from the last lecture: u.s. total energy consumption:u.s. transport energy consumption: product of...

From the last lecture: U.S. total energy consumption:U.S. transport energy consumption: Product of two numbers = ~ 20% of total U.S. energy consumption. Due to: Non-sustainable, fossil-fuel-driven, greenhouse-gas-producing, cars and pickups trucks, driven by individual Americans (Perhaps more if the E.I.A. classified our larger pickups and massive vans as "Trucks") Transportation = 27% = 27% LightVehicle = 59.7% Electrification of Transportation

So today's focus will be on new technologies that might: Lessen the impact of cars ALONE OR Lessen the impact of our energy system by integrating cars INTO it Why consider only cars? Well, look back at what we learned in earlier lectures: Trains: Small impact + Japan & Europe figured out solutions half a century ago We just need to wake up and match their 20 th century standard! Ships: Small impact + long distances demand a LOT of fuel energy Airplanes: Significant impact + long distances demand a lot of LIGHT fuel energy An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm

So other vehicles either have minor impact OR depend critically on: Energy per mass of fuel or energy per volume of fuel Data on energy per mass of fuel from earlier lecture: Conventional Battery = 0.001 x Gasoline's energy density Conventional Battery = 0.001 x Gasoline's energy density PC Battery = 0.01 x Gasoline's energy density TNT (0.65 Cal/gm) = 1/15 x Gasoline's energy density Butyl alcohol= 0.9 x Gasoline's energy density Kerosene / JP-4 / Jet Fuel= 0.93 x Gasoline's energy density Gas / Diesel= 1 x Gasoline's energy density Liquid Natural Gas = 1.3 x Gasoline's energy density Hydrogen = 2.6 x Gasoline's energy density Data mostly from from Richard A. Muller's book "Physics for Future Presidents"

Fuel densitys impact upon other forms of transportation: TRAINS: None - Solution for trains is to not carry around fuel Because, as enabled by limited number of fixed routes, You can pick it up as you go from either 3 rd rail or overhead lines FLIGHT: Energy per mass effectively precludes its battery-based electrification Solar electric planes are interesting but impractical Mass of storage containers likely also precludes H 2 power http://en.wikipedia.org/wiki/Railway_electrification_system http://en.wikipedia.org/wiki/Electric_aircraft

And as for shipping: Long routes mean that onboard fuel must store huge quantity of energy In 1950s and 1960s a nuclear powered merchant ship was tested: N.S. Savannah Entering San Francisco Bay in 1962: (She was beautiful I toured her a day or two later) But outside of cost be damned applications Such as aircraft carriers and ice-breakers (Where reactor mass can be an advantage) Nuclear powered ships never became practical Nor was public exactly delighted with the idea of mobile sinkable reactors Other clean alternative? Hydrogen, but wed need vastly cheaper sources http://en.wikipedia.org/wiki/NS_Savannah

An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm So in terms of impact + critical need for innovation: It really DOES pretty much come down to cars, SUVs and pickup trucks And while BIG trucks & buses do use use diesel as opposed to gasoline engines Requirements and demands are similar enough to cars That I'm willing to bet that they will be similarly electrified Making today's discussion relevant to ~ 75% of our current transportation energy But electrification strategies DO CHANGE based on a vehicle's: Average length of tripMaximum length of trip Type of trip (city stop & go vs. highway near constant speed) Number of trips per day / time spent idle between trips / WHEN idle...

Vehicle-to-Grid (V2G) Power Flow Regulations and Building Codes Review by the AVTA - INL http://www1.eere.energy.gov/vehiclesandfuels/avta/pdfs/evse/v2g_power_flow_rpt.pdf No surprise: Family vacations & visits are among our longest trips (~ 15-40 miles) But next longest are our immensely more frequent work-related trips (~ 15-30 miles) Length of our trips figures into maximum range expected of an electric vehicle Which led Department of Energy labs to study our driving habits:

Vehicle-to-Grid (V2G) Power Flow Regulations and Building Codes Review by the AVTA - INL http://www1.eere.energy.gov/vehiclesandfuels/avta/pdfs/evse/v2g_power_flow_rpt.pdf Classifying trips by their destination: Shows that most of our driving is shorter trips to work / school / stores: Most frequent type of trip figures into typical range of an electric vehicle

90% of the time our cars are parked in one of only two locations: 60 % of time at home (blue) + 30% of time at work (green) 40% of the time "fleet" trucks are parked at their base (red) But they are gone gone (presumably on the move) the rest of the time Fraction of time spent (available) at different locations figures into recharging of an electric vehicle Vehicle-to-Grid (V2G) Power Flow Regulations and Building Codes Review by the AVTA INL: http://www1.eere.energy.gov/vehicl esandfuels/avta/pdfs/evse/v2g_pow er_flow_rpt.pdf Or, figuring out where our vehicles spend most of their time:

Plug in Hybrid Vehicle Infrastructure Review, Kevin Morrow Donald Karner James Francfort - DOE 2008 http://avt.inel.gov/pdf/phev/phevInfrastructureReport08.pdf Are these trends changing? Yes: "Gotta have a pickup, SUV, or van!""Gas crisis is over, hit the road!" "Drive farther and...""Rack up those miles!"

What then are the goals and priorities in electric car design? For fossil-fuel-plant-charged electric car, onboard 60% conversion is misleading NET fossil fuel energy conversion rate is one third of that ~ Same as gas-fueled car An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm + OR 17 21% x 59 62% x 33% 19.5 - 20.5% x 17 21% = 1 Gasoline Car Efficiency: Electric Car Efficiency: To get rid of fossil-fuels, right? Hold on a minute! Dont forget this slide from the preceding lecture:

An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm Abandoning gas just shifts problem to largely fossil-fueled Grid! And right now, our cars burn their fossil fuel (gasoline) more cleanly than many of our power plants burn their dominant fossil fuel (coal) This is changing, but change will take decades to complete Until then: Totally electric cars will be as dirty as current gas cars So wisest priority might may NOW be: Gasoline cars using less gasoline This is what hybrid electric vehicles (HEVs), such as the Prius, are all about But you have to concede that our current love for hybrids is as much about: Saving our pocketbooks (gas $) as it is about saving the planet Nevertheless, we got this one right. And one of my engineering maxims is: Always take credit for your accidental successes as youll surely be credited for your accidents

An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm Hybrid electric vehicles are thus about reducing gasoline consumption From last lecture, power required for highway driving was: P highway = air c drag A car velocity 3 air = air density c drag = drag coefficient A car = cars cross-section To save fuel need: Smaller, skinnier, more slowly moving cars But power required for city (stop and go) driving was: P city = Mass car velocity 3 / 2 distance-between-stops To save fuel need: Lighter, more slowly moving cars, stopping less Here is the first BIG potential savings exploited by hybrids: Recycle most of the cars kinetic energy when it stops Via regenerative braking / kinetic energy recovery systems (KERS)

Recycling is made possible by the duality of electric motor/generators Gas or diesel internal combustion engines (ICE) cannot recycle energy Fuel is burned once => Producing combustion gases + heat => Vast expansion, driving pistons => Motion But recycling is possible in any vehicle incorporating an electric motor/generator: When accelerating or offsetting losses to air friction: Motor/Generator draws out energy from storage When decelerating (indeed, in order TO quickly decelerate!): Motor/Generator puts energy back into storage

An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm But this assumes that the energy storage unit itself is reversible: BATTERIES: We know that batteries CAN be rechargeable But some do this better than others. Further: Number of recharges / Rates of charge-recharge will now be important FUEL CELLS: We also know that they can be recharged (refueled) But how well, how many times, how quickly? Part of this is evaluated by an energy storage systems: Round Trip Energy Storage Efficiency In other words: Of the energy I put in, what fraction do I get back out?

From my Batteries and Fuel Cells lecture: Batteries and Fuel CellsBatteries and Fuel Cells Energy recovery from hydrogen fuel cells is HALF that of batteries U.S. National Renewable Energy Lab: "Hydrogen Energy Storage Overview" http://www.nrel.gov/hydrogen/pdfs/48360.pdf Round-trip energy storage efficiency for batteries and fuel cells Hydrogen Fuel Cells Batteries

http://www.pv-magazine.com/archive/articles/beitrag/advancing-li-ion-_100006681/501/#axzz3W4O57Ut4 But those data were for energy storage in Grid load leveling Here are data for more typical batteries, including lead acid & Li ion used in cars: Some of these entries are still for larger or more advanced versions But message doesn't seem change: Batteries are still about twice as efficient: Batteries ~ 80% vs. Fuel cells ~ 40%

To me, this seems to knock hydrogen fuel cells out of the game: Or at least out of the transportation game Because for regenerative braking / KERS to work well: We need to repeatedly recycle kinetic energy - every time we slow down! Its not just ONE energy round trip, its one after another after another... Storage: Kinetic energy:Recovered afterRecovered after Recovered after 1 st deceleration:2 nd deceleration:3 rd deceleration: Battery100%80%64%51% Fuel cell100%40%16% 6.4% Both storage methods degrade effectiveness of KERS, but fuel cells eviscerate it! Undercutting improvement offered by any electric car design Argument (and numbers) led me to drop hydrogen fuel from this lecture An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm

Also important for batteries: Charge/discharge rates + Possible cycles Data from the "Battery University" for: Lead Acid / NiCd / NiMH / Li ion (3 types) Lead Acid / NiCd / NiMH / Li ion (3 types) Ive superimposed highlighting for: Best data in green / Poorer data in red Best data in green / Poorer data in red Consistent with its current vehicle use, Li ion batteries win across the board: Density/Cycles/Volts/Current/Maintenance Density/Cycles/Volts/Current/Maintenance Only negative: Dont trickle charge (easily avoided in charger design) (easily avoided in charger design) http://batteryuniversity.com/learn/article/secondary_batteries

But in addition to exploiting electric motor/generator duality, electric car designs exploit another characteristic of electric motors: Electric motor torque and power vary little with rotational speed vs. Torque/power bands of internal combustion engine (ICE) - from last lecture: Both torque and power fall off precipitously at high/low speeds: Which is why with a stick-shifted ICE: - You must start in 1 st gear (and carefully slip clutch) - Because you'll almost certainly stall in other gear For all of their vroom, vroom roaring: Internal combustion engines are real whimps at low & high speeds An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm http://en.wikipedia.org/wiki/Power_band

With their 3, 4, 5 or more different gear ratios: Which is why you need to add big, complex, expensive transmissions Engine's Speed Car's Speed 4000 RPM 0 MPH 1 st Gear 2 nd Gear3 rd Gear4 th Gear 70 MPH Or the more recent alternative of "continuously variable transmissions:" http://nissanaltimaaustin.com/altimas- cvt-keeps-moving/

Transmissions must provide many, many possible input to output gear ratios Which must be either manually switched by the driver Or, in US, automatically switched by the transmission itself Optimum ratio, at any given time, depends not only on the vehicle's speed But also on if you want to accelerate more rapidly AND on if you want to burn less fuel Meaning that modern transmissions are computer-controlled marvels/beasts With built-in programming that reprogram's itself based on driver's habits! This makes a "transmission" very different than a "gearbox" Gearbox can be as simple as two fixed gears, one small, one large Reducing motor's naturally high speed (= "1-speed transmission") The need to add a "transmission" is a big deal

Fixed single-ratio (1-speed) gearbox: This one is built right onto the end of the electric motor of the electric motor (often just called a "gear motor") (often just called a "gear motor") Speed/acceleration/fuel-economy sensing, computer-controlled, multi-gear ratio, ICE automobile transmission: "Gearbox" vs. "Transmission" Top: http://electronics.stackexchange.com/questions/26175/automating-music-box-with-electric-motor Bottom: http://pixshark.com/automatic-gearbox-diagram.htm

Electric motors (e-Motors) can use simple (or no) gearbox because: Their torque/power bands are VERY different: Electric motors don't wimp out at very low speeds! From BMW's eDrive system (using 175 kW electric motor with Li ion battery): "full torque, which is typical for electric motors, is immediately available from a standstill and does not need to be built up first via the engine speed, as is the case with combustion engines." 1 1) http://www.bmw.com/com/en/newvehicles/i/i3/2013/showroom/drive.html

Is compounded, on left, by complexity/size of the to-be-attached gasoline ICE Driving us to use single large ICE + single large transmission to power any of automobile's wheels that are going to be powered Despite the fact that, when going in anything other than a perfectly straight line, all of the wheels want to turn at different speeds! Real solution, possible with compact electric motors, is to give each wheel (or pair) an independent drive system! The complexity of this vs. that:

Thus many Hybrid electric vehicles (HEVs) eliminate transmissions: At least in the electric half of these (super car to people's car) hybrids: Ferrari LaFerrari: ICE driving 7-speed transmission e-Motor is between ICE/transmission & rear wheels Thus charged by ICE thru transmission (or from wheels) But directly driving wheels w/o benefit of transmission Jaguar C-X75:Diesel-fed gas turbines charging battery Four e-Motors (one per rear wheel) directly driving wheels BMW i3:ICE driving e-Motor charging battery e-Motor directly driving 1-speed transmission to rear wheels Honda Accord:LOW/MED SPEED: ICE driving e-Motor charging battery e-Motor directly driving wheels HIGH SPEED: ICE driving wheels via 1-speed transmission Le Ferrarri: http://auto.ferrari.com/en_EN/sports-cars-models/car-range/laferrari/ Jaguar C-X75: http://en.m.wikipedia.org/wiki/Jaguar_C-X75 BMW i3: http://en.m.wikipedia.org/wiki/BMW_i3 Honda Accord: http://www.greencarreports.com/news/1087518_2014-honda-accord-hybrid-has-no-transmission-how-it-works

Full connection, engine/motors all the way to wheels = drivetrain Because we use one gasoline ICE with one transmission, our classic drivetrain is: But in a hybrid electric vehicle, we'll have at least an ICE engine + an e-Motor They can be configured in SERIES So that everything is always turning Or they can be configured in PARALLEL Where one motor/engine can be connected while the other is disconnected (or e-Motor remains connected but just spins idly) An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm Gas Engine Multi-speed Transmission Gas Tank

What was that about electric motor just spinning idly? A gasoline engine never spins idly (you'd have to force all its piston valves open!) But electric motor/generator, w/o electrical connections, is easy to turn Requiring ~ zero applied power / zero applied torque But when connected there's a strict relationship between desired speed vs. power Powered, but with no load, it achieves a specific speed for specific power PULL speed down (by attaching it to a load) and it consumes excess power PUSH speed up (by driving IT with something else) and it generates power Hybrid vehicles can exploit all of these modes of operation! An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm

Classic hybrid drivetrain is parallel: TOP battery powered electric motor/generator system is connected during: Regenerative braking: Power from wheels => battery Or possibly when starting from stop: Battery / e-Motor power => wheels Filling in until gas ICE gets up enough speed for adequate torque BOTTOM gasoline ICE system is connected when: Traveling at higher, steady, speeds (where ICE torque and power are high) BOTH would be connected when you need gas ICE to also recharge battery Figure is my modified version of one at: http://en.m.wikipedia.org/wiki/Hybrid_vehicle_drivetrain Gas Engine Multi-speed Transmission Gas Tank e-Motor / Generator

Gas Engine 1-Speed Gearbox Gas Tank e-Motor / Generator But newer series drivetrain can enhance HEV range/efficiency: Here wheels are driven ONLY by the electric motor (or motors, one per wheel) CENTER: Energy stored or released LEFT: Gas ICE + 1-speed gearbox driving generator sending energy (to center) RIGHT: Electric motor/generator Using energy (center) to drive wheels OR During deceleration using wheels to turn motor/generator sending energy (to center) Figure is my modified version of one at: http://en.m.wikipedia.org/wiki/Hybrid_vehicle_drivetrain

WHY does series drivetrain enhance HEV range/efficiency? In earlier parallel drivetrain, gasoline engine was trying to do TWO things: 1) Drive generator, charging battery = Steady speed / moderate power 1) Drive generator, charging battery = Steady speed / moderate power 2) Drive the wheels = revving up, crashing back down, revving up... One gasoline engine/transmission design cant do BOTH jobs efficiently (Its hard to just do crazy 2 nd job efficiently!) With new series drivetrain, gasoline engine/1-speed gearbox does only the first job And its the simpler charging job requiring steady speed / moderate power Allowing full (large, clunky) multi-speed transmission To morph into simple fixed 1-speed gearbox Car's Speed RPM 1 st Gear 2 nd Gear3 rd Gear4 th Gear

One downside to extended range hybrid electric vehicles In earlier parallel drivetrain hybrid electric vehicles (HEVs) Much or most of the time the gasoline ICE was powering the car With e-Motor/battery cutting in only when regeneratively braking Or when taking over from whimped-out ICE at low speeds In newer series drivetrain extended range hybrid electric vehicles (EREVS): e-Motor/battery are always driving or being driven by wheels Even while ICE is charging the battery Thus EREVs must generally have larger, higher capacity batteries With are still the weakest link in electric transportation! An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm

Leading to all electric "Battery Electric Vehicles (BEVs)" Which, for two wheel drive only, will revert to a very simple drivetrain: Not THAT much different from present day gasoline ICE drivetrain: An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm Better batteries will eventually eliminate internal combustion engines Gas Engine Multi-speed Transmission Gas Tank e-Motor /Generato r 1-speed Gearbox Battery AC/DC Converter

An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm But nearer term alternative is plug-in electric hybrid vehicles (PHEVs) Which is essentially the same today's HEV or EREV But with added component connected to battery: This would begin integration of US transportation into "the Grid" Why complicate matters (and vehicles) further: Why not just stick with HEVs or EREVs for now? Or jump directly to fully electric BEVs? Answers to the final BEV question: - Batteries aren't yet good enough - Grid is still dirtier than gas hybrids Answer to preceding question (why not stick with HEVs or EREVs?): Because there are subtle, and not-subtle, advantages AC/DC Converter

1) http://www.publicpower.org/Media/daily/ArticleDetail.cfm?ItemNumber=15901 If (and only if) Grid power were sold at a realistic hour by hour price: There would be big (unsubtle) advantage for the consumer Which comes from combination of these two earlier figures: Peak Grid Power 60% Midnight Noon Midnight 80% Power plants must meet evening demand But 40% of plants are then idled overnight 60% of our cars sit at home overnight 40% fleet commercial vehicles also sit idle in company's lot overnight sit idle in company's lot overnight If Grid power were market priced, hour by hour: PHEVs could charge overnight at equivalent of ~ 75 per gallon of gasoline 1

Sounds almost to good to be true? There are significant complications: 1) We'd need "smart" electric meters recording when we consume power No problem: Already being installed by many/most power companies 2) We'd need electrical outlets capable of supplying charging power Standard US household power outlets are 110 VAC / 15 Amp capacity This is called a Level 1 electric vehicle charging station 1 With its ~ 1.4 kW max power flow, PHEV would charge in ~ 5-8 hours Advantages: Existing outlets work, but needed in garage / parking space Charging PHEV would not overload household circuits Charging PHEV would not overload household circuits Disadvantage: Don't come home late or plan on going out tonight 1) http://secleanenergy.gatech.edu/files/King.pdf

Electric vehicle charging stations (continued) A Level 2 electric vehicle charging station is instead 230 VAC / 30 Amp capacity 1 Many modern homes have a single 230 VAC / 30 Amp circuit for electric oven But additional 230 VAC / 30 Amp circuit(s) would have to be added to garage Requiring licensed electrician to burrow new lines through walls... With resulting ~ 6 kW max power flow, PHEV would charge in ~ 4 hours Disadvantages: Cost of installation Could overload household power with multiple cars Level 3 electric vehicle charging stations envisaged at 480 VAC / 400 Amp capacity At ~ 192 kW max power flow, PHEVs could then charge in 1-2 hours But would overwhelm almost all present day household circuits And if neighbors copied, could crash local power system 1) http://secleanenergy.gatech.edu/files/King.pdf

Home Level 1: $878 Home Level 2: $2,146 Apartment Level 1: $833 Apartment Level 2: $1520 Cost of installing Level 1 or 2 stations in homes and apartment complexes 1 1) Page 31 of http: avt.inel.gov/pdf/phev/phevinfrastructureReport08.pdf

Next complication: 3) Can the Grid handle millions of new PHEVs? What if night-charging PHEVs draw more than otherwise idle 40% of Grid power? What if people instead plug in PHEVs when they first come home from work? For most of us this means evenings when Grid's already at full capacity Answers require more complex studies on likely PHEV sales Here are data collected by Tom King of DOE's Oak Ridge National Lab: 1) http://secleanenergy.gatech.edu/files/King.pdf

Free to choose their own PHEV charging times, citizens do this: Projections of daily Grid load with and without PHEVs (winter vs. summer): 1 PHEV charging only yields seemingly minor increase in winter peak load Actual data from 6 regional PHEV trials (w or w/o hourly adjusted power charges): 2 "76% of the electricity used for charging occurred during off-peak periods, additional 4% occurred during mid-peak, remaining 20% occurred during peak periods" 1) http://secleanenergy.gatech.edu/files/King.pdf 2) http://energy.gov/sites/prod/files/2014/12/f19/SGIG-EvaluatingEVcharging-Dec2014.pdf

Electrification of transportation and the Impacts on the Electric Grid Tom King, ORNL secleanenergy.gatech.edu/files/King.pdf So, with free choice, what is impact of PHEVs upon peak load? Small impact seen in regional test:But larger impacts predicted: Worst case prediction of increase in total US peak demand is over 150 GW Current total U.S. peak power is ~ 1000 GW => Predicted increase is thus ~ 15% May not sound like a lot, but it's more than enough to worry power companies

An Evaluation of Utility System Impacts and Benefits of Optimally Dispatched Plug-In Hybrid Electric Vehicles - NREL http://www.nrel.gov/docs/fy07osti/40293.pdf What if PHEVs were only charged in the middle of the night? In middle of night the Grid now operates at about 60% capacity Could millions of new PHEVs, charging overnight, push it over full capacity? Apparently not: Old 60% + New (40%) x (60%) => 84% Seemingly still leaving comfortable 16% excess capacity margin

So today's Grid could handle PHEV's if they charged overnight What about tomorrow's Grid, making much heavier use of renewables? If we continue to shun hydro/nuclear power, renewables will have to be solar/wind From my earlier lecture on A Renewable Distributed Grid: A Renewable Distributed GridA Renewable Distributed Grid Solar Power vs. Demand:Solar + Wind vs. Demand: Peak Power Use Midnight Noon Midnight Power of Renewable at Peak Peak Power Use Midnight Noon Midnight Power of Renewable at Peak An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm

Vision of PHEVs charging overnight in our garages just crashed Diminished role of hydro and nuclear slashes our overnight "base" power capacity But solar & wind would add new midday / afternoon capacity Could PHEVs take advantage of this new capacity? Yes, because: They'd then be parked "at work"Leading ORNL to propose this: Electrification of transportation and the Impacts on the Electric Grid Tom King, ORNL secleanenergy.gatech.edu/files/King.pdf Vehicle-to-Grid (V2G) Power Flow Regulations and Building Codes Review by the AVTA INL: http://www1.eere.energy.gov/vehiclesandfuels/avta/pdfs/evs e/v2g_power_flow_rpt.pdf

Smart Wireless Power Transfer Electrification of transportation and the Impacts on the Electric Grid Tom King, ORNL secleanenergy.gatech.edu/files/King.pdf">

Solar cells would not have to be right in the parking lot Simplification: Get power via Grid from remote solar/wind farms Complication: Your car's going to be charging for hours in a public parking lot You know that you are going get charged for that power What stops the next car from "borrowing" your paid-up power plug? Oak Ridge's idea: Forget the plug => Smart Wireless Power Transfer Electrification of transportation and the Impacts on the Electric Grid Tom King, ORNL secleanenergy.gatech.edu/files/King.pdf

Power transformer! It works for charging your electric toothbrush, it can also work for PHEVs! And the guy in the neighboring parking spot can't "borrow" anything Unless his car stands 5" high and can drive in under yours">

An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm Smart + Wireless: SMART: RF link is going to ID your car Then, via secure Internet, check for an approved credit card account And possibly "talk" to car about amount of energy desired... WIRELESS: In addition to the wireless communication above, there is: A coil buried in the parking lot beneath your car A coil buried in the parking lot beneath your carPLUS A coil built in to the floor of your car Magnetic induction => Power transformer! It works for charging your electric toothbrush, it can also work for PHEVs! And the guy in the neighboring parking spot can't "borrow" anything Unless his car stands 5" high and can drive in under yours

An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm PHEVs /BEVs seems to be prime customers for midday solar/wind power PHEVs /BEVs seems to be prime customers for midday solar/wind power But then you'll drive home, turn everything on, and peak out the Grid! Hold it! If your car arrives home with its battery still almost topped off Why not then sell some of its stored energy back to the power company? Or, cut out middle man, and have car help power your home? Power company might bite: They had excess power during the day => They'd sell to you for $$ Now, early evening, Grid demand is peaking, power is at its most expensive So they'd buy back power for $$$ But you need a fully charged up car in the morning to get back to work Fine, overnight they've got gobs of power => They'd sell to you for $

Buy at $$, sell at $$$, buy back at $? -($$) + ($$$) ($) = $ = Your potential profit What's in it for the power companies? In you case you hadn't notice: You're now part of the Grid's load-leveling power storage system Alternatives, as discussed in my Power Cycles & Energy Storage lecture, Power Cycles & Energy Storage Power Cycles & Energy Storage already cost power companies a LOT of money Solar and wind power will drive necessary amount of storage through the roof! So there is almost certainly some sort of Win-Win pricing structure that will allow both you and the power company to benefit that will allow both you and the power company to benefit Through its pricing, the power company could even "incentivize" you to buy PHEV / BEV equipped with larger battery than you might need just for driving! An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm

This idea is called V2G = Vehicle to Grid Many of its champions are at the University of Delaware An overview article see: "Electric and Hybrid Cars - New Load, or New Resource?" 1 The popular press has gotten really excited about this idea But power companies and representative organizations remain cautious A middle ground can be found in the National Renewable Energy Lab's report: "An Evaluation of Utility System Impacts and Benefits of Optimally Dispatched Plug-In Hybrid Electric Vehicles" 2 And in the Idaho National Lab's report: "Vehicle-to-Grid (V2G) Power Flow Regulations and Building Code Review by the AVTA" 3 (from which data are already sprinkled throughout this note set) 1) Power Utility Fortnightly December 2006: http://www.udel.edu/V2G/docs/LetendDenLil-LoadOrResource06.pdf 2) http://www.nrel.gov/docs/fy07osti/40293.pdf 3) http://www1.eere.energy.gov/vehiclesandfuels/avta/pdfs/evse/v2g_power_flow_rpt.pdf

An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm What issues do those reports raise / Why are power companies hesitant? You'd no longer be just a power customer, you'd be part of the power grid: Your garage charging station would consume power or deliver power If it malfunctioned, the rest of the Grid would have to be protected When it functions, it cannot push power out to Grid if Grid is being worked upon Less it electrocute some poor line worker Your house power meter must also be smart enough to collect information on: Your power consumed vs. time of day or week Your power delivered vs. time of day or week EQUALS exactly what you'd also need if you cover your roof with solar panels So this is already being worked out, making it the easy part

An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm But challenges then diverge from home solar power: Homeowners will individually contract for solar power installation and connection Which, with a bit more wire and a smart meter, is pretty easy But parking lots don't come with buried high power electric cables Nor do they come with buried smart, magnetically inductive, chargers Someone (organization, company, government agency) is going to have install Or, at least instigate, those installations P erhaps by 2030, when millions of PHEVs /BEVs might be charging daily, aggregate storage capacity will be of interest to big power companies But before that, power companies will be reluctant to revamp their whole system Suggesting need for long period of government subsidy and/or involvement?

An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm And then just think through the details of the PHEV scenario I discussed: At work your PHEV / BEV gets fully charged in the parking lot You drive home where Grid (and/or your home) draws power from car Then, in the depths of the night, your car recharges in the garage That doesn't really work Your car has got to ARRIVE at work with an almost empty battery So it has plenty of room to add daytime solar/wind energy To be borrowed by Grid/home during evening peak Then recharged only enough to get you BACK to work What if you unexpectedly add on an errand, drop of the kids, get caught in traffic? A PHEV's gas tank might save you (assuming you still check your gas gauge!) But with a battery electric vehicle, you'd be screwed

An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm So what happens then? Do you somehow program a safety margin into your car's overnight charge? Does your smart car note your driving pattern and figure out this margin for itself? Or could everyone involved agree that cars can arrive at work with extra charge Hey! What if we instead: Arrive at work with charged cars, Then discharge to Grid in early morning before solar & wind power strengthen, Then midday, when solar & wind ARE strong, recharge our battery, Then when we get home, discharge to Grid to help meet peak demand, Then in depths of night, recharge our car... Some graphs might help at this point:

1) Power Demand: 2) Power Production (constant base + solar peak + wind peak): 3) Location of PHEVs / BEVs: 4) PHEV Grid Charge / Discharge (driven by 1, 2, 3): 5) PHEV / BEV onboard energy (with intent that 2 + discharge of 4 => 1): ALL of the things I was just trying to balance throughout the day: Home Work Charge Discharge Charge Discharge

An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm This is really getting really complicated! And we haven't even considered one of the BIGGEST challenges:

Cost of power Figuring out new cost of business + fair profit is going to be HUGLEY more difficult!">

An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm What is the appropriate price of power (now varying hour by hour)? Ideally "the market" should decide, maximizing efficiency and all around benefit But free market power was tried by many states in the 1990's And what we got was gaming corporations such as Enron That took the money and ran, leaving us with brownouts or worse So it's more likely responsibility will fall on state Public Utility Commissions (PUCs) PUC's typically work with the public utilities (here, power companies) To figure out their real cost of doing business (now, hour by hour) Adding on modest, but supposedly fair, profit => Cost of power Figuring out new cost of business + fair profit is going to be HUGLEY more difficult!

An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm Power companies will have legions of tame experts working the problem They also fund organizations like the Electric Power Research Institute (EPRI) So their point of view should be well studied and represented But will our politically appointed PUC members be similarly well informed? And will they properly balance corporate and public interests? Don't get me wrong: I worked for a public utility for 21 years Not a power company but instead the Bell System Which was then the telephone company for 80% of America Public utilities are not the Gordon Gecko lizards that gave us the Great Recession Most are instead deeply committed to, and proud of, their history of public service But when you are proud of a history that has worked You become very reticent about giving up that way of working

An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm So based on both business uncertainties and corporate cultures The power industry is very apprehensive about this Brave New World of Power Thus, if we in the US are to derive maximum benefit from approaching opportunities: We as citizens had better progress from "I love wind / I hate nukes" To really understanding the subtleties of power systems And we'd better also make sure that: Our appointed PUC representatives are at least as well informed Which would represent a HUGE change in and of itself as I have never heard a word of public discussion about PUC appointments BTW: You DO realize that we're already neck deep into the topic of "Smart Grids" (tune in for more, next time...)

Credits / Acknowledgements Some materials used in this class were developed under a National Science Foundation "Research Initiation Grant in Engineering Education" (RIGEE). Other materials, including the "UVA Virtual Lab" science education website, were developed under even earlier NSF "Course, Curriculum and Laboratory Improvement" (CCLI) and "Nanoscience Undergraduate Education" (NUE) awards. This set of notes was authored by John C. Bean who also created all figures not explicitly credited above. Copyright John C. Bean (2015) (However, permission is granted for use by individual instructors in non-profit academic institutions) An Introduction to Sustainable Energy Systems: www.virlab.virginia.edu/Energy_class/Energy_class.htm

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