In an effort to distill a coherent state energy conservation policy from a variety of over-lapping legislative proposals. Maryland Gov. Harry Hughes has decided to back several energy-related bills, including one that would provide a maximum $50 state income tax credit for home owners installing energy-saving devices.

In some cases, Hughes is offering direct support for measures already proposed by legislators; in others, he is requesting substantial modifications of existing bills. The package, as Hughes would like to see it enacted, encludes measures that would:

Require major utilities, including Pepco, Potomac Edison, and Baltimore Gas & Electric Co. to provide their cusotmers with energy audits costing no more than $10. A senior Hughes aide said today that the utilities are lending their backing to this proposal, which allows home owners to receive expert advice on how they can reduce energy costs.

Further reduce the state tax on gasohol, lowering it from eight cents per gallon to six cents, then allowing tit ot increase one cent a year to a maximum of nine cents in 1983. An Eastern Shore Democrat, Sen. Frederick C. Malkus Jr., had orginally proposed reducing the tax to four cents a gallon.

Set up a $5 million fund, financed by state borrowing, and offer low-interest loans to home owners seeking to install energy-saving devices such as insulation, storm windows and weather stripping. The fund would be administered by the state Department of Economic and Community Development, which would set regulations, loan limits and interest limits.

Encourage state agencies to install heating systems based on such renewable energy sources as solar and wind power, instead of on such fossil fuels as oil and natural gas.

Expand the requirements that major buildings conduct energy audits.

The combination of proposals, which would cost the state an estimated $2.4 million next year, includes a little in the way of new ideas but put the governor on record with a specific energy conservation policy at a time when fuel costs and energy convservation have become major national preoccupations.

Originally, according to one senior administration aide, Hughes had intended to remain silent on this issue until he had an opportuntiy to see what measures Congress would enact, and then make complementary proposals of his own.

As dozens of overlapping and contradictory measures were proposed by legislators, Hughes and his aides decided that to take no action could leave a free path open for "bills that could do a lot of mischief."