Scientific American Plugs Plug-ins

The advantages of plug-in hybrids are probably quite familiar to most of the readers of The Energy Blog, but this article, via Felix Kramer of CalCars, is especially well written. I especially like their comments in the next to last paragraph where they conclude that the efficiency of a plug-in is much higher than that of fuel cell car.  If you want to read more than is below, you will have to fork over $4.95 at your local newstand. Felix nothing but praise for this article that is appearing in the current issue of Scientific American saying:

"Anything that goes into this 161-year-old magazine is exhaustively examined and 'vetted.'  Thus, it's a major signal that hybrid cars have arrived when an article called "Hybrid Vehicles Gain Traction" appears on pages 72-79 of the April 2006 issue (now on new-stands). That's also true for plug-in hybrids when the cover promotes the article with the phrase 'Plugged-In Hybrid Cars.' This article provides a superb overview of hybrid technology, Then it positions PHEVs as the logical outcome of the evolution of advanced technology vehicles, and explains their benefits. We present a few excerpts below."

By then [2010], next generation technology, called plug-in hybrids will offer motorists still better fuel efficiency as well as other perks: low-cost battery recharging overnight by simply connecting a 120-volt plug to an electrical outlet at home or work, very few trips to the gas station each year, and even the chance to sell surplus power back to the electric grid. Beyond the consumer benefits, however, the new plug-ins would help reduce the release of greenhouse gases by displacing emissions from millions of tailpipes to utility power plants. Today these facilities burn domestically supplied coal or natural gas, and in the future they should generate cleaner electricity from energy sources such as wind, solar or even advanced fossil-fuel systems that capture carbon dioxide for underground storage.

Some makers of full hybrids, such as Toyota and Ford, have replaced the standard Otto cycle engine used in most gasoline-powered cars with a more fuel-thrifty configuration based on the Atkinson cycle. A modern Atkinson cycle engine uses electronic controls and intake-valve timing to achieve greater expansion of the fuel/air mixture burning in the cylinder, thereby allowing the power plant to make more efficient use of the fuel. Engineers had only rarely used the Atkinson cycle before because its greater fuel economy comes at the expense of power output; however, in a hybrid, the electric motor can make up for the lost power. In highway driving, the Atkinson engine, combined with the energy savings from braking regeneration, can yield an overall hybrid system efficiency better than that of the modern diesel engine -- the leading internal combustion engine in this regard.

Plug-in hybrid electric vehicles combine the best of electric and hybrid-drive technologies...What is more, these plug-in hybrids should not be much more complex, heavy or pricey than present hybrid models. First, their internal combustion engines will shrink as their electric motors and batteries grow. Second, batteries and electronic components have been steadily dropping in price.

A conventional auto costs about 12 cents a mile to operate at current gasoline prices. A plug-in hybrid could run on electrons at three cents a mile using electricity costing about eight cents a kilowatt-hour, the current average residential rate. And given that half of American cars travel only 25 miles a day or less, a plug-in with a battery capable of providing power for a 20-mile range could cut petroleum-based fuel consumption by as much as 60 percent. Even a long-distance commuter driving a plug-in hybrid could go most of a typical day on less expensive electricity stored in an advanced batter that was topped up overnight via a conventional wall socket and partially recharged at work during the day.

Plug-in hybrids offer other unique benefits....One can speculate that a utility might lease a plug-in hybrid to a consumer or business willing to leave the vehicle connected when it was not on the road and to permit the utility to control when the vehicle's batter was charged and discharged depending on its generation or voltage-regulation needs. Such an arrangement would help utilities with load balancing, for instance. For policymakers concerned about global warming, plug-in hybrids hold an edge over another highly touted green vehicle technology -- hydrogen cars. Plug-ins would be better at utilizing zero-carbon electricity because the overall hydrogen fueling process is inherently costly and inefficient. Any effective hydrogen economy would require an infrastructure that could use zero-carbon power to electrolyze water into hydrogen, convey this highly diffuse gas long distances, and pump it at high pressure into the car -- all for the purpose of converting the hydrogen back into electricity in a fuel cell to drive an electric motor. The entire process of electrolysis, transportation, pumping and fuel-cell conversion would leave only about 20 to 25 percent of the original zero-carbon electricity to drive the motor. In a plug-in hybrid, the process of electricity transmission, charging an onboard battery would leave 75 to 80 percent of the original electricity to drive the motor. Thus a plug-in should be able to travel three to four times farther on a kilowatt-hour of renewable electricity than a hydrogen fuel cell could.

If current trends in fuel costs and concerns about climate change continue, we expect a broad market transition around the year 2020, when hybrids are likely to become a option for most models. Relatively soon thereafter, we believe plug-in hybrids will probably become the dominant alternative-fuel vehicle, with the speed of that progress determined primarily by oil price rises and government policy on climate change and energy security. Whenever the world's transportation system finally moves to replace oil as its main power source, the most plausible car design would be a flexible-fuel, plug-in hybrid vehicle running on a combination of zero-carbon electricity and a biofuel blend. If the performance of batteries were to improve substantially at some point, drivers might then gradually switch to all-electric cars. It makes senses for us to adopt this highly practical personal transportation technology as expeditiously as possible.

Resources:  "Scientific American Validates PHEVs w/Romm & Frank Article" , CalCars-News, March 16, 2005

Technorati tags: vehicles, batteries, plug-in vehicles, energy, technology

The Energy Blog: Scientific American Plugs Plug-ins

Comments

[Thomas]

I'm very excited that SA has spent 6 pages to write what is exactly my position regarding PHEVs, hydrogen and zero-carbon electricity!!! That should get the message to a broader audience.

Renewable energy + plug-in-hybrids = perfect symbiosis!

Even the idea of letting electrical utility companies control the charging of batteries to balance supply and demand is a cornerstone of of my personal vision of how renewable energy could supply 80% of our energy 25-30 years from now.

I should know this, but is the Atkinson cycle the one used in the Scuderi engine described a few posts ago?

I can't wait to get my hands on the April issue of SA! But $5 to download and print just that article is a little too steep for me!

-Thomas

[Engineer-Poet]

And another prominent voice gets on board.