Energy return looms large as we grope for ways to wean ourselves from fossil fuels. This book has got to be the definitive reference on solar photovoltaic power. It is a detailed and careful analysis. The book is bursting with interesting data and observations. Hall is certainly the world's expert on EROI and this is a nice addition to his body of work. That work concludes that energy returns likely in the range of 8 or so are really required for a sustainable energy system. Sadly, by a couple methods of analysis the Spanish solar experience points to an EROI of less than 2.5.

Out of date analysis and conclusions

This book presents, objectively, EROI calculation of the Photovoltaic energy generation system in a case well supported in data.
Even though there is not an explicit reference of the lack of considering energy consumption implications previous to make political decisions in the book, interested readers would be also interested in look for related literature. Energy politics have strong implications, but curiously, in most (if not all, I do not know) energy is not taken in account in the measure that this issue should be treated.

This is the first time an estimate of Energy Returned on Energy Invested (EROI) of solar Photovoltaics (PV) has been based on real data from the sunniest European country, with accurate measures of generated energy from over 50,000 installations using several years of real-life data from optimized, efficient, multi-megawatt and well oriented facilities.

Other life cycle and energy payback time analyses used models that left out dozens of energy inputs, leading to overestimates of energy such as payback time of 1-2 years (Fthenakis), EROI 8.3 (Bankier), and EROI of 5.9 to 11.8 (Raugei et al).

Prieto and Hall added dozens of energy inputs missing from past solar PV analyses. Perhaps previous studies missed these inputs because their authors weren't overseeing several large photovoltaic projects and signing every purchase order like author Pedro Prieto. Charles A. S. Hall is one of the foremost experts in the world on the calculation of EROI. Together they're a formidable team with data, methodology, and expertise that will be hard to refute.

Prieto and Hall conclude that the EROI of solar photovoltaic is only 2.45, very low despite Spain's ideal sunny climate. Germany's EROI is probably 20 to 33% less (1.6 to 2), due to less sunlight and efficient rooftop installations.

Spain saw much good coming from promoting solar power. There'd be long-term research and development, a Spanish solar industry, and many high-tech jobs created, since the components for the solar plants would be manufactured locally. Spain imports 90% of its fossil fuels, more than any other European nation, so this would lower expensive oil imports as well.

To kick start the solar revolution, the Spanish government promised massive subsidies to solar PV providers at 5.75 times the cost of fossil fuel generated electricity for 25 years (about a 20% profit), and 4.6 times as much after that. Eventually it was hoped that solar power would be as cheap as power generated by fossil fuels.

Financial Fiasco

The gold rush to get the subsidy of 47 Euro cents per kWh began. Because the subsidy was so high, far too many solar PV plants were built quickly -- more than the government could afford. This might not have happened if global banks hadn't got involved and handed out credit like candy.

Even before the financial crash of 2008 the Spanish government began to balk at paying the full subsidies, and after the 2008 crash (which was partly brought on by this over-investment in solar PV), the government began issuing dozens of decrees lowering the subsidies and allowed profit margins. In addition, utilities were allowed to raise their electric rates by up to 20%.

The end result was a massive transfer of public wealth to private solar PV investors of about $2.33 billion euros per year, and businesses that depended on cheap electricity threatened to leave Spain.

Despite these measures, the government is still spending about $10.5 billion a year on renewable energy subsidies, and the Spanish government has had many lawsuits brought against them for lowering subsidies and profit margins.

Solar companies went bankrupt after the financial crash, including the Chinese company Suntech, which sold 40% of its product to Spain. About 44,000 of the nation's 57,900 PV installations are almost bankrupt, and companies continue to fail (Cel Celis), or lay off many employees (Spanish photovoltaic module manufacturer T-Solar).

Nor were new jobs, research, and development created, since most of the equipment and solar panels were bought from China. But unlike China, where the government insisted PV manufacturing be supported by massive research and development (and cybertheft of intellectual property from the United States and other nations), the only "innovations" capitalists in Spain sought were the numerous financial instruments they "invented" to make money, such as "solar mutual funds". Far more money went into promoting and selling solar investments than research and development.

Prieto and Hall believe this fiasco could have been avoided if the Spanish government had invited energy and financial analysts to flow-chart the many costs and energy inputs to have had a more realistic understanding of what the costs would be versus the extremely small amount of electricity added to Spain's electric supply.

Solar advocates can learn from this analysis as well to design solar PV with far less dependency on fossil fuels. That can only be done by realistically looking at all of the inputs required to build a solar PV plant. Narrowing the boundaries to avoid these realities is not good science and leads to wasted money and energy that could have been better spent preparing more wisely for declining fossil fuels in the future, i.e. Heinberg's "50 Million Farmers".
Some energy statistics

Oil
- The world burns 400 EJ of power, though after fossil fuels begin their steep decline, there'll be 10-20 EJ less per year.
- Very large oil fields provide 80% of oil, and they're declining from 2 to 20% per year, on average at 6.7%.
- The rate is expected to increase to 9% if not enough investments are made - and perhaps 9% even if they are.

Spain's solar photovoltaic electricity

- It's the 2nd largest installation of PV on earth
- Produces about 10% of the world's PV power: 4,237 MW--equal to four large 1000 MW coal or nuclear power plants
- Solar PV would have to cover 2,300 square miles to replace the energy of nuclear and fossil fuel plants. You'd also need the equivalent of 300 billion car batteries to store power for night-time consumers.
- In 2009, these plants generated 2.26% of Spain's electricity, the largest percent of any nation in the world

2009 Types of PV Installations in Spain (ASIF. July 2010 report)
- 63% Fixed plants
- 13% 1-axis trackers
- 24% 2-axis trackers

Types of PV Used
- 0.6% HCPV
- 2.1% Thin Film
- 97.3% Crystalline silicon

Amount of Power generated
36% < 2 MW
20% 2-5 MW
44% > 5 MW

Where were the PV panels placed
2.2 Rooftop
97.8 On the ground (far more efficient than rooftop)

Why wasn't as much power produced as promised?

Only 66% of the nameplate, or peak power, was actually delivered over 2009, 2010, and 2011. The expected amount was 1,717 GWh/MWn but only 1,372 GWh/MWn were produced.

Typical losses in Performance Ration (PR) analysis (see Slide 14)

% Loss is the "loss factor in % over nameplate"

% Loss Reason

0.6 Mismatch of modules. One bad apple and all the rest are reduced to the lowest common denominator -- the least efficient module. Mismatches can occur from irregular shading, ice, dust, and other problems.
1.0 Dust losses can be as high as 4 to 6% if washing isn't done often enough
1.0 Angular and Spectral loss of reflection when the PV isn't directly aimed at the sun
5.5 Losses due to temperature
1.0 Maximum power point tracker
1.0 DC wiring
5.4 AC/DC output of inverter
0.4 AC wiring within the PV plant
2.1 Medium-voltage losses within the plant
0.0 Non-fulfillment of nominal power, Shadowing/Shading, voltage sags, swells, etc

Performance Ratio: 82

Other losses beyond the typical Performance Ratio: extended performance ratio factors

8.0 Peak versus nominal installed power factoring
2.0 Losses in the evacuation/connection line/transformers
11.4 Degradation of modules over time

Will PV modules really last for 25 years? If not, the EROI is less than 2.45

Prieto and Hall distributed the Energy Invested across 25 years, but it is not likely that PV (and other manufacturers) will honor their contracts for that long:
1) Many manufacturers are already out of business, and many more will go out of business as their level of technology falls behind advancements elsewhere in the world. Companies who took on lots of debt expecting higher subsidies are failing now and will continue to do so.

2) Events of Force Majeure, acts of god, wind, lightning, storms, floods, and hail are likely to damage facilities within the next 25 years.

3) The degradation of PV modules may be higher than 1%/year up to a maximum of 20% over 25 years. This figure was very hard to come by, since Solar PV manufacturers don't like to reveal it. Prieto & Hall found out by looking at commercial contracts.

4) Any component that degrades or fails, not just the PV itself, will lower the overall EROI.

5) As fossil fuels decline, it will be hard to find the resources to maintain society. These plants will not be high priority, since dwindling diesel fuel will be diverted to agriculture, trucks, and other more essential services.

6) Once fossil fuels begin their steep decline, social unrest will make it hard for businesses to operate.

Low EROI: The Devil is in the Details

Most of the book explains the methodology and details of how EROI was calculated. The level of detail even extends to each of the three types of facilities (fixed, 1-axis, 2-axis) for many factors. Below is a partial summary of the Energy Invested table 6.18 in the book with the Energy Invested and money-to-energy columns missing. You can also see an older version in slide 18). Economic expenses (not shown) were converted to GWh/year energy equivalents and spread across 25 years.

ENERGY USED ON-SITE
GWh/year Factors
56.6 Foundations, canals, fences, accesses
4.7 Evacuation lines and right of way
11.2 Module washing and cleaning
28.2 Self consumption in plants
138.6 Security and surveillance

ENERGY USED OFF-SITE TO MANUFACTURE INGOTS/WAFERS/CELLS/ MODULES AND SOME EQUIPMENT
GWh/year Factors
608 Modules, inverters, trackers, metallic infrastructure (labor not included)

OTHER ENERGY EXPENDED ON & OFF-SITE
GWh/year Factors
96 Transportation (locally in Spain, international (i.e. China)
148.4 Premature phase out of unamortized manufacturing and other equipment
0 Energy costs of injection of intermittent loads; massive storage systems (i.e. pump-up costs)
19.9 Insurance
26.4 Fairs, exhibitions, promotions, conferences
34.3 Administrative expenses
14 Municipal taxes etc (2-4% of total project)
8.7 Land cost (to rent or own)
16 Indirect labor (consultants, notary publics, civil servants, legal costs, etc)
6 Market or Agent representative
11.9 Equipment theft and vandalism
0 Pre-inscription, inscription, registration, bonds & fees
178 Electrical network / power line restructuring
39.6 Faulty modules, inverters, trackers
198 Associated energy costs to injection of intermittent loads; network stabilization associated costs (combined cycles)
0 Force majeure: Acts of God, wind, storms, lightning, storms, floods, hail
The 2,065.3 GWe of the above energy inputs used annually to generate electricity is 40.8% of all the electricity generated by the solar PV plants of Spain, resulting in an EROI of 2.45 (1/.408).

Most life-cycle analyses only consider the 608 GWe of the modules, inverters, etc. They also usually ignore some or all of the Balance of System energy expenses (energy used on-site) and the remaining factors.

I can't resist a few examples to give you an idea of how complex a solar PV plant is. Every factor had complications and nuances that made this book very interesting and entertaining to read.

The access roads from the main highway to the plant, which across all the PV plants in Spain added up to about 300 km (186 miles), used 450,000 m3 or 900,000 tons of gravel. That takes 90,000 truckloads of 10 tons each traveling an average of 60 km round-trip, or 5,400,000 km (3,355,400 miles) at .31 of diesel per km or 1,620,000 liters of diesel. At 10.7 KWh/liter, that's 17.3 GWh of fuel. Then you need to add the energy used by other equipment, such as road rollers, shovels, pickups, and cars for personnel, and the energy to grind, mix, and prepare the gravel and the machinery required.

There are also service roads onsite to inverters, transformers, and distributed station housings, the control center, and corridors between rows of modules. There are foundations and canals. A total of 1,572,340 tons of concrete was used, requiring 489.3 GWh of energy.

Surrounding all these facilities are fences 2 meters high that used 3,350 tons of galvanized steel, and another 3,350 tons of steel posts, or 385 GWh of energy.

Washing and cleaning. Solar plants tend to be in desert-like surroundings with little water. Spain is so short on water they've got the 4th largest desalinization capacity in the world. Solar PV can't be washed with tap or well water because they leave calcium and mineralized salts which degrade the PV performance, and can even scratch them. So the water has to be de-mineralized, decalcified, and sometimes even de-ionized. Washing might take place on average four times per year, but that's not nearly enough - dust storms and dust from agriculture plowing can happen any time of the year, perhaps even right after they've been washed.

Critics of this book will say cheaper and more efficient PV cells are on the way. But as Prieto and Hall point out, the most effect an improved solar PV could have on the overall EROI is a maximum of 1/3 because of all the other factors. Plus EROI goes down every time the oil price goes up, because that causes all of the other factors to increase. Press releases of solar PV breakthroughs can be very exciting, but keep in mind that none of these past improvements could replace fossil fuels: thin-film, nanotechnology PV, cadmium telluride cells, organic cells, flexible cells, rollable sheets of PV for rooftops, slate modules, multi-junction cells, back-junction cells with 20-40% efficiency, PV grapheme, etc.

These improvements have costs, that's part of what's meant by the "premature phase out" factor. Solar businesses and PV plants go bankrupt when out-competed if they can't afford to make expensive alterations and retrofits.
Spain PV plants 20 MW and 22 MW 2-axisTwo axis tracking PV Plants of 20 MWn and 22.1 MWp. Slide 25 states that to replace a nuclear plant 1/3 that of Fukushima with solar PV, you'd need to expand the area above 430 times to 190 square miles. Photo Source: [...]

Energy Returned on Energy Invested (EROI)

EROI = Energy returned to society / Energy invested to get that energy

Hall and Prieto believe that solar is a low EROI technology. Solar has too many energy costs and dependencies on fossil fuels throughout the life cycle to produce much energy. It's more of a "fossil-fuel extender" because PV can't replicate itself, let alone provide energy beyond that to human society.

Nor is solar PV carbon neutral. Too many of the inputs require fossil fuels.

Solar PV doesn't come close to providing the 12 or 13 EROI needed to run a complex civilization like ours.

In the introduction, the authors say that "we recognize that some of our inputs will be controversial. We leave it to the reader and to future analysts to make their own decisions about inclusivity and methods in general for a comprehensive analysis of EROI. Whatever your opinion, this study should really open your eyes to the degree to which fossil fuels underlie everything we do in our technological society."

But I would argue the boundaries can't possible capture all the oil-based antecedents. Fossil fuels are so embedded in every aspect of our life that we can't see them. Think about solar PV when you read my summary of Leonard Read's antecedents of a pencil.

Endnote: This book was only available online at the University of California. It's a shame libraries are putting many journals and books into electronic versions only. Especially this book. Microchips, motherboards, and computers will be among the first casualties of declining fossil fuels, because they have the most complex supply chains with many single points of failure, dependence on rare metals, and so on (see Peak Resources and the Preservation of Knowledge for details). I encourage you to get your (university) library to buy a hard copy of this book, so that future scientists and historians will understand why our society didn't replace fossil fuels with "renewables" even though we knew oil couldn't last forever.

References

Bankier, C.; Gale, S. Energy payback of roof mounted photovoltaic cells. The Env. Eng. 2006, 7, 11-14.

Colthorpe, Andy. 18 July 2013. Solar Shakeout: Spain's Cel Celis begins insolvency proceedings PVTech.

Fthenakis, V.H.C. et al. 2011. Life cycle inventories and life cycle assessment of photovoltaic systems. International Energy US Energy Investment Agency (IEA) PVPS Task 12, Report T12-02:2011. Accessed 19 Sep 2012.

Nikiforuk,Andrew. 1 May 2013. Solar Dreams, Spanish Realities. TheTyee.ca

Parnell, John. 22 July 2013. Spain's government accused of killing solar market. PVtech.

Parnell, John. 23 July 2013. Spanish government facing court action over cuts to solar support. PVTech.

Raugei M., et al., "The energy return on energy investment (EROI) of photovoltaics: Methodology and comparisons with fossil fuel life cycles." Energy Policy (2012), published on line doi:10.1016/j.enpol.2012.03.00897. See more at: [...]

Prieto & Hall, 15 Apr 2011. How Much Net Energy does Spain's solar PV program deliver? A Case Study. State University of New York 3rd Biophysical Economics Conference. Data sources for Energy Generated and Energy Invested slide 10, How monetary costs were converted to energy units. Slide 12, How the embodied energy costs and boundaries were determined Slides 17, and much more.

Spanish solar energy: A model for the future? Phys.org