Houston — Texas is running out of oil, but not out of sunshine. So as the ''oil glut'' appears to wane, more people here are turning to sun power.
Forecasting that by 1985 even oil-rich Texas will be using more energy that it produces, Samuel Ellison, a professor of geological sciences at the University of Texas, favors solar energy development as one way to help meet future energy needs.
Dr. Ellison isn't alone. The Texas Energy and Natural Resources Advisory Council says Texas has ''the immense potential of renewable energy resources: the power of the sun, the wind, flowing water, and biomass fuels harvested from the earth. Just as Texas has led the nation in the production of fossil fuels, which are now declining, so Texas could now lead the nation in the production of renewable fuels.''
Neighboring Sunbelt states see the same potential and the same risks. Arizona Solar Energy Commission officials attending a recent American Solar Energy Society conference in Houston complained that the solar energy option is being neglected. Commission spokesman Robert Sears said federal policies continue to subsidize the oil industry heavily through devices such as tax write-offs, depletion allowances, and channel-dredging for oil tankers -- just when the Reagan administration proposes to cut the federal solar research budget from a $ 570 million peak in 1980 to $72.9 million in fiscal year 1983.
Arizona supports the development of solar power with a major public-awareness program and a 35 percent tax credit for solar installations -- the highest offered by any state. It also paid to send a team to this year's solar conference in Houston. Because of budget cutting and priority switches, the few federal officials attending paid their own way.
Major industries also paid to attend and display the latest in solar technology. Alongside backyard designs such as a sleek and innovative wind turbine from Vermont, a high-powered team from McDonnell Douglas Corporation answered questions about the world's largest solar thermal power plant in Barstow, Calif. This $141 million, 10-megawatt Solar One plant now serves 5,000 to 6,000 customers.
Solar power advocates brought bright visions along with their sparkling solar collectors. Zoltan Kiss, president of Chronar Corporation, a small New Jersey high-technology firm, claimed a breakthrough in producing photovoltaic equipment used to convert sunlight into electricity. Offering a new method to cut production costs, Dr. Kiss explained that ''since virtually all alternatives to petroleum pose serious economic and environmental problems, America's future will depend on tapping the only truly renewable resource -- the sun.''
Other conference exhibitors showed off ways to turn trickling streams into electricity generators or to wire up skyscrapers to produce electricity from sunlight passing through specially engineered glass walls and from updrafts driving roof-mounted turbines.
But the visionaries at the Houston conference were balanced by realists. Thomas Hoffman, general counsel for the International Institute for Environment and Development, warned against trying to replace expensive oil with expensive solar hardware. He said solar energy's future will be guaranteed only when refined solar energy equipment can turn out energy more cheaply than competing sources.
Mr. Hoffman issued a double-barreled warning: ''If you have a solar energy business, don't fall into the trap of being a zealot on a crusade. And if you are a banker or an investor, don't fall into the trap of being an extreme skeptic, because you'll miss some opportunities staring you in the face. . . . Solar energy is not an end in itself. You are not selling solar energy. You are selling energy, and it is only the means to an end, and that end had better be a real energy need that somebody with money is willing to pay for.''