The Ergosphere
Tuesday, July 06, 2010

2 Californias or 1/30 of a Texas to replace offshore oil

(cross-posted at The Oil Drum, if the doomers dare to run it.)

Words have power, and I don't understand how someone with as long a record as Chris Nelder could be so careless with them.  Mistakes in calculations are one thing, but a wordsmith ought to know about misleading headlines and burying the lede.  This is why I can't explain his essay, 195 Californias or 74 Texases to Replace Offshore Oil.  He cannot fail to understand how his title will be taken out of context for years to come.  He claims "What I want to warn against is the thinking (or the sanguine confidence) that incremental efficiency gains and tiny contributions from renewables will do the job."  Unfortunately, he's given sound-bites to people who are going to conclude that it isn't possible at all.  That's just adding to our problem of stasis when we need to act.

Getting things wrong

Nelder starts with a gulf production level of 1.7 mmbbl/d, then multiplies by 5.8 mmBTU/bbl and divides by 3412 BTU/kWh to get 2.9 billion kWh/day.  This is the first error:  he equates raw heat value of crude oil to electricity (a mistake others have made before, and common enough that informed people should be aware of it).  If we're comparing a BTU of Gulf of Mexico oil used for transport, the losses in the chain from refineries to pipelines to heat lost in the engine and brakes counts.  The well-to-wheel efficiency has been calculated at 12.3%, meaning losses of 87.7%.  Electric vehicles are many times more efficient.  The losses in transmission, batteries and other systems in an electric vehicle might amount to 30%, so it takes nearly 6 BTUs of oil made into gasoline to do the same work as 1 BTU of electricity from wind.  Let's call this 5:1 for simplicity.  This equates 2.9 billion kWh/day of oil to 580 million kWh/day of electricity (about 24 GW continuous).

Next is the figure of "74 Texases".  Nelder uses 2008 numbers which come to 14.23 billion kWh in Texas, and 5.42 billion kWh in California.  Much is wrong with this.  Even in the slow year of 2009, US wind generation increased 28% year on year.  California figures would probably be lower in 2009 than 2008, but Texas wind generation increased 35.4% from March 2009 to March 2010†.  The necessary number of Texases is shrinking all the time.

He also talks about "trillions in infrastructure".  Is that realistic?  No.  If power line right-of-way, towers and wire cost $500,000 per mile and they account for half the cost of an HVDC line, a trillion dollars would buy 250 HVDC lines 4000 miles long.  This is enough for a line running ocean to ocean across the USA every 5 miles from Minneapolis to Key West, with plenty left over.

Last, he mentions 20 years of solid effort to get there.  I think we could do it in 8.

Getting it right

It should be obvious that a number like "74 Texases" is meaningless when the energy represented by "1 Texas" increases 35% per year for years on end.  What we ought to be comparing isn't whatever electricity we generate today, but total energy potential.

Those potentials are huge.  It only takes 24 GW of electricity to replace GoM oil as transport fuel, but Texas's potential is 745 GW average (6,527,850 GWh/year, source).  California's potential is about 12 GW.  So, 2 Californias or 1/30 of a Texas would do it.

Infrastructure is the other half.  If Texas wind farms produce 40% of the time, moving 24 GW of average power takes 60 GW of capacity, or 25 HVDC lines at 2.4 GW each.  25 lines 1000 miles long at $500,000 per mile is $12.5 billion.  Balance of plant might be the same.  This is a factor of 40 below even 1 trillion dollars.

How long to get there?  At least in the case of Texas, running out of the resource is not an issue.  If we need to multiply Texas wind power by 12, it would take:
7.4 years at 40%/year growth
8.3 years at 35%/year growth
10.1 years at 28%/year growth.
To slow things down to 20 years, the growth rate would have to be reduced to 13.2%/year.

Why it's important to get it right

Understating the difficulty of replacing offshore oil is likely to produce complacency:  "we can do it later".  Overstating the difficulty is likely to lead to defeatism:  "we can't do it, period."  Both lead to inaction.  If there is any problem we're facing, it is the refusal to act when we need to.  This is why I think Chris Nelder's poor choice of words is so wrong.

† I'd compare 2008 figures but the EIA's monthly figures by state only go back 1 year, the records on are spotty, and the EIA keeps changing the data published and doesn't provide comprehensive tables; all of this is very annoying.  If anyone has a contact at the EIA, please try to get this information on their web site.

A variety of HVDC advocates put the cost of long-distance HVDC transmission lines at between $1.5M and $2.5M per mile, depending on the voltage (higher voltage is more expensive). A trillion dollars still buys an awful lot of it.
If the ABB figures in this PDF are good, it appears to cost about $400k per km inclusive of the conversion stations for a 1500 km line.

I gave a little thought to that and the pictures I've seen of DC lines (only 2 wires for a dual circuit, positively tiny towers), and realized:  one AC right-of-way could easily be expanded to a quad HVDC circuit for a very small increase in per-mile cost.
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