The tangle of pipes at this industrial plant [in Corpus Christi, Texas] doesn’t stand out in this city built around the carbon-heavy business of pumping oil and refining it into fuel for planes, ships, trucks and cars. But this plant produces fuel from a different source, one that doesn’t belch greenhouse pollution: hydrogen. Specifically, hydrogen made from water using renewable electricity, also known as green hydrogen. This process could represent the biggest change in how fuel for planes, ships, trains and trucks is made since the first internal combustion engine fired up in the 19th century. … Turning hydrogen into liquid fuel could help slash planet-warming pollution from heavy vehicles, cutting a key source of emissions that contribute to climate change. But to fulfill that promise, companies will have to build massive numbers of wind turbines and solar panels to power the energy-hungry process. Regulators will have to make sure hydrogen production doesn’t siphon green energy that could go towards cleaning up other sources of global warming gases, such as homes or factories.