Bonn, June 29 - The West German government is seeking clarification from Moscow of reports that the Soviet Union is renewing its interest in a plan that link the electric power networks of Eastern and Western Europe.

The idea for such a power grid goes back almost 10 years and, in 1974, was part of a package of proposed cooperative agreements between Bonn and Moscow. As relations between the two countries, and between East and West generally, blew hot and cold in later years, the project foundered,

The reported renewal of Soviet interest could not only signal an important new international energy development but also would fit into a pattern of increasing Kremlin courtship of Bonn over the past year.

A spokesman for Chancellor Helmut Schmidt cautioned against exaggerating the significance of the reports until more details are available. But he said there is still interest here in the plan and that "it is still an attractive idea,"

According to reports from the West German news agency in Moscow, Soviet Energy Minister Pyotr Neporozhniy told officials from the Communist bloc countries of plans to expand Soviet electrification mostly by means of nuclear power. He also talked of the potential link-up of that network with a line running through Poland and East Germany into West Germany, hooking up with a grid that would also link other west European systems.

Earlier proposals to do this got stuck principally on the question of West Berlin, with Bonn wanting to ensure that the allied part of that divided city was part of the hook-up. This would mean Moscow would not be able to tamper with Berlin's power source without directly involving itself in a challenge to the West.

The Soviet minister reportedly said the Berlin problem was now "only a secondary question."

Washington Post correspondent Kevin Klose reported from Moscow:

Soviet-bloc governments have completed a three-day economic summit here by agreeing to a massive nuclear power station construction program through 1990.

The 10 prime ministers also pledged long-term improvements in consumer goods and transport facilities linking the Soviet Union and its East European allies.

The Soviet Union, which is now experiencing difficulty exploiting fossilfuel reserves, agreed to increase its deliveries of fuel and energy to the East bloc by 20 percent in 1981-85. The rate of increase in Soviet oil production is falling and targets have not been met for the first part of 1979.

Some Western analysts predict severe petroleum shortages here in the mid-1980s despite intense exploration and purchases of sophisticated oil field technology from the West.

The nuclear energy program is aimed at raising nuclear generating capacity in the bloc to 150 million kilowatts by 1990, a 10-fold increase from present levels. The bulk of the new capacity will be located within Russia and built cooperatively by Comecon.

Although conceding they have had several minor nuclear accidents, the Soviets are firmly committed to nuclear power. There is no U.S.-style public debate here about the wisdom of atomic plants.

As the summit was concluding yesterday on a confident note about the bloc's energy future, the official Soviet Communist Party daily Pravda in a frontpage, editorial called on the Soviet population to take new measures to save energy.

Last winter, the bitterest in a century, brought a widespread energy shortage in European Russia, with Moscow using twice its normal amount of natural gas. The problems reportedly caused factory shutdowns, which apparently contributed to the poor industrial production figures that have been published by the central statistical board.