Although many believe that algae will become one of the chief feedstocks for diesel and even hydrocarbon-like fuels, growing large amounts of algae and then converting the single-celled creatures remains expensive, said experts at the National Biodiesel Conference taking place in San Francisco on Tuesday.

Algae biofuel startup Solix, for instance, can produce biofuel from algae right now, but it costs about $32.81 a gallon, said Bryan Wilson, a co-founder of the company and a professor at Colorado State University. The production cost is high because of the energy required to circulate gases and other materials inside the photo bioreactors where the algae grow. It also takes energy to dry out the biomass, and Solix uses far less water than other companies

By exploiting waste heat at adjacent utilities , the price can probably be brought down to $5.50 a gallon . By selling the proteins and other byproducts from the algae for pet food, the price can be brought to $3.50 a gallon in the near term.But that’s still the equivalent of $150 a barrel of oil.

It’s only in phase II of Solix’s business plan that it will be able to drop production costs to $3.30 to $1.57 a gallon, or around $60 to $80 a barrel. Solix has set a goal of cutting the cost of making algae by 90 percent.