Tesla's hot Model S has no green-friendly rivals yet, but it's a safe bet that they're coming. Photo credit: Tesla Motors.

Plenty of investors feel that Tesla Motors' (NASDAQ:TSLA) battery-electric Model S sedan represents the future of automobiles. They may yet be proven right, but the truth is that battery-powered cars represent just one of several ways forward.

This week, giants General Motors (NYSE:GM) and Honda (NYSE:HMC) announced a big bet on another path: hydrogen fuel cells. In this video, Motley Fool contributor John Rosevear looks at the new alliance and at the challenges facing fuel-cell technology – and at whether it's time for Tesla to start worrying.

Fool contributor John Rosevear owns shares of General Motors. Follow him on Twitter at @jrosevear. The Motley Fool recommends General Motors and Tesla Motors. The Motley Fool owns shares of Tesla Motors. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.