributes French and U.K. energy savings last year to both countries' comprehensive regulatory conservation programs and, to a lesser extent, energy price increases.

Throughout the industrialized countries, growth in energy demand for home use and transportation has remained relatively constant since the embargo, while energy demand in the industrial sector has dropped. This is due primarily to the higher prices residual fuel commands compared to gasoline and other petroleum products, the Paris-based IEA economist says.

Van Vactor continues to be optimistic about the potential for energy conservation in the industrialized countries. "The fears often expressed about energy conservation - that it will result in a potentially lower standard of living - appear to be unfounded," his study concludes.