Comments on: Total Energy Use Down in US, Wind & Solar Up

By: John Semmelhack

John Semmelhack — Tue, 08 Oct 2013 04:58:27 +0000

Of the world's big economies,
Of the world's big economies, Germany has shown over the past 20-30 years that energy use and economic strength do not have to be coupled. Between the years 1990 and 2010, the German economy grew by ~30%, while source energy use dropped by ~5%.

By: Allison Bailes

Allison Bailes — Fri, 04 Oct 2013 16:29:06 +0000

David B.:
David B.: Thanks. When I was writing the article, I meant to point that out. When you read it, I didn't have that caveat in there, but I did add a paragraph later, with a link to the NREL report you provided.

Dennis B.: If you say so... ;~)

John S.: Yes, you're right. The energy for the coal mining and gas drilling and PV manufacturing would show up under industrial. For imported sources, like petroleum, it mostly wouldn't show up at all. But even with the gas you use to transport your blower door, you haven't included everything. What about the fuel to make your blower door or your truck? What about the fuel that powers you - food? What about the fuel that went into producing the food? As you say, it does indeed get complex.

A lot of folks in the peak oil movement talk about EROEI - energy returned on energy invested and try to do the kind of full accounting you mention. A hundred years ago, oil had an EROEI of about 15 or so. For each unit of energy you put in, you get about 15 units of energy out. The number is a lot closer to 1 now because the easy oil is mostly gone.

By: John Semmelhack

John Semmelhack — Fri, 04 Oct 2013 03:24:23 +0000

A little “fine print
A little “fine print” on the LLNL graph – I’m pretty sure the 38.1 quads of source energy for electricity do not account for “pre-combustion” energy…that is, the amount of energy it takes to extract, process and transport fuels to the power plant. For instance, I was just driving through West Virginia. It takes a lot of energy to blow up mountains, dig up the blown up mountains, sift out the coal, “dispose” the coal slurry, truck the coal over to the rail cars, and send the coal over to the power plant. The LBNL report that David Butler pointed to shows that we should add about another 5% (1.9 quads) to the electricity generation source energy to account for this pre-combustion energy, and back those 1.9 quads out of the industrial and transportation categories. This kind of accounting gets pretty complex, though…that’s probably why the LBNL report (using 2004 data) has not been updated since!

Similarly, if we wanted a more accurate accounting of energy used in buildings (commercial and residential), we should back out some amount of energy from transportation and industrial to account for building materials extraction, production and transportation…not to mention the fuel used by me(!) to transport my blower door to the fine builders who use my services.

By: Dennis Brachfeld

Dennis Brachfeld — Thu, 03 Oct 2013 22:03:29 +0000

A lot of info, even for those
A lot of info, even for those In the know, the rest of us simply go with the low flow!

By: David Butler

David Butler — Thu, 03 Oct 2013 21:24:34 +0000

Here's a report from NREL
Here's a report from NREL that provides source energy factors as of 2004: Source Energy and Emission Factors.

See Table 2 for electricity by region, and Table 5 fuel, including delivery costs for LPG, fuel oil, etc. Keep in mind that regional electricity factors often don't reflect a given utility's generation mix.

If anyone is aware of a more recent study, please share!