Renewable Energy from Algae Biomass

Algae for Electricty
Algae can be processed with many existing thermal technologies to create electricity. The algae biomass generated from the algaewheel system has a higher BTU value than most biomass feed stocks. The BTU value ranges from 8,000 - 15,000 BTU per pound depending on the waste that is being treated and the resulting algae that is produced. By comparison, pure wastewater sludge has a per pound BTU value of about 3,750, agricultural byproducts about 4,200, wood about 5,000, and coal averages about 10,500. Thermal technologies to process algae include direct combustion, pyrolysis, gasification, and co-firing. Algae can also be processed using anaerobic digestion to produce biogas. These processes result in different end products (i.e. gases, steam, and heat) which then can be converted to electricity.

Combustion technologies, such as furnaces and boilers, convert biomass fuels into several forms of useful energy, including hot air, hot water, steam and electricity.

Pyrolysis is a rapid heating process in which the biomass is converted to liquid pyrolysis oil and syngas. Oil may be further refined into usable products and the syngas can be used as a fuel source.

Gasification converts biomass into a combustible gas called producer gas and char. The producer gas can be burned directly for space heat or drying, converted by catalysts to a variety of liquid bio-fuels, or it can be burned in a boiler to produce steam.

Co-firing biomass as a secondary fuel in a coal-burning power plant helps reduce sulfur dioxide and nitrogen oxide emissions, and decreases net carbon dioxide emissions from the power plant.
Anaerobic Digestion is a biochemical process in which bacteria digest biomass, resulting in the production of digester gas (primarily methane). Algae also provide meaningful secondary benefits for digesters, including significantly enhancing the digestion of other biomasses and significantly reducing digester nuisance gases.

In addition to the advantages noted above with respect to various thermal processes, using algaewheel biomass also provides consistency, continuous supply, greater thermal value, and elimination of transportation by growing the biomass on site. Depending on the technology employed to produce electricity, the cost of producing electricity will generally range from six to twelve cents per kilowatt hour, which is competitive with most other sources. Any company that has a reliable nutrient source and meaningful power demands should consider an algaewheel system for the purpose of building a self-sustaining electric supply. Also, power companies, particularly coal-fired power companies with access to a reliable nutrient source, should consider an algaewheel system for the combined purpose of CO2 capture and biomass production.

Algae for Bio-fuel
Algae can be utilized for the production of many types of bio-fuels including bio-diesel, ethanol, biobutanol, gasoline, jet fuel, and others. Unlike conventional terrestrial plants such as soybeans, corn, sugar cane, and others, algae can be produced 365 days per year, can be grown in any climate, is not restricted by soil type, and does not compete with food crops. Simple cost-effective greenhouse enclosures have proven adequate in controlling the growing climate for productive light and temperature ranges.

In addition to the geographic versatility of algae, a 20-year study conducted by the US Department of Energy has shown that algae are capable of producing vastly more bio-fuel per acre than terrestrial plants. Current estimates by experts in the Bio-fuel industry and the Department of Energy report that algae can yield 1,800 to 9,000 gallons of bio-fuel per acre depending on the type of technologies deployed to produce the algae and type of fuel being produced.

One of the primary issues identified in the Department of Energy study was the cost of production. Based on our discussions with third parties currently working to convert algae to biodiesel, proposed processes can convert 1 ton of algae into 100 to 200 gallons of biodiesel. Depending on site conditions, the nutrient source, and CO2 supplementation a one-acre algaewheel facility will produce between 1.5 and 3 tons of algae per day per acre. Such yields could be converted to 150 to 600 gallons of biodiesel. The algaewheel component of the required infrastructure for such a facility would be $.64 to $2.50 per gallon depending on yields.

While many would consider this a solid value proposition, they don't represent the whole picture. One must still consider the algaewheel system's potential as a multi-functional system and potential government incentives. The facility could be structured for wastewater treatment and CO2 sequestration, as well as biodiesel production with the proper site selection. The potential ancillary revenue streams from this type of operation are significant, and could reduce the cost of the bio-fuel feedstock to zero. Furthermore, the current social, political, and economic environments have combined to yield some very meaningful incentives from the federal government and many state governments, which can significantly offset production and facility costs. Bio-fuel companies should view their current and proposed facilities with a very critical eye, and evaluate the potential use of the algaewheel system to produce their bio-fuel feedstock.

Links:

Richard G. Lugar Renewable Energy Center
http://www.lugarenergycenter.iupui.edu/forum.html

  
http://www.nationalalgaeassociation.com/


       
http://www.eere.energy.gov/



http://www.nrel.gov/



http://www.dsireusa.org/



http://www.mwk-biogas.com/