Exam 2 Review Biofuels and LCA of biofuels Biofuels fuels obtained from recently deceased biomass Exist as solids liquids or gas Biogas ethanol and biodiesel First generation produced in the traditional manner from sugars starches fats and oils soybean oil palmseed oil sugar cane corn beets Second generation produced using new technologies from non food sources Cellulose straw wood biowaste Third generation algae biofuels which are expected to wean society completely off of fossil fuels LCA of biofuels interpretation reporting LCA general goal and scope de nition inventory analysis impact assessment Vertical analysis product and project based perspective fossil fuel inputs used during cultivation amount of fossil fuels replaced by biofuels and amount of GHG released due to clearing of areas with high carbon storage value Horizontal analysis regional national and global perspective land is a limiting factor for biomass production Land use change for expanding agriculture may lead to increasing GHG emissions and a loss of biodiversity Bounded by Biofuel crop cultivation and conversion processing Climate change responses Mitigation reducing the human alteration of climate through reduced emissions and other practices avoiding the unmanageable Ex Carbon capture and Sequestration CCS Carbon capture removing carbon dioxide out of the ef uent gas streams Carbon sequestration permanently storing carbon dioxide in deep aquifers or the ocean Ex Kyoto Protocol EU GHG trading future climatic conditions Adaptation adjusting sectors of our society impacted by climate to be better suited for Goal of predicting future climatic conditions allows society to respond by changing impacted sectors to be more suited to any future altered climate Exposed sectors impacted by climate change but has the capacity to adapt to Vulnerable sectors impacted by climate change but has limited capacity to adapt future climatic conditions wildlife Difference between radiative forcing and climate sensitivity Radiative forcing is the balance of the incoming heat from solar radiation and the outgoing heat radiated from the planet outgoing terrestrial radiation commonly given in W m 2 Climate sensitivity predicts how the climate reacts to various radiative forces commonly given in degreesC Wm 2 Factors that affect radiative forcing natural and anthropogenic Natural Changes in albedo could also be human caused i e deforestation cloud cover solar intensity obliquity orbit eccentricity precision of the equinox Anthropogenic GHG concentrations and atmospheric particulate matter Stabilization triangle wedges Socolow and Pacala Trimmed projected carbon output carbon savings forms the wedge A wedge is a strategy to reduce carbon emissions that grows in 50 years from zero to 1 gtC yr Giga tons of carbon year The strategy has already been commercialized at scale somewhere Methane management forests soils fuel displacement in electricity generation sustainable energy decarbonized transport fuels energy ef ciency and decarbonized energy all make up the stabilization triangle from 2004 2054 Each strategy reduces carbon emissions and builds the wedges of the stabilization triangle Understanding the range of sustainability de nitions Weak requirement vs strong sustainability Systems thinking that incorporates the three spheres economy society environment into decision making Addressing energy supply sustainably Accepted characteristics to make our energy supply affordable and sustainable Account for negative externalities in GHG emissions air and water quality and Suf cient energy supply Ef cient technology Environmental protection Adequate infrastructure biodiversity impacts Sustainability science approach to problem solving Contested eld sense of urgency complex issues Interdisciplinary Grid parity occurs when an alternative energy source can generate electricity at a levelized cost that is less than or equal to the price of purchasing power from the electricity grid Most commonly used when discussing renewable energy sources notably solar and wind power Reaching grid parity is considered to be the point at which an energy source becomes a contender for widespread development without subsidies or government support All calculations in lecture slides ALL Homework Assignments Example 2 1 The temperature of water in a tank has been raised by 10 F Assuming the water weighs 12 pounds how many BTU of heat was added to the water What is this energy in joules Solution Energy BTU mass T 12 lb 10 F 120 BTU Energy J 120 Btu 1055J 1BTU 127kJ Example 2 2 How much energy in kWh is used to make popcorn in an 800W microwave oven How much is this in Joules BTU Note that the popcorn setting is typically 2 mins Solution Energy Power time Power 800W 0 8kW time 2mins 0 033hrs Energy kWh 0 8kW 0 033hr 0 026kWh Energy J 0 026kWh 3 6 10 6 J 1 kWh 93 6kJ Energy BTU 0 026kWh 3412 BTU 1 kWh 88 74 BTU Example 2 3 If Ocotillo Power Plant just east of campus on University Drive can produce 340 MW of electricity and has a thermal ef ciency of 30 how much heat does it need to produce Thermal Ef ciency Useful Work Heat Input Heat Input Useful Work Thermal Ef ciency Heat Input 340 MW 0 3 1 133 MW of heat 133 x 10 9 kWh 479 x 10 15 J Example 2 4 In 2011 Arizona used 454 x 10 12 BTU of petroleum Gasoline has an energy density of 47 MJ kg How much fuel in kg in gallons is this Gasoline weighs about 3 1 kg per gallon so Arizona used about 3 3 billion gallons of gasoline in 2011 10 2 x 10 9 kg Example 3 1 500 Btu of electric energy is required to make a cup of coffee a How much bituminous coal is required if the coal plant has a thermal ef ciency of 35 and bituminous coal has an energy density of 28MJ kg b How much will this cost in Arizona Solution a i Calculate heat input required to make a cup of coffee Thermal Ef ciency Useful Work Heat Input Heat Input Useful Work Thermal Ef ciency 500 Btu 0 35 1429Btu ii Convert from Btu to Joules 1429 Btu 3 6 MJ 3413 Btu 1 51MJ iii Calculate how much coal is required 1 51 MJ 1 kg coal 28 MJ 0 054kg 54g b Convert energy required from BTU to kWh 1429 Btu 1 kWh 3413 Btu x 9 6 c 1 kWh 4 02 cents Example 3 2 Arizona has an annual base load of 20 000MW and a Summer peak capacity of 26 000MW If the shortfall is made up by pumped storage with an ef ciency of 90 at a height of 1200m what is the required volume of the reservoir in m 3 Example 6 1 For the following transmutation equations i complete the equation and ii identify the