Some recent work

[musicman]

Depends how you make the comparison. There are lots of new homes that aren't energy efficient at all as compared with other new homes. And since we're talking about how urban areas that exist in the present day are being developed with new housing stock, it is perhaps more important to compare apples to apples.

Where are these "new homes that aren't energy efficient at all"? when i'm say relatively i'm talking of a factor less than an order of magnitude.

Relatively, the new construction is energy efficient. Could any building be made more energy efficient? of course but that comes with a cost. We could all use 2x6's for external wall construction and increase the insulating R factor. but most builders sure don't.

I made the comparison between old and new because building codes have improved by making some energy efficient items mandatory.

[KinkaidAlum]

Denisty without planning isn't a great shake.

The above tin can alley does NOTHING to foster a sense of community. It does nothing to foster a walkable environment. It does nothing to create more green spaces around town.

While these are a bit different in that they were built in an existing industrial zone, most of them replace single family homes with multiple units. The end result is just more people taxing the roads, sewers, and other city services.

[woolie]

Ah yes, I forgot all about electricity being the primary driver of CO2, and that does kind of lend some credibility to the urban heat island issue contributing to CO2 output by way of inducing AC use. At the very least, anyway, it would seem to be an offsetting factor. Do you happen to know what amount of output of CO2 output is necessary for each kilowatt hour in the Houston area? Preferably not only accounting for CO2 from operations, but also caused by power plant materials fabrication, construction, and maintenance?

I've been wanting to make that comparison on the light rail vs. bus and BRT debates on other threads, as well.

Yikes.

It varies by region because of the differing mix of electricity sources. Coal emits approx. 2lbs/kWh, gas about 1.3 lbs/kWh, nuclear and hydro obviously 0. Nuclear/hydro typically consist of about 20% and 10% respectively, but again, varies by region.

You allude to "Total Life Cycle Carbon Emissions Analysis" but this is something of a red herring and very contentious issue in the energy community. It is because the energy used to construct new plants doesn't necessarily have to come from CO2 emitting sources, even if it customarily has. It's an argument used to present nuclear plants as CO2 emitting in a Catch 22 situation: construction of nuclear plants supposedly emits CO2 because there aren't enough nuclear plants.. anyway, it's best to just focus on Operational Emissions of CO2.

The US average is somewhere around 1.5 lbs/kWh.

I'm not sure the % nuclear power Houston gets, Reliant doesn't have those figures on their website.

This is a 1999 report; changes since then are primarily increase in Coal/Gas, with nuclear/hydro stagnant:

http://www.eia.doe.gov/cneaf/electricity/p.../co2report.html

http://www.eia.doe.gov/emeu/aer/pdf/pecss_diagram.pdf

Electrified transport is much more efficient than gas transport, even when you take into account transmission losses, storage losses, etc. Large turbines are simply much, much more efficient than piston gas engines.

Edited April 13, 2007 by Ian Rees

[TheNiche]

Thanks for the data. Do you have any on the pounds per mile of various vehicles driven?

You allude to "Total Life Cycle Carbon Emissions Analysis" but this is something of a red herring and very contentious issue in the energy community. It is because the energy used to construct new plants doesn't necessarily have to come from CO2 emitting sources, even if it customarily has. It's an argument used to present nuclear plants as CO2 emitting in a Catch 22 situation: construction of nuclear plants supposedly emits CO2 because there aren't enough nuclear plants.. anyway, it's best to just focus on Operational Emissions of CO2.

The US average is somewhere around 1.5 lbs/kWh.

I can see how it might be contentious, but I think that what brings about questions are attempts at measurement and impact analysis. But it would be foolish not to recognize that in order to get to the point at which operational emissions are relevant, there must be emissions related to the construction of the devices that allow operational emissions. You could look at it like this: as a society, we have an increasing demand for energy and need to bring plants on-line incrementally to fulfill that need. For the analysis of each plant, we should take the past for what it is, and consider only operational emissions throughout those plants' useful lives. But for the new plant, we should consider the emissions and respective impacts over the course of its useful life.

Shouldn't there also be some adjustment for the timing of impacts of the emissions? After all, wouldn't it be preferable to have a particular amount of CO2 emitted in very small increments over 50 years rather than a very large amount this year? It would certainly be preferable to society for man-made climate change (if any) to occur at a slower pace than a more rapid pace.

Electrified transport is much more efficient than gas transport, even when you take into account transmission losses, storage losses, etc. Large turbines are simply much, much more efficient than piston gas engines.

Do you have any comparative stats?

[woolie]

Thanks for the data. Do you have any on the pounds per mile of various vehicles driven?

I can see how it might be contentious, but I think that what brings about questions are attempts at measurement and impact analysis. But it would be foolish not to recognize that in order to get to the point at which operational emissions are relevant, there must be emissions related to the construction of the devices that allow operational emissions. You could look at it like this: as a society, we have an increasing demand for energy and need to bring plants on-line incrementally to fulfill that need. For the analysis of each plant, we should take the past for what it is, and consider only operational emissions throughout those plants' useful lives. But for the new plant, we should consider the emissions and respective impacts over the course of its useful life.

Shouldn't there also be some adjustment for the timing of impacts of the emissions? After all, wouldn't it be preferable to have a particular amount of CO2 emitted in very small increments over 50 years rather than a very large amount this year? It would certainly be preferable to society for man-made climate change (if any) to occur at a slower pace than a more rapid pace.

Do you have any comparative stats?

Even with total life cycle analysis, nuclear is still by far results in the least CO2 emissions per kWh.

from IAEA

http://www.world-nuclear.org/info/inf100.html

The best internal combustion engines have efficiency somewhere in the range of 30%, 70% of the energy is lost to waste heat and entropy. Electric drivetrains have efficiency in the 85-90% range... so it's not even close.

Sooo...

Let's take a car with 35 MPG

1 BTU = 1055 joules

1 joule = 2.77

Edited April 13, 2007 by Ian Rees

[TheNiche]

Wow. Thanks for the numbers.

I like numbers.

[woolie]

Edited April 13, 2007 by Ian Rees

[TheNiche]

I'm not a climatologist, but I don't think it really matters much if the CO2 is released all at once, or the same amount spread out over years. Atmospheric CO2 is in equilibrium with CO2 in the oceans. I think the reaction rates for dissolving excess atmospheric CO2 are fast enough to take up the excess very quickly. What matters is the total amount of CO2 released.

If all you're considering is whether the amount of atmospheric CO2 in the atmosphere is ultimately the same, that may be correct, but I'm much more concerned with the impacts to human civilization (economics major) than I am with simply measuring the concentrations of CO2 in the atmosphere. So what I'm trying to come up with is an answer to this question: what is the time-series relationship between CO2 emissions and climate change? From that, I can get at least a general sense of when and how the impacts (both adverse and beneficial) would be felt.

And in that strain of thought it is absolutely better to have an adverse impact spread out over many years or hit all at once in the far-flung future than have it hit next year, and of course the opposite is true of any beneficial impacts. It is more or less a matter of deriving and maximizing expected Net Present Value to society on any given project.

[woolie]

If all you're considering is whether the amount of atmospheric CO2 in the atmosphere is ultimately the same, that may be correct, but I'm much more concerned with the impacts to human civilization (economics major) than I am with simply measuring the concentrations of CO2 in the atmosphere. So what I'm trying to come up with is an answer to this question: what is the time-series relationship between CO2 emissions and climate change? From that, I can get at least a general sense of when and how the impacts (both adverse and beneficial) would be felt.

And in that strain of thought it is absolutely better to have an adverse impact spread out over many years or hit all at once in the far-flung future than have it hit next year, and of course the opposite is true of any beneficial impacts. It is more or less a matter of deriving and maximizing expected Net Present Value to society on any given project.

I'm not sure I can answer that question; there's going to be some lag, but I don't know enough to put a value on it.

If your question is really, "Can a rapid construction programme to build nuclear/wind/solar energy save us, or will the CO2 emissions from construction amount to the same net effect in the short term?" the answer is definitely yes/no, respectively. It is perfectly possible to have a first-world, Western way of life with 1/3rd to 1/4th the emissions per capita of the US. How do I know? The US is about 20 tons person/year... France, Switzerland, are about 6 tons person/year... and this is without any actual attention paid to CO2 emissions. The bulk of this is due to high % of nuclear power or hydro power, increased transit use, and more efficient autos. I think you could bump down to 3-4 tons or less with serious CO2 reduction efforts. Any short term emissions from replacing our fleet of coal/gas plants would pay healthy dividends.

[marc]

Really cool perspectives. Houston looked really eerie.

[Vertigo58]

That last picture with the lights shining through the fog reminds me of the scene in ET where he goes home...

Reminded me of this scene...

and this one...

Edited April 19, 2007 by Vertigo58

[SoupaIntense]

very beautiful pictures. I love any pictures with shiny wet pavement reflecting lights.

[editor]

but with the amounts of concrete that surround them, they sure won't be anything major either.

Bamboo would be perfect for those spots. The development in Midtown that was once called Live Oak (then became Oakwood, don't know what it is now) used bamboo plantings in the smaller areas and they just thrived in Houston's climate. Really did a great job of turning ugly wooden fences into green leafy areas.

[Rio Grande Valley]

Great photos!!!