Energy Resources and Consumption PDF

Energy Resources and Consumption Renewable and Non-Renewable Resources 6.1 Fossil Fuels Fossil Fuels- Combustible deposits in the Earth’s crust – Coal, oil, natural gas Supply over 80% of energy used in North America Non-renewable resource – Fossil fue...

Energy Resources and Consumption Renewable and Non-Renewable Resources 6.1 Fossil Fuels Fossil Fuels- Combustible deposits in the Earth’s crust – Coal, oil, natural gas Supply over 80% of energy used in North America Non-renewable resource – Fossil fuels are created too slowly to replace the reserves we use © 2012 John Wiley & Sons, Inc. All rights reserved. Renewable Energy Those that can be replenished naturally, at or near the rate of consumption and can be reused. – Depletable Renewables: biomass (wood, charcoal, ethanol) Supply about 13% of energy in North America. Renewable Energy - Consumption Rate must be at or below rate of regeneration for renewables Global Energy Consumption 6.2 Make a claim about this figure. Make a claim about this figure. Developed vs. Developing Countries Developed countries typically have higher per capita energy consumption, but developing countries have higher total energy use. ○ Why do you think this is the case? Why might this be an issue in the near future?  Energy Consumption Fossil fuels are the most widely used energy source globally. ○ Oil: primarily used for vehicles/transportation ○ Coal: primarily used for electricity generation ○ Natural gas: secondary fuel for electricity and primarily used for heating Hydroelectric: 2nd largest source after fossil fuels Nuclear is the 3rd largest source Industrialization and Fossil Fuel Consumption Developing nations primarily rely on biomass (subsistence fuels) - Why? ○ Animal waste ○ Wood ○ Charcoal Can drive deforestation Factors that Affect Energy Use - Economics of a resource Availability - Reserves – Identified deposits from which we can extract the mineral profitably at current prices Price – Fluctuates with discovery of new reserves. Price drops, use increases Factors that Affect Energy Use Government Regulations ○ can mandate certain usage Gov’t cannot directly raise or lower prices of energy sources Gov’t can: ○ Tax to discourage FF use ○ Rebates/tax credits to encourage other energy source use. Fuel Types and Uses, Distribution of Natural Energy Sources and Fossil Fuels 6.3, 6.4, 6.5 and 5.9 Fossil Fuel Combustion for Energy Combustion is a chemical rxn between the fuel and oxygen ○ produces carbon dioxide and water and releases energy. Energy from fossil fuels is generated by burning them, producing heat ○ This heat turns water into steam, which generates electricity Electricity The flow of electrons in a wire Can be generated from almost any energy source – Energy source spins a turbine – Turbine turns a generator Bundle of wires spin around a magnet or vice versa – Spinning causes electrons to move in a wire = electricity Generating Electricity Generating Electricity Generating Electricity Power plants generate electricity to meet demand. A 1-megawatt power plant could produce 8,760 megawatt-hours a year powering about 796 average regional households. ○ Operating at 70% efficiency, like some natural gas plants, 6,132 MWh, powering about 557 homes. ○ Operating at 30% efficiency, like some wind power plants, 2.803 MWh, powering about 254 households. Fossil Fuel Formation Coal – Primarily found in sedimentary rock – Heat, pressure and time turned the plant material into carbon-rich rock (coal) Coal Types Amount of heat, time and pressure creates different forms of coal: peat (technically not coal), lignite, bituminous and anthracite Largest reserves of coal are the US, Russia, Australia, China and India Mining Terms Ore – a naturally occurring solid material from which a metal or valuable mineral can be profitably extracted. Spoils/Overburden – The overlying material that is removed during mining in order to gain access to the ore within the mineral material below. Tailings – are the waste materials left after the target mineral is extracted from ore. Coal Extraction Coal is extracted by mining Surface ○ Open Pit ○ Strip mining ○ Mountaintop Removal Surface mining requires the removal of large portions of soil and rock, creating overburden. ○ What could be some potential issues with this? Subsurface ○ Extraction from beneath the surface ○ Expensive Coal Extraction Impacts Disruption of land surface/habitats Erosion Mining waste storage and leakage ○ Slag ○ Tailings Acid mine drainage Groundwater contamination Atmospheric pollution ○ particulate matter ○ methane Human Health - respiratory, contaminated drinking water Coal Extraction Acid Mine Drainage Acid Mine Drainage (AMD) – Pollution caused when sulfuric acid and dissolved lead, arsenic or cadmium wash out of mines into nearby waterways Coal Combustion Impacts Releases large quantities of CO2 into atmosphere – Greenhouse gas Releases other pollutants into atmosphere – Mercury (can end up in ground and surface water) – Lead – Sulfur oxides – Nitrogen oxides Can cause acid precipitation Coal Combustion Impacts Coal Combustion Impacts Fossil Fuel Formation Oil (Petroleum or Crude Oil) – Sediment deposited over microscopic plants, algae and bacteria – Found in between layers of sedimentary rock – Heat pressure and time turned them into hydrocarbons (oil) Fossil Fuel Formation Oil (Petroleum or Crude Oil) – Heat pressure and time turned them into hydrocarbons (oil) Oil and Natural Gas Exploration Oil and natural gas migrate upwards until they hit impermeable rock Usually located in structural traps © 2012 John Wiley & Sons, Inc. All rights reserved. Oil Reserves - Middle east has been largest producer Petroleum Extraction Done by drilling into the ground Petroleum Extraction Hydraulic fracturing (fracking) Petroleum Refining Numerous hydrocarbons present in crude oil (petroleum) are separated – Based on boiling point Natural gas contains far fewer hydrocarbons than crude oil Oil Extraction Impacts Drilling: – Disruption of land and marine ecosystems (for exploration and drilling) – Leakage at drill site (on land and in ocean) Fracturing: – Large water requirements – Chemicals in fracking fluid – Leaks and spills from faulty equipment – Methane leaking into the atmosphere Oil Spills Leakage of petroleum onto the surface of a large body of water. – can happen during extraction and transportation Deepwater Horizon: 210 million gallons Exxon Valdez: 11 million gallons Oil Spills - Impact Can kill surface dwelling organisms (birds and other organisms) through toxicity or suffocation (being coated in oil), and by affecting buoyancy. Can prevent/inhibit photosynthesis of phytoplankton/algae - decreasing productivity Can cause marine organism death by toxicity through ingestion and movement through the food chain. Oil Spills-Cleanup Biological: using microorganisms such as bacteria, fungi and yeast to break down oil over time. Oil Spills-Cleanup Mechanical: booms and skimmers, burning oil off of surface waters Booms are used to contain oil, and then skimmers go across the surface of the water to remove oil, or oil is burned. Boom Skimmer Oil Spills-Cleanup Chemical: chemical dispersants designed to remove oil by breaking it down into smaller droplets Oil Spills-Cleanup Alberta Tar Sands Large deposits of heavy crude oil mixed with sand and clay found in Alberta, Canada. Oil is extracted, and boiled or mixed with steam to separate out the sand and other contaminants. Then oil is transported for processing. Keystone XL Pipeline Pipeline that takes oil from the Alberta, Canada tar sands to refineries in Texas. Extended pipeline was proposed, but has not been built Oil Combustion Impacts Produces CO2 Also produces CO, Nitrogen Oxides, PM and unburned hydrocarbons Runoff from impervious surfaces enters water sources Fossil Fuel Formation Natural Gas – Formed the same way as oil, but at temperatures higher than 100 °C – Largest compound of natural gas is methane (CH4) Natural Gas Contains methane, propane and butane – Propane and butane are used for cooking and heating in rural areas – Methane used for heat and to generate electricity in power plants Natural gas as vehicle fuel – Emit 93% fewer hydrocarbons, 90% less carbon monoxide and 90% fewer toxic emissions than gasoline © 2012 John Wiley & Sons, Inc. All rights reserved. Natural Gas Reserves Uneven distribution globally More than half is located in Russia and Iran © 2012 John Wiley & Sons, Inc. All rights reserved. Natural Gas Extraction Natural Gas Extraction Impacts Hydraulic Fracturing (Fracking) – Disturbance to land and habitat – possible methane leakage (into atmosphere and water) – fracking fluid can cause water contamination Transport – Leaks in pipelines Natural Gas Combustion Impacts Produces negligible amounts of sulfur, mercury and particulates. Does produce NOx, but at far lower amounts that oil or coal combustion. Newer gas power plants emit up to 50% less CO2 as compared to coal. Nuclear Power 6.6 Propose a reason for this: Nuclear Power Nuclear energy – Energy released by nuclear fission or fusion Nuclear fission – Splitting of an atomic nucleus into two smaller fragments, accompanied by the release of a large amount of energy Nuclear fusion – Joining of two lightweight atomic nuclei into a single, heavier nucleus, accompanied by the release of a large amount of energy Radiation emitted can be measured as becquerels (Bq) or curies. Radioactive Isotope Unstable isotope – nuclei is unstable and dissipates excess energy in the form of alpha, beta or gamma rays. (ex: Radon, radium, plutonium) Radioactive Decay – Emission of energetic particles or rays from unstable atomic nuclei Each isotope decays based on its own half-life © 2012 John Wiley & Sons, Inc. All rights reserved. Nuclear Fission Nuclear Fusion Way of the future? – Produces no high-level waste – Fuel is hydrogen Problems – It takes very high temperatures (millions of degrees) to make atoms fuse – Confining the plasma after it is formed Scientists have yet to be able to create energy from fusion - except we did! DOE Article Nuclear Fission Nuclear Fuel Cycle – Processes involved in producing the fuel used in nuclear reactors from mining to disposing of radioactive (nuclear) wastes Pros and Cons of Nuclear Energy Pros – Less of an immediate environmental impact compared to fossil fuels – Carbon-free source of electricity – May be able to generate H-fuel Cons – Generates radioactive waste – Thermal Pollution (water is not radioactive) – Many steps require fossil fuels (mining and disposal) – Expensive Safety Issues in Nuclear Power Plants Meltdown At high temperatures the metal encasing the uranium fuel can melt, releasing radiation Probability of meltdown is low Public perception is that nuclear power is not safe Sites of major accidents: Three Mile Island, PA Chernobyl, Ukraine Fukushima Daiichi, Japan Radioactive Waste Fuel waste continues to emit radioactivity. 3 kinds of waste: – High-level (spent fuel rods) – Low-level (contaminated PPE, tools, rags, etc) – Uranium mining tailings, and residue from uranium enrichment High levels of exposure can lead to acute organ failure, radiation sickness, death. Lower exposure can damage DNA, leading to cancer. Radioactive Waste Temporary storage solutions – In nuclear plant facility (require high security) Under water storage Above ground concrete and steel casks Need approved permanent options soon. © 2012 John Wiley & Sons, Inc. All rights reserved. Proposed Storage: Yucca Mountain (1978) Potentially hold 70,000 tons of high-level radioactive waste Tectonic issues have been identified License was abandoned as site in 2010 Biomass 6.7 Biomass and Biofuels Biomass is plant materials and animal wastes used as sources of energy. It can be burned directly as a solid fuel or converted into gaseous or liquid biofuels. – Can be used for heat, cook, industry – Burned to drive turbines and produce electricity Biomass Contains energy from sun via photosynthesizing plants ○ Oldest known fuel to humans- still used by half the world’s population Renewable when used no faster than it can be produced Can convert to biogas or liquids ○ Ethanol and methanol ○ Clean fuel Biomass Advantages – Reduces dependence on fossil fuels – Often uses waste materials – If trees are planted at same rate biomass is combusted, no net increase in atmospheric CO2 Disadvantages – Requires land, water and fossil fuel energy – Can lead to: Deforestation Desertification Soil erosion Solar Energy 6.8 Types of Solar Energy Passive Solar – absorption or blockage of sun’s heat – no mechanical or electrical equipment Examples of passive – using a solar oven to heat food – orientation of windows in infrastructure Active Solar – use of mechanical/electrical equipment to capture sun’s heat Examples of active – Concentrated solar thermal (solar water heaters – PV cells - photovoltaic cells Photovoltaic Solar Cells A wafer or thin film semiconductor (usually silicon) that they emit low voltage electrical current when they absorb solar energy No pollution and minimal maintenance Used on any scale – Lighted road signs – Entire building © 2012 John Wiley & Sons, Inc. All rights reserved. Photovoltaic Solar Cells More economical than running electrical lines to rural areas Can be incorporated into building materials – Roofing shingles – Tile – Window glass – Roadways Solar Farm Concentrated Solar Thermal Electric Generation Heliostats (mirrors) reflect solar energy onto a water tower to produce steam Mainly found in deserts - land use/habitat destruction Organism loss - birds get fried (minimal) Hydroelectric Power 6.9 Hydropower Most efficient energy source (90%) Most widely used form of renewable energy – 19% of world’s energy Traditional hydropower – Suited only to large dams New technology – Utilize low flow systems © 2012 John Wiley & Sons, Inc. All rights reserved. Hydropower © 2012 John Wiley & Sons, Inc. All rights reserved. Geothermal Energy 6.10 Geothermal Energy Enormous energy source from the heat of the earth. – 1% of heat in upper 10km of earth crust is equal to 500X the earth’s fossil fuel sources From Hydrothermal Reservoirs (trapped hot water or steam) – Created by volcanoes – Reservoirs used directly for heat or to generate electricity © 2012 John Wiley & Sons, Inc. All rights reserved. Geothermal Energy From hot, dry rock Geothermal heat pumps – Use difference in temperature between surface and subsurface – Great for heating buildings – Expensive installation © 2012 John Wiley & Sons, Inc. All rights reserved. Geothermal Advantages Renewable source of energy Low atmospheric emission Where accessible, it’s reliable and consistent Reduced land footprint Disadvantages Availability Open loop systems can release greenhouse gases and minerals (from vented steam) Can impact localized fish and wildlife pops Hydrogen Fuel Cell 6.11 Hydrogen fuel cells alternative to non-renewable fuel sources use hydrogen as fuel combining the hydrogen and oxygen in the air to form water and release energy (electricity) in the process water is the product (emission) of a fuel cell BMW hydrogen storage tank Hydrogen Fueling Stations Stations are currently operational in limited locations Hydrogen Advantages Low environmental impact - zero emissions Produce no carbon dioxide when the hydrogen is produced from water Very efficient Fuel cells are very simple Affordable lease programs with prepaid fuel Hydrogen Disadvantages - H fuel cells are based on a non-renewable and CO2 releasing energy source - most H2 production is done using methane - currently on widespread hydrogen fuel distribution system - H fuel store in gas form would require much larger tanks than current gas tanks - technology is expensive Wind Energy 6.12 Wind Energy World’s fastest growing source of energy Wind results from sun warming the atmosphere – Varies in direction and magnitude New wind turbines harness wind efficiently – Most profitable in rural areas with constant wind © 2012 John Wiley & Sons, Inc. All rights reserved. Wind Energy Few environmental problems – Kills birds and bats No waste (minus “retired” turbines)- no emission source of energy Biggest constraints: – Cost – Public resistance (NIMBY) © 2012 John Wiley & Sons, Inc. All rights reserved. Offshore Wind Farms Energy Conservation 6.13 Indv. Energy Conservation/Efficiency Lowering the thermostat Energy efficient appliances – including lighting – washers/dryers Conserving water – native landscaping – low flow showerheads – efficient toilets Efficient home design/insulation LED lighting Large Scale Conservation Increasing fuel economy/efficiency (CAFE - govt standard) Subsidizing electric vehicles, charging stations and hybrids Investing in public transportation Sustainable Home/Building Design Passive solar – double/triple paned windows simulate greenhouse effect Landscaping Design – deciduous trees to provide insulation/shade Proper insulation Green roofs Recycled building materials Energy Conservation - Transportation CAFE (Corporate Average Fuel Economy) Energy Conservation - Transportation Hybrids – use both gas and electricity – braking system charges battery Electric – use no gasoline, run totally on electricity Smart Grid Integration  Sample Question for Dimensional Analysis i. The number of cubic feet of natural gas required to heat the house for one winter 1. This problem wants to know cubic feet of natural gas needed each winter to heat the house. In math terms, it looks like this:  Sample Question for Dimensional Analysis 2. We know the house is 3,000 square ft. We also know that it takes 50,000 BTUs of heat per square foot to heat the home. Finally, we know that one cubic foot of natural gas supplies 1,000 BTUs of heat.  Sample Question for Dimensional Analysis 3. The next step is to pick the statements that will cancel the units you do not want. You want ft3 in your answer. You need to eliminate BTUs and ft2.  Sample Question for Dimensional Analysis 4. Now you need to eliminate BTUs. To do this you will need to use the equivalency that has BTUs on the bottom and cubic feet on the top. Sample Question for Dimensional Analysis 5. For part ii, you need an additional statement.  Energy Efficiency Systems will never be 100 % efficient (unless stated), so pay careful attention.  Energy Efficiency Now, if we add a third part to the question stating the system is 50 % efficient, then the output must be divided by the efficiency to determine how much input energy is needed. REMEMBER: A percentage efficiency must be changed to its decimal equivalent.