Les Jones

Is there not a process to turn "coal into something you can put in your gas tank" directly, rather than using it to distill the ethanol from corn mash?

I'm not sure how windmills and solar cells can have EROEIs of less than one. Is he really saying they produce less energy than they make to manufacture?

People generally don't think of money as units of energy, but they certainly can be viewed that way if one considers that it takes energy to manufacture goods. Heck, it takes energy to transport goods to market, and even to advertise those goods. But you mentioned something like that above.

The problem with solar and wind energy is that the equipment needed to store the energy (batteries) has a significant maintenance cost, as well as a very large initial outlay. Disposing of the toxic batteries after they have passed their useful life also has to be figured in.

An example can be seen in nuclear electricity. The radioactive elements that fuel a nuclear power plant last for years, and one would think that you could get free electricity from the plant as sson as it is built and placed online. But elaborate safety mechanisms have to be installed and constantly maintained, which increases costs significantly. You also have to figure out what to do with the fuel when it comes time to dispose of it, which is a non-trivial problem considering how the media has been trumeting for the past 30 years that all things nuclear are bad.

I have yet to read the linked article, but I'm already leery. The numbers for geothermal seem absurdly high, and I'm not sure that it would even work unless some really expensive drilling was first done.

James

"Is there not a process to turn "coal into something you can put in your gas tank" directly, rather than using it to distill the ethanol from corn mash?"

Yup, CNG. The primary step to catalytic ethanol conversion is gasification, which yields a gas that could be used directly. But you couldn't use *existing* vehicles for that.

If they're converting they'd do better with butanol, I bet. Much more energy dense than ethanol.

The windmills less than one thing is because they're counting the energy required to produce the 17mph wind.

Yeah, I forgot about the batteries.

I remember reading that the payback period for a home solar panel installation was about 20 years. That was for simple payback, not adjusted for 20 years of inflation. So I guess it may very well be true that solar isn't yielding much energy overall.

Does biodiesel come under the Energy Intensive Corn category?

I recall reading that virgin biodiesel is somewhat more efficient than ethanol, but I don't have a source handy.

These figures seem fairly accurate, but there are surely methodological questions. Solar equipment can be expensive, but how much of the expense is due to small-scale production? Also, solar delivers power at the point of consumption, avoiding both the loss of powerline transmission and the cost of building and maintaining a power grid. Is that taken into account? Most of the other fuels require engines or boilers or other equipment before their yield is actually useful, but those costs do not seem to be included.

Another trend I've noticed in these sort of calculations is the use of per-pound measures, which is a great, but misleading way to make an SUV seem comparable to smaller vehicles. Solar panels would suffer similar distortions if yield is arbitrarily divided by weight.

Lastly, exhausts and by-products are important considerations not part of these calculations. A fuel that yields energy more efficiently but also yields respiratory illnesses or mercury pollution loses favor in a more inclusive analysis.

Question:
How many gallons of regular gasoline can be produced from one barrel of average crude oil?
i.e. What is the yield?

Solar PV panels have an energy pay-back time of 2.5 - 3 years at present technology, and "almost 4 yr for multi-megawatt, ground-mounted systems. Prospects for improvement of the energy balance of PV systems are discussed and it is found that for future PV technology (in 2020) the energy pay-back time may be less than 1.5 yr for roof-top systems and less than 2 yr for ground-mounted systems (under the same irradiation)."

This is science fact. Not a "fract" from ultraconservative nerds who crawl inside the internet creating stupid theories like "net yield of solar energy is negative". BS! Wake up people.

Check this out.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2W-4177N2J-3&_coverDate=11%2F30%2F2000&_alid=468535993&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5713&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=f3715024a6a8f4568479b57d13c7a5b2

From that link:

"Prospects for improvement of the energy balance of PV systems are discussed and it is found that for future PV technology (in 2020) the energy pay-back time may be less than 1.5 yr for roof-top systems and less than 2 yr for ground-mounted systems (under the same irradiation)."

So that study is speculating on future technologies, not current ones.

if current studies indicate improvements to get payback time 2.5 3 years, it is because current tech is not far away from such specs. in fact, worst payback time with current tech is below 12 years, and can reach 3-4 years:

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V50-439MD43-2&_coverDate=12%2F31%2F2001&_alid=469245653&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5772&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=753887e7a9a0aa592fb0b3eed0d9c1f1

Also for future tech improvements in PV solar panels check this link out. It sure doesn't seem like a dead-end road path out there. Quite the opposite.

http://www.technologyreview.com/read_article.aspx?id=17246&ch=energy