Houston pays for nuclear power: costly STP heats up local electricity bills. (Houston Lighting & Power Co.'s venture into nuclear energy costs; South Texas Nuclear Plant)

The staggering costs associated with the South Texas Nuclear Plant are just beginning to hit consumers in the pocketbook.

Houston Lighting & Power Co.'s venture into nuclear energy cost the utility's average residential customer about $160 last year. And the price tag has already risen again in 1991.

HL&P's customers now pay the highest rates in the state of Texas, thanks largely to the company's $2.3 billion investment in the nuclear plant.

Top HL&P officials have long argued that the nuclear plant will ultimately save consumers money. In the last two years, however, the average residential customer watched the kilowatt-hour charge increase by 12.9 percent -- from 7.97 cents in 1989 to 9 cents in 1991.

The most recent hike of $313 million will go primarily toward recovering costs associated with the nuclear plant, says Graham Painter, a …