Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations KootK on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Let's burn more sunshine 4

Status
Not open for further replies.

fast4door

Mechanical
May 29, 2012
39
Climate change deniers, go away.

So let's say global warming is caused by pulling tightly-packed carbon out of the ground in solid/liquid form, then combining it with oxygen and creating more CO2 than there was previously. Let's also say we want to simply freeze the amount of CO2 in the atmosphere and dispense with this "sequestration" baloney. In that scenario, we would need a carbon-neutral course of energy. That leaves nuclear or solar or bio-fuels. I want to talk about bio-fuels.

Here's what I can't figure out. Nature has been capturing sunlight and turning it into carbohydrates and lipids for like a trillion years. There's tons of energy out there. We're really good at disassembling those hydrocarbon chains inside of cylinders, turbines, etc. We should be able get good old nature to make our fuel for us. Is there any hope to the people that want to make biodiesel from algae? Are the yields unrealistically low?
 
Replies continue below

Recommended for you

If the infrastructure is cheap and the running costs low, efficiency is not such a great concern. I think all methods have their limitations re location.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &
for site rules
 
The round the loop efficiency of stored hydro is around 80%, which makes it a bit more attractive. The killer is the huge volume of water and/or height difference required.



Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376
 
I was thinking along the lines of a small dam downstream of an existing dam. The increased hydro power capacity will drain the existing dam to fast so the water collected down stream could be pumped via solar power.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &
for site rules
 
pumped hydro at a commercial scale is very expensive. you need two large reservoirs, pumps, pipeline, makeup water plus a penstock and generator. transmission lines and then the environmental and dam safety permits also. much cheaper for a conventional powerplant
 
That's why I thought expanding the capacity of an existing hydro electric facility. Much of that is already in place.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &
for site rules
 
from the link, hydro-storage uses more energy than it produces (no surprise there, remember the 2nd Law of thermodynamics ... "you can't break even").

the point is that it smooths out the peak demands and over-supply of power, by producing power in peaks and consuming power in lulls; allowing mainline stations to work steadily at optimum efficiency.
 
Everytime you propose a new hydro facility, someone complains. Same thing with coal, oil, gas, nucular, and now wind.
The public seems fixacated on solar, however, not the steel production, sand extraction, or other processes it takes to make them.

After the recent fires, you would think someone would be calling for better forrest managment, and burning of trees. Which by the way is a solar to chemical energy, and probally the cheepest renewable energy storage. And it provids lots of jobs, which other renewable energy are magnitudes away.
The problem is harvesting, and transportation. But just as mine-mouth power production has been good for coal, maybe the same can be used for wood.
 
cranky108, people complain about solar as well, at least some of the large facilities planned. They're worried about the habitat loss etc, including from the power lines & access roads etc.

Pat, I've wondered about similar, I always have a feeling that I'm missing something though.

Posting guidelines faq731-376 (probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484
 
every form of electric power generation uses more energy than produced. there is no 100% efficient conversion technology available. hydropower is useful because the stored energy in the water is replenished naturally and the water is delivered to the penstock by a river, no trucking required. storing the water however takes capex to build and maintain a dam. double that if you plan to pump storage using a second dam. and approving the EIS for a new dam on a perennial stream is about as easy as getting the building permit for a new nuke. so in order to get around that, pumped storage may be built off stream, which makes it even more expensive. A good example of this is Taum Sauk in Missouri, which by the way failed a few years ago causing millions of dollars in damage and environmental impact. This failure has made it even more difficult to get any new pumped storage facilities permitted.

 
Kenat, you mean people complain like this?


EVERY solar project in California faces these same hurdles. "Wah, you're killing the tortoises." "Wah, you're ruining the view." And on and on. I'm not saying environmental impact reviews shouldn't be done, but they should be put in the context of trade offs: if we don't build this solar bloc, then maybe a coal plant has to increase production and will kill more animals somewhere else.

And for pete's sake, if we can use eminent domain to favor developers over homeowners in New Jersey, can't we just move the whiny nimbys?
 
Some utilities don't want to use eminent domain, because it looks bad in the press (I agree). But I also question why we need to put solar on empty land, when we have so many parking lots. I mean you get in your car and it's 200 degrees, so you turn on the AC to cool it off as fast as possible. Or you let your car run, while you scrape the ice off the windshield. Just put solar over parking lots are the energy savings that is distributed over the car owners should do you proud. A very good method to reduce the consumption of gas, and make lives easer.

What ever happened to the turban powered car? A great multifueled car that never went into production.
 
Cranky, I'm going to cut off the trolls and point out that sometimes it's kind of nice to get sun on your car in the winter. There are certainly pros and cons to your parking lot idea, but I think the larger point of using single-purpose space to become multi-purpose is a good one. Hence, panels on rooftops.

Also, I'm going to assume you meant to ask about a "turbine" powered car. A turban powered car would only get like one mile per Sheikh anyway.
 
Our cars are essentially turban powered now, aren't they?
 
first one to mention "pull starts" gets RF'd !?
 
Now now boys.

KENAT, I think you started this by declining to start it. Very devious. I'm proud of you boy.

Opps, there you go, some words have a very different inference in the USA to the rest of the English speaking world as Bert Newton, a very popular and particularly inoffensive talk show host here found out when he referred to Muhammad Ali as the boy during a live interview.


The incident is mentioned toward the bottom of the Logies section.

A full clip of the incident and context.





Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &
for site rules
 
OK, Turbine powered car. My point is where are the real multifueled cars?

Also wonder why we don't have combined cycle plants in cars?

And explain why some groups want to show off there solar panels? They don't impress me. Sort of reminds me of that movie with all of the billbords on each side of the highway. I'd much rather look at powerlines.

I'm not that keen on solar panels on your roof. I have some for heating water, but dosen't work. Now I need to figgure my economics to get it fixed, removed, or other. Since I may need new shingles in a few years, I might have to remove the panels anyway. And with no tax incentive to repair the panels/system, I think I can remove them for a few years, then have a new system installed and get tax incentives.

Which leads my noticing that we are becoming more a throw-a-way society again (we never stoped, but paused for some years).



 
Turbine powered cars? Power to weight isn't really an issue for a ground vehicle, whereas efficiency is. Didn't the Rover turbine cars of the 50's/60's have dreadful lag and general driveability.


- Steve
 
Response lag, cost, exhaust temperature - and parts whirling at 40,000+ RPM. Some failure modes due to impact would certainly be.... exciting.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor