Basic Electricity Patter

“You’ve got a few major units when it comes to electricity: Volts relate voltage, amperes (amps) describe the current, watts measure power and ohms refer to resistance. A pretty good analogy from HowStuffWorks relates the basic differences between them, plumbing style: Voltage is like water pressure, current (amps) is like the flow rate, and resistance (ohms) is like the size of the pipe. Increasing the voltage results in a greater current (more amps)—assuming a constant resistance-since increasing the pressure logically increases flow [Update: Clarified this sentence]. Power (wattage) is simply the voltage multiplied by the current (amps). One amp is equal to about 6.242 × 10^18 electrons per second moving through a point. And a single watt is equivalent to one joule of energy per second, but that doesn’t matter so much for our purposes.”

This little snip came from a Gizmodo article – How Electrocution Really Kills You

Spoiler Alert:  According to Adam Salvage of Myth Busters, “Seven milliamps. For three seconds. That’s all it takes.” (Enough to stop the heart.)

Convergence in Energy Density

Browsing The Bottomless Well by Huber and Mills (2005) this text on page 83-84 caught my attention:

“Burning $2-a-gallon gasoline, the power generated by current hybrid-car engines runs about 35 cents per killowat-hour (kWh). Fueled by $40-dollar-per-ton coal, may utilities sell off-peak power for 2 to 4 cents, and the nationwide average residential price is about 8.5 cents. Coal kilowatts are so much cheaper because coal is a low-grade fuel, and because a power plant’s huge furnace, boiler, and turbine are a lot more efficient than a V-8. All electric vehicles flopped in the 1990s because batteries can’t store enough power to provide range for long weekend trips. But plug-in hybrids still have the gasoline tank too, and the vast majority of the most fuel hungry trips are under 6 miles – well within the range of 2 to 5 kilowatt-hour capacity of the on-board nickel-metal-hydride batteries in hybrids already on the road, and easily with in the range of emerging automotive-class lithium batteries. The technology for replacing (roughly) one pint of gasoline with one pound of coal to feed one kilowatt-hour of power to the wheels is now here.”

While focus drifts to the plug in vehicle as a stabilizer of the grid in a two way relationship, the pocket comparisons were good enough to drive the text entry. Earlier in the text, improvements to drive trains to lower vehicle mass lead to this nice little comparison piece.

Electric Cars Considered

Plenty of good presentations on ted.com including Shai Aggasiz, recent Wired cover star:

Make Magazine is growing in fabulous ways and you’ll see why if you look at this post.  The article is well written by an involved, informed, and interested party and plenty of links, including the video above to round out your perspective on battery powered or otherwise electrified transportation.

While there are plenty of angles covered, including nightime low cost storage options in batteries to power cars in the daytime, there still is too little said on the need to conserve resources by lowering gross vehicle weight. The savings available in conservation remain to securely stuck to pocketbook economics