energy density

Paranoia, it'll destroy ya

rallain — Fri, 23 Jul 2010 09:25:02 +0000

Paranoia, it'll destroy ya

Check this out - NY Times: No Motors, but Mistrust at Tour de France.

So, the short story is that some people claim that Cancellara is cheating by putting a hidden electric motor in his bike. Now they are going to do random hidden-motor checks.

I have analyzed this motor-in-a-bike already:

Energy in a hidden battery: The short answer is that you could get about 500 watts for about 1.5 hours with a hidden battery that weighs 1.6 kg. Doable, yes. Advisable? Probably not. Also, you would probably hear the motor being used.
Do bikers cheat? In this post I look at some clips of Cancellara in cases where he could be using a hidden battery. Conclusion: he is not doing anything extra-human that would make it mean he could only do it with a hidden motor.

I propose the following: Let's make up some other rumor such as Cancellara is really a half-elf and see if they start doing random testing for half-elfness.

rallain Fri, 07/23/2010 - 05:25

Tags

bike

energy

Physics

Power

But half-elves have immunity against sleep, as well as low light vision. These are clearly unfair advantages.

The difference is that electric motors and batteries exist, unlike elves. Testing for different possible ways of enhancing a bike makes perfect sense, if for no other reason than to ensure that no one is tempted to cheat.

And if you cheat you had better make it in a way that isn't too obvious so your claim that you can't see cheating proves nothing. Just adding a few watts of electric energy during an entire race may give you that extra edge to end up first. Unless there is testing to make it impossible, at some point someone is bound to try, there is just too much prestige and money involved.

If I used that kind of tricks, I would build the system with a regenerator that recharges the battery from braking energy. The batteries could be smaller, and you could still get your 500 watt boosts for hours at best.

They also added strict limits on when you could swap bikes.

Since the top athletes can "only" produce about 500 W in sustained effort (measured by really cool wheels), you don't need to go that far to gain a huge advantage. And could you really hear it over the noise of several hundred chains on gears turning at 30 mph, more in a sprint, plus a crowd and motorcycles and cars?

But you can find the drive system pretty easily if you take apart the crank during an inspection, so taking that risk is in the same category as doping these days.

PS - If you can find an overhead shot of one of those sprints where Cavendish blew the wheels off the competition, I'd love to know what their speeds and accelerations looked like. The last one, where he and Petacchi started sprinting at the same time, might be really interesting.

There is an example of an overhead shot in this highlight video from the Tour (at about the 2:40 mark)
http://www.youtube.com/watch?v=p6RRp6mIrMI
but it would seem really difficult to pick out a clear scale. For example, I can't make out any of the 100 m markers.

Getting at a Tiny Portion of the Truth in Obama's Speech

sastyk — Wed, 16 Jun 2010 07:08:06 +0000

Getting at a Tiny Portion of the Truth in Obama's Speech

In 2006 when I first met Julian Darley, author of _High Noon for Natural Gas_ and the founder of the Post-Carbon Institute, the world was excited by then-famous "Jack" oil field find in the Gulf of Mexico. Both of us were watching the way the world was interpreting the data - people were claiming that there might be 10, 12, 15 billion barrels of oil - five miles down underneath the ocean. The media was excited, ignoring the fact that large oil field potential reserves are routinely revised - and almost always downwards. The public and the media, without enough knowledge of oil production assumed that the "Jack" find reserves were substantiated, realistic, and practically here. They missed the part about a decade to bring the field fully online, the enormous sums of money involved, and the huge technical challenges of drilling five miles under the ocean. Darley, framing the issue brilliantly, observed that "this isn't salvation, this is digging around in the couch cushions for loose change."

We've now learned (the hard way) a great deal more about the possible costs and hazards of deep water drilling, but most of us haven't learned the essential things we need to know about energy resources, including the fact that oil discovery peaked decades ago, and that our current oil situation pretty much is digging in the couch cusions..

Unless you've heard the words "peak oil" and had some reason to investigate them, and found yourself launched into a crash course on drilling rigs, geological formations, tar sands, unconventional oil and liquids, seawater pumping and extraction technologies (and how many people do that), it is really hard to understand why so many people are so very worried about our energy resources. Indeed, it is more than that - the knowledge that a solar panel isn't equivalent to a barrel of oil in any easy way is counter-intuitive, as are many other necessary concepts.

The idea that nations and institutions routinely inflate their reserves for political and economic gain isn't too shocking - but most people assume that oil reserves are easily fact checked, and that agencies with the word "International" in them are confirming these facts. That we aren't, and in fact that the most famous of these, the IEA was recently accused by a whistleblower of inflating reserves under pressure from the US and other nations not to cause economic panic, is not something everyone knows. So when a company says "billions of barrels" we relax, secure in the knowledge that those crazy people who say the oil might end must be wrong, and think that oil can't really be a problem.

Last night, Barack Obama actually came close to talking about peak oil. He didn't use the words, but he used the language that peak oil analysts have been using for years, and it was clearly implied. He said:

One of the lessons we've learned from this spill is that we need better regulations better safety standards, and better enforcement when it comes to offshore drilling. But a larger lesson is that no matter how much we improve our regulation of the industry, drilling for oil these days entails greater risk. After all, oil is a finite resource. We consume more than 20% of the world's oil, but have less than 2% of the world's oil reserves. And that's part of the reason oil companies are drilling a mile beneath the surface of the ocean - because we're running out of places to drill on land and in shallow water.

For decades, we have known the days of cheap and easily accessible oil were numbered. For decades, we have talked and talked about the need to end America's century-long addiction to fossil fuels. And for decades, we have failed to act with the sense of urgency that this challenge requires. Time and again, the path forward has been blocked - not only by oil industry lobbyists, but also by a lack of political courage and candor.

The consequences of our inaction are now in plain sight. Countries like China are investing in clean energy jobs and industries that should be here in America. Each day, we send nearly $1 billion of our wealth to foreign countries for their oil. And today, as we look to the Gulf, we see an entire way of life being threatened by a menacing cloud of black crude.

We cannot consign our children to this future. The tragedy unfolding on our coast is the most painful and powerful reminder yet that the time to embrace a clean energy future is now. Now is the moment for this generation to embark on a national mission to unleash American innovation and seize control of our own destiny.

Obama here begins to make mainstream some very basic concepts. First, that deepwater drilling is simply not the same thing as sinking a well on land into proven reserves - it is a much chancier and costlier experience, and depends, among other things, on high energy prices. He uses the language of the end of cheap oil. He points out that we've been talking about a transition to renewables for decades but haven't gotten very far, and that we have to make substantial changes quickly. He even mentions WWII and acknolwedges there will be costs to this shift.

What Obama doesn't get (or doesn't think we're ready for) is the other 90% of the relevant knowledge. That starting a transition to renewable energies now, 30+ years after we should have, has real costs - and presents real limitations of what we can potentially replace. Obama leaves out the insights of the Department of Energy's "Hirsch Report" which observed that a smooth and stable transition to renewables would take 20 full years *before* the oil began to peak.

Obama isn't ready to admit what his own Army knows - in the JOE report released this spring, the US Army warned of a peak oil crisis - and soon. Their projected rapidity of scenarios for a PO transition should highlight the reality that we simply aren't going to replace this quantity of oil with renewables in 2-5 years.

By 2012, surplus oil production capacity could entirely disappear, and as early as 2015, the shortfall in output could reach nearly 10 million barrels per day," says the report, which has a foreword by a senior commander, General James N Mattis.

It adds: "While it is difficult to predict precisely what economic, political, and strategic effects such a shortfall might produce, it surely would reduce the prospects for growth in both the developing and developed worlds. Such an economic slowdown would exacerbate other unresolved tensions, push fragile and failing states further down the path toward collapse, and perhaps have serious economic impact on both China and India."

Obama doesn't explain that most renewables are less energy-dense than oil or natural gas - that it isn't a 1-1 transition, one solar panel or wind turbine for X barrels of oil, but that we need more renewables, and have to run faster and faster to keep up. Obama doesn't explain that at every stage in the renewable transition, we depend on stable prices for oil, coal and natural gas - that we don't make solar panels with solar panels, but with fossil fuels, and that shifts in price can change the economic equation dramatically.

It would have been too much to ask for all this information - the best presidential speeches are pithy. And it would also be too much to ask Obama to admit that it is only now, when people are asking "where the heck were you during this spill" that he's committing publically to fulfilling his promises, only now that he's talking about our energy limits, after approving increased offshore drilling and discussing the way the magic oil off our coasts would fix our problems. It is only now that we've already started sacrificing that he's ready to call for sacrifice. And it all depends on language that implies that we can keep everything largely the way we want it to be - that costs will be largely economic, that a clean energy economy is something that will look like our own, that this isn't going to hurt too badly, that the economy can recover and we can have a low-cost transition and a "victory" that gets us all the things we dream of.

And there was a time when all that was true. When Jimmy Carter was making essentially the same speech Obama just did, only in a cardigan, that was entirely feasible. It was almost certainly doable in the 1980s, and probably into the early 1990s. Now it is not. And Obama didn't tell us about the most basic problem - that the speech he just gave is precisely the kind of speech that has been part of the process of not doing anything. That when George W. Bush said we had to get off foreign oil, and Bill Clinton said we had to get off foreign oil that they too talked about clean energy economies and incentives and making a better world for our kids.

And it isn't that they didn't necessarily even mean it. It is that the oil-addicted culture of America is so deeply dependent on fossil fuels and the economic growth they power that no leader, left or right has ever been able to figure out how to do this shift meaningfully - once we passed the critical moments at which we could have powered a smooth transition, the reality of making words energy - the economic and personal costs, the change required in our culture, those were too big to conquer.

The speech that needs to be given hasn't happened yet, and every year it gets harder to give. It begins with the classic acknowledgement that good physicians give "this is going to hurt." And it explains why - why the greater good comes from endurance. It begins acknowledging that everyone wasted a golden opportunity, and that now our choices are governed by material physical realities - that we face the pain of living with what is possible, rather than what is desirable. It includes both a call to build what renewable energies we can, and also the acknowledgement that we will not be living anything like the present American way of life. It involves a real call to sacrifice - the kind of sacrifice past generations endured in incredibly difficult times, the kinds of sacrifice that cost them a great deal, but for a vastly greater goal. It probably involves unpalatable words like "rationing." It will involve admitting fault and responsibility, and then moving on, telling the public what they need to know, but also engaging them in the project of creating a future for their children and grandchildren.

Winston Churchill could have given that speech - in fact, he did, among other times in his "Be Ye Men of Valor" speech - with its blunt acknowledgement of the deep unlikelihood of success and the odds against them, it helped galvanize everyone into great sacrifice at great stakes.

Our task is not only to win the battle - but to win the war. After this battle in France abates its force, there will come the battle for our Island -- for all that Britain is, and all the Britain means. That will be the struggle. In that supreme emergency we shall not hesitate to take every step, even the most drastic, to call forth from our people the last ounce and the last inch of effort of which they are capable. The interests of property, the hours of labor, are nothing compared with the struggle of life and honor, for right and freedom, to which we have vowed ourselves.

Abraham Lincoln could give that speech, indeed, he did in his Second Inaugural Address:
Neither party expected for the war the magnitude or the duration which it has already attained. Neither anticipated that the cause of the conflict might cease with or even before the conflict itself should cease. Each looked for an easier triumph, and a result less fundamental and astounding. Both read the same Bible and pray to the same God, and each invokes His aid against the other. It may seem strange that any men should dare to ask a just God's assistance in wringing their bread from the sweat of other men's faces, but let us judge not, that we be not judged. The prayers of both could not be answered. That of neither has been answered fully. The Almighty has His own purposes. "Woe unto the world because of offenses; for it must needs be that offenses come, but woe to that man by whom the offense cometh." If we shall suppose that American slavery is one of those offenses which, in the providence of God, must needs come, but which, having continued through His appointed time, He now wills to remove, and that He gives to both North and South this terrible war as the woe due to those by whom the offense came, shall we discern therein any departure from those divine attributes which the believers in a living God always ascribe to Him? Fondly do we hope, fervently do we pray, that this mighty scourge of war may speedily pass away. Yet, if God wills that it continue until all the wealth piled by the bondsman's two hundred and fifty years of unrequited toil shall be sunk, and until every drop of blood drawn with the lash shall be paid by another drawn with the sword, as was said three thousand years ago, so still it must be said "the judgments of the Lord are true and righteous altogether."

With malice toward none, with charity for all, with firmness in the right as God gives us to see the right, let us strive on to finish the work we are in, to bind up the nation's wounds, to care for him who shall have borne the battle and for his widow and his orphan, to do all which may achieve and cherish a just and lasting peace among ourselves and with all nations.

Unfortunately, it remains to be seen as yet whether any man or any woman can give that speech in this generation and before the realities thrust upon us make our speeches moot.

Sharon

sastyk Wed, 06/16/2010 - 03:08

Tags

Brilliant. Who can make this argument these days in a Capitol inundated with bribes? At least Obama said part of the argument, but not all of it. Its like saying, "I'll only halfway shoot you. Thats how centrist I am."

Thanks for the link, Sharon. I just went and listened to Obama's speech. Is it just me, or does anyone else find it significant/interesting that the words "unleash" and "resilience" passed the president's lips, and the word "transition" several times - all in the context of the nation's use of energy?

I didn't vote for Obama, but I am *SO* grateful that I can at least stand to listen to the voice and words of our president, after a long 8 years in the desert.

Kate - Yeah, he TALKS a good game, but is he actually going to DO anything? He knows what happened when Jimmy Carter dared to suggest that Americans conserve, and he knows much of the public is even more rabid about the issue now. Is he likely to throw away his own very successful career for the sake of a doomed effort at real change? This Congress clearly will not impose any serious limits on anyone; if they somehow did, supporters would be thrown out of office in 2012, or washed out by a tide of coal company money, and the new bosses would repeal everything. As Greer says about the French Revolution, we have delayed action until the costs of acting are so intolerable to the elites that nobody is willing to take voluntary steps to ameliorate the situation; all we can do is wait for Moloch to collapse under its own weight. And that's a problem too, because I see many indications that the American people are ripe for the fascist "solution" to their self-inflicted decline, and the vision of a Nazi-like regime with 10K nuclear weapons is beyond frightening.

And there was a time when all that was true. When Jimmy Carter was making essentially the same speech Obama just did, only in a cardigan, that was entirely feasible. It was almost certainly doable in the 1980s, and probably into the early 1990s. Now it is not.

The time when all that was true, was feasible, was long before the late 20th century.

It involves a real call to sacrifice -

If this is the message: a call to "sacrifice," then the gig is up. No one wants to sacrifice any personal or familial perks for the "greater good," for the "good of society." Why should they? When one takes care of oneself & one's family society takes care of itself. If you want to win people over to a lower impact lifestyle the way to do it is to emphasize how healthy, wholesome, satisfying... such a lifestyle is. The way NOT to win people over is by calling simple living a "sacrifice."

Alas, if we all started bicycling to the grocery store next week, the entire growth-based economy would collapse, so even many people who are not employed in making cars, pumping gas, or providing medical care to run-over pedestrians and asthma victims would be thrown out of work. There would be economic hardship, hence "sacrifice," and if the government did not admit as much, industry and its front groups would be quick to get the message out in the most biased possible way (e.g., "you won't be able to go to your own doctor anymore...").

In a society devoted to greed and scapegoating, mutual action becomes impossible. Some of us may limit our own current guilt and future pain by limiting consumption voluntarily, but the Amurrican Way of Life as a whole is going to go over the cliff with the gas pedal to the floor, and Obama is not going to change that; that being the case, I doubt he means to try at all, only to give a few speeches that will make him look like he tried.

Thank you, Sharon. I'm an Obama supporter, but the speech--and your post--makes it clear that no politician can deal with this thing. He can't educate, can't supplicate, can't cajole, without giving away the central dilemma: a consumer economy based on oil is completely unsustainable, and a transition economy moving toward cleaner energy (no energy is "clean") is politically unrealizable.

Iâve been pacing back and forth after reading Sharonâs insightful analysis, and Iâm thinking that President Obama will make that next speech. He will. What weâre failing to see is that last night he held out a baton of sort. A somewhat smaller baton, perhaps, but a baton nonetheless to help us * help him * help us seize this precious moment in time.

It wasnât possible to introduce Peak Oil in full force during last nightâs speech. Why? Because the gusher is gushing, thatâs why. The planet in the Gulf of Mexico continues its hemorrhage, and President Obama couldnât go beyond introducing basic information. That would not have worked, and I think we need to trust his instincts.

Surfacing here today to declare that the next move is yours and mine will probably cause a combination of yawns of sheer boredom and spits of utter disbelief. Weâve gone LIVE, Boys and Girls, and we didnât notice. Now is the opportunity to crank it up on high and bring the matter of Peak Oil in real time.

Are you ready to rumble?

For starters, Iâm thinking it would be outstanding to see the most experienced team of national Transition Town folks pack up their pop-up tents and light sleeping bags and deploy to Louisiana, Mississippi, Alabama, and Florida for a time. They could mingle appropriately with Gulf Coast residents and listen to concerns. Unless theyâre in place already, they would be an important presence at this time.

Next, it would be ever so splendid if we could see a global reaction of acknowledgement and support for President Obamaâs speech, using his words as a propelling platform to bring Peak Oil in the greater limelight of mainstream populations around the world.

The shift weâve been waiting for is here. Itâs today. Itâs now.

For those of us who share the awareness of the serious nature of Peak Oil and global climate change, we can continue to be supportive and patient, and tolerant and understanding of each other at home and everywhere else we find ourselves, as we join locally across the globe to prepare ourselves for a different way of living.

You know as well as I do there is no turning back. I have to trust that a framework of meaningful governmental action will unfold swiftly to help us all keep moving forward.

With a strong heart that knows and a bright spirit that shines: Letâs rock and roll!!

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OOOOOOOOOOOOOOOOOOOOOOOOOO
WWWWWWWWWWWWWWWWWWWWWWWW

Your lovable community advocate,

Danielle Charbonneau
Tucson, Arizona

Good points.
But when we talk about the sacrifices people made in the best, we must realize that even then there was considerable resistance and politicians had to be, well "political" when addressing the public.
For example, during early 1942, U-Boats were able to see their targets at night backlit by the lights of beachfront cities and resorts of the Eastern Seaboard. Even when the Navy got around to requiring blackouts, there was resistance from coastal resorts.
If you read through McPherson's "Battle Cry of Freedom" you'll see that Lincoln's call for sacrifice were not universally accepted and he had to continually maneuver politically to get the job done during the civil war, despite constant criticism from the left, right and middle as well as the public.

I would like to point out the President does not rule the country! He is NOT a dictator and must abide by consensus and our principle of three branches of government.
Here we have a man that could not have a worse state of affairs at the start of his term. It has not been getting better and the Republican members are doing everything measure to block progress. The sad state of our country is on their shoulders!

CNN is reporting that Obama's speech was too complex:

... almost at 10th grade level

http://www.cnn.com/2010/POLITICS/06/16/obama.speech.analysis/index.html…

Welcome to the Idiocracy (and p.s. Drink Brawno, it's got electrolytes ;-)

I haven't read all the replies but found your post via Google Alerts. Yes, Deepwater has got people talking in more peak oily ways (see my post of 15 June 2010 on http://mandymeikle.wordpress.com/). I've been researching & giving talks on peak oil for 6 years now and the thing we need to be focusing on is, I think, 'net energy' and the energy returns from various ways of geting energy. Very little research has been done into this.

There are so many pointers to the fact that we are at or very close to peak production but all are easy to deny if they don't suit your version of what's real (e.g. perpetual economic growth!) Unless we explain to people that we cannot replace the energy from oil and that we have to reduce energy demand (not just 'carbon') then people aren't going to prepare for the inevitable low-energy future. As prices rise, we will all have to adjust our ways but how much easier it will be if we do that now, voluntarily. I do not think that some eco-dictator is the answer - people HATE being told what to do, especially if they don't understand it!

I am writing a book (Net Energy in a Nutshell) which I hope will get the concept of what energy is over in a simple way. I'd love to have comments on my blog as there doesn't seem to be a box to tick to know if anyone replies to me on this site (I'll never remember to check!)

Jeremy, who said he was? We're talking about his speech, which is the president's job. Apologetics serve no one.

EdK - I'm certainly not proposing that Obama will magically create a fairy land of political consensus - but when you run for president into a deep hole, you've volunteered for the job of getting people out, including dealing with a great deal of internal conflict.

DD, actually, calls to sacrifice for a greater good work pretty well when there's a clear and present threat, and we both know that PO and climate change could be framed as an immediate and serious threat - for cripes sake, we're in war in Iraq about a fake serious threat - we can articulate a real one. Think back to 9/11 - all that frustrated desire to sacrifice, to change, to do something for the good of your country. Frame the crisis properly, and sacrifice isn't that hard.

We've been saying for years "you just have to tell everyone how great it is" - and we do that. But everyone else - advertising, tv, etc... is telling everyone how great buying crap and driving and everything else are. Just as water has no advertising budget and coke does, and thus coke outgrows water every year, that's true of "sustainable simple life" - it gets a surprising number of people but it can't move mountains.

You move mountains by engaging people in something bigger than themselves - people make sacrifices of huge sorts all the time for their internal vision of themselves as part of a greater endeavor. They send their kids to die in war or go themselves. They go to jail, march in protests and get shot. They fast, they pray, they change their lives radically for their culture. Sacrifice isn't the problem - it is the narrative of collective action.

Sharon

You move mountains by engaging people in something bigger than themselves

Or with house sized back hoes. It's a shame that on something like this Obama can't be more like Bush (didn't think I'd be ever saying something like that...) - here's what we're going to do, if you don't like it you're not American enough, and I don't particularly care if you have anything to say about it, because ner-ner-ner I'm not listening.

Alas, if we all started bicycling to the grocery store next week, the entire growth-based economy would collapse, so even many people who are not employed in making cars, pumping gas, or providing medical care to run-over pedestrians and asthma victims would be thrown out of work

To quote Bill Maher over the last two weeks "F*ck your jobs"

they pray

Therein lies the problem, a five year old with a bucket and a spade digging clumps of oil off the beach for 5 minutes does more to fix the problem than ten million man hours of prayer, default position for far too much of the country - I've done my bit, I prayed, I'll do the same again tomorrow, and the next day, and the next day. All while driving my kids 5 minutes to soccer in my hummer.

Ewan R - when you say to someone whose whole life was set up to coerce them ever deeper into the life of a corporate slave dependent on corporate products, "F*ck your jobs," what they hear is "F*ck the roof over your head" and "F*ck feeding your kids." This does not make them eager to cooperate with whatever you have in mind. People who are dependent on their jobs for their physical or legal survival need OPTIONS, not snarky remarks.

It depends on whether you define "pray" as something you do internally by talking, or with your hands and your muscles. The idea of prayer as a purely abstract, purely separate from action idea is kind of a mainstream protestant set of assumptions, but that isn't the only kind of prayer there is. And religion is actually extremely good at making people make sacrifices for something larger -I'm not trying to persuade anyone to change their opinion of religion, but I do think it is worth considering its merits.

I personally am only interested in forms of either hope or prayer that cause one to break a sweat.

Sharon

The Archdruid has a relevant column today about how magic and ritual (including prayer) function effectively to change consciousness, but not material reality. OTOH, he adds that it works to change attitudes only if you want it to work, whereas most Americans today actively do NOT want to change their attitudes.

DD, actually, calls to sacrifice for a greater good work pretty well when there's a clear and present threat, and we both know that PO and climate change could be framed as an immediate and serious threat -

A lot of my thinking is predicated upon game theory applied to evolutionary biology, as pioneered by John Maynard Smith. It was this work, among others, that led George Williams to dismiss group selectionist thinking in the 1960s. Game theory math is a bit beyond me (Eric probably has a better handle on it, especially if he's read von Neumann) but Maynard Smith used it to introduce the concept of the Evolutionary Stable Strategy (ESS). Simply put, "sacrifice" of one's own self-interest for the good of the group isn't an ESS because it's too subject to defection (cheating) for it to not become infiltrated to the point of collapse by defectors. The potential rewards of defection are simply too great, and the sanctions against defection too weak, for "sacrifice for a greater good" to function as an ESS. William Hamilton worked out the dynamics of kin selection and Robert Trivers that of expectations of reciprocal altruism - the two seeming exceptions to the rule which aren't actual exceptions. Surely you're familiar with the game of iterated prisoner's dilemma, which addresses these dynamics (Poundstone is a good source). When does it serve one's interests to cooperate and when does it do so to defect? If everyone else is cooperating the cost to the group of one or a few defections is low, hence group sanctions on defectors are weak. When defection becomes widespread the few remaining cooperators are disadvantaged. If others are voluntarily forgoing reproduction for the sake of the population my own children are benefited by reduced competition. If others are choosing to curtail fossil fuel consumption the reduced demand drives down prices making it more affordable for me to waste gas. Etc. One may argue that humans are different, and cite anecdotal examples of individual "sacrifice" for the group good but on average and over the breadth of the population, these examples are insignificant compared with the degree & magnitude of selfish defection. If one is going to champion a Cause that does not constitute an ESS, one is attempting to buck the tide of four billion years of organic evolution. Good luck with that.

Yeah but, in fact, you see evidence of altruism and generosity that is, at least, not immediately rewarded, both in humans and in other animals. You see relatively stable human cultures where within-group cooperation seems to outweigh cheating and has done so for many generations, with the aid of cultural training and social sanctions on cheaters. If the math tells you that the facts are impossible, then the math is wrong, not the facts.

If I understand where DD is coming from then I don't think the facts in any of the cases you're discussing are impossible under the math - altruism works under ESS when "sacrifice" for the good of the group isn't necessarily either a sacrifice (as it will be repaid in the long term - particularly in an ESS where non-reciprocators are punished) or for the good of the group (sacrificing for the good of ones own relatives for example - technically you should be willing to die for 2 siblings, 4 cousins, 8 half cousins (or something along those lines... been a while since I've done/read the math))

Well, why do men frequently volunteer to fight in offensive wars, whether ultimately just and defensive in nature (World War 2) or not (any of them since)? In both World Wars, many men volunteered before they were drafted, and actually fought to get IN to the military. Had an individual man dodged the draft, and let others get killed to prevent his country from being conquered, that would be obviously the best thing for his personal Darwinian fitness.

The handy thing about humans, as opposed to other semi-intelligent species, is that you can get some idea of their proximate motivations because they talk. Many people who take such actions assert that they love their community or nation enough to risk, or even sacrifice, their lives for it, and when you go back through thousands of years of history you find warriors in different cultures expressing similar motives of honor and patriotism. If the ability to feel these motivations is destined to be weeded out by natural selection, it's happening awfully slowly.

(apologies to Sharon et al for going massively off topic, and to DD for probably mangling the explanation)

Patriotism in time of war appears to me to at least fit somewhat under the punishment for non-altruism and the reciprocal altruism part of the ESS theory - men who aren't patriotic in times of war tend to be shunned, and at least up until the Vietnam era those returning from war were lauded as heroes - draft dodging and not risking your life isn't necessarily best for your darwinian fitness - also there would have, in evolutionary terms, been fitness benefits associated with going off to war and risking life and limb (spoils of war, not least of which are extra mates) as well as benefits to relatives etc (spoils of war, one of me is worth two of my brother, 4 cousins etc - keeping in mind that for the vast majority of human history our immediate social network was likely to be pretty closely related risking life and limb for the social group becomes a lot more easy to explain - with the vast upsurge in population sizes and social networks it is just that we haven't necessarily caught up in terms of best ESS for the population size we interact with - which also explains why improbable events seem so amazing to us etc etc - our brains weren't built to deal with populations of thousands, let alone millions)

Hopefully Americas obsession with God is finally coming to an end, He doesn't exist people and isn't going to save you, wake up America. Stop praying and start changing things.
Here is something I read a while back:
A front-page story in the Daily Progress here in Charlottesville, Va., recently described a group of people who said they had given up on politicians and were beginning to gather at gas stations to publicly pray for cheaper gasoline. These are people who are seriously hurting because they need gas to get to work and back home, and they can no longer afford it. I don't want to laugh at their acts of desperation, but that is exactly what politicians will do, politicians who are no doubt thrilled to see people standing in parking lots talking to the sky rather than standing in their offices talking to them.

Yeah but, in fact, you see evidence of altruism and generosity that is, at least, not immediately rewarded, both in humans and in other animals.

Only animals capable of recognizing individuals of their own species engage in reciprocally altruistic behavior, dewey. Sometimes altruism is not immediately rewarded; sometimes it never will be rewarded because the benefactor of such altruism is a defector, or dies or migrates away before the behavior can be reciprocated. Sometimes altruistic behavior is simply pathological, in the sense that it lowers an individual's fitness without ever being reciprocated. As for war, we all know that every war (so far) has been followed by a baby boom such that population lost during hostilities is more than compensated within a generation. Cite anecdotes to the contrary all you want but there's simply no denying that on average, unreciprocated altruism towards those who aren't related by blood isn't an evolutionary stable strategy and hence is actively selected against. I.e., those who voluntarily lower their own fitness on behalf of some supposed group benefit will have whatever genes that contributed to such maladaptive behavior less well represented in the gene pool of subsequent generations.

Energy in a hidden battery

rallain — Fri, 11 Jun 2010 09:18:51 +0000

Energy in a hidden battery

Back to the discussion about hiding an electric motor in a pro racing cycle. Before, I looked at a video of Fabian Cancellara to see how his speed and acceleration compare to other bikers. The claim on the internet is that he pulls away so fast that he must have a motor hidden in his bike.

Just to be completely clear, I don't think he is cheating. Then why bother? If you ask that then this must be the first time you reading this blog. I welcome you. No, but really, this is what scientists do. How hard would it be to cheat?

From my analysis, it seems that a person could ride like he does without a motor. But, the question is: how much power for how long could he get if he DID hide a motor? I am going to assume that you could put some batteries in just two parts of the bike. Here is a typical bike with some estimated measurements.

The other post is where the motor would go - so no batteries there. Now, how big is the inner diameter of these tubes? I am going to estimate the outer diameter at about 4 cm. I guess a 3.5 cm inner diameter is not unreasonable. Right? So, what volume of space for batteries are we dealing with here?

Next question - what kind of battery would I put in there? Here is Wikipedia's page on energy density. In the chart, there is a Lithium ion nanowire battery with an energy density of 2.54 MJ/kg. I don't know anything about this kind of battery. I would use this, but I don't even know the mass density (or the volume energy density). The next highest on the list is a Flouride ion battery with an energy density of 1.7 MJ/kg or 2.8 MJ/L. Just for comparison, Wikipedia lists the lithium ion battery with an energy density of 0.7 MJ/kg and 0.9 MJ/L.

If I used the fluoride ion battery, how much energy would I have stored?

That seems like a lot of energy. But now, what if I want to run a 500 watt motor? How long would that last?

Well, what about the mass of this battery? Using the mass energy density and a total energy of 2.8 MJ:

1.6 kg seems really too low for the mass. That is a weight of just 3.5 pounds. I guess you would also have the weight of the motor, but that shouldn't be too much. So, maybe if you are James Bond and have access to this kind of stuff, this is possible. (I still don't think he cheated).

What if you do not have access to these Fluoride ion batteries? What if you just use lithium ion? I would only have 0.9 MJ of energy which would last 30 minutes at 500 watts (oh, assuming 100% efficiency - which is obviously not going to happen). Also, this battery would have a mass of 1.2 kg. Not too bad.

rallain Fri, 06/11/2010 - 05:18

Tags

I feel like an extra 3.5 lbs isn't worth the trouble. How about the rest of the race, where you're carrying the dead weight? How long would the race need to be to make the motor not worth the benefit? Sorry, no time to crunch the numbers now. :)

Agreed jg, 3.5 lbs is A LOT of extra baggage when talking about elite cycling. Not worth the trouble. Additionally, any bike weighing that much during inspection before the race would be quickly noticed and talked about.

Love the analysis Rhett. Fun to get my learn on. Thanks.

You also have to worry about the noise from a 500 W motor.

It would be kind of cool if it were true, though. There is something special about those blatant cheaters. Scoring a goal with your hand in football, installing an extra button in your foil, or best of all, take the subway during a marathon.

In any discussion of whether or not 3.5 lbs is "worth the trouble" or not, you need to figure out what numbers you're comparing.

Typical mechanical power outputs for cyclists during the hill-climbing stages of the Tour de France are on the order of 400 to 500 Watts. Peak outputs at various times are probably close to 1 kW.

So, by Rhett's numbers, if a 500 W battery could add 100% of the bicyclist's average power for 90 minutes, while adding less that 3% of the bicyclist+bicycle weight, I can't see how that would not be worth it, especially in a shorter stage.

Of course the analysis neglects motor weight and that jazz, but instead of "not too bad" or "not worth it", the numbers in the analysis would suggest "incredible advantage".

So, does this mean you're going to declare the DDWFTTW cart to be a hoax, because there is enough room in the cart to hide batteries?

(Never mind the fact that the cart's build is well documented and anyone is invited to inspect it).

500w for 93 minutes would be more than plenty for a 20 mile round trip bike commute (if you're not too much of a leadfoot), including a generous buffer for battery degradation or side trips!

Jared's right! The weight would be a dead giveaway. They'd get nailed in inspection for sure; these bikes are already trimmed down to where they'll only handle a handful of races at most. Add the weight of a motor and batteries and frame reinforcement to handle the motor's load, and you have enough of a deviance to warrant a full disassembly before the race. But if it sneaks through and the rider wins... There's an inspection after the race, too. The leader's bike doesn't exactly get by with a quick look-over.

Cyclists can do things like this; it's part of the strategy. If the legs alone can keep one in the pack until breakaway time, a cyclist can use his/her arms deadlift-style against the bars for a burst of acceleration well into a race. But it's a gamble - hang back a little, save that energy for your hat trick, and hope the leaders don't peel off over the horizon early on.

Interesting back-of-the-envelope calc. However, I think that the load capacity (or whatever you call the rate power can be delivered) is a pretty decisive factor.

When you're looking for high rates of power at very low weights, I think super/ultra-capacitors are a favored approach (if money isn't a tight constraint.)

For a "cheat" bike, assist just on the acceleration with very low extra weight seems like a more plausible way to go. The motor weight seems like it would be the biggest challenge.

One thing to note when asking if it's "worth the weight" is that there is a minimum weight limit set. Some manufacturers have managed to build frames that are lighter than this limit, and then they typically add lead weight to bring it to spec. If, for example, they managed to build it 3.5 lbs below the minimum, they would have to add 3.5 lbs of weight. At that point there is no weight penalty for adding the motor, since that weight would be added anyway, as ballast.

Power source for a lightsaber

rallain — Tue, 02 Feb 2010 18:23:47 +0000

Power source for a lightsaber

This one has been on my mind for quite some time. What kind of power source would you need to run a lightsaber? I was actually worried recently about this post when I saw the Discovery Channel show "Sci Fi Science". In that particular episode Michio Kaku talks about how you would actually build a lightsaber. The episode was a little silly, but the science wasn't too bad. In end Michio decides to build a type of hand held plasma torch. Doing this, he estimated that the lightsaber would need a power source on the order of mega-watts.

He didn't do what I was thinking. I am thinking about the scene from Phantom Menace where Qui Gon tries to cut through a door at the beginning. It looks like this:

Comment Notes:

Usually, I save this for the end. However, let me go ahead and pre-emptively address some comments (that are similar to what happened with the flying R2-D2 thing.)

Yes, I know light sabers are magic. I also know that they run on these cool crystals. This will not stop me from making an estimate anyway.
Oh, I know I am estimating some quantities. That is ok. At least I can get a ball park figure for this.

Before I get into the calculation, there are a couple of background topics to discuss.

Blackbody Radiation

I am not going to get into too much detail, so let me just get to the good stuff. A blackbody is an object that gives off light due to its temperature, not because light is reflecting off of it. When things are hot (even when they are not) they give off electromagnetic radiation. This is true for dense (solidy) objects, not for low density gases. These objects give off a wide range of 'colors' of light with the wavelength of the peak of the distribution related to temperature of the object. PhET has a pretty good blackbody simulator. Here is a screen shot:

I added the arrow to point out the "peak" in the spectrum. As the object gets hotter, this peak will get larger and move to the left. More light of a shorter wavelength will also be produced and the color of the blackbody will change. Two excellent examples of a blackbody: the Sun and an incandescent light bulb filament. Here is another example - Built on Facts has a great image of a hot stove element. As this thing heats up, it produces light mostly in the infrared region. You can actually see this with a video camera (since they detect IR even though you don't want that). As the element gets hotter, this spectrum it produces shifts towards shorter wavelength and starts to look red (don't touch it). If you got it even hotter, it would look more yellowy.

The point is that you can determine the temperature of a blackbody by the color of light is giving off. Let me leave it at that (although it is possible to make it much more complicated). In the clip from Phantom Menace, I will use the color of the hot door to determine its temperature.

Thermal Energy

How much energy does it take to increase the temperature of a material? Well, this depends on the change in temperature, the mass of the object and the specific heat of the material. Here is the relationship between these:

Q is the heat (even though I hate that word). Think of Q as the amount of energy you put into the thing. When talking about this thermal energy stuff, I like to talk about a pizza in an oven on some aluminum foil. Suppose you put it in the oven until the temperature is 350 F. Can you touch the aluminum foil? Yes, but don't touch the pizza. The aluminum foil has a very low mass and thus not very much thermal energy (so it doesn't really hurt). This is not true for the pizza.

There is another thing to consider with thermal energy. What if the material changes phases - that is to go from a solid to a liquid. This also takes energy that depends on the mass of the stuff and the type of material.

Here L_f is called the latent heat of fusion.

Measurements and Estimates

Temperature

What is the temperature of the metal (I assume it is metal, but it doesn't really matter) door? Here is a shot of the door being cut (melted) by Qui Gon. I used the PhET simulator to match the color of the heated parts of the door to blackbody temperatures.

This seems pretty rough, but it is a start. One problem is that the screen captures might be a slightly different color. Oh well, it is close enough.

Mass of stuff

This one is a little bit more difficult. First, the whole door gets hot (you know from thermal conduction). But what is the mass of the stuff that is at 2700 K? What is the mass of the stuff at the 5200 K? Let me start with the hotter stuff. I am going to estimate that the QuiGon makes a line about 2 meters long and that the melted part is the width of a lightsaber blade (7 cm?). How deep is it? Just by looking at the lightsaber poking through the door, I am going to guess 20 cm thick. With these guesses, I can get an estimate for the volume of melted material.

And so the mass would be:

Where rho is the density of the material - which of course I do not know.

What about the mass of the other hot stuff. Instead of making a whole bunch of small estimates, I am just going to say this is 2 times as much as the melted stuff. If you are not happy with this estimation, I am ok with that.

Material

This one is just waiting for some discussion. "Hey DOOD! How can you calculate the energy of that stuff. The Trade Federation totally stole some secret transparent aluminum material and it has a really low density!" I agree, this could be something weird. However, I don't know how to estimate the specific heat or density of weird stuff. Let me make the assumption that this is something like a known material. So, what material is metal and melts around 5000 K? Or at least a melting point greater than 2700 K - because that hot part could be hotter than the melting point. If it was made of an element, probably the best fit would be something like Tungsten or Carbon. Those do not see likely. Titanium melts at 1930 K. If it is an element, I would pick titanium - because it is cool. Another option would be steel. Some steel melts at around 1600 K. What about ceramic? That has a high melting point. Unfortunately, my googling abilities were unable to produce enough data on ceramic.

So, here are my choices along with estimated densities and other stuff. Note that my sources are wikipedia, http://chem.lapeer.org/PhysicsDocs/Goals2000/Laser1.html and http://www.engineeringtoolbox.com/specific-heat-metals-d_152.html.

Notes:

I couldn't find the latent heat of fusion for diamond, so I used graphite instead
Specific heat capacity is tricky, I know this. It really isn't constant over a wide range of temperatures. The ones listed are most likely for room temperatures.
For carbon, I picked diamond. They are the Trade Federation. They can afford a diamond door.
The last material "fake" is my estimate for a material that seems reasonable that will give the lightsaber the lowest power consumption.

Energy and Power

Now on to the good stuff. First, how much energy did it take to heat up that much stuff and to melt some of it? I will assume that the door started near room temperature (~295 K). Let me break the door into the stuff that just heats up and the stuff that heats up, melts, and then heats up some more. This would require energy on the amount: (I am using m_a for the non-melting and m_b for the melting stuff. Also, C is the specific heat capacity and L the latent heat of fusion.)

I guess I should be clear about my variables.

I already declared the masses (above)
T₀ is the room temperature - or starting temp of the door.
T₂ is the final temp of the non-melting door.
T_melt is the temperature that the door melts.
C₁ is the specific heat capacity of the solid door.
C₂ is the specific heat capacity of the liquid door.

At this point, I am going to cut the lightsaber a break. Since I have no clue about the specific heat capacity of the door in its liquid state, I am just going to leave that part off.

To calculate the power, I just need the time it takes for this change in thermal energy.

The time is the one thing I feel comfortable determining. You know, because they showed it in the movie. From the movie, Qui Gon took about 9 seconds to make that cut in the door. Bring on the calculator. As I have done before, I will put this in a spreadsheet so you can change the values if you do not like them. (I had a complaint about embedding zoho sheets, so I will try google docs)

This gives a power of 28 kWatts. At least it is not 1.21 gigaWatts - you know what they would need for power like that? Oh, note that in the spreadsheet, I left C₂ in the calculation, but its value is 0. If you want to change that to something, go ahead.

Energy Source

The power needed to cut that door tells me something, but not everything about the energy source for the lightsaber. I want to estimate the energy density of the energy source. To do that I will estimate how long the lightsaber will run without recharging. This is a tough one. Maybe they run forever - I will not assume that because it wouldn't be as much fun. Really, how long would it have to run for it to be useful? I say at least 2 hours of continuous use. That seems reasonable, doesn't it? How much energy would that be? Using the same power formula:

How big is the energy source in the lightsaber? Taking an estimate on the high end, I will say it is a cylinder with a radius of 3 cm and a length of 15 cm. I think that is plenty big enough. If this is the case, then the energy density of this power source would be:

What can I compare this to? What about the best evAR battery? Wikipedia has a nice table of energy densities. Just for comparison, 4.7 x 10¹¹ J/m³ is 470 MJ/L. On the table, this puts it somewhere between Octanitrocubane explosive (no idea what that is) and Beryllium + Oxygen (again no idea). As far as batteries go (known Earth-batteries), it seems like the highest energy density is the fluoride ion with 2.8 MJ/L.

Ok, I get it. The jedi have some secret power source.

Also

Qui Gon also just sticks his lightsaber in all the closed doors of the Trade Federation ship and heats them up. I could have also used this an estimate the power. But, I didn't.

rallain Tue, 02/02/2010 - 13:23

Tags

latent heat of fusion

ligtsaber

specific heat capacity

temperature

analysis

You forgot to take into account the emitter, casing and controls for the lightsaber. So the power source would have to have an even higher energy density.

Also of interest is waste heat; up above you had 28.5kw, if that is at 99% efficiency there is still ~300w to get rid of. If it is 90% then there is about 3kw. They had better be bloody efficient, otherwise Qui Gon is going to cook his hand.

Finally, what happens if this 4.7x10^11 J/m3 power source gets hit?

I always thought that Lucas missed a great opportunity. I would have made it so that the Jedi focuss the force into the lightsaber. Then only a powerful jedi could get a fully potent weapon.

A light-saber runs on 3 D-cell batteries.

(Or at least, the original prop, which was made out of a 3-cell Graflex flash tube.)

We do know the Star Wars universe has access to some truly ludicrous power generation capabilities. The Death Star packs several times the gravitational binding energy of an entire planet into a power core that's at best a few cubic kilometers in size.

"They had better be bloody efficient, otherwise Qui Gon is going to cook his hand."

That close to all that molten whatever, he's going to cook his hand just off the radiant heat.

David is on to it. You didn't include "The Force" in your calculations, Rhett.

Don't forget, when figuring the energy density that the light saber may not be required to produce the full power if nothing is in the beam. Thus, without anything interacting with the beam, the power consumption may only be a few Watts (or even less).

Dave

@Dave,

Very good point. I thought of that, but did not take it into account because I had no way of doing so. But you are correct.

Cubane is a hydrocarbon arranged like a cube, you have 8 C atoms at the corners, bonding to 3 other C atoms. You have one bond sticking out into space. Since this gives you a C-C-C bond angle of 90 degrees, there's a lot of strain energy already in the unsubstituted molecule. in ONC, the eight hydrogens are replaced with nitro groups, for a C8N8O16 total molecular formula. Which likes to decompose to 8 CO2 and 4 N2 and a lot of energy. When I was in grad school that was our geek-LOL molecule, but surprisingly, that thing got synthesized and is stable to 200 C or so.

Awesome! I am glad I stumbled on this blog! I just love this sort of back of the envelope type problem!
http://scientificilliteracy.blogspot.com/2010/02/fun-back-of-envelope.h…

I used to bullseye womp rats in my T-16 back home, it's energy capacity is not much bigger than 470 MJ/L.

@Rob,

good one.

What about a microscopic black hole. That would explain why only Jedi or the Seth could construct such weapons. By focusing the force on a single atom at the heart of the power cell, the power of a singularity is what powers a high energy plasma stream shaped into a tube by a containment field forming a saber. This is also why construction of this weapon is the last test of a Jedi or Seth. The fail safe of such a power source is that if containment of the singularity is lost, say during battle, the microscopic blackhole simply evaporates and becomes inert.

According to what sources we have for lightsabers, while the Force is necessary in the construction of your most basic lightsaber, a generic "energy cell" is all that is required to power it, which is basically the Star Wars equivilant of a battery. However, through some sort of psuedo science, a lightsaber recycles its energy while the blade is not in contact with anything, therefor, it can run indefinately, and only loses energy when it strikes another saber or object. However, there are some Jedi and Sith who do construct more complex sabers, and some of these can be powered directly by the Force, plus there's nothing stopping a Jedi or Sith from focusing the Force through their saber to intensify it, probably why in all of the tabletop RPGs to date, a lightsaber does more damage when wielded by a more powerful Jedi/Sith. I'd have to say there are way too many variables to determine how much power the "energy cell" produces, but kudos for actually attempting the calculation. However, I must say, i disagree with your assumption that a lightsaber's blade is 7cm wide, that would put it roughly 3 times wider than the emitter shroud of my custom-built saber prop, and a 7cm blade width is roughly double the diameter of most replica sabers, and saber wide enough to produce a blade that wide would be nearly impossible to grip comfortably one-handed by your average sized Jedi.

Battery to power a house for a week

rallain — Tue, 29 Dec 2009 16:23:19 +0000

Battery to power a house for a week

I saw this post about Panasonic's home battery. The claim is that this will lead a battery that can power a house for a week. I wonder if I can estimate how big this battery would be.

First - to estimate the energy a house consumes. My first approximation is that you could probably run a house off of a 5000 Watt generator, but this probably isn't the average power use for a house. It is probably lower. I am going to go with an estimate of 2000 Watts as the average power over 1 day. How much energy would this be for 1 week?

The article above claims that it is a lithium ion battery. According to Wikipedia, the energy density of a lithium-ion battery is on 0.46-0.72 MJ/kg. For the purposes of this calculation, I am going to go with an energy density of 0.8 MJ/kg. I can calculate the mass of this house battery as:

This is around 3000 lbs. Of course, this calculation assumes a 100% efficient battery - or maybe that is already taken into account into the wikipedia energy density. Anyway, even at 3000 lbs, this is possible for a house, right? How big would it be? The wikipedia page lists the volume energy density as 0.9 MJ/L, so this would make the volume:

This isn't too bad - like the volume of a small refrigerator.

I, for one, welcome such a battery. Even without solar panels or something, this would be awesome for the cases where we lose power in the house.

Update

I made some changes thanks to commenter Emory K (Emory K gets 10 bonus points). I don't know what I was thinking, but I said there were 24 hours in a week. Hint - that is wrong. I guess I shouldn't blog on vacation or I am bound to make mistakes.

rallain Tue, 12/29/2009 - 11:23

Tags

(24hr / 1 week) ?

@Emory K

You are TOTALLY correct. I have updated the post to correct the error. Thanks!

In 2001, the average American home consumed 737 MJ of electricity per week, while the average Japanese home consumed 341 MJ/week. Since Panasonic's batteries are aimed (for now) mostly at the Japanese market, they'll probably aim for something in the neighbourhood of 400 or 500 MJ. Assuming 0.9 MJ/L, that'd work out to 0,45 cubic metres - still quite a bit of space, but manageable.

Having endured 3 days in winter a few years ago, I agree this would be very cool. But this is a battery that would flatten your house if it ran away with itself. Would love to have them on the market for a little while before I install one.

Maybe they'll become a standard home appliance. A week's buffering ability would certainly make solar and mini-wind more practical though. If nothing else, it would let you buy electricity during low-demand hours when it's cheaper.

that is going to be one expensive battery. i would hope more that Panasonic's achieved a breakthrough in Li-Ion battery lifetime than for them to have improved the energy density.

and yes, as george mentioned, if that thing shorted out the best you could hope for would be a devastating house fire. the worst-case scenario would more resemble a gas explosion.

Humm... From my last power bill, 370 KWh/month (pretty consistent over the last couple of years) = 1332 MJ. 32 day billing period, so that's 287 MJ per week. Still a nice fire if it goes bad.

So how about the same calculations for a high-speed flywheel? (Or a bank of small ones.) No exotic chemistry to catch fire (deal with possible failures by putting the unit in a pit), no significant conversion losses, trivially easy to measure the amount of stored energy to prevent over-charging...

should still be hr/day ...

@hans,

AHHHHHH. Ok, how about now? (fixed it).

Now multiply that number by the number of households in, say, the USA (~100M) and you get some idea of the amount of lithium needed. Not so bad I guess since it's one of the most common elements - refining it is an issue though. Think of the floor loading and the fire and explosive hazard too. Given the violence of poorly crafted Li-Polymer batteries in laptops over the past 8 years, I wouldn't want a giant sized sucker near me.

Small-scale power sources all have their uses (from batteries + solar panels through RTGs - including the RTG that LANL is developing for domestic use), but for cities you just can't beat off-site generation. Even if wind and solar thermal power become big things, I suspect some material will have to be cycled to store and release energy - perhaps a nitrogen/hydrogen system or an oxygen/hydrogen system.

Stackable sets of batteries would seem the way to go. With material between them to prevent a massive fire hazard.
You might be able to get away with a smaller battery if you are constantly recharging it from a renewable source.

You could also have some of your appliances with their own solar panels to offset consumption further.

@MadScientist:

... suspect some material will have to be cycled to store and release energy - perhaps a nitrogen/hydrogen system or an oxygen/hydrogen system.

Assuming you can get a reasonable hydrogen storage system working. And where is all that hydrogen going to come from? Getting it from hydrocarbons (least expensive) creates lots of CO2. Getting it from water requires a bunch of energy, which has to come from somewhere. Unless the stored hydrogen is in some kind of non volatile (and somewhat heavy) molecule, I don't want large amounts of it stored too close to my house.

I ask these questions because of this article by Robert Zubrin, which I haven't independently verified. Is he full of crap, or are you talking about something completely different?

I'd want my battery outside, or in a fire proof box vented outside in case it explodes. Neat idea, you could even make money with your battery by shifting power from low load to high load times on the grid. Feed roof solar power into it as well.

hydrogen, however stored, is an energy storage and transport system, not an energy source. it's another kind of battery technology, whether you burn it (to fuel a heat engine of some sort) or feed it to a fuel cell for electricity. yes, you have to spend energy to get hydrogen, just as you must spend energy to recharge a Li-Ion cell. the only question is which one'll work better for the particular battery application you have in mind.

i don't know what the current market prices of H2 are, but i'd be very wary of any assumptions that they would have to remain static in the face of vastly increased demand. Zubrin may have a point about it currently being too expensive to run cars on, but that tells us little about its cost in a world where cars do in fact routinely run on it. sure, his back-of-the-envelope estimates show that we can't power any great number of cars on hydrogen produced by the method he picks, but he never demonstrates that that method is the only one we could reasonably pick for such an application. it may be the most commonly used one today, but we don't need (or want) to run any fleets of vehicles on hydrogen today.

(and estimating the heat loads on a hypothetical hydrogen tank hypothetically launched from Jupiter as it hypothetically reenters Earth's atmosphere...? the man cannot be writing at all seriously. i don't even know why he threw that line in there, given that the number he mentioned can only have come straight out of his nether regions. he's grinding an axe, and i'd like to know why.)

The other problem with H2 is embrittlement of metals. They are devilishly slippery to hang onto.

The other question here is that if it were economic to put such a battery in a house, it would be even more economic to put a really large version into a housing development since the pooled resource is going to be used more efficiently than one subject to the kinds of volatility of an individual user. You could also isolate the battery-bank more easily and cost-effectively. But then, why not do it at the level of whole towns and cities?

Load curves there are even more predictable. Of course, at that scale vanadium flows might be best.

I've also heard that Phosphor-ion batteries are being developed with rapidly improved charge/discharge cycling times and reliability.

As others have pointed out, fly-wheels are a possibility, and one might add, in places where hydro is a factor, retro-fitting pumped storage may be more cost effective and cast a smaller footprint.

"they" above refers top H2 molecules of course

Hence:

those H2 molecules are devilishly slippery to hang onto

@James

"No exotic chemistry to catch fire (deal with possible failures by putting the unit in a pit),"

Dig the same pit. Experience same problems of keeping the pit separate from whatever the weather throws at your region. Add batteries to said pit. Enjoy?

@Shawn #12:

The generation I'm thinking of will be outside of cities - perhaps a solar thermal plant to convert ammonia to 3H2 + N2 or some such; it has to be some chemical that can be cycled, not react just once like hydrocarbon + water = CO2 + H2. Alternatively of course you can electrolyze water but that's quite a job and I can't imagine how it would be practical on a large scale. It will be interesting to see what solutions people come up with. The gas cycling is for energy storage and must rely on surplus energy. I can't imagine how the needed volumes of gases could be stored either; you could pump them into sandstone deep in the ground but the energy losses along the way are getting pretty big (conversion of the gas, pumping for storage, pumping back out).

In rural areas large(ish) batteries + solar panels or wind generators + LED lighting can certainly provide all the light that people would need. In cities you have issues of shading and roof area vs. living areas so solar panels are of virtually no use in cities.

We'll be burning fossil fuels as the primary source of energy for decades yet, so I imagine some power plants in the next 10 years may convert hydrocarbon to H2 and pump the CO2 into the ground or else simply burn coal and chemically capture some fraction of the CO2 to pump into the ground.

@Shawn: Ooops ... I missed a comment on Zubrin's article. I haven't checked his numbers for the energies of reactions, but he is absolutely right about consuming far more energy producing hydrogen than you could possibly get out of burning the hydrogen. I should probably print his article and go through his calculations - I'd like to see if his estimate of a 650L hydrogen fuel tank is correct (but I do agree with him that hydrogen is not a sensible fuel for vehicles). The only sense in producing hydrogen is to do it with surplus energy and to burn it later to provide energy when you want it. Many hydroelectric plants do things which sound equally silly and waste a lot of energy - buying surplus power from the (mostly coal-fired) grid to pump water up into the reservoir so that the water turbines can be run a little longer when the gates are opened.

At the power level of a city use a Lofstrom loop.

We already have a super energy source (Sun) & super flywheel (Moon).

Most 'modern' 'essential' gadgets could easily be vastly more efficient if the engineers quit designing 20th century products in 18th century horse & buggy paradigms and marketed with 21st century brain-numbing advertising. What's the difference between texting while in a car today and telegraphing from a railroad car in the 1900s? Do you want to be so reliant on electricity that you basically live inside a battery? AM crystal radios worked without electricity, can internet? Has anyone even bothered to try? The heavy reliance on the electrical plug-in is making people somewhat less creative, batteries may be a step up, but its good to think of the human body as more than just freight to be carriaged around in petro/electro wheelchairs and coddled by electro-chemical stimulants. Why the heck can't cell phones operate from fat storage cells? I know some large folks that talk all day, they could burn off a lot of mass with all that chatting! /rant

AM crystal radios worked without electricity

i quite assure you, they did not. the receivers might have seemed to, but only because the transmitters were using that much more electricity on their behalf.

This Lithium/Ion battery is just plain crap.
I live on a boat, and the only batteries which are used as long life stationary batteries are lead batteries.

I have lead batteries of approximately 1100Ah in 24V. Ah is the only unit you can rely on. This type of batteries can never be discharged less than 33%, so only 750Ah can be used. You also need a 24V/220V converter : XANTREX TRACE are best (220V because I live in France, there are 110V version).
1100Ah lead batteries weight 1000kg.

The devices using most power are :
- central heater (for heating and especially water circulation during winter) : 60Ah per day
- refrigerator : 15 to 30Ah per day
- 'sleeping' devices that people don't want to switch of (TV, DVD...). Personaly, I plugged them on a switch-plug to switch them of all in a row.

That means I can live approximately one week without recharging it.
Recharge is about 10% constant load with the TRACE, so 70Ah, and takes more than 10 HOURS...

Most important : 1100Ah batteries price : 2500$. Life expectancy : 15 years.

What are the numbers for Lithium/Ion ?