Published!
It was a surprisingly long process. I think most of the delays were due to my own lack of experience. Hopefully, they are lessons learned, and my next trip through the publishing gauntlet will be easier, faster, and hopefully even more fun.
My uncle asked me if I would try to explain what I did in simple terms, so here it goes.
There is a thingy called a tokamak that is basically a very fancy Thermos. It keeps hot things hot. If you can make the stuff inside hot enough, it will work like a nuclear reactor. This is interesting because it is possible to build much better, much safer nuclear reactors this way. The trouble is, these Thermos things cost billions of dollars. The one they are building in France is going to cost something like nine billion bucks, and it will get barely hot enough enough to work as an experiment. Real ones would cost even more.
The good news is that the current designs for these fancy bottles only use a few percent of their heat-trapping capacity. That's what 'beta' means in the title; you can think of it as the heat-trapping efficiency of the machine. This is different from the energy efficiency, though. The heat trapping efficiency is more like how full you can fill the Thermos. Right now, we are building a nine billion dollar Thermos, and only filling it to 2% of its theoretical capacity. If we could use more of the heat-trapping capacity, then you could maybe reduce the cost by a factor of ten or a hundred (or increase the performance by that much).
So, this line of research is all about computer simulations of these doughnut-shaped nuclear Thermoses, and how they behave when they are nearly full.
In some other papers, I helped show that it is likely possible to build a nuclear Thermos that you can fill almost all the way up. In another paper, I also helped my friend Pierre show that it is possible to start with a nearly empty Thermos, and fill it to nearly full without anything bad happening (it all comes down to how you pour, to stretch the metaphor).
Typically, you have a theory that you trust, and you want to know if your computer simulation matches the theory. In this case, however, we built a computer simulation that contained very few assumptions. It solves Maxwell's equations (for magnetic fields and currents) and Newton's equations (for moving masses). This is nice, because those equations have been tested really, really well over the last 130 years. It also means that you can take the output of the computer program, and very easily check to see if it is correct.
As a result, we had the opposite problem one normally faces in science; a computer program that we trusted, and a theory that maybe we didn't. In this paper, I used the computer program to validate that the theory was correct. I did this in an unusual way. The theory is approximate, and so we expected it to go funny in some places. I treated the computer-generated output as the "exact" solution, and showed that when you subtract the theoretical result from the result we got from the computer, the difference is precisely the amount by which we expected the theoretical result to go funny. (In more rigorous language, I proved that the deviation from the numerical result has the same scaling as the error term in the expansion.)
Here is a link to the paper, in case you don't have access to AIP.
An endorsement withdrawn
To be clear, I do hope he wins, and I will vote for him. I hope he finds a way to win back my endorsement. However, I simply cannot actively support him after his vote on FISA.
Kudos to Obama for his artfully penned response to the gigantic groundswell of outrage, but this is something that leaves me profoundly disappointed. FISA was an unnecessary, rotten, law to begin with, and this law takes it from rotten to putrid.
Let me put it this way. Say you are an FBI agent, and you are working on a case. You think you need a wiretap ASAP. If you don't feel that the case is compelling enough to wake a judge up at 4 AM to get her to sign a warrant for your wiretap, then the agency probably shouldn't waste its time and resources pursuing the case.
The whole reason for requiring warrants to search and seize property is to focus law enforcement on compelling cases. The system is designed to weed out speculative and frivolous investigations, and investigations for improper purposes (political intimidation, for example). The administrative burdens placed on law enforcement are SUPPOSED to be burdensome. Sure, we should feel sympathy for the plodding investigator as he navigates through the red tape. But we should also recognize that the hassle he must undergo is a sort of administrative calisthenics. It makes for more thorough investigations, more accountable practices, and more successful prosecution.
If we want to help our hypothetical plodding investigator, we shouldn't make his job simpler. We should give him more material resources. Worried about not getting warrants quickly enough? How about expanded staffing to process warrants? Better IT infrastructure to handle the process faster and more efficiently? Or heck, why not just set aside office space for judges nearby the operations center? Processing warrants is one of the key duties of serving on the bench, and in my experience, judges generally take all parts of their jobs very seriously.
Even if we grant, for a moment, the ridiculous "ticking bomb" scenario that seems to motivate all conservative thinking on domestic security, special legal "tools" like FISA are still totally unnecessary. Terrorism cases are not unique in the urgency with which they must be pursued, or in the scope they must cover, or in the potential number of victims. Ordinary homicide investigations can be just as urgent; racketeering and organized crime cases can be just as broad in scope; environmental cases can involve just as many victims. Terrorism is unique only in the sense that it can potentially combine these aspects. Terrorism cases are bound to be complex and difficult, but the difficulties have nothing to do with complying with appropriate judicial oversight. Any competent homicide detective knows how to obtain a warrant when she needs one in a big hurry. The FBI organized crime people know how to obtain warrants for complex investigations. Investigators who handle environmental cases often use the potential for mass casualties to obtain authorization to conduct wide-ranging investigations. Terrorism investigators need to do all those things at once, and so they need low caseloads, a lot of very competent support staff and a well-run computer network.
As with any other class of investigation, we should not expect better results by relaxing judicial oversight, or in the case of the new FISA law, no oversight whatsoever. Quite the contrary. Exception from the fourth amendment allows more latitude for sloppy work, but won't help an honest cop catch any bad guys. What conservatives are really asking for when they rail against judicial oversight is that they don't want honest cops; they want Gestapo.
Naturally, conservatives don't want the EPA or the Forrest Service to have expanded investigative or enforcement powers. Extra-constitutional intrusions into the private lives of Americans are evidently reserved for manly things. For girly things, like protecting spotted owls from logging companies and children from arsenic poisoning, conservatives never fail to come out in favor of judicial micromanagement. This works in concert with their habit of appointing industry lobbyists to the judiciary.
What angers me about Obama's position (and the Democratic leadership) here is that they conceded a fundamental philosophical point to the GOP. They are granting that security theater is more important than the law. Not only that, but in the same stroke, they endorsed the criminal behavior of the people involved in what is probably the largest and most serious breach of the fourth amendment in our history. I cannot abide it.
I will vote for Barack Obama, but I'm not going to endorse him, or give him any more money. Instead, I encourage you to contribute to the Electronic Frontier Foundation.
First day of solar production
The array produces between one and three kilowatt-hours for every hour of sunlight, so for today's half-day of production, we've generated 13 kwh.
Here's the read-out on the inverter :
Sadly, I don't have a way of getting the data out of the inverter yet. Once I add the RS-232 module, I'll have have more interesting things to say about our system. I'll post some pictures of the array itself once we've passed inspection.
The Sunny Boy inverter has an interesting user interface. There aren't any buttons -- you interact with the display by knocking on the front panel with your knuckle.
Solarizing!
- 14 SunPower 230 watt panels
- One SMA Sunny Boy 3000 inverter
- A second digital utility meter
- AC and DC disconnects with lockout-tagout switches.
Here is the equipment after delivery and upacking :
We were supposed to get a Sunny Beam monitoring station, but evidently there are some issues with buggy firmware, so they won't be available until September (more about that later).
So far, roof has been preped, the mounting rails are installed, the conduits are bolted in place, the DC wires are pulled, and the inverter has been bolted down. All that's left is to hang the panels, do the AC wiring, and get the inspection.
The installer crew was supposed to finish that on Friday, but evidently they decided to take the day off. The project manager at EE Solar pitched a fit. Nick, the crew boss, called on Friday to say he was really sorry. I told him that his schedule is his business, but if he can't come when he promised, he ought to let us know. On Moday, I'll ask him to run some extra conduit for ethernet to make amends.
The carbon cutting game
So, I decided to play a little game: Let's pretend that America has just ratified a treaty that obligates us to cut our CO2 emissions by, say, 50%. How do we do it?
First, let's see how our emissions break down by economic sector :
Since about 1978, emissions from the industrial sector have been fairly flat. Meanwhile, transportation has been exploding, and overtook industrial emissions right around the end of the Clinton administration. Commercial and residential emissions have been growing at a steady clip, with residential emissions leading the way.
First, let's look at the biggest, fastest growing culprit, the transport sector.
No surprises here. Petroleum, mostly gasoline, makes up the overwhelming majority of emissions, with natural gas just barely registering. The single most effective measure we can take to cut emissions, then, is to cut petroleum consumption in the transportation sector.
This is going to be difficult. The trend has been an inexorable rise for more than half a century, and probably longer. Even the oil shocks of the 1970s don't look very impressive on the 50-year scale. In fact, in the decade prior to the shocks, there was a rise in the rate of emissions (and thus consumption), and the shock resulted in a regression to the previous trend. So, we're going to need more than just improved fuel economy. We're going to need new technology. Most importantly, we're going to have to get people to stop driving so much.
This is a tall order; if we want people to drive less, we need to uproot the automobile fetish that our country has developed. This will require a big mobilization of cultural assets. Right now, people will sacrifice a great deal of money, time, space, convenience and health to own a car. This preference has to be reversed. Culturally, we need to find a way to make car divestiture a desirable achievement. It has to be cool not to have a car. Here is an area where entertainment can play a positive role. For three generations, it's been the opposite, with movies and television fetishizing car culture from the very beginning.
We need movies and TV shows that exploit the coolness of riding the train, or walking to work, or riding a bicycle. This shouldn't be difficult. Good entertainment is all about human interaction, but the automobile is the most isolating mode of transportation possible. If you want to write about people, then trains, buses and bicycles are fertile venues, while cars are not. If we've got TV shows that revolve around crimelab investigations and people with magic and superpoweres, why not a TV show about bus drivers? There are a hundred angles you could take on that idea; it could be a noir drama, or it could have a supernatural element, or it could be a crime show. You could set it during the Montgomery Bus Boycott and make it a historical drama. You could set it during and after 1929, and make it a period piece.
Here are three policy initiatives that could get things moving in the right direction. First, all cities with public transportation have registered trademarks for their systems. The federal government could create a fund that would pay for product placement of these public transport "brands" in movies and TV. The more positive the circumstances of the placement, the larger the bonus.
Second, attack consumption directly. Raise fleetwide fuel economy standards. Raise taxes on gasoline and diesel. Go after really conspicuous consumption with direct measures; refuse to certify new Hummers, Ferraris, and Vipers as road-worthy. Give people tickets for driving aggressively.
Third, fix Amtrak. Create an endowment to support its operation and expansion so that it won't be at the whim of Congressional funding. Fund the endowment with fuel taxes, tolls on interstate freeways, and fines levied on the airlines for violating the Passenger Bill of Rights. The Atlantic and Pacific coastal cities should have rail service like France's TGV -- 200 mile per hour express trains with reasonably priced coach tickets.
Next, let's have a look at the industrial sector.
The clearest trends are volatile but stagnant conditions in petroleum and natural gas emissions while coal emissions crash and electrical emissions soar. Looking at the beautifully anticorrelated trends in coal and electricity emissions, I suspect something fishy is going on here. Let's have a look at electricity generation.
Ah ha! The industrial sector is outsourcing its coal burning to the electricity generators, who are burning coal like there's no tomorrow, if you'll pardon the gallows humor. Emissions from electricity generation are actually somewhat higher than for transportation, though they are on the same order. However, the trend in emissions from coal is actually significantly steeper than for petroleum use in the transport sector.
The coal explosion in the electricity generating sector is responsible for the rise in emissions in other sectors as well. For example, the commercial sector :
The emissions due to electricity in the commercial sector notch almost perfectly into the trend for emissions from coal. The residential sector doesn't notch in quite as clearly, but the trend holds.
It's the same trend across all non-transport sectors. We see the stagnation of petroleum and natural gas emissions while coal vanishes and emissions due to electricity explode, following the trend of coal in the electricity sector.
This makes it very clear. The absolute emissions and the growth of emissions in all non-transport sectors of the economy are due to burning coal for electricity. You'd expect coal to make up most of our electric generating capacity, wouldn't you?
Nope. Coal is responsible for most of the emissions from electricity generation, but only about a third of the electricity. We get about twice as much electricity from natural gas, but it's responsible for a relatively small fraction of our emissions.
Of course, this should be fairly obvious from the chemistry of coal and methane: Coal is more than 90% unsaturated carbon, consisting of long chains of double and triple bonded carbon atoms and aromatic cyclic structures, mixed with amorphous graphite and some volatile hydrocarbons, while disassociated methane is four-fifths hydrogen by volume. Coal is mostly carbon, and natural gas is mostly hydrogen.
The upshot is this; if we can wring about 30% worth of efficiency improvements from the non-transport sectors of the economy, we can do away with our coal plants altogether. This will cut the emissions of the industrial sector by about 40%, and 65% and 75% for the residential and commercial sectors, respectively.
Alternatively, we could aim for about a 15% efficiency savings, and double our nuclear capacity, or increase our renewable capacity by about fivefold. Whatever policy is chosen, it is abundantly clear that it must result in the eradication of coal from our electric generating portfolio. Even petroleum and natural gas are better.
Our prospects in the non-transport sectors are actually pretty good compared to the transport sector. We have a mix of different technologies, none of which make up a plurality of our portfolio, and most of the emissions can be attributed to the second-largest minority component. We have 1,493 coal plants which have an aggregate capacity of 335 gigawatts. That is an equivalent capacity to about 55,833 wind turbines. That many turbines would cost about $446 billion to procure and install. For comparison, the direct cost of the Iraq war has been about $478 billion, as of today.
Technically speaking, a 50% reduction in CO2 emissions is not far-fetched. It's well within our ability to build and to finance. A 20% reduction could probably happen without any noticeable drag on our economy whatsoever -- we just need to provide good incentives for saving electricity, and preferentially shut down coal plants.
Don't be afraid of mandatory carbon caps, even aggressive ones. If we can blow half a trillion dollars on a pointless war that gains us no advantage whatsoever, we can afford to fix our emissions problem. Maybe not both at the same time, but we'll be leaving Iraq soon anyway.
Peadal power
My usual workout includes a ten mile bike ride, which I usually complete in about 45 minutes with heavy resistance. According to the machine at my gym, I burn about 500 calories, or 2.1 megajoules, in the process. I'm going to assume the machine means kilogram calories, which is what you see on food labels.
Evidently, I'm putting out a bit more than three quarters of a kilowatt. That's a bit more than one horsepower, which is 745.7 watts. This is a bit surprising -- that's not too far shy of what Wikipedia says you'd expect for the first six seconds of a cycle sprint (900 watts). A professional cyclist can hit about two kilowatts during a sprint. So, 775 watts sustained over 45 minutes is not too shabby.
If they had bothered to wire my exercise bike into the grid, LA Fitness would have obtained 581 watt-hours from my efforts. In Pasadena, we pay $0.15 per kilowatt-hour, so I managed to produce a little less than a dime's worth of electricity. If a hundred people did the same workout, which is roughly what I'd expect over the course of a day, we would together generate $8.72. The gym could save that much by switching off the TVs when no one is watching, or turning down the music a little. The electricity you can generate on an exercise bicycle isn't worth the wires that would carry it.
According to the Department of Energy, the average American household uses about 29.2 kilowatt-hours of electricity per day, so you'd have to pedal at the sprinter's pace of 1216 watts, all day, every day, just to keep up with your household use.
My 2.1 megajoules of peadaling is actually a lot of energy. What astonishes me is that even this rather large amount of energy is worth so little.
Update : My friend Chris points out that the bike at the gym is probably reporting some kind of estimate total power, including power dissipated as heat, that it extrapolates from the work you put into the mechanism. He suggests that around 20-25% of the calories you burn are available as work, so that means I am putting somewhere around 155 to 194 watts into the bike. This probably has an error of 50% or worse, since the bike is extrapolating the total power from the mechanical power, and then I'm extrapolating back to the mechanical power from the result. The actual electricity one could generate is more like $0.02 worth.
Boiling Nukes
Surprisingly, though, the electricity production of a given power plant is usually not limited by the reactor. We know how to build staggeringly enormous reactors, and even small reactors can be designed to run extremely hot. Rather, the generating capacity is limited by the heat capacity of the cold reservoir, which is a function of the natural environment in which the power station is situated. Nuclear reactors are cooled by water, so the generating capacity of a nuclear power plant is directly proportional to the quantity and temperature of water available from the environment.
So, what happens when there is a drought? Or a heat wave? Or both? The heat capacity of the cold reservoir shrinks, and the generating capacity of the power plant shrinks with it. It doesn't matter how big and fancy the reactor is if there isn't enough cooling water.
The water in the Tennessee River has gotten so hot this summer -- more than 90 degrees Fahrenheit averaged over a day -- that the TVA was forced to shut down one of the reactors at Browns Ferry. The heat capacity of their cold reservoir has shrunk so much that they can only operate two of their three reactors. The TVA is already suffering from reduced production at their hydroelectric stations due to drought conditions.
The lesson here is that nuclear power isn't simply a solution to global warming. It a technology that is threatened by global warming.
Turnabout
I wonder if it has ever occurred to the friends of the administration to wonder how these various expanded powers might be exploited by a hypothetical power-hungry, incompetent and ruthless ultra left-wing Democrat. It wasn't that long ago that people were actually somewhat concerned that a seemingly moderate Democrat might turn out to be a card-carrying Communist taking his instructions (or his ideas) straight from the Politburo. On the basis of such a possibility, wouldn't one want to blunt the power of such a disastrous individual by insisting on a limited executive?
I think we can take Republican party's embrace of expanded executive power as sufficient proof that they understand that the radical left is dead. They know that the most sinister thing the Democratic party has to offer is a few small-time crooks and the occasional philanderer. We can take the very fact that supposedly serious people are willing to promulgate the idea of a "unitary executive" as evidence that the advocates of the theory do not expect their political opponents to exploit such powers.
They are probably correct. If one may indulge in some speculation, what would Al Gore, had he been elected and had turned out to be a foaming-at-the-mouth enviro-communist, have done with the power to indefinitely detain people as "enemy combatants?" Whose phones would evil-universe Al Gore illegally wiretap? I can't imagine any answer to these questions that isn't just plain silly.
Barring some exceedingly bizarre event (e.g., the conquest of the United States by space aliens), I will probably vote for one of the Democratic presidential candidates next November. For the first time in living memory, we face the refreshing dilemma of choosing among genuinely good candidates, rather than the drudgery of selecting the least odious. I have to admit that even my least favorite Democratic candidate would probably make a pretty good president. But I wouldn't trust any of them with the wiretapping powers Congress granted to this president by passing the legislative turd that I shall dub the Illegal Wiretapping Reauthorization Act of 2007.
So there you have it, folks. The Republican leadership trusts any Democrat to exercise executive power responsibly and effectively. If they didn't, then they would be less enthusiastic about the expansion of executive power. Clearly, they trust the field of Democratic candidates more than I do.
Posts
