A global benchmark of clean energy stocks is outperforming major equity indexes and even gold, as investors respond to soaring demand for renewables needed to power the boom in artificial intelligence.The S&P Global Clean Energy Transition Index has surged close to 50 per cent since US President Donald Trump’s April tariff announcements caused havoc across markets. That compares with the roughly 35 per cent gain delivered by both the S&P 500 Index and gold over the same period.Investors have turned more pos ...