Let there be hybrids

In Leonardo DiCaprio's film "The Eleventh Hour" Environmental Entrepreneur Paul Hawken states that the most exciting thing about the times we live in now -- given the environmental and social challenges facing us -- is the opportunity (one might even say the responsibility) to remake the world. It's probably safe to say that it will take nothing less than that for civilization to have a shot at surviving this century.

So for starts how about dramatically changing the way we move ourselves and goods around in ways that really begins to move society towards emissions-free transportation systems? Plug-in hybrid vehicles are poised to play such a disruptive role. With some serious support for research and development and a modicum of political vision and courage, we could transform the transportation sector -- perhaps just in time to save ourselves from oblivion. (GW)

Could Germany set the standard? (GW)

Full Charge Ahead

Wind and solar power could completely replace petrol and diesel fuels in Germany. The wind and solar powered cars aren’t yet available. But a new generation of batteries and electric motors is boosting hopes of zero-emission mobility.

By Martin Bensmann
New Energy
August 2007

Felix von Borck is the proud owner of an Oscar. Not a polished one on a shelf – this one’s in the garage. The name is all it has in common with the gilded Hollywood accolade. Four wheels and electric propulsion are the outstanding features of a high-tech automobile called Oscar based in Darmstadt, Germany. From the front the small car looks a bit like a VW Beetle crunched from all sides. At the back the chassis drops suddenly perpendicularly as if it was cut off.

The small crunch ball was developed by the Academic Solar Technology Group Akasol e.V. headed by von Borck. In 1990 Akasol grew from the group of developers of the Pinky solar racing car at the Darmstadt University of Technology. Now numbering more than 50 students, engineers, scientists and other interested people the group aims to develop environmentally friendly and efficient vehicles.

Their newest product has room for two adults or an adult and two children – not exactly grand. And so Little Oscar, 2.5 metres long and 1.2 metres wide – resembles the legendary Messerschmidt cabin scooter of the 1950s much more than a modern automobile.

Interior space and cargo room don’t look any better in the other electric vehicles now on offer. They only partly meet the needs of present users. But many families do have two vehicles, a station wagon or van and a smaller car. Short local trips are usually done with the compact car, often carrying several people. For these uses hardly adequate electric vehicles are available able to match conventional ones in space and costs. It doesn’t look any better in the middle-class segment.

However, some hybrid models are on offer, that is vehicles running on both liquid fuel and electricity. The Asian corporations Toyota, Nissan and Honda dominate the field. Since 1997 market leader Toyota has sold just over a million hybrid vehicles. Last year 100,000 were bought in the United States, 3,000 in Germany. The numbers also show that even for the most established supplier of this environment friendly technology hybrid vehicles are still a niche product. They amount to about four per cent of Toyota’s sales.

Not enough research

And so Oscar is also likely to interest only a few users. Even so, its performance ratings are quite impressive. A fully loaded battery will drive it 200 kilometres. It’s lighter than the Smart, has a battery charge capacity of 17 kilowatt-hours and can do a top speed of some 130 kilometres an hour. Oscar is thrifty, consuming 8.5 kilowatt-hours per 100 kilometres, which corresponds to fuel consumption of under a litre.

Though it won’t do as the family car, the low-consumption model could serve well as a city-hopper. Von Borck points out that “50 per cent of all car trips are shorter than five kilometres, 90 per cent shorter than nine kilometres”. Studies by various manufacturers have found that on average a car is driven only 20 km a day in Germany. Electric cars could easily deliver that with their stand-by times. The big gain would be electric vehicles saving a lot of CO2 -pollution in the transport sector because of their efficiency and low emissions. But the power they use would have to be cleanly produced.

Von Borck emphasises that the main thrust of his team of designers in building models is to prove feasibility. Safety is another main issue. Does a tiny car like the Oscar have traction? The Akasol designers are pretty rough with Oscar when testing it. One car was sacrificed to a crash test after its third birthday. Other models have it a bit easier. Just recently an Oscar passed the so-called elk test of a car’s ability to swerve safely to avoid a hypothetical moose on the road.

Naturally the Darmstadt engineers are not making light of the safety issue. But it is just one of many the designers have to work on. “We need new developments in the battery area as the storage medium, in the electric motor and in the light construction of the bodywork,” says von Borck. He wants the European Union to launch a research initiative and to set up a “Zero Emission Car Platform” that puts a test fleet on the roads. He thinks 100 million euros split between Brussels and German promotion programmes should suffice for the project. Von Borck believes that would be enough to build 1,000 new electric vehicles.

€100 million is only a tenth of what the German economics ministry has spent just on 100 prototypes with fuel cell propulsion. Not only the German government has put a lot of money into the fuel cell and hydrogen, with meagre results so far (new energy 1/2007). The introduction of fuel cell vehicles has dropped far back, if it ever does become a mass phenomenon. Even in the high-end stage the technology is three times less efficient than an electric motor. The main reason for that is the high energy input and loss in producing hydrogen.

It has to be green power

You could conclude that the electric vehicle’s biggest problem is not its battery, nor motor, nor comfort, but lack of research funding. And this although there’s probably no more efficient use of electricity than in electric vehicles. So argues the Federal Environment Agency (UBA) of the German government. “Electric mobility makes sense only if it’s achieved with green power,” says the UBA’s transport expert, Andreas Ostermeier. “Those who call for electric vehicles must also consistently develop renewable energies.” He points out that too much CO2 is still emitted to produce a kilowatt-hour of electricity.

Ostermeier cites two factors for the new positive attitude to the electrically powered car of the German government’s highest authority on the environment. Lithium-ion batteries have significantly cut costs and the introduction of hybrid propulsion is playing an important part. “The physical parameters, such as energy density, of lithium-ion batteries are already adequate for many applications in electric vehicles. A major drawback of these power packs are the high costs,” Ostermeier explains. He adds that their use in port able equipment, such as laptops, has cut costs considerably in recent years. If costs continue to drop in the midterm, the lithium-based systems could also become attractive for electric vehicles, he says. Conditional on these price drops, he says, electric vehicles could soon become competitive with conventional cars for many uses over short and medium distances. “Refi ned biogas and cleanly produced power for electric vehicles are now the most promising propulsion energies to make a meaningful future contribution to a sustainable transport energy supply in terms of climate protection and volume,” predicts the expert for alternative drive trains and fuels.

7,000 wind turbines power Germany’s fleet

That’s a vision welcomed by Johannes Lackmann, President of the German Renewable Energy Federation (BEE). He calculates that about 7,000 large wind converters of the fi ve-megawatt class would produce 100 terawatt-hours of power. That’s enough to replace 400 terawatt-hours from fossil fuels because electric vehicles need significantly less power per kilometre. Road transport in Germany consumes 600 terawatt-hours per year. Lackmann suggests that the remaining gap could be filled by biofuels. Lackmann puts the lithium battery costs at €2,500 to €3,000 per kilowatt-hour. Depending on the number produced, the battery costs drop dramatically. The proportional storage costs per kilowatt-hour can also be substantially reduced in relation to the number of charging cycles. In mid-June the US company Lithium Technology Corporation (LTC) in Plymouth Meeting in Pennsylvania presented a new battery technology that comes close to future demands. The company presented a retrofitted Toyota Prius with plug-in hybrid technology (see box), which is claimed to consume the equivalent of 1.88 litres of fuel per 100 km and is propelled by the company’s newest battery generation. LTC claims that the new battery can deliver more than 240,000 km of driving.

For the battery of the retrofitted Prius, 63 lithium iron phosphate cells of a new type were used. For the negative electrodes LTC uses graphited carbon, for the positive electrodes lithium iron phosphate. This battery chemistry delivers a median discharge voltage of 3.2 volts and in the Prius battery stores 35 ampere-hours per cell. The 63 cells are series-connected, enabling them to deliver a nominal voltage of 200 volts. Thus the entire battery contains seven kilowatts of energy, enough for 50 kilometres of solely electric propulsion.

With this battery the Americans may have made a breakthrough contributing to the further development of all hybrid and electrically powered vehicles. The lithium ion technology stores power in higher quantities and much faster than the nickel metal hydride battery used hitherto, which enables better use of energy recovery (braking energy is stored in the battery) and shortens the recharging periods.

Environment friendly hot-rods?

British carmaker Lightning also touts a new technical development. The London engineers have put a new type of battery into a sports car, the Lightning GT. The battery was developed in the USA from titanium and ceramic components by the Altairnano company in Reno, Nevada, with the aid of nanotechnology. It is claimed to have a useful life of at least 12 years and be capable of 15,000 recharges.

It is certainly no thrift-vehicle. The sport racer has four wheel hub motors that deliver 700 horsepower. The recharging time of the high-tech battery is noteworthy. The company claims it takes just 10 minutes. Fully charged, the car is claimed to have a range of 400 kilometres. Both numbers are unusual at the present time. Electric vehicles usually have to be connected to the grid for at least a few hours to recharge their batteries and hardly anyone gets further than 150 km with one fi lling. There’s not likely to be a rush to buy the Lightning GT because of its €200,000 price tag. Not least the car is an expression of a new trend in the automobile and monetary upper class. Zero-emission mobiles are the rage. Hollywood stars and multi-millionaires are showing up in great numbers in environment friendly luxury vehicles. And horsepower junkies can alternatively buy the Tesla or Venturi Fétish. The designers of these fast cars show very graphically what can be technically realised now.

The question is whether hightech-made individual components will ever be available as affordable mass goods for the general vehicle market. And so, too, carbon fi bre is hardly likely to become a cheap product for making the car bodywork of the future. Some designers have recognised this drawback. In the conventional segment smart engineers are tinkering for example with the Loremo, a German-made car with the lowest consumption built from affordable materials.

First there will be hybrids

In addition to cost, comfort, reach and lifespan, infrastructure is delaying the proliferation of electric vehicles. “It is imaginable that vehicles with corresponding battery storage have a reach of about 200 km. To continue the journey, batteries could be exchanged,” says Johannes Lackmann. “At special service stations robots could remove the empty battery from the vehicle through a trapdoor in the floor and replace it with a recharged one.” In towns there could be dedicated charging stations.

“Conventional drive will be the most important in the foreseeable future, the improvement potentials for clean diesel and petrol engines are still considerable,” argues Thomas Schlick, CEO of the German Association of the Automotive Industry (VDA). He says purely electric vehicles would be most suitable now and in the years immediately ahead for limited mobility uses. A combination of combustion engine and electric motor – the hybrid – is better, he says. A big potential for hybrid propulsion is also seen by Professor Ferdinand Dudenhöffer, transport expert at the Gelsenkirchen University of Applied Sciences. The biggest markets for hybrids are now North America and Asia. “Currently about 400,000 hybrid vehicles are sold per year worldwide, with an upward trend. Compared with the global vehicle market of about 56 million cars sold annually the hybrid share is very small,” he says.

Like VDA’s Schlick, he sees purely electric propulsion still far off. Dudenhöffer expects the combustion engine to dominate for another 20 to 30 years. He also dismisses as unrealistic service stations where batteries are replaced after 200 km. “For that you need a completely new infrastructure. You only need to look how slowly gas driven cars are coming on to the market. In Germany 10,000 fuel stations are operating, it’s hard to imagine equipping them all with reserve batteries,” Dudenhöffer argues.

But considering the small market volume he doesn’t think the German and American car industries have missed out on the hybrid technology. “They’ll very quickly catch up with the Japanese,” predicts the mobility specialist. To speed the process, alliances are being formed. For example BMW, Daimler and General Motors have joined forces to present a petrol-electric full hybrid by 2009.

But the main attention of the large German car manufacturers is neither on electric vehicles nor hybrids. A lot more work and money is going into improving conventional combustion engines to make them cleaner and more efficient. Mercedes, for example, is touting its “clean” Bluetec Diesel. In addition to the usual particulate filters the new system has catalytic converters. Mercedes has two versions of Bluetec to suit different models. In the first system four catalysers reduce the emission of air pollutants and soot particles. The second version does even more. Separate injection into the exhaust system of the reducing agent “Adblue”, a special urea-based substance developed by Mercedes, cuts nitrogen oxides by about 90%.

VW puts its main focus on TSI technology in its petrol models. TSI combines turbocharging, supercharging and direct fuel injection. With this technology even smaller cylinder capacities are to achieve the performance of larger engines. A drivetrain delivers approximately the potential of a six-cylinder engine with the consumption of a four-cylinder one. In the midterm VW intends to use the concept in all its petrol engines. And in the long term the company wants to combine petrol and diesel technology in one engine. That means the cleanliness of petrol with the effi ciency and frugality of diesel in one machine. VW calls it the combined combustion system (CCS).

BMW continues to focus on inefficient hydrogen. Ford, Volvo, Saab and Renault want to boost their green images with biofuels. Apparently VW is the only maker looking at electric mobility as a pure propulsion form.

Association sees drivetrain future in hydrogen

“Our vision is the zero emission vehicle. That’s why the VDA regards hydrogen as the energy source of the future,” says Schlick. He sees both electric power generation from hydrogen with the fuel cell and the direct combustion of hydrogen in the engine pointing the way beyond the fi nite fossil sources. He argues that hydrogen can be obtained from many sources but the clear aim is to produce it regeneratively. But he doesn’t expect hydrogen, even in a fuel cell, to conquer the market before 2020.

It’s surprising that the German motor industry lobby still clings to the hydrogen vision. Wasn’t electric drive three times as energy efficient as the hydrogen chain? The car companies appear to have recognised that long ago. Many have scaled back their hydrogen activities or are setting other priorities. For example, VW’s head power train researcher Wolfgang Steiger sees two central challenges for the company. In the midterm conventional engines will be increasingly powered by biofuels, in the long term electric mobility will conquer the market. And that’s where the research activities of the biggest German car maker are headed.

The potential in switching to electric mobility is enormous. The present capacity of all German combustion vehicles is about 15 times that of all the country’s electric power stations, calculates BEE president Lackmann. “There’s enormous power in this mobile energy park,” he says. But so far this fleet passes its power only to the engine and into the air. He sees electric vehicles assuming an important function as energy storage systems in future. Power from the battery vehicles could also be fed into the grid, thereby taking a lot of strain off the power stations and making some of them superfluous.

Power industry favours the electric car

Because this would have fundamental consequences, the power industry is also taking an interest in the subject. Surprisingly, the German Electricity Association (VDEW) takes the view that it is possible to operate all German personal transportation with electric mobility compatible with the environment and climate. “We did some projections. Even if one took just wind-generated power and based the calculations on expansion scenarios, including offshore, then wind energy alone has the potential to displace all petrol consumption in Germany,” says Roger Kohlmann, deputy director of the VDEW. It would take about 35,000 megawatts (MW) of installed wind energy capacity. Precisely the same figure has been calculated by the BEE.

Ralf Bischof, managing director of the German Wind Energy Association (BWE), is happy to hear affirmation from the established energy industry that wind energy can make a much larger contribution to the energy supply than just electricity. “In the long term we will also deliver considerable contributions in the mobility and heating sectors. Wind energy will become one of Germany’s most important primary energy suppliers.” Bischof sees the big attraction of plug-in vehicles in giant battery storages spread throughout the country. “Cars are parked 23 hours of the day, mostly near a power outlet. Combined with modern communications technology we can thus make an enormous contribution to controlling power range and short-term storage to buffer wind and solar peaks,” Bischof says. But he does see a limitation. “The replacement of oil as the drivetrain energy only by wind power is sub-optimal macroeconomically, the vehicles also have to get a lot more efficient.”

The VDEW is likely to knock on the BWE’s door soon because an alliance is to be forged to discuss the topic across the stakeholders in wind converter manufacturing and battery production, power companies and the automobile industry. “The whole thing also needs political support,” suggests Kohlmann. “Our aim is to have the e-mobility option included in the federal government’s energy programme.”

No wonder the power industry is so keenly involved. Electric mobility would be a vast business for the companies. Given the urgent need to raise energy efficiency and to cut energy use, there’s hardly any scope for power sales to rise in Germany and Europe at large. On the contrary, consumption must and will drop. If the electricity industry could serve the transport sector, a large new market would open up. The power industry would be able to fire up the automobile industry and give the oil industry a run for its money. So, exciting prospects for an as yet small sector. And with those prospects the name “Oscar” for an electric vehicle is not a bad choice at all.

Micro-hybrid

This powertrain system is especially frugal in stop-and-go traffic. The vehicles are equipped with a belt-driven electric motor and control system, and an intelligent belt tightening system which enables the stop-start and generator operation. With that the combustion engine can be switched off when the vehicle is stationary, for example at a light or in a tailback, and restarted automatically without a noticeable time lag. Together with an energy management system up to 6% fuel can be saved. Vehicle type: for example the BMW 1 series since 2007.

Car with wind converter

Anyone buying a Venturi Eclectic can order a small wind power turbine (400 - 800 watts) as an accessory. Instead of petrol or diesel, the three-seater, open at the sides, runs on electricity. In eight hours, for example at night, the small wind converter generates enough power for a run of 15 kilometres. The futuristically designed little buggy also loads its battery with a 2.5 square metre solar roof area. An hour of sunlight loads enough power for the Venturi Eclectic to run one kilometre.

Mild-hybrid

This type of propulsion saves when braking. In this system the electric motor is situated on the crankshaft between the engine and transmission. In addition to the automatic stopstart facility and the generator function this system uses the braking effect of the electric motor in generation mode to recharge the battery. This process is called recuperation.

For enhanced driving performance the electric engine in motor mode provides additional boost thereby supporting the starting or acceleration phases of the combustion engine, for example. Up to 18% fuel can be saved. Vehicle type: e.g. Honda Civic IMA, since 2006.

Full-hybrid

Vehicles with this drivetrain can be powered optionally purely electrically or by combustion engine. When operated in town traffic purely electrically no emissions occur. In the design there has to be deeper intervention in the drivetrain and vehicle structures than with the micro and mild hybrids. Some full hybrids need a second clutch, a higher electric propulsion capacity as well as a traction battery with corresponding energy content.

Because voltage has to be increased for more performance a second electric system is added to the present 14-volt system. A transmission connects the two. This kind of powertrain can save up to 25% fuel. Vehicle type: Since May 2006 the Lexus GS 450h is available in Europe, the most prominent model is the Toyota Prius.

Plug-in-hybrid

The power socket hybrid, also called plug-in hybrid electric vehicle (PHEV) is a vehicle whose battery can be additionally charged externally from the power grid. Most have larger batteries than full hybrids, but basically they’re a mixed form between them and purely electric vehicles.

While one powertrain, the electric motor, is determined by the designation ‘hybrid-electric’, the other, called the ‘range extender’, for now is optional. In the present models and prototypes it’s usually a conventional combustion engine. The second powertrain in future models might be a fuel cell or a small, highly efficient diesel engine.

On short runs or in town traffic the electrically powered car runs emission-free and frugally with power from the battery. On longer runs or when the battery is empty, the car keeps going with the range extender. Vehicle type: Only test vehicles as yet; the Toyota Prius is to have these features in future.