Distributed Energy Resources Distributed Energy Resources DISTRIBUTED ENERGY
Distributed Energy Resources
Distributed Energy Resources DISTRIBUTED ENERGY RESOURCES (DER) • • Solar Wind Fuel Cells Combined Heat & Power / Cogeneration
Solar A Little Bit of History… The Photovoltaic Effect Edmund Becquerel 1839
Solar 1954 • Gerald Pearson • Daryl Chapin • Calvin Fuller
Solar Rural communications systems in the 1950 s were the first terrestrial applications of PV technology. Nearly every satellite and spacecraft since 1958 has relied on a PV system for power generation.
Solar The Photovoltaic (PV) Effect
Solar Distributed Electricity Distribution The “GRID” An electric utility produces electricity at a power plant and delivers it to consumers through transmission lines, substations, distribution lines and transformers.
Solar Distributed Electricity Distribution Distributed generation systems produce electricity close to where it is used.
Solar Clean Electricity
Solar PV technology is ideal for areas where conventional utility-supplied power is unreliable or out of reach
Solar 5 Advantages of Solar Energy 1. No moving parts = very little maintenance 2. Environmentally friendly 3. Abundant resource for the next 5 billion years 4. Plentiful raw materials 5. Costs decreasing dramatically
Solar 5 Disadvantages of Solar Energy 1. Only functions when the sun is shining 2. Energy consumption is usually higher when the sun is NOT shining 3. Land & habitat loss 4. Hazardous materials in manufacturing 5. Water usage
Distributed Energy Resources DISTRIBUTED ENERGY RESOURCES (DER) • • Solar Wind Fuel Cells Combined Heat & Power / Cogeneration
Wind Early “WINDMILL” Afghanistan 900 AD
Wind Jacobs Turbines 1925 – 1985 Smith-Putnam Turbine 1940’s Vermont
Wind Types of Modern Electricity Generating “Windmills” Small ( 10 k. W) • Homes • Farms • Remote Applications (e. g. water pumping, telecom sites, icemaking) Intermediate (10– 250 k. W) • Village Power • Hybrid Systems • Distributed Power Large (250 k. W – 9 MW) • Central Station Wind Farms • Distributed Power
Wind Turbine Perspective Workers Blade 112’ long Nacelle 56 tons Tower 3 sections
Wind
Wind Farm Example
Wind Energy Potential In the U. S.
Wind 1980’s California Wind Farms • • Older Technology Higher RPMs Lower Elevations Poorly Sited
Wind Todays Wind Turbines are Installed with Modern Methods and Technologies • • • Utility Engineers Geophysical Engineers Concrete/Structural Engineering Turbine Engineering (ME/EE/Aerospace) Site/Civil Engineering Microelectronic/Computer Programming Business Expertise (Financial) Legal Expertise Meteorologists
Wind Modern Turbines Are Relatively Quiet
Wind 5 Advantages of Wind Energy 1. Environmentally friendly 2. Abundant resource 3. 45 -50% efficiency 4. Land area efficient 5. Decreasing cost
Wind 5 Disadvantages of Wind Energy 1. Capital intensive 2. Noise 3. Aesthetics 4. Wildlife threat (birds, bats, etc. ) 5. Unpredictability of wind
Distributed Energy Resources DISTRIBUTED ENERGY RESOURCES (DER) • • Solar Wind Fuel Cells Combined Heat & Power / Cogeneration
Fuel Cells Fuel cells are electrochemical cells consisting of two electrodes and an electrolyte which convert the energy of chemical reaction between fuel and oxidant directly into electrical energy.
Fuel Cells Ordinary Combustion Process Fuel Oxygen Combustion Products Heat
Fuel Cells Fuel Cell Process Fuel Oxygen Oxidation Products Electricity
Fuel Cells Principle of a Fuel Cell A fuel cell consists of… FUEL ELECTRODE • • • Fuel Electrode Electrolyte Another electrode Oxidant ELECTROLYTE ELECTRODE Fuel cells directly convert chemical energy into electrical energy. OXIDANT
Fuel Cells
Fuel Cells Types of Fuel Cells Alkaline Fuel Cell (AFC) Molten Carbonate Fuel Cell (MCFC) Fuel Cell Solid Oxide Fuel Cell (SOFC) Phosphoric Acid Fuel Cell (PAFC) Polymer Electrode to Membrane Fuel Cell (PEMFC)
Fuel Cells
Fuel Cells PAFC Fuel Cells • First fuel cells to be used in the electric power industry • Considered the “first generation” of modern fuel cells • Most advanced fuel cells after alkaline types
Fuel Cells Characteristic Features PEMFC PAFC Primary fuel H 2 Electrodes Graphite Carbon Electrolyte Polymer membrane(Perfluoro sulphonic acid) Phosphoric acid soaked in silicon matrix Catalyst Pt Pt Operating temperature 50 – 1000 C (typically 800 C) 150 – 200 0 C Major applications Stationary and automotive power Stationary power Advantages • Solid electrolyte reduce corrosion & electrolyte management problems • Operates at low temperature • Quick start up • Higher temperature combines heat power • Increases tolerance to fuel impurities Disadvantages • Expensive catalyst • Sensitive to fuel impurities • Expensive catalyst • Long start time • Low current & power
Fuel Cells 10 Advantages of Fuel Cells 1. High efficiency of energy conversion (approaching 70%) from chemical energy to electrical energy. 2. Low noise pollution & low thermal pollution. 3. The chemical process involved is clean. It does not produce polluting exhaust. Byproducts are water & waste heat. 4. When fossil fuel is used as a reactant, environmentally undesirable gases are not produced since there is no combustion in the process. 5. Hydrogen-Oxygen fuel cells produce potable drinking water.
Fuel Cells 10 Advantages of Fuel Cells 6. Designs are modular, therefore the parts are exchangeable. 7. Low maintenance cost. 8. Fuel cell performance is independent of power plant size. The efficiency does not depend on the size of power plant. It remains same for the plants of MW or k. W or W size. 9. Fast start up time for low temperature system. 10. The heat co-generated increases efficiency of high temperature system.
Fuel Cells 6 Disadvantages of Fuel cells 1. 2. 3. 4. 5. 6. High initial cost. Life times of the cells are not accurately known. Large weight and volume of gas fuel storage system. High cost of pure hydrogen. Hydrogen can be stored in lesser volume by liquefaction but liquefaction itself require 30% of the stored energy. Lack of infrastructure for distributing hydrogen.
Distributed Energy Resources DISTRIBUTED ENERGY RESOURCES (DER) • • Solar Wind Fuel Cells Combined Heat & Power / Cogeneration
Combined Heat & Power (aka Cogeneration) • Generation of multiple forms of energy in one system: heat and power • Combined heat and power (CHP) integrates the production of usable heat and electricity, in one single, highly efficient process. Defined by its “prime movers”… • • • Reciprocating engines Combustion or gas turbines Steam turbines Micro-turbines Fuel cells
Combined Heat & Power CHP or Cogeneration Principle
Combined Heat & Power Benefits of Cogeneration • Increased efficiency of energy conversion • Lower emissions, especially CO 2 • Ability to use waste materials • Large cost savings • Opportunity to decentralize the electricity generation • Increases diversity of generation plants
Combined Heat & Power Common CHP Configurations The two most common CHP system configurations are… • Combustion turbine with a heat recovery unit • Steam boiler with steam turbine
Combined Heat & Power Combustion Turbine with Heat Recovery Unit • Combustion turbine or reciprocating engine CHP systems burn fuel (natural gas, oil, or biogas) to turn generators to produce electricity and use heat recovery devices to capture the heat from the turbine or engine. • Heat is converted into useful thermal energy, usually in the form of steam or hot water.
Combined Heat & Power Steam Boiler with Steam Turbine • With steam turbines, the process begins by producing steam in a boiler. • The steam is then used to turn a turbine to run a generator to produce electricity. • The steam leaving the turbine can be used to produce useful thermal energy. These systems can use a variety of fuels, such as natural gas, oil, biomass, and coal.
Combined Heat & Power Efficiency Advantage of CHP • CHP is highly efficient • By using waste heat, CHP plants can reach efficiency ratings in excess of 80%. This compares with the efficiency of gas power stations which range between 49% and 52%. Coal-fired plant fare less well with an efficiency of around 38%.
Combined Heat & Power Typical CHP System
Combined Heat & Power The five most commonly installed CHP power sources…"prime movers“… offer these efficiencies: • Steam turbine: 80 percent • Reciprocating engine: 75 -80 percent • Combustion turbine: 65 -70 percent • Micro turbine: 60 -70 percent • Fuel cell: 55 -80 percent A CHP system's efficiency depends on the technology used and the system design.
Combined Heat & Power Environmental Benefits Because less fuel is burned to produce each unit of energy output, CHP reduces emissions of greenhouse gases and other air pollutants. • CHP systems offer considerable environmental benefits when compared with purchased electricity and thermal energy produced on site. • CHP systems require less fuel to produce the same amount of energy so less fuel is combusted and greenhouse gas emissions are reduced. • carbon dioxide (CO 2) • nitrogen oxides (NOx) • sulfur dioxide (SO 2)
Combined Heat & Power
Combined Heat & Power Economic Benefits CHP can save facilities considerable money on their energy bills due to its high efficiency, and it can provide a hedge against electricity cost increases. Reduced energy costs: • Using waste heat recovery technology to capture wasted heat associated with electricity production, CHP systems typically achieve total system efficiencies of 60 to 80 percent, compared to 50 percent for conventional technologies. • CHP systems typically use natural gas which is often cheaper than purchased.
Combined Heat & Power Economic Benefits • Avoided capital costs: CHP can often reduce the cost of replacing heating equipment. • Protection of system interruption: Through onsite generation and improved reliability, CHP can allow facilities to continue operating in the event of a disaster or an interruption of gridsupplied electricity. • Less electricity purchased from the grid = facilities have less exposure to rate increases. • CHP systems can be configured to operate on a variety of fuel types, (natural gas, biogas, coal, and biomass) therefore, a facility could build-in fuel-switching capabilities to hedge against high fuel prices.
Combined Heat & Power Reliability Benefits Unreliable electricity service represents a quantifiable financial, safety, and health risk for some companies and organizations. CHP is an on-site generation resource and can be designed to support continued operations in the event of a disaster or grid disruption by continuing to provide reliable electricity. • CHP systems can be designed to continue operating in the event of grid outages to supply continuous power for critical functions. • Costs of designing and configuring CHP technology for outage protection can be estimated and evaluated after identifying and quantifying the value of reliable power to facility operations in monetary terms.
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