Regenerative braking in the Lexus CT 200h

I've been driving my Lexus CT 200h for about two years and about 39,000 miles. In that time, I've learned a lot about driving techniques to minimize specific fuel consumption (g.p.m., gallons per mile). I've also given some thought to what it is about a hybrid that makes it more fuel efficient. One of those items is regenerative braking, where some of the kinetic energy in the moving vehicle is used to charge the battery rather than to heat the brake rotors. This is done by having the energy of the moving vehicle turn the electric motor backwards, thus making it a generator and thereby charging the battery. Of course, friction brakes are also used.

I've wondered just how much of the braking energy goes into the battery and have been hard pressed to find data for this. However, the CT 200h has a display option for "Consumption" (see photo at left). It's difficult to see (click to enlarge) but there are small boxes in the vertical bars that indicate mileage by the minute. Each complete box, according to the legend, represents 50 watt hours of energy (180,000 joules). At the top of a hill, I applied sufficient braking to keep my speed at approximately 35 m.p.h. At the bottom of the hill, a stoplight brought me to a stop.

I can calculate the energy difference from 35 m.p.h. at the top of the hill to 35 m.p.h. at the bottom of the hill by using Google Earth to find the elevation change. I determined it to be 103 meters. Because my speed didn't change, neither did my kinetic energy, therefore the reduction in my potential energy went to some combination of heating my brake rotors and charging my battery.

My best estimate of the mass of the vehicle with the 1/4 tank of gasoline and myself and my baggage is 1,600 kg. Therefore, the potential energy lost in the descent is ~E=mgh=1600kg*9.8\frac m{s^2}*103 m=1.62*10^6joules~. The display shows "E" boxes and fractions of "E" boxes and my best estimate, assuming that 3.5 "E" boxes are shown is that ~3.5*50Wh=175Wh~ or ~630,000joules~ were sent to the battery. I don't think it could be lower than ~585,000joules~ or higher than ~675,000 joules~.

Assuming that I'm interpreting the cryptic display correctly (and that Ed Davies doesn't haul me up short!), about ~630000/1620000=38.9\%~ of the potential energy went to charge the battery. The rest was dissipated as thermal energy in the disc brake rotors and, ultimately to the atmosphere. The battery pack in the CT 200h is a 1.3 kWh Ni metal hydride battery. The 630,000 joules equal 0.175 kWh or 13.5% of a full charge for the battery. Per the owners' manual, I'm able to drive in "EV mode" (battery only) for two miles, but I'd best accelerate slowly even by my standards, and not exceed about 20 m.p.h.

As an aside, this is the energy in about 18 cm^3 of gasoline. Figure I'd have to burn about four times that, or 72 cm^3 to charge the battery with the engine at 25% efficiency. And, of course, the regenerative braking isn't effective when the battery is fully charged, isn't used (much) in hard stops, etc. Still, it does increase overall fuel efficiency.

Finally all of these figures have large "error bars," the regenerated energy on the display, the elevations from Google Earth, the mass of the vehicle, and the ability to stay at precisely 35 m.p.h. (although really, all I need is to be going at the same speed when I stop logging as when I start so that the kinetic energy is unchanged). Still, it's enough for me to have a good idea of what the regenerative braking can give me.

Update: Based on a comment by Gabriel Grosskopf, I measured the distance over which I descended. It was 1,530 meters, thus the slope is 3.86 degrees (0.0673 rad). The typical instrument landing system glideslope is 3 degrees though a few, such as VNY - Van Nuys - at 3.9 degrees, are steeper. Assuming that I drove the 1530 meters at 35 m.p.h. or 15.6 m/s, it took me 98 seconds to put 630,000 joules into the battery. This is a charging rate of 6,440 watts or 6.4 kW. As mentioned in a previous post, when I put fuel in my gasoline tank, I'm adding energy at a minimum rate of 11 mW, about 1,700 times as fast. To be fair, we'll divide that by four since IC engines are much less efficient than electric motors. So we're adding useful energy at 2.75 Mw or 430 times as fast. Coincidentally, the Nissan Leaf touts a 6.6 kW charger to charge its 24 kWh battery.

Senators Grill Refiners Over High Prices Amid Oil Boom - Bloomberg

Senators Grill Refiners Over High Prices Amid Oil Boom - Bloomberg:

'via Blog this'

My dismay with our elected representatives comes again to the fore. In the linked article above, we find Ron Wyden, Democratic Senator from Oregon and Chair of the Senate Energy and Natural Resources Committee saying "Our people want to know why the flood of new domestic crude oil isn't lowering prices at the pump. There is no question that the lower oil costs are not getting through to Americans' wallets."

To the left is a plot of oil prices (WTI) over the last five years. I'm having a very difficult time spotting Wyden's "lower oil costs." There are so many supply and demand issues that play into not only the price of crude oil (which is a world wide market and cannot be affected in any reasonable way by the Senate) but on the price of finished products from oil such as gasoline. These sorts of speeches constitute pure political pandering. But he's a politician so I guess it's to be expected (a la the scorpion in the fable of the scorpion and the frog)

Do I enjoy paying $4.099/gallon for my gasoline? No, but I'm averaging 51 m.p.g. so it doesn't hurt me as badly as many others and, were I King, I'd increase gasoline taxes by $0.25/quarter for the next three years. Many who read this will be relieved that I'm not King.

Windation and the Turbo Windmill 5000

I've composed several posts regarding building integrated wind energy. Pictured at left is the Turbo Windmill 5000 by Windation. It's designed for rooftop installation and is represented to be "permit ready." It's dimensions are 9' X 9' X 10' and it weighs 2,200 pounds. This is claimed by Windation founder and CEO Mark Sheikhrezai to be "less than half" of the weight of an HVAC system. What particular HVAC system is the subject of this comparison is not stated.

The "5000" is the nameplate capacity of the turbine in watts, whose cut in wind speed is 2.7 m/s and whose most effective operating range is stated to be 4.5 to 9 m/s (for the SI unit impaired reader, these are 6, 10, and 20 m.p.h. respectively). It's a vertical axis wind turbine (VAWT) and thus is agnostic with respect to wind direction. The turbine itself is fully enclosed, thus eliminating the possibility of bird and bat kills.

In an interview at the CleanTechies blog, Sheikhrezai claims that the Turbo Windmill 5000 utilizes a proprietary vacuum system that "captures and funnels turbulent wind in a smooth, counterclockwise stream" and that thereby "a vortex is created beneath the internal turbine enabling a vacuum effect, pulling more wind into the frame and amplifying input loads." Sadly, he then states that "energy available in the wind is proportional to the cube of its speed." This is false, power is proportional to the cube of speed, energy is proportional to the square of speed. We'll forgive Sheikhrezai this transgression. Sheikhrezai states that the Turbo Windmill 5000 can produce 10,000 kWh per year with an average wind speed of 7.2 m/s (a bit over 16 m.p.h.).

OK, let's dive into a "back of the envelope" plausibility calculation. Using the photo above and assuming that the 9' dimensions are horizontal, the 10' dimension is height and that the only wind entrance is the "yellow" portion, I can use Tracker to scale the wind accessible dimension as 7.25' X 3.43' or 2.31 m^2. First, what's the total power in wind of cross sectional area of 2.31 m^2 travelling at 7.2 m/s? We have a volume, ~V~, of 7.2 meters X 2.31 meters passing any given point in one second. The air's density, ~\rho~, (assuming sea level - most favorable for the calculation) is 1.225 kg/m^3. We use ~E=1/2\,m{v}^{2}~ and ~m=\rho\,V~ for ~E=1/2\,\rho\,V{v}^{2}~ or 52,800 528 joules each second or a power of 0.528 kilowatts. This certainly doesn't indicate that the power claims are implausible. Windation claims to capture about 10% of the available power (assuming that the 5 kW nameplate capacity is for 7.2 m/s wind speed - if it's for a higher speed, they're claiming still less efficiency).

Update: Thanks to Ed Davies for causing me to take a look and realize that I'd been off by a couple of orders of magnitude (using 122.5 instead of 1.225 kg/m^3 for sea level mass density of the atmosphere). How embarrassing! So, what to make of the claim of 5 kilowatts? Working backwards, what would this imply for a wind speed? Betz' law provides the theoretical limit of turbine efficiency (the maximum fraction of the energy available in wind that can be captured) at about 59%. The best efficiency I've seen for a turbine is about 70% of the Betz limit or, in round numbers, 42% of the power in the intercepted wind. This is achieved by horizontal axis turbines (typically much more efficient than VAWTs) of enormous size at ideal wind speeds. But let's generously assume that the proprietary vacuum effect enables Windation to capture and utilize 45% of the wind's power. So, 0.45*(available wind power)=5000 watts and available wind power is 5000/.45 = 11,100 watts. Working backwards and solving the equation above for speed and plugging in 11,100 watts, we find a wind speed of 19.9 m/s or just under 45 m.p.h. And the generous assumptions are beyond unlikely to be met in a real installation.

With respect to the claim of 10,000 kWh/year at average wind speed of 7.2 m/s, it's hard to say. "Average" doesn't work well here. Say we had an hour of wind at 7 m/s and an hour at 7.4 m/s. Then say we had 4.2 m/s and 10.2 m/s. Because of the proportionality of power to speed cubed, the two hour span with the more extreme speeds would generate about half again as much energy yet both have, in a sense, the same "average" wind speed. That said, if the Turbo Windmill 5000 generates 5000 watts for a year (365.25*24 or 8,766 hours) it would result in 43,830 kWh so it doesn't seem like an excessive claim (IF, of course, it can generate 5kW). No cutoff speed is given. Much deeper information on wind speed distribution is here.

Update (see above): 10,000 kWh/year is a continuous power of (10,000 kWh/year)/(8,766 hours/year) or 1,140 watts. Proceeding as above, with the generous assumptions there, we're talking about a steady wind of 9.3 m/s or 21 m.p.h. Now, admittedly, a variable wind that has periods of very high speeds may improve on this but, on the other hand, my efficiency assumptions are extremely generous and highly unlikely to be realistic.

Finally, I have to point out that 10,000 kWh would cost me about $1,200 from the City of Anaheim Public Utilities. The price for a Turbo Windmill 5000 given at the web site (where, sadly, I found the sentence "the machine can generate 5 kilowatts of power per year") is $45,000. It's implied but not stated that this includes installation. The claim is that "With the available incentives and rebates, it is estimated that the initial expenditure of $45,000 can be recovered in five to seven years." Payback period is a poor indicator of the desirability of an investment when considering periods beyond two years, but even with that, we must be talking about a LOT of rebates and incentives.

So:

Energy claim:                                                                                                   Economics claim: 

Update: An excellent overview of building integrated wind is here.

Update 2: While looking for further information to attempt to better understand Windation's claims, I noted that the article linked above was published in 2010. I'm not sure why it wound up in my inbox recently, but I decided to see if the firm is still a "going concern." The last update on their web site is from November of 2012 and I find no record of bankruptcy proceedings. However, their corporate address is 1007 Florence Ln., Apt 1, Menlo Park CA. Here's a Google Streetview screen shot of their corporate HQ:

Windation has claimed that they'd install a unit at the Palo Alto Medical Foundation in the first quarter of 2010. I located architect's renderings of the installation and then found the facility as constructed in (where else?) Google Streetview, and the Turbo Windmill 5000 was not installed as of the photo date of March, 2011.

Doing a lot more reading about "building integrated" and "urban" wind, the field seems to be full of dodgy claims and outright scams. I don't know which category, if either, Windation falls into but a lot more information on these topics can be found at Paul Gipe's site. The pertinent information is here.

Update 3: In my further digging, I located a video of an actual unit (well, possibly an actual unit, one can't really tell as it's sitting on some sort of pavement area and the intake is covered). But something does, in fact, exist. The video was uploaded on November 5, 2011 and Windation left a response to a viewer comment "a year ago." The video is FAR from professionally produced. It's embedded below for your viewing pleasure.

I have to say that this is very disturbing in that false claims, vaporware and dubious business practices provide ammunition for those who would claim that renewable energy is a chimera and that increased business as usual is our only option. It further muddies the water with respect to what constitutes sound investment opportunities in the so-called "green space." Finally (yes, finally), it's a shame that the "green press" uncritically embraces such products and schemes without doing the necessary evaluation.

Solar sells - anything

I was watching something on the Discovery Channel (which used to be about 70% watchable and 30% "I'll pass" and is now about 90% unwatchable) when I saw an ad for the "Bell & Howell Solar Charger." While "Bell & Howell" apparently still exists as going concern, they also license their trademark "to makers of various electronic consumer products." The Solar Charger is the product of one such maker. Should you have chosen to click on the link, you'll have had the opportunity to see the charger allegedly in action "instantly" charging iPhones, iPads, a handheld GPS, and all manner of  devices. Besides the sun, the charger is also capable of charging from a computer USB port, but the advertising touts a scantily clad woman at the beach, apparently using the sun to charge her iPad.

Let's take a look. The specifications are scant at best and hard to find. I've been able to determine that the battery is a 410 mAH (milliamp hour) Li ion battery. I'm going to assume that this is at 5 volts (the required charging voltage for an i-Device). I'd really like to have specifications for its capacity in watt hours. But, assuming as stated, it's 2.05 watt hours. Now, an iPhone battery has a capacity of 5.4 watt hours, so a full charge, neglecting efficiency, on the solar charger would charge a dead iPhone to about 38% of capacity. An iPad has a 42.5 watt hour battery and thus the charger will provide just under 5% of a full charge. Mine shuts down at that percentage. The "instantly" claim isn't supported by current battery technology in the devices, so the devices must simply operate off of the charger (to the extent that it works at all).

But what about the sun? The Amazon page for the charger lists its dimensions as 5" L X 1.5" W. Using the free and terrific Tracker Video Analysis software (which works just fine on jpegs) I determined that the "high efficiency solar cell" is about 1.46" X 0.85". This is ~8.00*10^{-4}{m}^{2}~. I'll also assume the cell to be 20% efficient. I'll use ~350\,{\frac {w}{{m}^{2}}}~ as a good average for available insolation in my area. That yields a charging rate of about ~8*10^{-4}*350*0.2 = 0.056~ watts and a time to charge to capacity of ~2.05/0.056=36.6~ hours. Others at various review sites cite (sites cite? I like it) two days, which doesn't seem unreasonable. On the web site video, they show the unit being charged under a table lamp. Umm... good luck with that.

I actually have several solar chargers for my various devices, all of them are quite bulky as you'd expect. Solar power density is just not that high. It's amazing that a profit can be made by slapping a trivially small solar panel on what is otherwise an extremely poor quality auxiliary charger for your portable device. And, don't forget, for an extra $10 you can get it with a three bulb LED flashlight. Finally, they'll send a second charger free (just pay separate processing and handling). My rating for this product:

Low hanging fruit revisited

Photo credit: Lincolnloop.com

About three years ago, I posted an article on the "low hanging fruit" in fuel savings. In that article, I demonstrated that for a given increase in m.p.g., the lower the starting m.p.g. (before the increase) the more fuel will be saved by that increase. Thus, a driver who drives 12,000 miles per year and increases from 15 m.p.g. to 18 m.p.g., either by purchasing a new vehicle or changing driving habits, will save about 133 gallons of gasoline per year. Another 12,000 miles per year driver who increases from 25 m.p.g. to 28 m.p.g. will save only about 51 gallons per year. The best way to understand this is to think of gallons per mile or, more transparently, gallons per 100 miles, the inverse of m.p.g. This number is 100*1/(m.p.g.) Thus, the first driver uses 6.67 gallons per 100 miles before the change and 5.56 gallons per 100 miles after. This driver saves 1.11 gallons every 100 miles. The second uses 4 gallons per 100 miles before and 3.57 after. This driver saves 0.43 gallons every 100 miles.

I was reminded of that post by this article in Energy Trends Insider. The article discusses a construct from the Department of Energy (DOE) at a new website that discusses the so-called "eGallon." This number purports to give the quantity (or cost) of the electricity that it would take to move a "typical" electric vehicle (EV) as far as a gallon of gasoline takes an "average" conventional car. This is where the "low hanging fruit" concept comes in. Replacing a 20 m.p.g. vehicle with an EV saves MUCH more than replacing a 30 m.p.g. vehicle. The 30 m.p.g. vehicle goes half again as far on a gallon and thus the eGallon costs more for that driver.

I applaud the DOE for attempting to clarify the possible savings in fuel expenditure vs. electricity expenditure but, in some cases, it may be very misleading. The calculation is further complicated by the wide variance in how electricity is priced in various localities.

As to the "low hanging fruit," the plot below shows, for a driver who drives 12,000 miles per year, how many gallons of fuel are saved per year by moving from one m.p.g. driving regime to a higher one. It plots initial m.p.g. from 10 to 40 and final m.p.g. from whatever was the initial m.p.g. to 120 m.p.g.  The "front" axis is initial m.p.g., the axis that extends back and right is final m.p.g., and the vertical axis is gallons saved. As can be seen in the rightmost portion, the savings from a high starting point are not nearly as large. It's also easy to see, especially at the left end, that the big gains are in the initial improvements - the slope is dramatically steeper than at the higher final numbers.

India burning coal at fastest pace in 31 years, will eclipse China as world’s coal power

India burning coal at fastest pace in 31 years, will eclipse China as world’s coal power:

'via Blog this'

 Yes, well, it's hard to imagine that a country or society that lets these things happen is going to care much about CO2 emissions from a coal fired power plant (not that we in the U.S. don't have our own slums and our own group of people who don't care about CO2 emissions from coal fired power plants).

Misallocation

A couple of things will come as no surprise to my regular readers. The first is that I consider myself to be a true conservative and that the foolishness, hypocrisy, obstructionism, and fact-free opining that passes for conservative commentary today is a source of deep embarrassment to me. The second is that I consider the ability to ensure a reliable and sustainable supply of primary energy to be one of, if not the, greatest and most important challenges we face not only in our nation but in the world (the other possibilities include "peak everything" and self-poisoning of our species, the latter including pollution of all types, CO2 emissions, etc.).

Thus, it is deeply disappointing, though not particularly surprising, that the full House Appropriations Committee approved along party lines, a bill with deep cuts to renewable energy projects and, particularly, to arpa-e, an organization whose annual "Energy Innovation Summit" I've attended the last three years. The $30.4B bill is $2.9B below the 2013 level and $700M below the sequestration level. arpa-e, in particular, received a cut from $252M to $50M, a reduction of 80.8%. This is tantamount to the committee saying "we don't want arpa-e." President Obama (of whom I'm certainly no fan) requested $379M. You can read the committee's press release here.

arpa-e is engaged in funding of high risk, high reward projects in the energy field and funds technologies from fuels and generation to storage to distribution to control, as well as carbon capture, efficiency in buildings, transportation technologies, and many others. Can anyone deny that these technologies constitute the way forward in a coming (if not here already) time of energy limits?

Energy Subcommittee Chairman Rodney Frelinguysen (R-N.J.) was quoted as saying "It is our job to make do with what we have, not with what we hope to have." I wonder where the money could possibly be found?

Down the rabbit hole...

Image Credit: Dr. Dave Goldberg at io9.com

There sure are a lot of people out there that are much smarter than Einstein, Dirac, Boltzmann, Maxwell, etc.

In my post on the MIST Engine, I stumbled upon a treasure trove of unrecognized brilliance.

Amuse yourself with these geniuses at your leisure. If only mainstream science weren't so closed-minded, physicists and cosmologists could be open to such brilliance.

Update: Woah! This one is simply too good to leave out!

"Free" energy

Image Credit: Sweet Samoa

In my feeds from the soon to be late, lamented Google Reader (the company whose motto should change to "Evil R Us") I've included the aggregator "Alternative Energy News." Many of the articles are interesting and discuss important ideas and developments. Others... not so much. For example, articles from "Pure Energy Systems Network" (PESN)" are aggregated. This is a site that delves into the world of such exotica as gaining useful energy from  zero point energy, magnet motors, motors that are alleged to run on the energy in cavitation, energy from "low energy nuclear reactions (LENR - the new name for what used to be called 'cold fusion')," and others. The sense of the site is, unsurprisingly, that any or all of these could change the world but for the oppression of the powers that be (our government and corporate overseers).

The subject of this post is the "Molecular Impact Steam Technology (MIST)" engine. This technology claims to utilize hypersonic water jets to "explode hydrogen bonds" in water, thereby releasing enormous energy, thus producing dry steam without heat input. MIST claims a "10:1 overunity factor," meaning that the energy available in the steam is 10 times greater than the energy used by the pump utilized for the water jets.

The claim is that one pound of water, using 127 btu of input energy results in dry steam with an energy content of 1,100 btu. First, let's convert to SI units using Cloudy. Rephrasing, 134*10^5 joules converts 0.454 kilograms (or 25.2 moles) of water into steam with an energy content of 1.16*10^6 joules.

Now, typically energy is released upon the FORMATION of bonds, not on the breaking of bonds (nuclear fission of atoms larger than iron is, of course, an exception). Therefore, the "exploding of hydrogen bonds" does not pass the initial "sniff test." Enthalpy of formation of hydrogen bonds in water is subject to significant variation, but a reasonable number is about -23.3 kJ/mol. This means that the formation of hydrogen bonds RELEASES about 23.3 kJ (kilojoules) for each mole of water. These 23.3 kJ must be SUPPLIED to each mole to break these bonds. In other words, energy must be supplied to break the bonds, breaking them does not release energy.

On their web site, there are many pages with calculations and data and a couple of papers on tangentially related topics. I'll dissect one such page.

The claim is that the increase in specific kinetic energy (J/g or J/kg) in moving from a jet velocity of 810 m/s (where there was no dissociation from liquid water to steam when the jet impacted the chamber wall) to 3000 m/s (when steam was created) is from 320,000 J/kg to 4,500,000 J/kg. This is correct. But they claim this proportionality to v^2 as a kind of "mechanical advantage." Of course, the energy to accelerate the water must be supplied to the pump.

They then meander into a paragraph that mentions a 10 h.p. pump providing the pressure to process 120 pounds of water per hour. They state that 10 h.p. is 7.46 kW. So far, so good. They then divide by 60 and state that this is 124.3 watts per minute. Say what? Watts is already a "per unit time" unit. That is, the watt is a rate, not a quantity. Watts per minute is an acceleration of power, surely not what they mean. Heaven knows what they DO mean.

They then say that they pump 2 pounds of water per minute at 30,000 p.s.i. and 3,000 m/s. They next state that this is "1139 watts using only 124.3 watts of energy." Oh, brother! The watt is not an energy unit, it's a rate of supplying energy or doing work. The 124.3 came from  dividing the pump power of 7.46 kW by 60 for reasons unknown. So they believe that they're getting 1139 watts of output for 124.3 watts of input and that "the rest of the energy comes from the energy contained within the bonding of the molecules of water." Of course, breaking these bonds ABSORBS energy (specifically, around 20 kJ/mol or 1,120 kJ/kg).

It's hard to know whether they're aware that they're selling snake oil or just misguided. Perhaps they create steam more efficiently than a flame fire-tube or water-tube boiler (I'm no expert on the efficiency of boilers) but they certainly aren't achieving overunity by the freeing of hydrogen bond energy in water.

Wasted energy

Nope, I'm not talking about the 75% of the energy in the gasoline in your car going out the exhaust pipe as waste heat, or the cooled/heated air escaping your house because it's not as "tight" as it could be. I'm not talking about anything to do with the inefficiency of the use of primary energy. I'm (against my usual nature) using a more colloquial meaning of "energy" here. I'm talking about foolish expenditures of "mental energy" on schemes that either will produce no useful energetic results or such a trivial amount of energy that it's a waste of time to bother.

I've previously written of the foolishness of humans as generators via walking and revolving doors, the silliness of one of the Discovery Channel's "Project Earth" programs (they were all fairly silly but I focused on a specific one). I've got two more examples.

The first is something akin to the "human powered generator," that is, it would probably work from a technical point of view but be useless in any practical way. I was pointed to it by a post in Tom Sanwson's Swans on Tea blog entitled "This Claim Won't Fly." The post referred to an article on CNN's site about Airbus working with UNESCO to challenge engineering students in a "Fly Your Ideas" competition.

Of the ideas described in the article, one sounds far out (shape shifting engines to reduce noise footprint), one marginally practical (powering jets with a supercooled mixture of biomethane and LNG), and one ... let's just say silly. That last one is to use seats upholstered in a thermoelectric fabric to use passengers' body heat to generate electricity. University Putra Malaysia team leader Tan Kai Jun envisions generating "100 nanowatts of voltage." Like Tom Swanson, I'll ignore the fact that watts is not a unit of voltage, but rather a unit of power.

"It's a small amount, but imagine this collected from 550 seats throughout 10 hours of flight. A plane has a lifespan of a few hundred flights -- over time that's a big reduction," Mr. Jun Tan says."

Tom ran some numbers, but I'll do the same. The "age" of an airliner is measured in pressurization cycles, and a "typical" airliner may have 51,000 flight hours and 75,000 pressurization cycles in its useful life. Let's consider an airliner with 400 seats (say, a B777) and 51,000 hours. We'll assume the plane flies with an average load capacity of 95%. So we have 400*51000*.95 = 19,380,000 seat hours. Using the the Google Chrome extension "Cloudy Calculator" and multiplying hours times 100 nanowatts (the calculator does all conversions) we find that we've generated 1.9 watt hours over the life of the aircraft. I pay about $0.12 (12 cents) per kilowatt hour at my house, so this almost two watt hours is worth a smidgen (one of my favorite units - slightly smaller than a skosh) over a fiftieth of a penny.

Looked at another way, Jet A fuel (used in airliners) has an energy density of 35.3 megajoules per liter. 1.9 watt hours is about 7,000 joules, or 0.007 megajoules. So, over the lifetime of the airplane, the passengers would generate electrical energy equal to the chemical potential energy in 0.2 milliliters of jet fuel. Of course, a heat engine such as a turbofan might operate at, say, 45% efficiency so we'd actually need to burn a bit under half a milliliter to generate those 1.9 watt hours. I suspect that this development will not revolutionize flying.

The next post will cover a different type of silliness - one that's either a fraud or pie in the sky.

Embarrassed to be conservative one more time (but likely not the last)

As I've stated repeatedly, I'm conservative by nature. I'd like to conserve resources (financial, natural) and our civil liberties. This is what conservatism means to me and what it used to mean to others who so self-label. Now, though, it seems to have come to mean "conserving my opinion on the way things are regardless of factual evidence that I'm wrong." An entire media universe has sprung up around this false conservatism, nowhere more clearly demonstrated than in Fox News' coverage of science.

Below is an embedded clip from "Media Matters" with some of sillier utterances of false conservative talking heads. Please don't construe my embedding of this video as an endorsement of the politics of Media Matters, I'm in deep disagreement with their viewpoint on many matters as well. But watching Bill Nye the Science Guy when he's asked if volcanoes on the moon are related to global warming on Earth is priceless. He clearly is struggling to retain his composure when asked a question that any sixth grader should understand is ludicrous. And birds will redo their chromosomes in a generation or two???

I'm going to have to come up with a new name for my point of view - identification with such as these is repugnant.

Privacy

Certainly, this post will stray from my topic space as I've done in the past. I feel compelled to opine on the NSA leaks saga (purposely not calling it the Edward Snowden saga for reasons that will be apparent).

In my life I've been a tin foil hat arch right wing reactionary, a socialist, a strident atheist, a Christian (as I believe today), a doctrinaire libertarian, and many others. But one thing in my belief system and philosophy that has never wavered is my staunch belief in a right to privacy. The Fourth Amendment ostensibly assures us of our right to be "secure in our persons, houses, papers, and effects, against unreasonable searches and seizures...."


This right has been continuously eroded by Congress, by the Courts, and by the Executive branch. In my opinion, far and away the most egregious violation is the odious "USA Patriot Act of 2001." In causing the Congress to pass, the President to sign, and the people to accept this blatant violation of the founding principles of our Country, Al Queda and Bin Laden in fact have won. The nation we were no longer exists.

Now, of course, the ability to infiltrate into every private area of all of our lives should the mood strike has been the heartfelt desire of anyone involved in law enforcement, no matter how tangentially, from time immemorial. But it wasn't to have happened here.

Now, along comes Edward Snowden. I'm completely disinterested in who he is, what his motivation was, where he went to school (or didn't), or anything else about him personally. My forlorn hope is that his revelations will cause a backlash against the encroaching "security at any cost" rationale behind the actual "we need the power because we want it" motivation of our security nation overseers and the actions they've undertaken to accomplish this goal.

Sadly, the propaganda machine, from right to left, has succeeded in making the debate (such as it is) about Snowden. Is he a traitor? A whistleblower? A Chinese spy? A frustrated loser? A narcissist with a martyr complex?

I don't care. The fact is that those who have promulgated and supported the activities revealed by Snowden are the real traitors here, and that will be lost in the debate about Snowden.

Rates vs. quantities - more unit confusion

It's widely accepted (though not universally) in the renewable energy/clean tech/green community that one of THE major problems in the widespread adoption of such renewable sources of electricity as solar and wind is their intermittent character. It's further believed that the ability to store the energy from these sources will enable their intermittency to be smoothed out, thus making them a reliable source of energy and enabling them to become much more easily integrated into the grid, possibly even a source of baseload power.

I read today that my state, California, has, through our Public Utilities Commission, set a goal of "1.3 gigawatts of energy storage by 2020." My state is certainly at the leading edge of sustainability with AB32, the Global Warming Solutions Act of 2006, the Cap and Trade Program, and many others. But I worry about people who make laws write regulations and yet aren't able to distinguish between rates and quantities.

Here's a link to the Assigned Commissioner's Ruling on this. Throughout the document, Carla Peterman discusses storage in megawatts. But a "watt" is a rate of energy utilization, or rate of performing work. A megawatt is a million joules per second. Certainly, the rate at which a storage system can deliver energy is important, but the key is the quantity that can be stored. This would be measured in watt hours, kilowatt hours, megawatt hours, gigawatt hours, terawatt hours, etc. Or, equivalently, in joules, megajoules, etc. Saying "we need 1.3 gigawatts of storage" is analogous to saying San Francisco is 80 miles per hour away from Los Angeles.

A typical gasoline pump will pump, conservatively, around five gallons per minute. Each gallon of gasoline has a chemical potential energy through oxidation of about 132 megajoules. Thus, when you fill your tank, you're delivering energy at the rate of 132*10^6 joules/gallon * 5 gallons per minute/60 seconds per minute or 11 megawatts. About 120 people filling their tanks are delivering energy at about the 1.3 gigawatts mentioned by the PUC. But this doesn't tell you a thing about how many miles these 120 drivers can travel. To know that, you need to know the capacity of the 120 tanks in gallons (along with the rate of fuel consumption of the vehicles).

To provide a bit of orientation as to the rates being discussed, in 2011, California generated or imported a total of about 292,454 gigawatt hours of electricity. This is a rate of about 33.36 gigawatts so the storage being discussed could deliver a bit under 4% of the average California rate of electricity usage.  Of course, the planned storage is divided between different utilities and geographical locations and would be deployed locally. But key to the discussion is FOR HOW LONG? A second? A minute? An hour? A day? Nothing in the document tells us.

Addendum, June 15, 2013: It's bad blog form to edit a posted blog without saying so. In reviewing the above, I realize that, while it's quite true that capacity is a fundamental metric of the viability and practicality of storage, rate is also important. I alluded to that above but I want to make it clear that I realize that vast capacity is not relevant if the rate at which it can be delivered isn't matched to the demand present in the area served.

This merits a bit of analysis of what sort of capacity might "match" a delivery rate of 1.3 gigawatts. For a starting point, let's take a look at the 4% calculated above. And I'll arbitrarily assume that we'd like to be able to "even out" the output from intermittent sources over a 24 hour period with a reserve capacity (no wind, cloud covered sky, whatever) for three days. In three days, on average, California might use (3/365)*29,2454 or about 2,400 gigawatt hours of electrical energy. 4% of this is 96 gigawatt hours.

Arguably, the storage method with the best combination of capacity, dispatchability, delivery rate, and efficiency is pumped hydro storage. If we assume a round trip efficiency of 75%, we'll need to store 128 gigawatt hours of energy. Hoover Dam delivered, at its 1984 peak, 10.348 terawatt hours so, in an average three day period in 1984, it delivered 10348*(3/365) = 85 gigawatt hours. So we're talking about something like one and a half Lake Mead/Hoover Dam storage schemes.

By the way, this goes to show just what an amazing resource gasoline is. 3032 gasoline pumps can deliver the energy equivalent to the entirety of California's average electrical consumption.

Update: The Blenheim-Gilboa Power Station in New York can deliver electricity at the rate of 1.6 gigawatts and, per a comment in a post on pumped hyrdo storage at one of my favorite sites, Do the Math, can deliver this for 16 hours for a total of 25.6 gigawatt hours. Another site says 1,000 megawatts for eight hours, or 8 gigawatt hours. In any case, storage of the magnitude specified is certainly achievable.

Also, as seen here, it's clear that pumped hydro plants are typically rated in rate in watts rather than capacity and, in fact, it's difficult to find the energy capacity in megawatt hours or gigawatt hours. In a comment in the article linked above, Ben K. say that this is because generating plants are rated in this way. But I don't see that this is a valid reason. A generating plant generates continuously as long as coal, natural gas, uranium, etc. is delivered - the amount of source material is not the issue. In a storage facility, the amount of source material (compressed air, battery chemical potential energy, water, flywheel rotational energy, capacitor electrical charge energy, whatever) is THE issue. After all, we look at battery storage capacity in terms of amp-hours which, at a fixed voltage, is a measure of quantity of energy.

Reaching Energy Limits in a Finite World | The Energy Collective

Ignoring the slight tendency toward self-promotion at the end, here's a very insightful essay on the converging limits of energy and financial resources by Gail Tverberg. I look forward to her further fleshing out of the self-reinforcing feedback loop of the decreasing availability of high grade, high EROEI energy resources with their consequent increasing costs and the decreasing availability of financial resources to overcome these problems.

Reaching Energy Limits in a Finite World | The Energy Collective:

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arpa-e 2013

I've just finished attending the arpe-e Energy Summit for 2013. It was certainly the most star-studded of the three I've attended (Elon Musk, Dr. Steven Chu, T. Boone Pickens, Michael Bloomberg, a handful of Senators and Congresspersons spoke, presented, or participated in panel discussions).

There seemed to be, even for Dr. Chu, the strong sentiment that "the era of energy scarcity is over" based on recent increases in U.S. fossil fuel production, primarily due to tight oil (Bakken Shale, Barnett Shale, Eagle Ford Shale, etc.) and shale gas (Marcellus Formation, etc.). This led to a certain "yeah but..." sentiment in that the existence of arpa-e (advanced research projects agency - energy - a funding mechanism for bringing early stage energy technologies ultimately to market and modeled after "DARPA") is based on the need for the U.S. to develop clean, renewable energy sources not dependent on fossil fuels. The "yeah but..." seemed to be along the lines of "yeah, but even though we have all these new fossil fuel resources, we need to develop clean, renewable alternatives to fossil fuels because:

• U.S. fossil fuel users are still subject to world pricing pressures
• Climate effects of burning all of this fossil fuel may be catastrophic
• We still have a huge trade imbalance due to the need to import oil
• We are spending billions in the Persian Gulf and elsewhere to defend our ability to import oil

All of these things are true and are certainly good reasons to develop the capabilities represented by the many firms and institutions participating in the Summit. But the underlying concept that the tight oil and shale gas will free us from concerns about fossil fuel shortages is very flawed.

Kurt Kobb of the blog Resource Insights seems to me to have the most insightful information with respect to the real prospects for a fossil fuels energy revival in the U.S. I'd suggest starting with this post and reading all of Kobb's information on unconventional fossil fuel prospects. There is also a huge amount of pertinent information from experts at The Oil Drum site. The most comprehensive and authoritative document I've located on this topic is here, a free downloadable pdf.

The cliff notes version is that these unconventional sources have characteristics that make it extremely unlikely that we'll not have to worry about fossil fuel shortages and high prices for decades to come:

• They are much more expensive to drill than conventional sources
• Their depletion rate is dramatically higher than conventional sources

Thus, both economics and geology argue strongly against our entry into a new world of energy abundance. Does that mean that the alternative reasons for funding research into clean, renewable energy sources should be ignored? It does not, but the primary reason - our society's need for reliable energy to turn the wheels of civilization - has not disappeared in the midst an unconventional fossil fuel cocktail.

Dr. Chu, in his keynote address today, had some figures and charts for which his summary was "are we in danger of running short of fossil fuels? I don't think so." Unfortunately, he blew by these slides with little commentary beyond that and no time for me to find the source or even photograph the slide. Hopefully, the materials to come post-Summit will enable me to determine what gives Dr. Chu (a man for whom I have huge respect) such confidence.

Cassandra's legacy: The Twilight of Petroleum

A cold hard look at the future of petroleum production adjusted for actual energy availability. It's well worth absorbing in detail in light of the celebratory articles on US energy independence, International Energy Agency production estimates, etc. that paint a view of the world of energy through rose colored glasses.

Cassandra's legacy: The Twilight of Petroleum:

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Atmospheric Vortex Engine

Credit: Atmospheric Vortex Engine

Below is a link to a fascinating and promising concept for generation of electricity called the "Atmospheric Vortex Engine." The FAQs even include a pretty extensive and (on my relatively cursory review) accurate primer on thermodynamics. When I first read of this concept I pooh poohed it but I saw it linked in several sites that I respect and went back for a closer reading. I've come to think that it has significant potential.

I'd divide the possibilities into two "bins." The first is as an auxiliary generator at existing thermal power plants, where the site claims that power output of the plant can be increased by 20% (read the site to see how this would work). In this application, the generator could operate on the same duty cycle as the thermal plant.

The second bin would be a stand alone installation operating between solar heated ground or water (without dedicated collectors) and the much cooler temperatures clear up to the tropopause (!). In this application, I presume that the duty cycle would be less than 24/7 (though it should be much longer than a photovoltaic or concentrating solar thermal plant) and thus would provide less than continuous power and suffer from a reduced but similar intermittency issue as solar or wind generators. For all such installations, grid-scale storage would be a huge advantage.

In any case, this concept is one to keep sight of.

Atmospheric Vortex Engine:

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The Archdruid Report: Into an Unknown Country

The link below is to John Michael Greer's (the Grand Archdruid of the Ancient Order of Druids in America) first post of 2013. In it, he describes his 2012 predictions and how they played out against the actual events of the year. He then makes predictions for 2013, followed by a "to do" list to prepare for the events that he foresees.

Don't let the Druid slant throw you off. This is a deep, creative, accurate thinker with much of value to add to any discussion of energy, economics, history, and culture. Don't mistake him for a doomer in the James Kunstler (for my take on Kunstler, see here) mode either.

The Archdruid Report: Into an Unknown Country:

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Energy - what can be done (Part 2)

In my first post in this series, I discussed possible primary energy savings in the area of commuting to work. In the second post in the series, I want to address what might be saved in terms of personal/passenger transportation other than commuting. Such things include vacations, shopping, miscellaneous non-commuting trips, etc. Such transportation can utilize light vehicles (cars, light trucks, SUVs), airlines, etc. I will include work-related travel other than commuting in this category (e.g., my trips to Houston or Washington D.C. for conferences). Again, I'll be relying on the Transportation Energy Data Book. For light vehicles, I'll use data from Chapter 8, for air travel, it will be Chapter 9.

In the previous post in this series, I had five bullet points for possible methods to reduce energy use in commuting. A similar list would apply here:

• "Trip combining"
•  Use of public transportation
• Utilizing more fuel efficient vehicles
• Driving more slowly (and other efficient driving techniques)

For household vehicle use, the latest data that can be used for these calculations is 2009. From Table 8.1 we find that ~2.957*10^{12}~ (almost 3 trillion) miles were travelled. From Table 8.9 we determine that 71.3% of these miles, or ~2.108*10^{12}~ (about 2.1 trillion) of those miles were NOT commuting to and from work. I'll need to engage in a bit of interpretation to determine the average fuel economy of the household vehicles travelling these miles. I'm using the Transportation Energy Data Book Quick Facts to infer that the average light vehicle fuel economy is 20.45 (calculated from the weighted average of cars and light trucks). I'm also working on the assumption that the figures represent EPA estimates. So we can estimate that ~2.108*10^{12}/20.45=1.031*10^{11}~ (103.1 billion) gallons that come from ~5.425*10^{9}~ (5.425 billion) barrels of oil.

Trip combining saves fuel in a couple of ways. First, a warm engine uses less fuel than a cold one. Second, multiple out and backs from home can be minimized. So going to the store, then from there to the cleaners, to the nail shop, to the mall, etc. rather than out and back to each saves a significant amount of fuel. It's hard to get a quantitative handle on this since it will be different for each household, each driver, and each day so I'll arbitrarily speculate that this type of trip planning will affect the 33.3% of vehicle miles travelled for "shopping" and "other family/personal business" in Table 8.9 (link is above). Further, I'll speculate that 10% of this fuel consumption can be saved. So the potential fuel and oil savings are ~0.333*0.1*1.031*10^{11}=3.433*10^{9}~ (3.433 billion) gallons from ~1.810*10^{8}~ (181 million) barrels of oil. This is enough oil for a bit under 10 days of consumption in the U.S.

As I mentioned in part 1 of this series, use of public transportation may or may not save fuel and I'll dedicate a post to my thoughts on this at a later time.

The calculations I used in the part 1 for utilizing more fuel efficient vehicles and changing driving methods can be used here as well. First, we'll use an increase from 20.45 to 30 (in this case) m.p.g. (noting that there is a large number of vehicles that do much better than this). This would reduce the 103.1 billion gallons used in non-commuting personal transportation to ~2.108*10^{12}/30=7.027*10^{10}~ (70.27 billion) gallons, a savings of 32.8 billion gallons that come from 1.73 billion barrels of oil. In the U.S., we consume this amount of oil in about 92 days. We are now officially getting someplace!

As to more efficient driving, so as to be conservative, I'll assume these more efficient drivers are driving the more efficient vehicles from the previous paragraph. I'll then assume that we can convince/incentivize/coerce 25% of them to drive in such a way as to exceed the EPA estimates (on which the previous calculations in this post have been based) be 10%, i.e., to achieve 33 m.p.g. (noting that I exceed the EPA estimate by 22% without using the more extreme hypermiling techniques such as pulse and glide, extreme drafting, etc.). In that case, the 70.27 billion gallons would be reduced to ~2.108*10^{12}/33=6.388*10^{10}~ (63.88 billion) gallons, a further savings of 6.39 billion gallons of gasoline that come from 336 million barrels of oil - 18 days worth.

As previously, let's arbitrarily reduce the savings by 25%. We can then estimate that about 1.7 billion (dropping a bunch of significant figures) barrels of oil per year. This represents about 25% of our consumption.

And not burning these 1.7 billion barrels would result in not emitting 605 billion pounds or 303 million tons of carbon dioxide.

Combined with the 9% from commuting, it's reasonably possible, without massive technology boosts, lifestyle changes, etc. to save over a third of the oil we consume just by adjusting the way our households utilize personal vehicles.

Next up: Freight

Why hybrids?

In my first post of a planned series on what we can do to reduce our nation's utilization of primary energy, I mentioned what might be done by replacing some of the current light vehicle fleet  with more efficient vehicles. And, as I've mentioned on multiple occasions, my personal vehicle is the hybrid Lexus CT200h. The CT200h has an EPA combined city and highway estimate of 42 m.p.g., comprised of a highway estimate of 40 m.p.g. and a city estimate of 43 m.p.g.

Does the hybrid configuration confer an advantage? A comparison with a high-mileage non-hybrid vehicle will be enlightening. For this, I'll select the Chevy Cruze Eco. This vehicle achieves an EPA combined city and highway estimate of 33 m.p.g., comprised of a highway estimate of 42 m.p.g. and a city estimate of 28 m.p.g.

The first thing to note is that the Cruze's highway estimate is very slightly higher than the CT200h. This is because, on the highway, the CT200h's propulsion is provided by its internal combustion engine, with the electric motor only providing power for hill climbing and passing. And the CT200h is a significantly heavier vehicle, primarily due to the additional equipment required for the hybrid drive train (hybrid battery, auxiliary 12 volt battery, electric motor and generator, and other associated equipment). These Cruze advantages are slightly offset by the fact that in most hybrids (though not the CT200h) utilize a smaller internal combustion engine, which is sufficient due to being able to rely on supplemental torque and power from the electric motor when needed. This smaller engine can operate at a better point in its engine map and will suffer lower pumping losses. The vehicles have very similar drag coefficients and drag areas  and so drag forces are roughly equivalent.

The second thing to note is that the city mileage for the CT200h is significantly higher. This is because city driving often consists of starts and stops, acceleration, etc. The hybrid vehicle  utilizes regenerative braking (more later) to store some of the kinetic energy added in acceleration from stop to speed rather than dissipating all of it as heat. It also utilizes the very efficient electric motor to start from a dead stop. And, of course, plug in hybrids (the CT200h is not such a vehicle) store significant energy that doesn't come from burning gasoline at all. It must be noted that ALL of the energy used in my CT200h comes from burning gasoline, regardless of whether the battery pack is charged by coasting down a hill, the regenerative braking system, etc.

So it's pretty clear that hybrids have the potential to achieve superior fuel economy compared to similar non-hybrid models. The extent to which fuel can be saved by a specific driver will depend on a couple of things - particularly driving habits and the division between city and highway driving.

What are the particular aspects of the hybrid drive train that enable such a vehicle to achieve better fuel economy than an equivalent non-hybrid vehicle? As mentioned above, one of the major items is the hybrid's ability to utilize some of the energy added to the vehicle by the internal combustion engine that the non-hybrid wastes.

First among these is regenerative braking. This is a system wherein part of the braking action effected by pressing the brake pedal is provided by having the wheels turn a generator against the torque of the generator action (think of the exercise bicycle at a gym - as you turn up the resistance, the energy you input through the pedals powers a generator that may power a display, etc.). The generator charges the battery, whose energy can then be used for acceleration, or even as the sole motive force at low speed.

Second is recapture of energy during coasting. As I let off the accelerator to slow down, go down a hill, etc., again, the turning of the wheels is used to run the generator and charge the battery. In the CT200h, both of these actions can be monitored in a display in the dash and in more detail on the monitor that also displays the GPS map, and other information I may select.

Next and again as mentioned above, the non-hybrid must have a sufficiently large engine to provide power for all required driving regimes (plus some to spare). This is much more than is required for constant speed driving. For any internal combustion engine, specific fuel consumption is lowest (i.e., the engine is more efficient) when operating near its maximum torque specification. Thus, the non-hybrid vehicle operates at a relatively inefficient portion of its engine map during a large portion of miles driven.

Further, the larger engine has significantly larger pumping losses as low pressure in the cylinders during the intake stroke draws in the air/fuel mixture, and while pumping the burned air/fuel mixture out of the cylinder and into the exhaust system.

The internal combustion engine in the hybrid can typically be sized significantly smaller than the engine in a non-hybrid vehicle (though such is not the case in the CT200h vs. Cruze Eco comparison - the CT200h utilizes a 1.8 liter engine as compared to the base model Cruze Eco's 1.4 liter engine). This is because, in those regimes where high power is required (acceleration from a stop, hill climbing, passing, acceleration onto freeway, etc.) the internal combustion engine can be supplemented by the electric motor.

There are other "nickel and dime" enhancers of fuel economy. For example, when I stop at a light (and assuming the hybrid battery pack is sufficiently charged) the internal combustion engine turns off. This also occurs gliding down a hill, gliding to stop, etc.) and, of course, the stopped engine doesn't burn any fuel.

In summary, the main fuel savers are recovery rather than dissipation of kinetic energy, lower engine size, and operation at more efficient points on the internal combustion engine's map.