Shares of Renewable Energy Group (REGI) - Get Report  are up 1% year-to-date, but have soared 34% since their late January low. The biofuel maker's CEO Daniel Oh said there is more to the stock's resurgence than a spike in the price of crude oil.

"Biofuels are not as tightly tied to oil as people think because biofuels deliver climate benefits with their own cash value," said Oh.

In the first quarter of 2016, Renewable Energy posted revenue of $305.6 million on 98 million gallons of fuel sold. The company sold 63.7% more gallons of fuel than the previous year, resulting in an increase in revenue of 32.3%.  

Oh added that the regulatory conditions that have been challenging the industry are now more stable and "all the presidential candidates are highly supportive of advanced biofuels".

Oh said the company's European business is improving. Renewable Energy's German subsidiary, Petrotec, sold 10 million gallons of biofuel and contributed $1.4 million in adjusted EBITDA during the first quarter. Oh expects to pursue profitable expansion in Europe using Petrotec as a platform for international growth.

In terms of domestic growth, Oh said the company is expanding its Ames, Iowa laboratory, which will geographically expand the work being done by its life sciences division and further connect to development and commercialization expertise.  In January, the company announced an agreement with ExxonMobil (XOM) - Get Report  to study the production of biodiesel by fermenting renewable cellulosic sugars from sources such as agricultural waste.

Last week Renewable Energy priced an offering of convertible senior notes. The company is offering $132 million in aggregate principal of 4% convertible senior notes due 2036. Renewable Energy Group will use $62 million of the net proceeds to repurchase a portion of outstanding 2.75% convertible senior notes due 2019.

In separate transactions, the company will use $35 million of the proceeds to repurchase about 4.1 million shares of its common stock through one of the initial purchasers or its affiliate as its agent.