SWES 210 1st Edition Lecture 29Outline of Last Lecture II. BioenergyIII. Biomass for electricitya. Biofuelsi. Ethanolii. Advantagesiii. Problemsb. Biodiesalc. Other biofuelsOutline of Current Lecture IV. Solar technologiesa. PV cellsb. How a PV cell worksV. Germany goes solarVI. Promoting global instillationVII. Concentrated solar power techniquesVIII. Geothermal energyCurrent Lecture- Solar technologies- there are differenceso Solar oven (focus heat on the food with mirrors)o Photovoltaic (PV) cells (solar panels)o Concentrated solar power (commercial power station applications) Power tower Trougho Photovoltaic (PV) cells= directly converts solar energy into electricity using a PV cell made of a semiconductor materialo Small PV cells are in flashlights, phone chargers, lanterns, watches and calculatorso Small arrays= power parking meters at UAo Larger arrays= power homes (~5-10 kW)o Very large arrays= used for utility scale power (>10MW) One nuclear reactor: 1000MW)- How does a photovoltaic cell worko Sunlight strikes array panel with photovoltaic cells. These cells then concentration the sunlight into n-type layer (phosphorus enriched) which is then transferred to the junction causing electron flow. Electricity is then generatedThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Enough sunlight strikes the earth in one minute to power us for a yearo Other technology we use every day that applies this idea is computer chips.- Which country has the most installed solar capacity?o Germany- Germany goes solar (1/3 of solar capacity)o Germany produces the worlds mot solar power Yet it is cool and cloudy o The Feed-in tariff system requires utilities to buy power from anyone who generates ito Peaked at 50% electricity from solar on a day in June 2014, 38 GW installed (as of Feb 2015)o 90% of solar panels are on houseso solar power accounted of 6.2% of germany’s energy- up front costs are high- economic incentives and leasing options (0$ down) promote installation (i.e. solaCity)o net metering (US)= the value of the power the consumer provides is subtracted from themonthly utility bill producers of PV electricity can sell their power to a utilityo Feed in tariff’s (Germany, UK) pay producers more than the market price of power, so power producers turn a profit- may be guaranteed over long term- What is the total electricity capacity in US?o 1000GW (1TW)- in Tucsono 5 new solar panel facilities (>10MW) since October 2012- concentrated solar power techniqueso “power tower” = mirrors concentrate sunlight onto receiver on top of a tall tower heat is transported by fluids (molten salts) to a steam- driven generator to create electricity lenses or mirrors track the suns movement- commercial scale- ivanpah solar project- Mojave deserto took almost 4 years to completeo covers more than 5 square miles of the Mojave deserto 392MW (20MW largest before spain)o 2-450 ft towers with boilers on topo 173,5000 twin mirrors (heliostats) direct sunlight to heat water in boilers- abengoa’s Solana= the US’s first large scale solar panel plant with thermal energy storage system,begins commercial operation in Arizona (280 MW)- car companies take expertise in battery power beyond the garageo a home by Honda and the UC Davis is expected to make more energy than it consumeso tesla is coming up with residential and industry scale batterieso future- solarcity, tesla residential battery pack, and an energy management system package- geothermal energyo geothermal energy= thermal energy from beneath earths surfaceo radioactive decay of elements under extremely high pressures deep inside the plant generates heat heat rises through magma, fissures, and cracks or heats groundwater, which erupts as geysers or submarine hydrothermal ventso geothermal power plants use hot water and steam for heating homes and generating electricityo globally, one third of geothermal energy is used for electricity, the other two thirds for direct heatingo nesjavellir geothermal power station in