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samboct -> Global warming talk by Steven Chu (nobel laureate) (12/17/2007 6:17:51 PM)
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Since there seems to be a fair amount of interest on this board on the topic of global warming, I thought I'd post the following. No, it's not off the 'net- I doubt anybody would publish the talk. These are my notes from it- Steven Chu gave the talk at the November 2007 MRS (Materials Research Society) meeting in Boston. The title of the talk is The World's Energy Problem and What Can We Do About It? Steven Chu is a Nobel Laureate in physics, and from seeing him talk and interact with the audience, he's a sharp guy (D'Oh), but well grounded and not arrogant- he's easy to talk to. He's also one of the authors on the IPCC report on climate change. Why do I think that nobody would publish the talk? Because it's too general for readers of Science (and more political) and no newspaper is going to send a reporter to an MRS meeting- odds are that they wouldn't understand most of it. (I get lost at a bunch of the talks.) But there were several thousand people at this talk and if our free press is going to be censored by corporate interests, bulletin boards may be the next best bet.
Steven Chu- LBNL- The World’s Energy Problem and What can we do about it?
1) Climate Change
2) 2-3B people don’t have access to modern forms of energy
3) Fresh water supplies are dwindling
Water issues in California-In the Sierra’s an optimistic reduction in snowmass is in the range of 30-70%. In British Columbia, ~ 40% of the pines are gone (which help stabilize snow and reduce runoff.) Tibetan glacier which supplies 1/3rd of humans globally with water is decreasing at a rate of 1.2m/yr. Northern Arctic icepack looks like it’s down 50% compared to 1985-2005. Ice is rolling off Greenland- flow increasing at 40 m/day.
IPCC report that just came out predicted a sea level rise of 0.5-1.0 m. (probably in a century) however, it doesn’t include tipping points- assumes a linear model. Unfortunately frozen tundra (now warming from reduced ice cover) has lots of CO2 and methane- could trigger Greenland ice sheet melting. Currently we’re in a warm spell-for the last 700k years- ice ages are 4-6C colder.
Energy Conversion- interesting way to put energy- it’s a servant. US has 350 GJ/yr/capita- 100 energy servants- but China has about a dozen per capita.
Free markets will fail when faced with a commons problem- i.e. air, water, pollution, overfishing, climate change. This calls for regulation in addition to higher energy prices.
Regulation example- from 1970-1982, refrigerator efficiency increased by a factor of 4. Note that inflation adjusted market prices fell by 2x. Commercial buildings are now 2x more efficient. However, National Association of Homebuilders are fighting against any target set by the federal gov. Additional examples- seat belts, catalytic converters (really in error, catalytic converters weren’t legislated, pollution controls which required them were.)
Electrical base load generation- most commonly used method for generating electricity globally is coal- think it’s about 67% of electrical generation. Overall efficiency of converting coal to energy is 27%. US efficiency is at 36%, Japan: 41%, Russia: 17%, China: 13%, India:10%.
Materials needs for improving energy delivery-(hey, it's an MRS meeting)
Need high temp metals- 600C for supercritical steam boilers.
CO2 sequestration- oil fields use MT/yr of CO2. Need to sequester GT/yr to put 10% of CO2 underground- i.e. 2-3 orders of magnitude increase. (Don't think anyone takes this seriously.)
Stern report (http://news.bbc.co.uk/1/hi/business/6098362.stm)- one time cost of 1% of world GDP would stabilize CO2 emissions by 2020 at current levels.
Wind- theoretically can capture 59% of wind energy- available plants are hitting 5/6ths, hence mature technology.
Transmission issues- shipping electricity more than 500 km, should use DC, not AC. Need to put AC high up in the air to reduce energy losses- AC wastes energy by polarizing the ground. Can carry more power with DC. Grid issues- the last major blackout was traced to a tree branch falling on a powerline in Ohio.
New materials needed for the grid.
1) Better solid state components
2) Better insulators, switches, and diodes. Need to step up and down more easily.
As an example, undersea cable between Germany and Sweden 680 kV.
Lithium batteries- it’s a materials problem. Using the existing Co polymer want more cycles, deeper discharge.
Biofuel problem- most of world is either desert or cold –how do you grow it?
Need factor of 10 cheaper PV (think he’s wrong here- PV mfg today is probably at 10 cents/kw from the mfg- but since it’s in scarce supply, cost is factor of 3-4x higher.)- little cheaper CSP (concentrated solar power)
For better PV (photovoltaics)- distributed junction nano solar cell- electrons conducted by nanorods, holes conducted by polymers.
Biomass. In 1900, 1.7B people globally. In 2005- up to 6.5B people. But the total amount of agricultural land has not increased- may have actually decreased slightly.
In terms of biofuel crops- Misacanthus grass- it’s a weed- doesn’t need much to cultivate in terms of water, fertilizer or work. Other options- perennials –switchgrass- much less nitrogen erosion. Problem- costs 3x as much to break down grass to ethanol as corn. Labs being funded at $150M/yr. Use gut processes from termites- microbes in the termite gut breakdown cellulose very rapidly. Sequencing termite guts. Example- production of intumescents.
How to split water, CO2. Problem- not enough fresh water in the world if using biomass for energy production. In terms of CO2- we know how the photosynthetic core in a plant works- except that we can’t get it to work in the lab. Probably no good artificial photosynthesis system happening soon.
Retail energy business is $1T, which is about 10% of high tech businesses.
You should note that no one in the audience questioned the idea that anthropogenic sources are increasing global warming- but in a certain sense- it doesn't matter. These are the observed effects from whatever cause.
A couple of other things to note- nuclear is absent from the above discussion. Solving the cellulose to ethanol conversion really solves a lot of problems in a hurry- yet we're only spending $150M/yr. We've also got a model of how it can work- i.e. the termite gut. Converting the existing automotive fleet to ethanol is very low impact on the economy- I still think these types of challenges help the US economy rather than hinder. But that's my views, and I should let Steven Chu speak for himself.
Sam
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