52 degrees Fahrenheit. At that temperature,materials lose all their resistance and electricity flows without loss. Toreach this low temperature, the system must be cooled by liquid helium.Extensive research is being done to make superconductivity take placeat a higher (but still very cold) temperature of about 216 degree Fahrenheit, which would greatly reduce the cost. Despite this low temperature,the new superconductors are called high temperature superconductors.4This is not a technology that will be commercialized anytime soon, but isnevertheless a technology to watch for the future.
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TYPES OF POWER STORAGE SYSTEMSAs mentioned earlier, in these next types of power systems, electricity isconverted into a different type of power, which can then be converted backto electricity when it is needed. The intermediate form of power can bepumped-hydro, compressed air, hydrogen for a fuel cell, or mechanical energy in a flywheel.
Pumped-Hydro StorageAs mentioned earlier in this chapter, pumped-hydro refers to pumpingwater into a tank so it can drain out later to drive a turbine/generatorsystem to produce electricity. Conventional pumped-hydro storage usestwo water reservoirs, one above the other. During periods when electricity demand is low, surplus electricity is used to pump water into theupper reservoir. Then when the electricity is needed again, the waterin the upper reservoir is allowed to flow via gravity through water turbines to generate electrical power. About 70 percent to 85 percent ofthe electrical energy used to pump the water up into the upper reservoir can be recovered, meaning there is a loss of 15 percent to 30 percent. Pumped-hydro was first used in the 1890s in Italy and Switzerland. Today over 90 gigawatts of pumped-hydro storage is in operationaround the world, which equals about 3 percent of total global generationcapacity.5
Compressed Air Energy StorageCompressed air energy storage systems use off-peak electrical power tocompress and pump air into airtight chambers underground. Then whenelectricity is needed during peak hours, the air is released from the underground chambers. The air is heated and expanded through a combustionturbine to generate the needed electricity. The underground chambers aregenerally caverns cut out of impervious rock formations, salt caverns, ordepleted gas or oil fields.There are at least two such systems currently in operation. One islocated in Huntorf, Germany, and the other is at McIntosh, Alabama.The $65 million McIntosh plant in Alabama was funded primarily by theAlabama Electric Co-operative. The system has a rated capacity of 100megawatts and uses a deep limestone mine as the storage chamber. Twoother compressed air systems are planned for Norton, Ohio, and Markham,Texas.6
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Fuel CellsA fuel cell is typically thought of as a primary electricity generation methodthat converts hydrogen into electricity. However, a fuel cell can also beused as an electricity storage device and may in fact eventually play a bigrole in that regard. For example, the U.S. National Renewable Energy Laboratory and Xcel Energy just unveiled a wind-to-hydrogen demonstrationproject.7 The project will use a wind turbine to produce electricity to poweran electrolysis machine that in turn produces the hydrogen. The hydrogencan then be used for any purpose, but the main eventual goal would be touse the hydrogen to drive a fuel cell to produce electricity.Combining a wind turbine or solar power system with a fuel cell is away to overcome the disadvantage that the wind and sun are only intermittent sources of power. When the wind is blowing or the sun is shining, some of the electricity from the wind or solar power system would bediverted to drive an electrolysis machine to produce hydrogen. (See thediscussion on fuel cells in Chapter 7 for more information on hydrolysis,which uses electricity to split water into oxygen and hydrogen.) The hydrogen can then be stored and used to power the fuel cell when the windor solar power system is offline. In this way, the overall system can produce power 24 hours a day, 7 days a week. The overall system would bea 24/7 electricity generation system with zero greenhouse gas or wasteemissions.
FlywheelsMost modern flywheel systems consist of a rotating drum that is mountedon a vertical shaft. The shaft is supported on a stator by an electromagneticbearing that virtually eliminates friction and wear. The stator is connectedto a motor/generator. When surplus power is applied to the motor duringoff-peak periods, it causes the flywheel to spin faster. During peak loadperiods, when extra electricity is needed, the spinning flywheel turns thegenerator and generates electricity. To minimize the drag on the spinningdrum, the drum is housed in a vacuum chamber. Flywheels can be up to98 percent efficient, which means that 98 percent of the electricity used tocause the flywheel to spin can be recovered as usable electricity. Only 2percent is lost in the storage process. Figure 12.1 shows a schematic diagram of a flywheel.One of the problems with a flywheel is that it spins at such a high rateof speed, up to 100,000 rpm, that the rotating drum can literally fly apart.Modern drums are made of carbon-fiber materials to avoid this problem.However, since there is still a danger of the rotor breaking up, the entire
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FIGURE 12.1 Flywheel SchematicSource: Reprinted by permission and courtesy of Beacon Power Corp. (www.beaconpower.com).
unit is housed in a strong container to prevent any release of debris in theevent of failure.
TARGET MARKET SIZESThe storage and backup of electricity is big business. The size of the marketis a bit difficult to estimate because of the wide variety of electricity storagemethods. The market in any case is destined to grow much larger due toincreased electricity usage in general and the increased need for powerprotection and backup for businesses and sensitive electronic equipment.The global market for large battery systems is about $15 billionper year, according to the Electricity Storage Association (ESA),which represents electric utilities and researchers in advancedstorage technology.6 The ESA estimates that the industrial batterymarket, which is more limited and services motive applications (forklifts,materials handling trucks), uninterruptible power supplies, power qualityapplications, standby, and reserve batteries, amounts to $5 billion per
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year.8 The industrial battery market as of mid-2007 was growing at anannual rate of about 7–8 percent in terms of units, according to EnerSys.9The main companies involved in the industrial battery market are Enersys(NYSE: ENS), Exide Technologies (Nasdaq: XIDE), and C&D TechnologiesInc (NYSE: CHP).The global market for small batteries used in portable electronic devices like cameras, phones, laptop computers, etc. is about $50 billion, ofwhich about $5.5 billion is for secondary (rechargeable) batteries, according to the Battery University.10 The small battery market is growing at arate of about 6 percent per year.11For the advanced power storage technologies, BCC Research says thatthe market for super capacitors, flywheels, and superconducting magneticstorage systems was $9.1 billion in 2005 and estimates that it will grow to$12.2 billion by 2010.12
Companies with Advanced Power Storage Productsr Active Power, Inc. (Nasdaq: ACPW). Active Power (www.activepower.com) designs and manufactures uninterrupted power supply (UPS)products. One of its products is a flywheel UPS system that is marketed under the name of CleanSource UPS. That product producesabout 40 percent of the company’s revenue. This system is also marketed by Caterpillar, Inc. under the name of Cat UPS. Another ActivePower product for UPS systems uses thermal and compressed air storage and is marketed under the name of CoolAir UPS. Active Power isbased in Austin, Texas, and produced $25.0 million in sales in 2006.r American Superconductor Corp. (Nasdaq: AMSC). American Superconductor Corp, (www.amsuper.com) has two main product lines:(1) power converters that are used as electronic components by windfarms to regulate and convert the DC power generated by a wind farm;and (2) high-temperature superconductor (HTS) wires that carry upto 150 times as much electricity as a comparably sized copper wire.The HTS wires are sold mostly to the utility transmission market.American Superconductor recently received a major contract from thecity of New York to lay new superconductor wires between power substations in the city to improve the robustness of the city’s power network. The company has other products for the utility grid market thatswitch, control, and modulate power. In the 2007, fiscal year endedMarch 31, 2007, the company had total revenue of $52.2 million.r Beacon Power Corp. (Nasdaq: BCON). Beacon Power Corp. (www.beaconpower.com) was founded in 1997 as a spinoff of SatCon’sEnergy Systems Division to develop flywheel-based energy storage.The company designs and develops products and services to support
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stable, reliable and efficient electrical grid operation. Beacon successfully demonstrated a prototype for a megawatt-level, utility-gradeflywheel-based system to provide sustainable frequency regulation service. In late 2006, the company was awarded a contract by the Department of Energy to design a large-scale power plant based on thedemonstrated technology. In 2006, the company had total revenue of$969,000.r C&D Technologies, Inc. (NYSE: CHP). C&D Technologies (www.cdtechno.com) is a manufacturer of electrical power storage systems. The Standby Power division manufactures lead-acid batteries forbackup and standby power. The Power Electronics division manufactures the control equipment that is used in the company’s other products. The Motive Power division manufactures the lead-acid batteriesused in the motive market, which includes forklift trucks and othermaterial handling equipment. The company is headquartered in BlueBell, Pennsylvania, and has manufacturing plants in several locationsaround the country. The company has been in operation since 1906 andhad revenues in the fiscal year 2007, which ended on January 31, 2007,of $525 million.r Capstone Turbine Corp. (Nasdaq: CPST). Capstone Turbine (www.capstoneturbine.com) develops and manufactures microturbine technology solutions for use in stationary distributive power generationapplications. The microturbines are compact generators of electricity.They operate on the same principles as a jet engine, but can use a variety of fuels including natural gas, diesel oil, kerosene, and propane.The products are designed for producing electrical power for commercial and small industrial users. Capstone’s microturbines run on fossilfuels and the turbines therefore emit greenhouse gases and pollutants,but the company is considered by many to be an “alternative energy”company because it provides distributed power generation productsthat allow users to operate off the grid or have nongrid power backup.The company was founded in 1988 and is headquartered in Chatsworth,California. In the fiscal year 2007 ended March 31, 2007, the companyhad revenues of $21.0 million.r Distributed Energy Systems Corp. (Nasdaq: DESC). Distributed Energy Systems (www.distributed-energy.com) manufactures distributedelectrical power systems that produce and store power at a customeror remote location. The systems are both standalone for power use inremote locations or for connection to the grid. The source of power forthe generation can be from wind, solar, oil, natural gas, or biofuels. Thecompany also produces hydrogen gas generating systems that producehydrogen from water. To complement the hydrogen generators, thecompany provides hydrogen fuel cell systems to generate electricity.
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The small fuel cell/hydrogen generating systems are designed for usein laboratories. The larger systems are designed for industrial use. Thecompany was founded in 1974 and is headquartered in Wallingford,Connecticut. In 2006, the company had revenue of $45.9 million.r SatCon Technology Corp. (Nasdaq: SATC). SatCon Technology(www.satcon.com) manufactures products for electrical power conversion and control. The products are used in areas such as alternativeenergy, hybrid electric vehicles, and distributed power generation. ThePower Systems Division provides UPS systems used for power backupand power quality; inverters to convert the DC power produced by fuelcells, solar power, or wind power into usable AC power; and equipment to permit alternative power sources to be connected with thegrid. Both the Electronics and the Applied Technology divisions design and build specialty products for both commercial and militarycustomers. The company was founded in 1986 and is headquarteredin Boston. In 2006, SatCon had total revenues of $28.8 million.
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C H A P T E R 13
CleanTransportationElectric Hybrids Are Charged Upand Ready to Go
he world has a transportation problem. There are presently about 800million vehicles on the world’s roads, with more than 200 million ofthose vehicles operating in the United States.1 There are alarming estimates that there will be some 2 billion vehicles on the world’s roads by2050. Virtually all of the vehicles that are currently on the road are equippedwith internal combustion engines that burn fuel and spew various contaminants and greenhouse gases into the air. In fact, about 27 percent of allgreenhouse gas emissions in the United States come from the transportation sector, according to the Environmental Protection Agency (EPA).2 Asto specific greenhouse gases, the EPA estimates two thirds of all carbonmonoxide and almost one half of all ozone-forming emissions come frommotor vehicles.The transportation sector is clearly a big part of the energy problem,both from the standpoint of greenhouse gas emissions and from the standpoint of energy security since the U.S. imports 60 percent of its oil, whichis mostly used to power America’s vehicles. Clean energy solutions in thetransportation sector would go a long way toward solving the world’s overall greenhouse gas emissions problem, as well as America’s problem ofbeing addicted to oil.
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THE INTERNAL COMBUSTION ENGINE:CAN IT BE SAVED?The internal combustion engine is the propulsion device that is used in virtually all of the world’s vehicles. In the internal combustion engine, gasoline (or some other combustible fuel such as ethanol) is fed into a cylinderwhere it is ignited. The resulting explosions drive pistons, which turn acrankshaft and ultimately the wheels via the transmission system. The exhaust from the small explosions is expelled through the muffler system intothe atmosphere. The bottom line is that the internal combustion engine relies upon the burning of fuel as the propulsion source. The burning of fuelinevitably releases CO2 and other gases and contaminants into the air.Aside from the greenhouse gas emission and pollution problem, theinternal combustion engine is also very inefficient. The overall efficiencyof a gasoline-powered car is only about 20 percent. That means that only20 percent of the energy contained in the gasoline is actually convertedinto mechanical energy. Some of the energy is used to run the various fans,pumps, and other devices and the rest is wasted as heat or unused mechanical energy.Over the years scientists have done many things to make the internalcombustion engine more efficient and also less harmful to the environment.Car engines today are much better than even five years ago. However, regardless of what scientists do to make the engine better, it is still an internalcombustion engine that burns fuel.The U.S. federal government got involved in the effort to reducethe environmental impact of the internal combustion engine in 1975 whenit passed the Energy Policy Conservation Act. The Act was passed in response to the 1973–1974 Arab oil embargo. The goal was to double new carfuel economy by model year 1985. The Act set mileage standards to forcethe car manufacturers to get more miles from a gallon of gas. The standardswere called the Corporate Average Fuel Economy (CAFE) standards.3Since 1975, nothing has been done to raise the standards to more realistic levels. Now, with the growing problem of climate change and highergasoline prices, some leaders in Congress are mobilizing to raise CAFEstandards. Yet, U.S. automakers and their political supporters in Congressare doing everything they can to block or at least water down the increase.Many consumers are not waiting for Congress to raise fuel standards. They are instead voting with their pocketbooks and are simplybuying vehicles that have better gasoline mileage and increasingly,gasoline-electric hybrids. In fact, Toyota officially became the world’slargest automaker in April 2007, taking over the position from GeneralMotors. Toyota gained the world’s largest market share by focusing onquality and fuel economy.
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ALTERNATIVE FUELS FOR THE INTERNALCOMBUSTION ENGINEThere are fuels that can be used in an internal combustion engine that arecleaner than others. Using cleaner fuels would represent a small step forward toward cleaning up transportation sector pollution and emissions.
Cleaner Diesel FuelDiesel engines are more efficient than gasoline engines, but their exhaustfumes still expel pollutants and greenhouse gases. To make diesel engines more environmentally friendly, the U.S. Environmental ProtectionAgency has mandated that ultra-low sulfur diesel (ULSD) fuel must beused in the future. The new fuel is 97 percent cleaner than current dieselfuel in terms of the sulfur content. This mandate has implications forrefiners and manufacturers alike. Refiners started producing ULSD fuelin 2006 but both diesel fuels will be on sale for the next few years. Alldiesel fuel sold in the United States must be ULSD by 2010. The newfuel can be used in today’s diesel cars and trucks, but the real benefitsof the new fuel will not be realized until the new compatible engines arein use. Starting with the 2007 model year, manufacturers can only produce engines that are compatible with ULSD. The new engines using ULSDare expected to meet the same emission standards as gasoline-poweredvehicles.4
Natural-Gas-Powered VehiclesEngines that use natural gas as fuel operate like a gasoline combustionengines with only minor differences. Natural gas is still a fossil fuel andreleases pollutants and greenhouse gas emissions. However, natural gasburns cleaner than gasoline and releases fewer pollutants. Disadvantagesof natural gas vehicles include (1) the gas storage cylinders are so bulkythat they take up a lot of trunk and cargo space; (2) the range of a natural gas vehicle is limited to about 200 miles versus a 300-mile range of agasoline-fueled car; and (3) refueling locations are still limited.Natural gas has been used as fuel for vehicle fleets for many years,mainly because natural gas is typically cheaper than gasoline. These fleetsinclude taxicabs, transit and school buses, delivery trucks, public workstrucks, and the like. What these all have in common is that their daily driving range is within the mileage limit of a single fill-up of fuel so their fueltanks can be filled at the end of each day at the garage where the vehiclesare stored.5
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LPG VehiclesLiquid petroleum gas is a fossil fuel that is refined from natural gas orpetroleum. It is the same LP gas that is used for heating and cooking inmany parts of the country. The technology for using it in cars has beenaround for decades. There are currently over 9 million vehicles in 38 countries that use LPG for fuel, according to the World Liquefied Petroleum GasAssociation. In the United States, there are about 300,000 cars with LPGengines. The advantages are that (1) the harmful emissions are about halfthose of a gasoline engine; (2) the LPG engine runs much cleaner and therefore needs less maintenance; and (3) LPG is usually cheaper than gasoline.Many automobile models that have an LPG engine as an option areavailable from major auto companies like Ford, General Motors, andChrysler. However, most cars with the LPG option are also equipped withan alternate fuel system for gasoline. The cars can run on either LPG orgasoline and the car can switch from one to the other automatically. Theadvantage of the dual fuel system is that there is no danger of running outof fuel if an LPG refueling station is not available.6
Hydrogen-Boosted EnginesAn emerging technology is to add hydrogen to the gasoline mixture to enhance the overall combustion quality. The small amount of hydrogen wouldbe extracted from the gasoline by a reformer device added to the engine.The hydrogen would make it possible to increase the amount of air usedin the gasoline ignition, thus making it possible to use less fuel. Scientistsbelieve this technique could create a fuel-economy gain of 20 percent to30 percent.7
Biofuel VehiclesEthanol and biodiesel are becoming more popular as transportation fuels.Ethanol, which is simply alcohol, has been added to the U.S. gasoline supply in some regions for years in order to make the gasoline burn cleaner,but usually at levels only up to 10 percent of the mix. Flex fuel is the namegiven to vehicles that can use any mix of gasoline and ethanol, ranging fromstraight gasoline, to E10 (10 percent ethanol and 90 percent gasoline), toE85 (85 percent ethanol and 15 percent gasoline). There are already about6 million flex-fuel vehicles on U.S. roads today and looking ahead manufacturers expect to sell about 2 million more flex-fuel vehicles each year.Ethanol reduces the amount of pollutants and the CO2 emitted from a vehicle, but the fact remains that ethanol is still powering an internal combustion engine. Biofuels will be discussed in more depth in the next chapter.
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ELIMINATING THE INTERNAL COMBUSTIONENGINEThese improvements to the internal combustion engine are all helpful, butthe fact remains that the internal combustion engine is still burning fueland is releasing pollutants and CO2 into the air. The real solution is to usea propulsion method that does not burn fuel and that produces zero pollution and zero CO2 emissions. There are three main propulsion technologiesthat fall into this category: compressed air, fuel cells, and electric vehicles.These technologies will now be discussed in more depth.
Compressed-Air-Powered VehiclesA French company, Moteur Developpment International (MDI), has developed two compressed air cars called the MiniCAT and CityCAT (seewww.theaircar.com).8 These vehicles will be manufactured first in Indiaby Tata Motors (Mumbai: TTMT IN) and sold there in 2008. According tothe developer, the two vehicles are designed for city use. CityCAT, for example, will have top speed of about 68 mph and will be able to travel about125 miles before needing an air recharge. The air recharge will take only afew minutes when done with a high-pressure pump at specially equippedservice stations. The vehicle also has a small built-in compressor that canbe plugged into a 220-volt power source to recharge the tank. That rechargetakes about six hours.9MDI says that they are also working on an air/gasoline hybrid that usesan onboard gasoline powered compressor to refill the air tanks on the road.With this arrangement, the travel distances are limited only by the amountof fuel needed to run the compressor. The company says the vehicle shouldbe able to travel thousands of miles on a tank of gas.MDI has signed deals to bring the vehicles to 12 more countries. Thethree-seater compact MiniCat will sell for about $10,000 and the six-seaterCitiCat will sell for about $16,000.10 The main downside to these particular vehicles is that they use a fiberglass construction and they may not beable to pass U.S. crash tests. Nevertheless, MDI has at least validated thecompressed air engine technology.
Fuel-Cell-Powered VehiclesThe fuel cell has been billed by some as the ultimate solution for poweringthe world’s transportation fleet since a fuel cell produces only heat and water as waste. A fuel cell vehicle produces zero emissions, which is a highlyattractive attribute. However, as noted in Chapter 7, creating the hydrogen
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in the first place can be an emission-producing operation. In addition, thereis the challenging task of producing, transporting, storing, and deliveringmass quantities of hydrogen, which is a highly flammable gas that requiresspecial handling. The United States is having enough trouble trying to getE85 ethanol tanks installed in the nation’s service stations let alone building a completely different hydrogen delivery infrastructure. Moreover, fuelcell manufacturers are still a long way away from producing a fuel cell vehicle that comes even close to the cost of current vehicles. Nevertheless, avariety of manufacturers are moving full speed ahead on trying to developeconomical and practical fuel cell powered vehicles. This book’s companion Web site at www.ProfitingFromCleanEnergy.com has links to videosclips of various fuel cell concept cars.The most attractive application for fuel cell vehicles over the near tomedium term is for fleet vehicles such as buses and delivery trucks. Thesevehicles return to a home base each night, which allows them to be refueled from a central location. Vehicle fleets powered by fuel cells wouldrepresent a step forward, even if the hydrogen is produced by reformingnatural gas since the total emission and pollution amounts would still bemuch less than from a gasoline or diesel powered vehicle.
HYBRID GASOLINE-ELECTRIC VEHICLESMost consumers have a hard time taking the thought of an all-electric vehicle seriously since the pictures of electric vehicles we usually see in newspapers and magazines look more like an overgrown golf cart than a vehiclesomeone would want to take out on a highway. However, most consumersare not aware of the rapid advances that are being made in the field of electric vehicles. Moreover, pairing an electric motor and a gasoline enginecreates a gasoline-electric hybrid vehicle (HEV) that has a greater rangethan either an electric or a gasoline vehicle alone.Sales of hybrid electric vehicles are in fact starting to take off. In 2006,sales of hybrids in the United States rose +28 percent from 2005 to 254,545vehicles, representing 1.5 percent of U.S. auto sales, according to R. L.Polk.11 U.S. hybrid sales accounted for about two-thirds of total world hybrid sales in 2006. Global hybrid sales in 2006 rose +25 percent to 378,000vehicles and have shown fairly steady growth in the past three years, asseen in Figure 13.1. Global hybrid sales hit a monthly record of 51,400 inMarch 2007 and are on track to reach annual sales of nearly 500,000 vehicles in 2007, which would be up 22 percent year-on-year.12Toyota Motor Corp (NYSE: TM) is by far the world’s leader in hybridsales. In the United States, Toyota accounted for 79 percent of hybrid sales
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50Thousands of Vehicles
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FIGURE 13.1 Global Hybrid Vehicle Monthly SalesSource: “Worldwide HEV (Hybrid Electric Vehicle) Sales,” MarkLines, July 2007,http://www.marklines.com/en/numproduct/index.jsp.
in June 2007, according to HybridCars.com (see Figure 13.2).13 The nextclosest competitor is Honda (NYSE: HMC) with a market share of 10 percent. Ford (NYSE: F) weighs in with a market share of 7 percent, and General Motors (NYSE: GM) with a market share of only 2 percent.Regarding individual hybrid models, as of mid-2007 there were 12 hybrid cars on the market made by six different automakers.14 The mostpopular hybrid vehicle by far is the Toyota Prius (www.toyota.com/prius),which accounted for 50.9 percent of hybrid vehicle sales in June 2007,according to HybridCars.com. The next most popular hybrids were theToyota Camry (15.9 percent market share), Honda Civic (9.3 percent market share), and the Ford Escape (6.3 percent market share).15The gasoline-electric hybrid vehicle has both a gasoline internal combustion engine and an electric motor to provide propulsion for the car.The batteries that drive the electric motor are charged either constantly orwhen the vehicle is slowing down, depending on the design of the system.The batteries cannot be charged from an external source. The two big advantages of gasoline-electric hybrid vehicles are that they reduce pollutionand CO2 emissions and get better mileage.Mileage for hybrids is measured in miles per gallon of gasoline, eventhough the vehicle may run on electricity some or even most of thetime depending on the length of the trip and the type of driving. EPAmileage estimates for hybrids run all the way from the lower end of 25 to
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Toyota
7