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135 comments on EROI on the Web part 2 of 6, (Provisional Results Summary, Imported Oil, Natural Gas)

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Robert Marston on April 8, 2008 - 6:17pm Permalink | Subthread | Parent | Comments top

EROEI over time is a great point. Which leads me to another thing I noticed in the article:

The EROEI numbers for CSP are ancient -- 1986??? Can't you find newer numbers? In 1986 CSP plants were fairly new and EROEI over time has been on the increase for CSP, thermal and solar towers.

I'm looking for more recent CSP numbers but I found the numbers on the ASPO site to be, in some cases, more favorable for renewables than the ones posted in the above.

Hydropower 11.2 (33.6)
Nuclear (light-water reactor) 4.0 (12.0)
Solar
Power satellite 2.0 (6.0)
Power tower 4.2 (12.6)
Photovoltaics 1.7 (5.1) to 10.0 (30.0)
Photovoltaics Thin-Film 7 (21) to 40 (120)
Solar Thermal to find
Wind 80 (240)
Geothermal
Liquid dominated 4.0 (12.0)
Hot dry rock 1.9 (5.7) to 13.0 (39.0)
Table Notes: Estimates of energy return on investment (EROI) ratios for some existing and proposed fuel supply technologies. Numbers in parentheses for electricity generation include a quality factor based on a heat rate of 2,646 kcal/kWh (10,493 BTUs/kWh) (source: http://energycrisis.com/aspo-usa/2005/).

A solar tower is a kind of CSP and here it is listed as a 4.2 EROI. It also adds a break out for thin film photovoltaics which the original post has failed to mention.

One thing I did find is that the energy payback time for CSP is 5 months to one year depending on the system:

"The energy balance is outstanding: the payback period for the energy expended in production of the components is 5 months. The materials used (concrete, steel, glass) can be recycled. The specific land use is quite low at 2 hectacres per MWel. The property needed has a very low value. There is no social or ecological problems associated with its use. There are no hidden social costs in the form of environmental pollution, additional social services, or resulting economic effects. Solar thermal plants use materials that are available and affordable worldwide. For the most part they can be constructed and operated by local labor."

http://www.schott.com/solar/english/download/schott_memorandum_e.pdf

If the energy payback time is five months then to state that the EROEI on a system that will last 25 to 50 years is 1.8:1 is ludicrous.

If you want to be taken seriously, you need to take a hard look at your data and determine if it's telling the truth as it stands today and is an accurate representation of FACTS or if it's simply a long chain of inaccurate, outdated, and issue-slanted statistics.

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Undertow on April 8, 2008 - 7:36pm Permalink | Subthread | Parent | Comments top

If you want to be taken seriously, you need to take a hard look at your data and determine if it's telling the truth as it stands today and is an accurate representation of FACTS or if it's simply a long chain of inaccurate, outdated, and issue-slanted statistics.

Surely that's exactly why the draft is posted here?

While it is still in draft form, it is hoped (with some help from TOD readers) to be refined and directed into the formal peer review literature. But Professor Hall (and I) believe this type of thinking also needs to be considered outside the academy, and increasing the level of energy discourse in our nation is one reason for him choosing to display his draft essays on theoildrum.com.

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Robert Marston on April 8, 2008 - 10:11pm Permalink | Subthread | Parent | Comments top

Well my refinement would be to:

1. Get more recent numbers on Concentrated Solar Power from a variety of sources. You can start with the solar towers subset from ASPO USA (1985) and then do an EROEI calculation by collecting industry figures for other concentrated sources. Some plants have been in operation now for years and you should be able to go to the industry to get good data points.

2. Break out Photovoltaic and Thin film EROEI figures.

3. Look at nuclear from within the US RE regulatory issues and outside the US. I'd be very interested to see what kind of numbers you'd get in France, for example, which seems very successful in nuclear at the moment.

When I saw these old numbers I had to laugh. EROEI for a renewable infrastructure in place will scale upward over time even with the added cost of maintenance etc.

Here's another EROEI list I found that seems to scale with the ASPO data and supports a CSP (solar tower) EROEI estimate of approx 4:1.

http://www.eroei.com/eroei/evaluations/net-energy-list/

Also, I found a study by Lorin Vant-Hunt, professor of physics at the University of Houston, that referenced the EROEI for a concentrated solar power system to be 27:1 over 30 years for the system:

http://www.ases.org/divisions/electric/SED_April06_nwsltr.pdf

The newsletter cites a study in 1991 that did a comprehensive EROEI study of a solar tower or heliostat with molten salt storage on site. The researcher also noted that though she had not performed a study on trough or Sterling CSP systems she thought EROEI numbers would be similar to the ones she found for the heliostat.

The primary reference for the work is an article: "Solar Thermal Electricity: an Environmentally Benign and Viable Alternative" pp 157-166 published 1992-1993.

In all, I think this represents a more rational current range with conservative estimates for CSP at around 4:1 and optimistic estimates up to 27 or more. Lorin Vant-Hunt noted 40+ EROEIs when materials used in the heliostats were recycled.

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mdsolar on April 9, 2008 - 12:08am Permalink | Subthread | Parent | Comments top

Brad F noted that there are some miscalculations (or typos) in the table. The number without salt storage should be 34 not 44.

These values for silicon PV should be useful:
http://www.nrel.gov/pv/thin_film/docs/lce2006.pdf

Chris

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JonFreise on April 9, 2008 - 1:23am Permalink | Subthread | Parent | Comments top

I did a quick analysis of the Nevada Solar One project using googled data.

Cost $266 million.
125e6 Kwh per year (23% capacity factor).
Lifetime 40 years (length of land lease).
I used 13Mj per $ number from article above. (the whole thing is glass and stainless steel + turbines)

5.21 EROI

Operating expenses (repair, cleaning, staff) were not factored in.

Actually, looking at the tables from 1975, it looks like glass and stainless are even more energy intensive per $ than turbines. Ok. If I use glass and steel Mj/$ then we get back down to 3.4 EROI. I think that is going to be too low because the whole plant cost will include less energy intensive items. A wider boundary analysis gives the lower bound on EROI.

Sigh. No wonder they keep building coal plants.

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mdsolar on April 9, 2008 - 10:54am Permalink | Subthread | Parent | Comments top

Well, this may point to an issue with applying MJ/$ to technology that is still scaling. What level of reinvestment is being put towards growth? How are early development costs being apportioned? What is the expected cost at the anticipated optimum scale (200 MWe)? Once the cost settles then the figure you used might be usefully applied.

Bottom up may have some advantages when assessing developing technologies, but here are some cost figures for 100 and 200 MWe plants: http://www.renewablesg.org/docs/Web/AppendixE.pdf

And here is a report on an LCA for a parabolic system that comes out to EROEI~25: http://www.latermotecnica.net/pdf_riv/200702/20070215003_1.pdf

This is in italian but the same authors have IEEE publications on this subject.

Chris

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JonFreise on April 9, 2008 - 12:22pm Permalink | Subthread | Parent | Comments top

I agree that later production models will have higher EROI. One off designs with custom made parts imported from around the world are going to be expensive. But I see this as setting the lower bound. And it gives those doing the bottom up analysis a rough target to shoot towards to make sure they are including everything. The one with a value of 34 left out labor & construction cost. It is very easy to leave things out of a bottom up analysis.

Finally, the 5:1 answer makes some sense in that CSP is still delivering power at higher cost than nuclear. (And you are putting nuclear at 7?) So that would be roughly correct.

I think CSP is going to take off. The newer designs are all about getting costs down and efficiency up.

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mdsolar on April 9, 2008 - 1:13pm Permalink | Subthread | Parent | Comments top

I'm not so sure that the EROEI has to change to get the cost to come down. Or perhaps it would be better to say that the cost of the manufacturing plant is front ended too much to make a dollar to energy conversion useful? The learning curve effect would be a separate thing I think. Still, $0.11/kwh now is pretty similar to $0.03/kwh from a plant whose financing was set 45 years ago.

Chris

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JonFreise on April 9, 2008 - 2:59pm Permalink | Subthread | Parent | Comments top

Hi Chris,

Thanks for that link to the Appendix E Solar Thermal. There were quite a few useful bits of data and I did an EROI for the last two SEGS plants at Kramer Junction.

I ended up with an EROI of 9.3 for costs as they stand today. That includes all construction costs as well as operations and maintenance. It turns out that more energy is spent in maintaining the plants than was required to build them. They have a program underway to drop the O&M cost from $25/Mwh down to $10/Mwh. If that program is successful, then the EROI will increase to 14. This assumes a 40 year plant life. If the life is shorter, then the number drops substantially.

All and all that is a pretty good number considering the output is electrical power. And it has very few environmental side effects (except water use).

As far as the Nukes value goes, I was thinking of the MIT study (now several years old) that put new nuke $0.08/Kwh. It would be higher now of course (inflation, rise in steel & concrete).

If you want the spreadsheet, send me an email.

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mdsolar on April 10, 2008 - 8:12am Permalink | Subthread | Parent | Comments top

I started a thread here: http://europe.theoildrum.com/node/3795#comment-327648
that seems to indicate that estimated costs are going up faster than inflation but the only price for nuclear power I'm really interested in (outside of energy analysis) is the price without the Price Anderson subsidy and with the full cost of waste disposal and decommisioning, which is unknown. The UK estimate of $12,000/kW for decommissioning is interesting.

The other price I'm interested in is the price of carbon dioxide to make the scenario in fig. 6 of this preprint happen:
http://www.columbia.edu/~jeh1/2008/TargetCO2_20080317.pdf

My guess is that it is impoverishing and we'd need to ration instead but maybe I'm too influenced by the inelasticity of gasoline.

Thanks for the offer though.

Chris

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JonFreise on April 8, 2008 - 9:44pm Permalink | Subthread | Parent | Comments top

Hi Robert. I appreciate your frustration with studies being 20 years out of date. Lucky for you, you don't have to sit on the sidelines. Dr. Hall has published enough information that you can jump in and do the heavy lifting yourself.

Here is how I would start: Find the total construction cost (materials, labor, everything) for a CSP power plant. Then convert those $ into $(2005) then use the Mj/$ value in the article to convert that into energy. Then calculate the energy output of the plant (factoring in true capacity factors etc). With that data you should be able to get a value for EROI.

I have not read the schott memorandum, but bottom up studies tend to over estimate the EROI because anything left out causes the EROI to go up. The sloppier the math, the better (sounding) the result! So I would dig into that analysis in more detail. What was included in "energy expended in production of the components"?

Dr. Hall did a calculation for a Coal Power plant that you might enjoy reading:

Hall, 1979, "Efficiency of Energy Delivery Systems: 1 An Economic and Energy Analysis", Environmental Management, Vol3, No 6, pp 493-504 (make sure you get parts 2, 3 also).

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