Shares of Plug Power (NASDAQ:PLUG) stock are up by about 35% during the past month. According to Citi, there are several factors behind the surge.The first is a play on renewable energy companies resulting from an increased energy demand from artificial intelligence (AI). According to the International Energy Agency (IEA), the energy used in AI, data storage and cryptocurrency is forecasted to double by 2026.The second factor is a short squeeze, which seems rational. As of May 15, PLUG stock had a high shor ...