In a nation thirsting for energy, he loomed like a messiah: a small-town engineer who claimed he could run a car on water. The assertion - based on the premise that he had discovered a way to easily split the oxygen and hydrogen atoms in water molecules with almost no energy - would, if proven, represent a stunning breakthrough for physics and a near-magical solution to Pakistan's desperate power crisis. By the grace of Allah, I have managed to make a formula that converts less voltage into more energy," the professed inventor, Agha Waqar Ahmad, said in a telephone interview. "This invention will solve our country's energy crisis and provide jobs to hundreds of thousands of people." Established scientists have debunked his spectacular claims, first made one month ago, saying they violate ironclad laws of physics. The quest to harness chemical energy from water is a holy grail of science, offering the tantalizing promise of a world free from dependence on oil. Groups in other countries, including Japan, the United States and Sri Lanka, have previously made similar claims. They have been largely ignored. Not so with Mr. Ahmad, even if he is an unlikely scientific prodigy. He graduated with a degree in mechanical engineering in 1990 from a small technical college in Khairpur, in southern Sindh Province, he said in the interview. For most of his career he worked in a local police department. He is currently unemployed. But he sprang up at a moment when Pakistan was intensely aware of its power shortcomings.