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HomeMy WebLinkAboutWind Diesel 101 Presentation RichStromberg 02-2013-WWind Diesel 101 Rich Stromberg Alaska Energy Authority Seward/AVTEC -Feb 2013 AEA Wind Program Values http://www.akenergyauthority.org/programwind.html •Involve the local community throughout all aspects of the project to increase local ownership. •Be kind when judging our predecessors. They didn’t have the benefit of the hindsight we now possess. •Make data -driven decisions. •Admit when we’re wrong. •Approach problems and projects holistically. Developed integrated solutions. •There is great opportunity to increase cost savings and learning when we improve existing wind systems. •Think and plan for the long term. •Understand that wind energy isn’t always the best solution. 2 This will be on the test! First Law of Thermodynamics: Energy can be changed from one form to another, but it cannot be created or destroyed. An important facet of the Second Law of Thermodynamics (which deals with entropy): In the process of energy transfer, some energy will dissipate as heat. Everything we do with village energy systems is based on these two concepts. 3 What makes the wind? 4 What makes the wind? 5 Global Wind Patterns 6 Zooming in, winds become more complex and variable. 7 Zooming in, winds become more complex and variable. 8 Zooming in, winds become more complex and variable. 9 How windy is it, really? Anecdotal weather data or observations can be deceptive. For example: A few windy days get some people wanting to install wind turbines. It only takes one rainy day for people to think that fire danger is reduced. A short cold spell can fool us into not seeing an overall warming trend. Our bodies can sense the weather, but we need to collect data to understand the long-term climate. What matters is the wind speed throughout the course of an entire year. 10 How windy is it, really? The formula for wind power is: Power = 0.5 x Rotor Swept Area x Air Density x Velocity3 Thus, doubling the wind speed from 3 meters/sec to 6 meters/sec increases the power by 8X. 7 meters/sec wind speed adds another 58% increase in wind power over 6 meters/sec. 11 How windy is it, really? Measure the wind for a minimum of one year. 12 How windy is it, really? Met towers require a permit from the FAA and consultation with US Fish & Wildlife, State Historic Preservation Office and possibly other agencies. 13 What the raw data shows 14 Summarize data into information 15 Summarize data into information 16 Shape of the wind distribution 0 5 10 15 20 250 3 6 9 12 Frequency (%)Probability Distibution Function, All Sectors Speed 29.2 A (m/s) Actual data Best-fit Weibull distribution (k=1.99, c=7.39 m/s) 17 Wind distribution vs. turbine power curve 0 5 10 15 20 250 3 6 9 12 Frequency (%)Probability Distibution Function, All Sectors Speed 29.2 A (m/s) Actual data Best-fit Weibull distribution (k=1.99, c=7.39 m/s) 18 Wind distribution vs. turbine power curve 0 5 10 15 20 250 3 6 9 12 Frequency (%)Probability Distibution Function, All Sectors Speed 29.2 A (m/s) Actual data Best-fit Weibull distribution (k=1.99, c=7.39 m/s) 19 Wind distribution vs. turbine power curve 0 5 10 15 20 250 3 6 9 12 Frequency (%)Probability Distibution Function, All Sectors Speed 29.2 A (m/s) Actual data Best-fit Weibull distribution (k=1.99, c=7.39 m/s) 20 Wind Classifications •Class 1/Poor: Pursue options other than wind •Class 2/Marginal: High costs of development in rural Alaska prevent an economical project. •Class 3/Fair: A large project on the Railbelt may be cost effective. Remote village projects may have a payback longer than the 20-year life of wind turbines. •Class 4/Good: A well-designed project will have a payback of 15-20 years. •Class 5/Excellent: A well-designed project will have a payback of 12-15 years. •Class 6/Outstanding: A well-designed project will have a payback of 10-12 years, but damaging high-wind events may be a concern. •Class 7/Superb: Project developer may want to use a smaller rotor or find a sheltered site to protect turbines from periodic damaging winds. 21 Harnessing the wind’s energy •Kinetic energy in the wind is converted into rotation of the main turbine shaft as air moving across the rotor creates lift, turning the rotor and main shaft. •Early forms of wind turbines/mills may have used the principle of drag instead of lift, but lift is more efficient. 22 Wind turbine drive train Rotor attaches here Brake Gear box Yaw motor Generator 23 A Typical Remote Alaska Village Washeteria Power house School Wind turbines Residences Residences Tank Farm 24 Wind-Diesel system challenges •The design and integration of power systems is a complex matter and although the models make it look simple, it is never that easy. •By their nature renewable generation are stochastic (uncontrolled) and vary with the resource. •The amount of variation and thus the amount of system control to handle the variation depends on the –Renewable resource being used –The load –Power system design 25 Can your existing electrical distribution system support wind technology? Do you have newer diesel gensets with fast, electronic injection controls or mechanical governors? Are your gensets sized so that you can run at optimum fuel efficiency both when the wind is blowing and when it’s calm? Are your distribution lines, transformers and meters up to code? Are your phases balanced? If you can’t answer “yes” to all of these questions, you could save more money by fixing your existing power system. 26 Different Integration Issues There are two general types of integration issues –mechanical and electrical •Mechanical: The connecting of different devices within the power system and making them work together. •Electrical: Insuring that the power system power quality is sufficient to meet the needs of the customers 27 Building Design and Space Adding new equipment can take up a lot of space •Switch gear •Grid stability equipment •Control boxes •Spare parts Building design may be problematic •Heating •Layout •Living arrangements 28 Making Sure the Equipment Can Talk •Supervisory Control •Component Controls –Diesels –Wind turbines –System stability devices •Controlled thermal loads –May be installed in other buildings –Switching speed –Outside control 29 Upgrading Diesel Controls Diesels will need to operate in an automatic fashion, which may require the upgrading of the diesel controls, but allow for manual operation if needed •Automatic startup and synchronization •Load sharing •Speed control Retrofit of existing diesel units can be complicated •Age of unit •Governor design •Fuel system •Compatibility, such as generator pitch •Space constraints within the power house and on the •diesels themselves 30 Plant Synchronization In many older (and smaller) plants only one diesel is run at a single time. Allowing more than one diesel to operate can be quite a problem, even following the addition of new controls •Governor design •Generator compatibility –pitch •Fuel system feed and return lines •Cooling system configuration and pumping Automated start and control capabilities will likely result in more diesel starts, most unattended, which may require the revamping of the diesel start system and starter battery. 31 Cooling System Current diesel plants have many different types of cooling systems –some integrated, some not, but all provide primary heat to the power plant and sometimes other buildings as well. In almost all cases the operation of the diesels provide more than enough heat for the plants needs, but in high penetration systems we would like to shut off the diesels •Plant goes from heat surplus to heat deficit. •To allow fast starting of the diesel engines, diesels in fast start mode must be kept warm May require revamping of the cooling systems •Implementation of electric boilers to allow use of wind energy •Allow specific engine cooling systems to be separated •Better energy management •Different or conflicting pumping requirements. •Heat efficiency of plant buildings may need to be considered 32 Integration of System Electronics Integration of a power system means that the plant must insure high Power Quality during and following the change •Variable renewable penetration of system •Power flow questions •Voltage variation on feeder lines •Level of technology/control existing in diesel plant If at any time you are not producing enough power, power system will collapse 33 Types of Power Quality •System stability -reliable power: Having power when you should have it. –Unscheduled blackouts –System failures –Voltage and frequency within acceptable limits –System power factor not overtaxing power system •The level of harmonic distortion -is the power being delivered usable? –Changing structure of the power –Sub-cycle quality of the power 34 System Stability Driven by maintaining system voltage, frequency and reactive power supply. •Voltage: Currently uses an active controller on the diesel. Alternatives are synchronous condensers or a battery bank and solid state or rotary power converter. •Frequency: A balance of power supply and demand, controlled by the throttle of the diesel. Can be solved through the use of dump loads or power converters. •Power Factor: Balancing active and reactive power as needed by the inductive motors and electronics on the system . Capacitor banks, motors or advanced solid state power converters. 35 Supply Side Options Options that affect only the power system as seen from the grid •Dump Loads: Fast acting resistors to balance the generation and load. •Dispatchable loads: Block heaters to use excess energy. •Synchronous Condenser: Provides reactive power and controls voltage. •Advanced power converters and small battery bank: Used to assist in managing power flows, power smoothing. •Active renewable control: Control power output of the renewable device. 36 Demand Side Options Control options that can be completed on the grid side to support system power quality •Distinction between critical and non critical loads –Dispatchable loads like resistance heating –Loads shedding where non-critical loads –Protection of sensitive loads •Installation of capacitors to smooth out rapid system fluctuations and partially correct systems power factor. –Replacing large inefficient loads 37 Penetration Instantaneous Penetration: –Voltage and frequency control –Reactive power Instantaneous Penetration = Wind Power Output (kW)/Primary Electrical Load (kW) Average Penetration: (generally a month or a year) –Total energy savings –Loading on the diesel engines –Spinning reserve losses/efficiencies Average Penetration = Wind Energy Produced (kWh)/Primary Energy Demand (kWh) 38 Old Wind Penetration Classes 39 y = 0.5589x -0.0261 R² = 0.7956 0.0% 10.0% 20.0% 30.0% 40.0% 50.0% 60.0% 0.0%10.0%20.0%30.0%40.0%50.0%60.0%70.0%80.0%90.0%100.0%% Excess ElectricityAvg. Wind Penetration Excess Electricity vs. Wind Penetration Level -Alaska Village Systems % Excess Electricity Linear (% Excess Electricity) Net electricity has greater economic benefit because it offsets 35% efficient diesel gensets with 100% efficient wind power (~65% benefit). Excess electricity has less economic benefit because it offsets 85% efficient heating oil boilers with 95% efficient electric boilers (~10% benefit). * Graph assumes diesel gensets can run at min 15% loading. Actual UNK Data 40 New Wind Penetration Classes Penetration Class Operating Characteristics Instantaneous Penetration Average Penetration Diesel runs full time Wind power reduces net load on diesel All wind energy goes to primary load No supervisory control system Diesel runs full time At high wind power levels, secondary loads are dispatched to insure sufficient diesel loading or wind generation is curtailed. Requires relatively simple control system Diesel runs full-time At medium to high wind power levels, secondary loads are dispatched to insure sufficient diesel loading. More complex secondary load control system is needed to ensure that heat loads do not become saturated during extended windy periods. Diesels may be shut down during high wind availability Auxiliary components are required to regulate voltage and frequency Requires sophisticated control system Medium 120%-300%20%-50% High 300%-900%50%-150% Very Low <60%<8% Low 60% - 120%8%-20% Exact numbers are not sacrosanct. 41 42 Low Penetration W/D Specifications •Equipment –Wind turbine or series of turbines –Dump load to smooth out power fluctuations –Capacitor bank used correct power factor if needed •Control –Wind turbine monitoring –Power control of wind turbines possible but not required –Minor controls to allow remote turbine shut down in extreme cases 43 44 45 Medium Pen W/D Specifications •Equipment –Wind turbine or series of turbines –Dump load to smooth out power fluctuations –Dispatchable loads to reduce loading on diesels and help control system frequency -May have capacitor bank •Control –Wind turbine controls –Power control of wind turbines possible but not required –Diesel control –System controller to maintain system stability and dispatch primary diesels and wind turbines as needed –Some power forecasting may be implemented 46 47 Batteries in Medium Penetration W/D Systems •Batteries can play a role in medium penetration systems •Used for short periods of load/supply time shifting •Not intended for diesel- off operation •An option to be weighed against/with more secondary loads, synchronous condensers 48 Batteries in Medium Penetration W/D Systems • Many types –Lead Acid (deep cycle and shallow cycle) –NiCad • Two uses/sizing: –Store energy to cover long periods (residential) –Store power to cover short periods (community wind-diesel) • Requires periodic replacement • Sensitive to environment • Life dependent on use and the environment 49 50 51 52 53 Systems and Components • Hybrid power systems are made up of separate pieces of equipment that are brought together to form a cohesive power system • Configuration and component size depend on the load and resource available at site • Controlling the power systems is a complicated question, both logically and technically. • Must understand the components 54 Dispatchable Generators • Generators that can be turned on with short notice. –Diesel, Gas, Natural Gas, Bio-gas • Usually require a lot of maintenance • Role depends on system design. • Wide range of old and new technology • Wide range of control 40 kW Diesel Generator 55 Other Active Power Control • Allows active control of grid stability • Allows access to small amounts of instantaneous power • Generally modular • Spinning losses • Long research history, very short operational experience Flywheel Low Load Diesel 56 Power Smoothing and Conditioning • Help to control voltage and balance active and reactive power needs on the grid • Primarily used when all diesel engines have been shut off • Might provide limited “storage ” • Has a standing loss 75 kW Synchronous Condenser Grid Conditioner 57 Secondary Loads and Community Heating • Remove excess energy from the grid • Help to control frequency • Made of resistive heating elements and some control • Two uses –Dispatched to provide heating (value added) –Fast -reacting heating elements exhausting to the open air. (dump load) 100 kW dump load 58 System Controls • The things that make everything work together. • Individual components and central control • High speed (behind the scene) and general control • Can Reduce staffing costs and increase service 59 Monitoring and Remote Access • Remote access allows oversight of system performance • Enables real time system interrogation and troubleshooting even when off site • With expert analysis system reduces maintenance and down time • Small incremental cost 60 Financial Impacts of PCE on W-D Village name:Anuqamute Total kWh produced:3,202,657 kWh sold:3,065,046 Station service:137,611 4.49% PCE eligible residential kWh:747,592 24.39% PCE eligible community facilities kWh:514,346 16.78% Non PCE and commercial kWh:1,803,108 58.83% Diesel kWh:2,202,657 68.78% Wind kWh:1,000,000 31.22% Non fuel expenses:$777,960 Fuel expenses $622,165 Calculated res/comm rate - before PCE $0.4568 Without wind energy Calculated PCE reduction $0.2973 Without wind energy Calculated residential rate after PCE $0.1595 Without wind energy Fuel expense with wind energy $436,460 Drop in fuel cost per kWh with wind $0.0606 Calculated res/comm rate with wind $0.3962 With wind energy Drop in Calculated residential rate $0.0606 Calculated PCE reduction with wind $0.2397 With wind energy Drop in PCE discount with wind $0.0576 Calculated residential post PCE rate $0.1565 With wind energy Actual change to residential rate after PCE----->$0.0030 Actual change to commercial rate with wind energy $0.0606 * Actual rates will be higher when residential customers exceed the 500kWh per month PCE limit.61 Conclusions • Many design options for hybrid systems –Very low penetration -relatively easy but minimal fuel savings –Low penetration -generally easy and simple –Medium penetration -more complex, challenging to find value-add secondary loads –High penetration -very complex, expensive and leading-edge • There is a lot of off the shelf technology that can be used to implement these systems but some level of skill is required to make them work • Power quality is a key issue, but not an insurmountable problem at any penetration • Approach is the same as building a power station, just different technology being implemented • Many organizations that would be willing to assist in any project development activity 62