A bite-sized cogeneration example

Continuing a thought started elsewhere, I thought I'd blog something about cogeneration and plug-in hybrids.  (Note that this is a quickie and not thoroughly cross-checked, there could be errors in the calculations - caveat reader.)

The plug-in hybrid concept is touted for its potential to eliminate petroleum, but there are valid questions about how quickly we could increase generation to supply them.  This led me to ask, what if we used petroleum to supply the energy?  Better yet, if it was used in cogenerators?

Assume for the moment that refined petroleum (sulfur and heavy metals reduced to acceptable levels) costs $12/GJ (crude currently runs about $11/GJ).  Company X switches its process heat system from natural gas at $10.00/MMBTU ($9.48/GJ) and 10% losses to a cogenerator system co-firing natural gas and fuel oil at 50% efficiency and 10% losses.  The company buys 1.25 GJ of oil to supplement each GJ of gas they formerly used, sells the electricity for $0.08/kWh ($22.22/GJ), loses 10% and uses 40%; their fuel costs go from $10.54/GJ delivered to the process to $24.48, offset by $27.78 in electricity sales.  The gross cost falls from $10.54 to $4.98/GJ of process heat; the cost of heat is cut in half.

The 2.25 GJ of fuel produces 1.125 GJ of electricity.  This travels over the grid, losing perhaps 10% en route to the customer; 1.01 GJ is delivered.  It is purchased by a GO-HEV owner whose vehicle uses 350 WH/mile (1.26 MJ/mile) at the charger.  The vehicle achieves 794 miles per GJ at the wall, or 357 miles per GJ of fuel delivered to the cogenerator; if the owner pays $0.12/kWh, the per-mile cost for electricity is 4.2 cents.

Last, assume that the electricity delivered to the GO-HEV replaces gasoline at the rate of 1/35 gallon per mile.

A barrel of crude oil is 42 gallons.  If we assume that the refined fuel oil has the same 6.1 GJ/bbl energy value as crude (probably not too far off), here's what the cogenerating system would accomplish with each barrel of fuel oil:

• Reduce process heat costs by $27.08/bbl ($5.55/GJ process heat savings / 1.25 GJ oil per GJ heat * 6.1 GJ/bbl).
• Provide 1525 kWh of electricity to the utility, of which 1372 kWh is delivered at a gross profit of $42.70/bbl.
• Allow the driver to cover 3921 miles at an effective economy of 93.4 MPG (52.4 MPG per gallon-equivalent of all fuel used).
• Displaces 112 gallons of gasoline.
• Save the driver $132.21 (3.37¢/mi) in energy costs compared to gasoline at $2.65/gallon.
• Save a total of 70 gallons of fuel (42 gallons used vs. 112 displaced).

Total fuel savings:  70 gallons of fuel (each barrel saves more than a barrel).
Gross cost savings and increased profits:  $223.71/bbl.

We have a number of policies regarding electric generation (existing regulations appears to discourage cogeneration), vehicles (air-quality policy encourages the small improvements produced by ethanol but not the much larger improvements possible with partial ZEV operation) all of which stand in the way of accomplishing this.  If we fail to examine these policies and make appropriate changes ASAP, we are fools.

(Posting this entry was an exercise in hair-tearing; see Stupid Blogspot tricks.)

UPDATE 2005-Aug-29:  I think I might have the figures correct this time.  As confirmation, here is a before-and-after table of energy expenditures and disposition for comparison purposes (not including losses in electric transmission or profits to the provider of electric transmission, which could account for the stray twenty bucks between this table and the list above and which I would have put in if I could think of a good way to represent it):

System	Fuel	bbl (equiv.)	Fuel cost, $	Heat, GJ	VMT	Net fuel cost, $
Industry	Nat. gas	1.0	57.83	5.49		57.83
Vehicle	Gasoline	2.67	296.91		3921	296.91
		3.67	354.74	5.49	3921	354.74
Cogen	Nat. gas	1.0	57.83			57.83
Cogen	Fuel oil	1.25	91.50			91.50
		2.25	149.33	5.49	3921	149.33

  ¶ 8/19/2005 05:48:00 PM 8 comments

 

Quotes w/o comment

All from Winds of Change.

Tarek Heggy:

... those who demand the impossible are not heroes but nihilists.

Joe Katzman:

Nothing wrong with being a critic in a time of military conflict. The question is, are you offering alternative plans of action and critique, combined with a clear and shared commitment to victory as the goal? Are you asking for a plan of action and the terms of victory? Is victory your starting point, and your first demand?

Cicero:

This war is vital -- and it is vital that it is understood. Is that possible? A friend of mine was whining about the price of gas the other day. Her SUV costs about $50 a tank now. No talk about how the SUV doesn't fit in the era of Islamic terrorism emanating from the sands of Arabia. We have our tax breaks, but no talk about financial sacrifices for this war. The President of the United States is seen strolling on his ranch holding hands with now-King Abdulla of Saudi Arabia, home of Wahhabism. Nuclear terror threats develop here within our borders while our two main parties argue about when we should remove troops from Iraq. On and on, there's endless examples of how Washington is failing to communicate the strategy and purpose in the Third World War, where Iraq is a battleground.

... to win this war, we might actually have to buy fewer things, pay more for gas, eschew wasteful energy practices, question the morality of multiculturalism, develop and share a strategy for winning, question our assumptions, and give up the notion that this is all for pretend.

  ¶ 8/17/2005 07:04:00 PM 1 comments

 

Immediate responses

What you see on the roads is a window into the thinking of society.  If my past few days are representative, not much has changed; SUV's are still cruising 5 and 10 over the posted limit, drivers of 4x4 pickups are still rushing up to slower traffic in 35 MPH zones and then braking to tailgate, and old GM cars are still peeling out of parking spots and rushing to get to the main road.

Despite regular gasoline around $2.50/gallon and premium 20 cents higher, people aren't even trading their lead feet for aluminum, let alone feathers.  That's how seriously they treat high oil prices.

The public is in deep denial.  How long this will continue is anybody's guess; I suspect that it will take bankruptcies and mortgage foreclosures as owners of big status trucks run out of credit before the idea really takes hold in the public consciousness.  Until then the vast majority of people will do nothing, and pretend that nothing needs to be done.

On the day that things flip, it will finally be possible to sell solutions to the public.  Unfortunately, very few people are going to make and stock fuel-saving products on the off chance that demand will materialize in time to keep their business solvent.  Economic collapse in a host of places around the world could easily occur first, each one leading to sags in both oil and import prices and putting off the local reckoning for a while.  Absent action by the government to create demand (as it has done for ethanol), fuel-saving products are a risky business until the day the crisis can no longer be denied.

In every crisis, there is opportunity.  What kind of products could be rushed out in weeks or even days, and start making a difference right away?  The people who sell them stand to make a lot of money if they are ready.

There are things we could do to respond to a fuel crisis very quickly.  Here's a list of ideas off the top of my head:

• "Get the lead out" throttle springs.  These would be installed at either the vehicle's throttle body or beneath the gas pedal and provide tactile feedback to discourage wasteful driving.
• Throttle restrictor plates:  little pieces of stamped sheet metal sold with a pair of gaskets.  'Nuff said.
• Pickup cab-to-bed fairings.  These could be blow-molded from sheet material in stock at plastics shops; add mounting hardware and you've got product.
• Wheel fairings for semi-trailers to direct air around those draggy rear axles.
• Inflatable boat-tail fairings for the square aft ends of the trailers themselves.  These could mount to the doors using glue or heavy-duty double sided tape, and be inflated by exhaust gas or turbocharger bleed air.  Deflated, they would allow the doors to fold back as normal.
• Inflatable half-round fairings for the front edges of the trailer, smoothing the airflow around the gap aft of the tractor's deflectors.

Combined with common-sense measures like slowing down on freeways, I suspect that a 20% cut in fuel consumption is possible for non-congested driving conditions.  This would achieve a similar effect to a drop in fuel prices from $3.00 to $2.40; enough to take the edge off until more permanent fixes can be implemented.

Entrepreneurs, I put these ideas which are not already patented by someone else into the public domain.  If you can turn any of them into a design and profit from it, more power to you.  ¶ 8/13/2005 02:03:00 AM 29 comments

 

Petroleum independence as a growth engine

Over at Winds of Change, I've been having a little discussion.  Jonathan Gewirtz of Chicago Boyz had this to say (emphasis in bold added):

I do not understand the concern about our "dependence on foreign oil." We depend on foreign oil because it is a good deal -- i.e., it's currently the cheapest way to satisfy our energy needs.

Me being me, I took this as an invitation to analyze the claim above.  (Most of this piece is taken from my reply which was directed conversationally at Jonathan, to whom I refer as "you".  Readers should interpret accordingly.)

Crude oil contains about 6.1 GJ/bbl, and is selling for about $60/bbl; call it $10/GJ in round numbers.  After 10% refining losses you're up to about $11/GJ; burned in a diesel at 35% efficiency each GJ at the output costs you about $31/GJ, or about $0.11/kWh in crude at the port of departure (at $2.50/gallon and 140 kBTU/gallon it costs about $.17 at the pump per kWh of engine output).  Gasoline cars average 17% efficiency, so those figures become 23¢/kWh of crude and 39.8¢ at the pump per kWh at the wheels (assuming 126,000 BTU/gallon HHV for gasoline).

We may soon look back on $2.50/gallon petroleum with wistful nostalgia.  (News from people of my acquaintance on the West Coast indicates that some already do.  Premium no-lead in the Seattle area is a squeak under 3 bucks, and diesel in California is over.  I'm happy that I can still fill my oil-burner for a smidge under two-fifty.)

Solar PV power costs about 25¢/kWh and is dropping steadily (there may also be quantum jumps as new technologies come to market).  Wind power is as low as 4.5¢/kWh and is also dropping as bigger turbines return more energy per dollar invested.  Crude was a good deal at $15/bbl, but is no longer.  Even if technical and political risks are ignored, it probably never will be again.

It's time to move away from petroleum.  I would already have moved, but there are no vehicles on the market that will let me "fuel" with electricity.  I expect this to change well before the 2010 model year, but that doesn't help today.

You don't even need to go AE [alternative energy] to benefit; if we had electric vehicles, we could use quite a bit less petroleum.  Combined-cycle gas turbines turn fuel into electricity at about 50% efficiency; allowing 7% for transmission losses, 10% each for charger and battery losses and 20% at the motor, the overall efficiency would be 30.1%.  Compared to burning fuel in a 17% efficient car you could burn the oil in CCGT plants, get 77% more miles per gallon and still have the steam-turbine exhaust for industrial process heat.  (Calculating more directly, if you burned straight crude in a powerplant which scrubbed the sulfur and whatnot and achieved 50% efficiency, the output energy would be 3.05 GJ/bbl or 20.2 kWh/gallon.  Given 7% transmission losses and 350 Wh/mile at the wall [about 35% more than the plug-in Prius+], an electric vehicle would achieve an effective 57.6 MPG.)

Crude oil at $10/GJ burned in a 50% efficient powerplant produces power at 7.2¢/kWh fuel cost.  If wind can substitute for 30% of this at 4.5¢/kWh, the average cost of the electricity would be 6.39¢/kWh (plus O&M on the CCGT).  The effective "mileage" of the aforementioned electric car would be 82.3 MPG; the plug-in Prius using 262 Wh/mile would get an effective 102 MPG on its all-electric driving.  Then you'd have all the air-pollution reductions coming along with that for free... can you list the market failures?

A vehicle achieving 57.6 MPG is getting more than double the CAFE standard for passenger cars; 82.3 MPG is approximately triple.  It appears that a change in the technology of transport energy delivery could cut the fuel required to run America's passenger vehicles by 2/3 with only a modest shift to renewables.  It would also replace a great deal of imported crude oil with much cheaper domestic energy supplies which have little or no price volatility.

The USA consumes about 134 billion gallons of motor gasoline per year (8.74 million barrels per day).  Eliminating 2/3 of this would cut 5.83 million bbl/day of demand, or over half a Saudi Arabia.  This in itself would reduce both world oil prices and price volatility.

The worst thing we could do would be to try and predict the future by shunting public resources, at the expense of economic growth, into this or that currently-favored technology.

If you mean that we should stop shunting public resources into defense costs for oil producers and routes and charge them at the pump instead, I could not agree more.  I can point to entire industries which have come to depend on that one market distortion, amounting to misinvestment of hundreds of billions of dollars.

Our current transport energy system is penny-wise and pound-foolish.  It evolved in conditions which are now history.  It's time to recognize this fact and move on.

What will happen if we do?  Replacing 11¢/kWh petroleum with 4.5¢/kWh wind electricity will cut the cost of the inputs by more than half, of course.  It will also make the future cost of the energy much more predictable.

The usual product of lower costs and greater certainty is more investment and economic activity.  The question has to be raised:  why are soi-disant advocates of growth opposing one of the biggest engines of growth of this century?  They should be its biggest fans.  ¶ 8/10/2005 01:49:00 PM 30 comments

 

Bad writing, bad thinking

I don't get a lot of mail, but what I do get is sometimes... interesting.

Some of it is good, some of it is bad, and some of it is strange.  The strange stuff usually comes from people who want something.  There was the person who wanted a third party to post more about alcohol (the inspiration for this); this person is so thought-challenged they were under the impression that the material here was research!  (For those of you who don't know, research tends to look more like this.)  There are legions of people out there who can't tell the difference between facts and gloss, or kilowatts and kilowatt-hours for that matter.

Then there are people who ought to know better.  I got a request from a new blogger trying to promote his site.  Unfortunately for him, he immediately got off on the wrong foot by larding his request with spelling and grammar errors.  A cursory scan of the site showed more of the same, plus fancy glitz like text crawls.

I'm not going to link to anything like that, and I said so.  Regardless of how "empowering" the author may feel his work to be, I think readers of The Ergosphere deserve good writing first and foremost, enclosing solid facts and good thinking.  Details count, and content is the be-all and end-all.  I don't simplify my English for machine translation, but I do my best to use proper spelling and grammar so that this blog is not more difficult to access than necessary.

My one-sentence negative response prompted a reply which closed with "fuck you".  This indicated to me that he didn't get the point, so I was somewhat more forthcoming regarding why I was not going to offer links (immaturity having been added to the list).

So here's a promise to you, readers:  The Ergosphere may have errors, and will have snide language directed at people with illogical or idiotarian tendencies.  But I will correct the errors when they come to my attention, and The Ergosphere is and shall remain a no-glitz zone both in the hosted content (as much as Blogger allows) and the links I provide.  I don't have to worry about meeting a schedule for an employer, so I don't have to try to write something to fill a slot on a particular topic; this is an amateur effort, meaning I do it because I love it.  I'll provide the best thinking I've got, and link you to the best I can find.

The Ergosphere:  All content, all the time.

UPDATE 15-Aug-2005:  I received another entreaty from this blogger.  Apparently, he either cannot take a hint or is baffled by spell-checkers.  "Charaties"?  Oh, for pity's sake....  ¶ 8/09/2005 05:28:00 PM 0 comments

 

Cheers and raspberries

Cheers to Alhamedi who pointed to this fix for the posts-shoved-below-the-sidebar bug.

Raspberries to Blogger support for not bothering to respond to repeated complaints when all they had to do was e-mail a link.  ¶ 8/09/2005 05:20:00 PM 0 comments

 

It's about time

NASA is finally going to quit messing around with the Model T of space vehicles and go back to what works; the Shuttle's replacement will be two vehicles, one heavy-lift cargo hauler and one much smaller people-carrier.  Both will use Shuttle SRB's, and the heavy-lifter will use SSME's as well.

NY Times coverage.

(Hat tip:  Slashdot.)  ¶ 8/02/2005 02:31:00 PM 21 comments