Can hydrogen be green? The debate heats up as the White House pours $7 billion into hydrogen hubs

• Hydrogen has the potential to be a climate solution, but right now it's a dirty business.
• The White House is spending $7 billion to spur "clean" hydrogen.
• Some climate advocates, scientists worry that fossil-fuel companies will cash in. 
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Most of us probably think of hydrogen in terms of H2O — the water we drink, bathe in, and cook with — but it has the potential to help build a low-carbon future.