Industry insiders see algae-based biodiesel as the most promising green fuel technology, according to a Greentech Media survey on advanced biofuels.

About 40 percent of the 249 participants said that biodiesel was the technology that showed "the greatest potential to transform the fuel industry."

The sentiment matches that of venture capitalists, who have put more money behind algae-based biofuel companies this year than ever before, according to the Cleantech Group (see Algae Biofuel Investments Explode).

The group last month reported $129.5 million in algal investments so far this year, even before the news that algal biofuel maker Sapphire Energy had raised an additional $50 million from Bill Gates' Cascades Investments (see Bill Gates Digs Algal Oil).

And in a report released Wednesday, Greentech Media senior analyst Eric Wesoff said that algae technology, along with cellulosic-ethanol technologies, helped drive venture capitalists to fund biofuels to the tune of $150 million this quarter alone (see Greentech Investments See Record 3Q).

But not everyone who took the survey agreed that slime would take over the fuel industry.

Electric vehicles took second place, winning votes of confidence from 18.4 percent of respondents. And 17.7 percent of participants picked the third-place winner, synthetic gasoline and diesel made using biological processes.

Next, at 14 percent, came liquids made from synthesis gas, or "syngas," which contains hydrogen and carbon monoxide and can be made by gasifying waste, coal or other fuel.

Meanwhile, butanol, an alcohol that advocates say could get better gas mileage than ethanol and be transported in oil pipelines, garnered only 6.4 percent of the votes. BP and DuPont in 2006 announced a partnership to develop biobutanol, and cellulosic-ethanol startup Coskata said in January it had developed an organism that makes butanol (see Coskata: Behind the Hype, Image 9).