Italy's Slimey Green Goo

The beautiful Italian city comprised of 118 islands in the saltwater marshes of the northern Adriatic Sea, has been suffering from rampant algae growth for years. Algae blooms and alien species have been attacking the waterways for decades, but the city’s days of simply scooping the slimy green goo from the water are over. Now it may power the ports themselves.

It was recently announced that the Port of Venice has teamed up with renewable energy services company Enalg to create a 40 megawatt power plant that will take the vast supply of algae and turn it into usable fuel. This 200 million euro ($272.6 million) project is already in the works, and, assuming everything goes according to plan, will be functional in 2011. This power plant is the first of its kind in Italy, and the third in Europe. If it’s successful, this technology will spread worldwide.

The process may seem like a complicated, drawn-out one, but it’s really very simple: the algae is cultivated in laboratories, put in large plastic tubes where an addition of water, carbon dioxide, and sunlight triggers photosynthesis, creating a usable biomass. Water is then removed from the algae using the capillary effect, cohesion, absorption, or transpiration pull. Algae produces oil which, when treated further, becomes a synthetic natural gas used to turn turbines which produce electricity.

The problems come in getting the oil from the algae, an energy intensive procedure, and in keeping impurities out of the algae culture. The process does require a lot of water, but it’s all recycled. All carbon dioxide produced is piped back into the process, creating a relatively self-sustaining, zero-emissions procedure. Carbon dioxide can also be captured from coal-fired power plants and fed to the algae, which can be grown in almost any place, and are ready for harvest about every 20 days.

According to experts, each acre given over to algae cultivation could theoretically produce the equivalent of thousands of gallons of oil (335 gallons of ethanol per acre of traditional bio-fuel crops vs. 100,000 gallons of algae fuel). Algae energy is more efficient than anything we’ve tried yet, including manufacturing ethanol from corn and biodiesel from soybeans.

Several companies are racing to find economic ways to turn algae into vegetable oil to be made into biodiesel and other fuels. The Department of Energy began looking into using algae energy in the 1970s, but deemed it too expensive, and ended research in 1996. What used to cost $875 a ton to remove water from the algae now costs only $1.92.

Although the plant was designed for micro-algae, it works with several other separating/dewatering applications. This kind of power plant is also powering breweries, refineries, and cement factories in Europe. Venice’s hope is to eventually generate enough power to satisfy the needs of the entire city. The Port of Venice is also considering installing a photovoltaic park that could produce 32 megawatts of solar energy.