What happened 

After two days of huge gains for Clean Energy Fuels (NASDAQ:CLNE), the company's shares fell as much as 12.3% in trading Friday. At 3:10 p.m. EDT shares were still down 10.8% and were steady going into the weekend. 

So what

The rise in shares over the last two days was driven by a new partnership with Chevron to bring cleaner fuel to trucks in the Los Angeles and Long Beach, California, ports. Shares nearly doubled on the news earlier this week, but are now dropping back to reality today. 

Natural gas truck driving on the open road.

Image source: Getty Images.

To be clear, this has still been a huge week for this natural gas energy stock. Shares are up 25% for the week, they just didn't hold the massive gains seen on Wednesday and Thursday. 

CLNE Chart

CLNE data by YCharts

Now what

Volatile stocks like Clean Energy Fuels can have big moves day to day, but as Foolish long-term investors, it's the bigger picture we want to take into account. The deal signed with Chevron this week is another incremental positive for natural gas fuels and could increase the amount of fuel the company delivers if trucks make the transition. But it's still a long road ahead to get natural gas to a significant market share, so we should expect more volatility ahead. Just hope that the news continues to be positive like it was this week.