What happened The stocks of companies focused on alternative energy development -- and the hydrogen economy in particular -- jumped today, bringing them back into the black for the week. Specifically, as of 3:45 p.m. EDT, shares of electric vehicle maker Nikola (NASDAQ: NKLA) bounced 7.7%, Plug Power (NASDAQ: PLUG) stock was up 5.4%, and Bloom Energy (NYSE: BE) shares jumped 6.75%. So what It's been a fairly volatile week for these stocks, with shares recouping double-digit declines to get closer to breakeven today. NKLA data by YCharts That amount of volatility isn't surprising for companies like these that are working to grow the hydrogen economy. And no company-specific news has come out to create today's bounce. But there are signs of progress in growing the feasibility of hydrogen as a fuel source globally, which investors likely take as positive indications for the business plans of Nikola, Plug Power, and Bloom Energy. Image source: Getty Images. Now what British power generator SSE and Spanish wind turbine maker Siemens Gamesa announced Monday that they will investigate the potential to develop green hydrogen from two onshore wind farms in Scotland and Ireland, according to a Reuters report. While this doesn't directly impact the U.S. companies also looking to grow green hydrogen production, the fact that there is a global push in the sector does give the overall industry more support. The potential overseas development aims to "work with green hydrogen customers across industries including transportation, major distilleries and gas network operators," according to the report. That, in general, is also what Nikola, Plug Power, and Bloom Energy are working to do. Plug Power recently announced a new agreement to produce green hydrogen, and just last month Nikola said it was investing in a clean hydrogen project in Indiana to support its planned fleet of hydrogen-powered semitrucks in the region. For its part, Bloom Energy said last week that it was going to work with renewable energy technology company Heliogen to use solar power and water to produce green hydrogen using Bloom's solid oxide electrolyzers. These are all speculative projects, and these companies are counting on a growing global hydrogen economy to realize the potential of their investments. When there is positive news that others are also moving in that direction, investors gain more confidence in the long-term prospects of companies like Nikola, Plug Power, and Bloom Energy. 10 stocks we like better than Nikola CorporationWhen our award-winning analyst team has a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* They just revealed what they believe are the ten best stocks for investors to buy right now... and Nikola Corporation wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of June 7, 2021 Howard Smith owns shares of Bloom Energy Corp and Nikola Corporation. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.Source