[SOUND] Hi, my name is Tom Murphy. I'm a professor in the physics departmentat UC-San Diego, and today we're going to talk about energy past, present,future, with a particular emphasis on the numbers. And when it comes to numbers, I advocate areal flexibility with numbers, and rounding and just sort of a, a loose manipulation, because math is a loteasier. If you don't take numbers so seriously andsome people laugh when I say that, but it's, it's really true thatmath is easier, division is easier, multiplication is easier if you can manipulate the numbers into somethingthat you can do in your head, then you canquickly understand the scale. Have a problem rather something can workor not work without getting bugged on thedetails. So, for the instance the number pi andthree are virtually the same thing. And ten over three and square root of ten,all about the same. So, you can simplify a lot of otherwise complicated math, just by being flexibleand so. For instance, you can round a year to 30million seconds. You don't need to know that it's 31.55million to do something useful. Likewise, the US population is somethinglike 300 million people. Forget the fact that it might be 308 oneyear and 310 the next, whatever. It's about 300 so, for example, the USuses something like 20 million barrels of oilper day. Now, if you have 300 million people using 20 million barrels of oil per day, that'sa pretty simple division problem and youcome up with 15 days per person per barrel of oil. So a person goes through a barrel of oilin about 15 days. And so, if you think about having a barrel of oil delivered to your house once every15 days. That's somewhat staggering and puts thingsin perspective. But oil is only about a third of our totalenergy demand. So you can scale that again simple math,now it's five days to go through the equivalent energycontained in one barrel of oil. So how much energy is that? Well depends on what units you like. Whether you like, gigajoules or joules orBTUs or [UNKNOWN] all are units of energy. But, you know, comes out to six, gigajoules, 6,000,000,000 joules,6,000,000 BTUs, 1,700 kilowatt-hours. And this is a very important point, if you divide energy by time, that's calledpower. And the units for power are watts. So if you take one watt is one joule persecond. So if you take six gigajoules, and divideby how many seconds are in five days, you end up with about 10,000joules per second, or 10,000 watts. That's a rate at which we go throughenergy. That's not watts per second. That's already a rate And that's a 24seven constant draw of power that each Americanis responsible for. Now, we'll come back to putting that inperspective. And for now, I just want to point out. If you take 10,000 watts or ten Kilowatts,multiply it by 24 hours, you get 240 kilowatt hoursper day. So, 240 kilowatt hours, that's now an energy cause it's a power, ten kilowattstimes a time, in hours, so, that's how manyenergy units we use per day as Americans. So, just to put 10,000 watts intoperspective. Imagine two clothes dryers running fulltime. They run at about 5,000 watts. Or, you could have, pick your appliance, hairdryers microwave ovens, toaster ovens,space heaters. They all run at about 1,700 watts andthat's actually not a coincidence. That's because household circuits areusually rated at 15 or 20 amps and so they're kind of maxingout. What a typical outlet can handle. So they're all about 1700 watts, you needabout six of those running full time to make10,000 watts. Here's an interesting one, a human thatcan, who consumes about 2,000 calories per day that turns out 2,000 calories is aunit of power per day. Sorry, 2,000 calories is a unit of energy. Per day that turns into watts, and itturns out to be 100 watts. So a human runs at about 100 watts. You need 100 humans to make 10,000 watts. That's basically saying that we have 100energy slaves working for us in America to do the things that we need to get done, sothat's quite a work force. You could also have 20-watt laptops. You'd need 500 of those CFL bulbs runningat 14 watts. You'd need about 700 of those. Cell phones charging. Maybe five watts to charge a cell phone so you'd need 2,000 of those to make up10,000 watts. Or, an idle charger might be drawing aboutone watt, so you'd need 10,000 of those. So that, hopefully, puts 10,000 watts intoperspective. That's what each of us is responsible for. Now if you know anything about yourelectricity bill, you might say 240 kilowatt hours a day is anawful lot. And you'd be right because if you look ata typical American household, the household usesabout 35 kilowatt hours per day. Okay. That's not a whole lot compared to 240,but we do have to keep in mind that. The primary energy it takes to come up with 35 kilowatt hours of deliveredenergy, it requires 95 kilowatt hours of primary energy from coal [INAUDIBLE] nuclear orwhatever else. So okay and natural gas it's also about 35kilowatt hours a day usually the gas bill is intherms. So that looks a little bit different, but,you can always convert units between each other ifyou need to. A typical household uses about threegallons of gas a day, each gallon has about 36 kilo watt hours,contained in it in energy. So that's a little over 100 kilo watthours in gasoline. Add all those up you've got about 235 kilowatt hours a day, and it sounds like we've reached our 240, but not so fast because a household contains morethan one person. So when you work it all out it comes outto about 95 kWh/day per person spent in thehome or personal vehicle. Ok, that's just 40% of the total, sowhere's all the rest? Well we have a huge infrastructureSupporting our lifestyle. We have industry, we have agriculturegrowing our food, transportation to move things all around to our stores,to each other. We have the consumer and commercial world. We have defense and government. All those things take energy. All of that happens outside of ourhousehold. And, but I think that it's important torealize that it all happens on our behalf. Our standard of living demands that wehave these things happening, and so we really have to takeresponsibility for all that energy. And also realize that almost all of it comes from fossil fuels, which are finitein nature. If you've never looked at it, the EnergyInformation Agency puts out every year an annual energy reviewThis is from 2011, and they have some nice graphs where you seepictorially how much comes from domestic fossil fuel, how muchcomes from imported fossil fuel. Here's nuclear and here's renewable, mostly hydroelectric and some burningwood. And then where it goes, residential,commercial, industrial, transportation. They also have some nice diagrams thatsort of detail where, which things go to where. So 71% of petroleum goes totransportation, but you can ask the inverse question, say thattransportation gets 93% of its energy from petroleum, or nuclear power,100% of it goes to making electricity, but electricity ispretty diverse, 21% comes from nuclear. So a lot of great information on this kindof spider web. Diagram. So, one point I want to make that's veryimportant to me, is that, we live in a very special time and place,here in America at this age. Prior to now, we used muscle and firewoodto get our energy. And then we found fossil fuels, and anincredibly. Ramped up our energy production to a huge level, and we're near the top of thefinite. We know fossil fuels are finite. We're near to the top of this curve. What happens out here, nobody knows. Anybody who tells you they know, you can'ttrust them, because we don't, it's not ascripted future. So, I think it's very important to keepthis perspective that we're living in a veryspecial time. All the growth that we've seen is highly dependent on this surge in fossil fuelenergy. So now let's put things in perspectiveglobally. We have we've seen in the US 10,000 watts per person, that's ten to the fourthwatts. If you multiply by the number of people,300 million people in the U.S, you get three times ten to the12 watts. Or three [??]. So, that's the power usage of the US. The US is 20% of the world, global energydemand. So, you multiply by five to get 15terawatts. And I'll note that US uses 20% of theglobal energy with less than 5% of the world population,so think about that. So 15 terawatts for the entire world. If our dream, as stated by many, is to have ten billion people, which arecoming, live at US or Western standards, that impliessomething like 100 terrawatts of power necessary to makethat happen. And so, that makes the fossil fuel looklike an absolute tiny blip. And we have all this energy coming from presumably renewables to last you know,for the millennia. And it's not clear what makes us think wecan do this. There's no precedent for it. So, let's just look at some of therenewables and what we can get. So, solar power reaching land comes up toa staggering 20,000 terawatts. And, even if you have all kinds ofpractical limitations, you could probably easily get hundreds of terawattsout of solar, if you had to. So, that looks pretty promising. But take the next step down and we look atthe entire biological activity on Earth, allorganisms from plankton to elephants. We're looking at 60 terawatts or thereabout. And how much of that can we commandeer forour own energy needs? How much of the world can we basicallyenslave to satisfy our energy needs. Not all of it, presumably. So five or ten terawatts might bereasonable. The wind resources, fairly similar, fiveor ten terawatts. And then it goes down from there, so ifyou look at what you need To get 100 terawattscale. Solar is really the only renewableresource that is obvious, that can do the job. Nuclear is also interesting, but it's nottechnically renewable. Does mine things out of the ground, andhas a finite lifetime. So, but there's more to the story thanjust the abundance. Because you can look at different aspectsof energy resources. You can look at the abundance, thedifficulty, the intermittency. Is it a demonstrated technology? Can it fuel electricity? Provide heat? Or fuel transportation, is it publicly acceptable, nuclear has some troublethere. Can you put it in your backyard and howefficient is it. And when you look at all of these thingstogether and score them, red are bad things, and yellow, intermediateand blue are good, aspects across all those. across all those categories for thedifferent types of alternative energies and end up all thescores. You end up with something like, one tofive, whereas fossil fuels tend to be eight of ten ofthese points. So there is a big gap between the thebenefits of fossil fuels and if it were for thefact that fossil fuels are finite in creatingin creating a lot of greenhouse gases, we wouldn't beworried about this. If you want more detail in this, go to myblog, do the math, look at the alternative energy matrix, you cansee lot more detail in how this isconstructed. So the lesson for me is that this makes mesit up and pay attention because we're in an allhands on deck situation. We have a, an energy demand that's huge, and continuation of this underalternatives is not guaranteed. We don't know for sure that we can makethis work. There are problems and issues in the way. That suggests we need to tackle this with a research effort that dwarfs everythingwe've ever seen. You know, Apollo-scale project, Manhattanproject, Should look tiny compared to what we need to do to respond to this energycrisis of the future. So, but we don't know even if we do a lot of research, we're not going toguarantee that, that's going to work. So, we also are wise to think about waysto trim down, use less energy this way. So personally at home, I've reduced myenergy footprint by about four or five times, and I still live a Westernlifestyle more or less. And so you can do that, but it's not justat home. Your consumer choices matter. So, how often and where you travel, whatyou eat, you know, meat for instance, costs a lot of energy How canyou buy things or replace things? How can you wash your clothes? All those things matter. And those are choices. So, be a friend to us all, turn off a hair dryer or two and we'll all breath alot easier.