Chapter 2 the electric power industry+distributed generation feb 2011

Green Energy CourseRenewable Energy Systems Biên sọan: Nguyễn Hữu Phúc Khoa Điện- Điện Tử- Đại Học Bách Khoa TPHCM CHAPTER 2: The Electric Power Industry •Little more than a century ago there were no lightbulbs, refrigerators, air conditioners, or any of the other electrical marvels that we think of as being so essential today •Indeed, nearly billion people around the globe still live without the benefits of such basic energy services •The electric power industry has since grown to be one of the largest enterprises on the planet, with annual sales of over $300 billion in the United States alone •It is also one of the most polluting of all industries, responsible for three-fourths of U.S sulfur oxides (SOX) emissions, one-third of our carbon dioxide (CO2) and nitrogen oxides (NOX) emissions, and onefourth of particulate matter and toxic heavy metals emissions Major Electricity Milestones THE ELECTRIC UTILITY INDUSTRY TODAY Conventional power generation, transmission, and distribution system Electric utilities, monopoly franchises, large central power stations, and long transmission lines have been the principal components of the prevailing electric power paradigm since the days of Insull Utilities and Nonutilities Entities that provide electric power can be categorized as utilities or nonutilities depending on now their business is organized and regulated Nonutility generators (NUGs) are privately owned entities that generate power for their own use and/or for sale to utilities and others Nonutility generators have become a significant portion of total electricity generated in the United States From EIA Annual Energy Review 2001 (EIA, 2003) primary energy: The energy going into power plants end-use energy, which is the energy content of electricity that is actually delivered to customers • The numerical difference between primary and end-use energy is made up of losses during the conversion of fuel to electricity, losses in the transmission and distribution system (T&D), and energy used at the power plant itself for its own needs • Less than one-third of primary energy actually ends up in the form of electricity delivered to customers •For rough approximations, it is reasonable to estimate that for every units of fuel into power plants, units are wasted and unit is delivered to end-users Electricity flows as a percentage of primary energy Based on EIA Annual Energy Review 2001 (EIA, 2003) Distribution of retail sales of electricity by end use Residential and commercial buildings account for over two-thirds of sales Total amounts in billions of kWh (TWh) are 2001 data From EIA (2003) The load profile for the a peak summer day in California (1999) shows maximum demand occurs between P.M and P.M Lighting and air conditioning accounts for over 40% of the peak End uses are ordered the same in the graph and legend From Brown and Koomey (2002) Average retail prices of electricity, by sector (constant $1996) From EIA Annual Energy Review 2001 (EIA, 2003) CARNOT EFFICIENCY FOR HEAT ENGINES Over 90% of world electricity is generated in power plants that convert heat into mechanical work The heat may be the result of nuclear reactions, fossil-fuel combustion, or even concentrated sunlight focused onto a boiler Almost all of this 90% is based on a heat source boiling water to make steam that spins a turbine and generator, but there is a rapidly growing fraction that is generated using gasturbines The best new fossil-fuel power plants use a combination of both steam turbines and gas turbines to generate electricity with very high efficiency Steam engines, gas turbines, and internal-combustion engines are examples of machines that convert heat into useful work What we are interested in here is, How efficiently can they so? This same question will be asked when we describe fuel cells, photovoltaics, and wind turbines, and in each case we will encounter quite interesting, fundamental limits to their maximum possible energy-conversion efficicencies Heat Engines a heat engine extracts heat QH from a high-temperature source, such as a boiler, converts part of that heat into work W, usually in the form of a rotating shaft, and rejects the remaining heat QC into a lowtemperature sink such as the atmosphere or a local body of water A heat engine converts some of the heat extracted from a hightemperature reservoir into work, rejecting the rest into a lowtemperature sink Entropy and the Carnot Heat Engine The definition of Entropy (extremely important quantity ) is not very intuitive It can be described as a measure of molecular disorder, or molecular randomness At one end of the entropy scale is a pure crystalline substance at absolute zero temperature Since every atom is locked into a predictable place, in perfect order, its entropy is defined to be zero In general, substances in the solid phase have more ordered molecules and hence lower entropy than liquid or gaseous substances When we burn some coal, there is more entropy in the gaseous end products than in the solid lumps we burned That is, unlike energy, entropy is not conserved in a process In fact, for every real process that occurs, disorder increases and the total entropy of the universe increases Super Grid of the Future Integrates Superconducting Transmission with H2 Energy Carrier School Home Supermarket H2 Family Car Nuclear plant DNA-to-order.com H2 MgB2 Petroleum Reduction Energy Intensity As a Function of Degree of Economic Development and Electrification Potential Applications of Nanotechnology to Electricity/Energy • High strength, light weight transmission wires • Nano-catalysts for processes - conversion of hydrocarbons to syngas • White light emitting LEDs • Photochromic material for ‘smart’ windows • Thermoelectric materials for converting thermal gradient to electricity • Solid-oxide fuel cell electrodes and electrolyte • Materials for ultracapacitors • “Smart” sensors Quantum Dot Solar Cell Array: Conversion Efficiency > 70% Chalcopyrite ternary semiconductors Cu (Gad or In) (S or Se)2 p Quantum dots n Insulating medium Clean Power Billion tons of carbon per year (An illustrative example of global carbon emissions) Clean Power: Technologies that Fill Climate Change Gaps Technologies that make sense anyway: • • • • • End-use efficiency Plant improvement Nuclear Renewables Biomass Technologies for a carbon-constrained world: • • Capture and disposal Tree planting and soil carbon enhancement Technology breakthroughs • • Zero Emission Power Plants (ZEPPs) Low-temperature water splitting • CO2 capture under ambient conditions Power For All Distinctions Among Four Social Conditions Annual GDP/capita International Collaboration Global R&D, global investment, global peace, global technologies 104 104 Amenities Education, recreation, the environment, intergenerational investment 103 103 Basic Quality of Life Literacy, life expectancy, sanitation, infant mortality, physical security, social security 102 102 Survival Food, water, shelter, minimal health services Source: Chauncey Starr Annual kWh/capita DG Technology Evolution Cost Projections vs Size over Time 500,000 100,000 Solid Oxide Fuel Cell (a) Photovoltai cs $/kW 10,000 Industrial Gas Turbines PEM Fuel Cell 1,000 Solid Oxide Fuel Cell (b) 100 Nominal Time Span 2000 -2010 Pulverize d Coal IC Microturbine Engine s s AeroCT Combine d Cycle 100 100,000 500,000 10 1 10 Size in kW 1,000 10,000 IGCC Technology Issues Gas Cleaning Oxygen Membrane Oxygen Cost-Effective MultiContaminant Control to Ultra-Clean Specifications Moderate Temperature Hg Removal at Elevated Temperatures Integrated Specifications with Downstream Process Requirements Integration with NOx Reduction Processes Fuel Gas Durability of the Membrane Integration with Overall Process Low-rank Coal Hydrogen Coal Injector Reliability Single Train Availability Durability of Refractory Material Durability and Accuracy of Monitoring Devices Alternative Feedstocks Feed System Reliability Gasification Heat Removal Temperature Measurement & Control Source: USDOE H2/CO2 Separation CO2 Durability of Membranes Low Flux Contaminant Sensitivity Heat Removal Nuclear Power Revival Public support will be conditioned on: • Emission reduction requirements • Competitive cost structure • Inherent safety • High efficiency and high fuel utilization Candidate Breakthrough Technology: Pebble bed modular reactor (PBMR) Renewables Breakthrough Challenges Technologies that change the business proposition • 25% efficiency for PV (copper indium diselenide) at 30 to 50$/m2 • Quantum dots for high-efficiency PV power • Biomass low-cost, dedicated gasification facilities • Wind low-cost diurnal (or longer) storage • Wind siting issues • Integration of distributed renewable power with industrial and agricultural applications What 10,000 GW of Global Generating Capacity Means • Tripling current world power plant capacity • Adding 200,000 MW/yr • Investing >200 billion USD per year It’s equivalent to: • < years of current world automobile engine production • Less than 0.3% of world GDP • Less than the world spends on cigarettes, etc It can and must be done! Conclusion: Electricity is Necessary, but not Sufficient for Human Development • Four Linked Global Needs – – – – Protection and restoration of Earth’s life support systems Managing processes crucial to human welfare Elimination of human poverty Stabilizing global population • Integration of digital quality electricity with the knowledge-based industries of the future • Creating a new mega infrastructure to meet those needs ... factor as the ratio of average power to rated power The average cost of electricity is the slope of the line drawn from the origin to point on the revenue curve that corresponds to the capacity.. .CHAPTER 2: The Electric Power Industry •Little more than a century ago there were no lightbulbs, refrigerators, air conditioners, or any of the other electrical marvels that... total electricity generated in the United States From EIA Annual Energy Review 20 01 (EIA, 20 03) primary energy: The energy going into power plants end-use energy, which is the energy content of electricity