CAIRO — President Abdel Fattah el-Sisi likes to flaunt his plans for modernizing Egypt, like the flashy new administrative capital rising from the desert outside Cairo. But most Egyptians view his rule as a time of painful belt-tightening, with soaring inflation, a currency crash and cuts to subsidies that have made fuel, electricity and water more expensive.

Now there is a ray of hope emerging a hundred miles offshore.

It comes in the form of a windfall natural gas discovery with the potential to lift Egypt’s limping economy, build a new commercial alliance with Israel and, maybe, even revive the country’s diminished regional clout.

Egypt’s gas push is part of a tectonic shift in energy and geopolitics. Natural gas, long a poor cousin to oil, is gaining importance and becoming a tool for countries to leverage power and prestige. Advances in the shipping of liquefied gas have made it a global fuel and strengthened the hand of countries that until recently were not major energy exporters, including the United States and now Egypt.

The flood of new gas has been bad news for traditional exporters, particularly Russia, which has had to slash gas prices to maintain sales to Europe. Many European countries have long sought to reduce their dependence on Russia and are eager to establish new suppliers even if that means doing business with autocratic states like Egypt and Qatar, a longstanding gas supplier embroiled in a bitter diplomatic feud with its Persian Gulf neighbors.