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What: Shares of fuel cell company Ballard Power Systems Inc. (NASDAQ:BLDP) jumped a whopping 54% in July after the company signed a key supply deal.

So what: The biggest news item of the month was a deal with Guangdong Nation Synergy Hydrogen Power Technology to create a joint venture to make fuel cell stacks in China. There's an $18.4 million payment scheduled for a technology transfer, and then a $150 million "take or pay" agreement to supply membrane electrode assemblies to the venture over the next five years. 

Zhongshan Broad-Ocean Motor also agreed to a strategic collaboration deal and invested $28.3 million for a 9.9% stake in Ballard Power during July. 

Now what: Amid the excitement over deals announced in China, Ballard Power Systems also announced a $5.8 million loss in the second quarter of 2016. And therein lies the challenge for investors in this space. The hydrogen market seems like a huge opportunity, but it's been marred by losses across the industry. And until that changes, I think it's too high risk for investors to be jumping in. Energy technology is tough business, and we still have no idea when hydrogen may reach a tipping point and become a big source of energy around the world.