Lesson 4.2: How do alternative energy technologies work? Marisol Mercado Santiago, Ph.D.

Acknowledgements and disclaimer This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-1333468. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the view of the National Science Foundation.

How this information might help you? Because of the climate situation worldwide, many engineers are needed to design, test, and deliver technologies that make use of energy alternatives. This presentation gives information and shows videos useful for you to see how these technologies work. It might also help you in your first-year engineering courses.

Alternative energy resources Biomass Wind Solar Geothermal Tidal (rise and fall of ocean water on a shore) Water flow (hydropower) Nuclear For each alternative: write their advantages or disadvantages. Bring also information from the Lessons to the power point.

Biomass to energy technology Biomass could be a renewable resource if it is not harvested faster than replenished. Biomass energy comes from bioorganic materials such as food waste, wood, agricultural waste, and animal waste that can be either burned directly as a solid fuel or converted into liquid biofuels.

Biomass to energy technology Biomass can be converted to biofuels. Ethanol and biodiesel are two examples. Ethanol is derived from fermentation of plant sugar. Starch from plant-based sources is converted to simple sugars, through a yeast fermentation. The byproduct is distilled to make ethanol. http://www.youtube.com/watch?v=F-oEmD4VKLo Image source: http://www.energyfuturecoalition.org/biofuels/fact_ethanol.htm#1

Ethanol conversion 1. The materials are grinded in the “biomass handling” phase 2. Diluted sulfuric acid is added to the biomass to generate the chemical reaction called “cellulose hydrolysis” 3. The process releases simple sugars from the material. 4. Cellulose enzymes are bought or might be produces in the same site. 5. Glucose is produces out of the chemical reactions from cellulose enzymes and the biomass. 6. Glucose is converted into ethanol through the process of fermentation. 7. A yeast or bacteria is added to the substance to produce the necessary chemical reactions. Xylose (a five-carbon sugar), is fermented with genetically engineered bacteria or zymomonas mobilis. 8. “Ethanol broth” is produced from the fermentation of glucose and the five-carbon. 9. The ethanol broth is dehydrated to remove the water. The final product and other byproducts of the biomass-to-ethanol engineered processes is used to fuel an electric generator. Information source: http://www1.eere.energy.gov/biomass/abcs_biofuels.html

Advantages of biomass energy Disadvantages of biomass energy Reduced CO2 emissions High net energy yield from oil palm crops Reduced hydrocarbon emissions Potentially renewable Large-scale farms dedicated to biomass for biofuels can decrease biodiversity in a region Biodiesel can be more expensive than regular diesel Can make engines hard to start in colder weather Large-scale lands are needed to support the megawatts needed to provide energy to a town. Usually more than the land needed for solar energy   Source: Miller, G. T., & Spoolman, S. (2009). Living in the environment: Concepts, connections, and solutions. Pacific Grove, CA: Brooks/Cole.

Wind energy technology Video URL: http://www.youtube.com/watch?v=LNXTm7aHvWc

Wind energy technology NOTE: modify this slide to fit in the context of your cultural/ethnic group.

Wind energy technology NOTE: modify this slide to fit in the context of your cultural/ethnic group. http://www.cwet.tn.nic.in/Docu/WPD_New_Map_feb_2010.pdf

Image source: Hodge, B. K. (2010) Image source: Hodge, B. K. (2010). Alternative energy systems and applications. Hoboken, NJ: Wiley. Where V = wind speed; A is the swept area of blades, and the p is the air density.

Advantages of wind energy Disadvantages of wind energy High efficiency Low electricity cost No CO2 emissions to operate it Can be located at the ocean Land below turbines can be used to for farming Visual pollution Plastic components made of petroleum A backup system is needed when winds are low Can kill birds and interfere with migratory pattern of birds Source: Miller, G. T., & Spoolman, S. (2009). Living in the environment: Concepts, connections, and solutions. Pacific Grove, CA: Brooks/Cole.

Solar energy technology Solar cells are usually made of silicon (semiconductor material) Engineers who create this technology usually work in the microelectronics industry. Trained in electrical and materials engineering. Video: http://www.youtube.com/watch?v=AmWrGPKcMNM The energy is collected from the sun’s radiance in solar cells on a building. A pumping system pumps water in the pipes. The water will be heated through the solar panel system and it will go to a heat exchanger that will emanate hot vapor into the house New video: http://www.youtube.com/watch?v=1gta2ICarDw&feature=fvwrel

Image source: http://ausra.com/pdfs/SolarThermal101_final.pdf NOTE: modify this slide to fit in the context of your cultural/ethnic group. Image source: http://ausra.com/pdfs/SolarThermal101_final.pdf

Advantages of solar energy Disadvantages of solar energy Moderate environmental impact No CO2 emissions relating to operating it Fast construction Low efficiency High cost Needs backup and storage system May disturb desert areas The energy is collected from the sun’s radiance in solar cells on a building. A pumping system pumps water in the pipes. The water will be heated through the solar panel system and it will go to a heat exchanger that will emanate hot vapor into the house Source: Miller, G. T., & Spoolman, S. (2009). Living in the environment: Concepts, connections, and solutions. Pacific Grove, CA: Brooks/Cole.

Geothermal energy technology Engineers who design geothermal energy plants need to apply knowledge of geoscience and physics in their work Dry rocks in which heat has been accumulated up to reach temperatures of 200° C or more Image source: http://radio86.com/focus/science-technology/china-power-geothermal-steam-below

Geothermal energy technology Video URL: http://www.youtube.com/watch?v=kjpp2MQffnw

Advantages of geothermal energy Disadvantages of geothermal energy Very high efficiency Lower CO2 emissions than fossil fuels Low cost at good sites (Tibet region) Low land use and disturbance Moderate environmental impact Can be depleted if used too rapidly Moderate to high local air pollution Noise and odor High cost, except at the most concentrated and accessible areas Source: Miller, G. T., & Spoolman, S. (2009). Living in the environment: Concepts, connections, and solutions. Pacific Grove, CA: Brooks/Cole.

Tidal energy technology Video URL: http://www.youtube.com/watch?v=gcStpg3i5V8

Hydropower energy technology (dams) Video URL: http://www.youtube.com/watch?v=cEL7yc8R42k

Hydropower energy technology (dams) Advantages of hydropower energy Disadvantages of hydropower energy Low-cost electricity Reservoir useful for fishing and recreation May provide drinking water to surrounding neighborhoods Reduces downstream floods Displaces people around the river Can destroy forests Risk of failure can be devastating Disrupts migration of fishes and other aquatic animals Source: Miller, G. T., & Spoolman, S. (2009). Living in the environment: Concepts, connections, and solutions. Pacific Grove, CA: Brooks/Cole.

Nuclear energy technology URL of the video: ..\Videos\How nuclear energy works - YouTube.flv Add info from the lesson! How nuclear energy works: http://www.youtube.com/watch?v=VJfIbBDR3e8 Fukushima accident http://www.youtube.com/watch?v=YarjI1FwsuA

Fukushima Accident Explained URL of video: http://www.youtube.com/watch?v=YarjI1FwsuA

Advantages of nuclear energy Disadvantages of nuclear energy Large fuel supply Emits 1/6 as much CO2 as coal Moderate land disruption and water pollution Needs government subsidies High environmental impact – with major accidents Risk of catastrophic accidents No widely accepted solution for storage of radioactive wastes Source: Miller, G. T., & Spoolman, S. (2009). Living in the environment: Concepts, connections, and solutions. Pacific Grove, CA: Brooks/Cole.

What do you know about energy alternatives in Tibet What do you know about energy alternatives in Tibet? Which technologies could be more suitable? Which technologies could harm more Tibet’s environment? NOTE: modify this slide to fit in the context of your cultural/ethnic group.

Summary How some alternative energy technologies work Biomass to energy conversion. Ethanol conversion. The potential of wind energy in India and Tibet How solar energy systems work. The potential of solar energy in Tibet How a geothermal energy technology work How tidal and hydropower energy technologies work. How nuclear energy technology works Advantages and disadvantages of each technology NOTE: modify this slide to fit in the context of your cultural/ethnic group.