SolarByTheWatt.com » Analysis

Do Solar Photovoltaic Modules Have to be UL Listed? Are There Other Certification Options?

SolarByTheWatt_com — Wed, 28 Oct 2009 21:34:16 +0000

OK, here we are coming back to an issue that was brought up by us early on and we were trying to get different opinions on. It is the UL listing of photovoltaic equipment, it having to be listed, at all.

It seems like everyone who purchases photovoltaic modules in the US is verifying whether the modules are UL listed.

What does that mean and where does the concern come from?

Well here is the latest of what we find.

The requirement really comes from the National Electric Code (NEC), but the requirement does not directly specify that the listing should be by UL (Underwriters Laboratories – a company).

The exact requirement states:

“…

Chapter 6 Special Equipment

…

ARTICLE 690—SOLAR PHOTOVOLTAIC SYSTEMS

…

690.4 Installation.

…

(D) Equipment. Inverters, motor generators, photovoltaic modules, photovoltaic panels, ac photovoltaic modules, source-circuit combiners, and charge controllers intended

for use in photovoltaic power systems shall be identified and listed for the application.

…”

In section 100 there is the definition for listed:

“…

Chapter 1 General

…

ARTICLE 100—DEFINITIONS

…

Listed. Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services, and whose listing states that either the equipment, material, or service meets appropriate designated standards or has been tested and found suitable for a specified purpose.

FPN: The means for identifying listed equipment may vary for each organization concerned with product evaluation, some of which do not recognize equipment as listed unless it is also labeled. Use of the system employed by the listing organization allows the authority having jurisdiction to identify a listed product.

…”

In the same article we look up the definition for Authority Having Jurisdiction (AHJ).

“…

Authority Having Jurisdiction (AHJ). An organization, office, or individual responsible for enforcing the requirements of a code or standard, or for approving equipment, materials, an installation, or a procedure.

FPN: The phrase “authority having jurisdiction,” or its acronym

AHJ, is used in NFPA documents in a broad manner, since jurisdictions and approval agencies vary, as do their responsibilities. Where public safety is primary, the authority having jurisdiction may be a federal, state, local, or other regional department or individual such as a fire chief; fire marshal; chief of a fire prevention bureau, labor department, or health department; building official; electrical inspector; or others having statutory authority. For insurance purposes, an insurance inspection department, rating bureau, or other insurance company representative may be the authority having jurisdiction. In many circumstances, the property owner or his or her designated agent assumes the role of the authority having jurisdiction; at government installations, the commanding officer or departmental official may be the authority having jurisdiction.

…”

(this is for reference purposes only; the NEC text is copyrighted and isolated use of extracted instructions from it may be very insufficient for many purposes)

Ok so, obviously UL is considered to be “an organization that is acceptable to the authority having jurisdiction” as worded in Article 100 and ties in with the Article 690 point 690.4 (D) for photovoltaic equipment. So it’s is widely accepted that a UL listing (and labeling) assures that the equipment meets the NEC requirements.

What about other testing organizations though? There is no reason for monopoly of UL.

Well we are not able to find a list of such organizations but we came across information about one more company that does testing – Intertek ETL SEMKO. They state that their ETL labeling and listing is as good as the UL one.

Here is what they say on a brochure you can look up here.

(Click here for the Intertek ETL SEMKO brochure.)

“…

When it comes time to test your products to North American product safety standards, you may be led to believe that your choices are limited to certain marks, such as the UL Listed Mark. In reality, there are others equally recognized and accepted — prominent among them, the ETL Listed Mark issued by the ETL SEMKO division of Intertek.

…”

(again we are only quoting here for the purpose of supporting this article; Intertek’s text is copyrighted and all trade marks are their ownership)

The whole brochure is an interesting reading on the topic.

So we are finding that UL is not the only possible listing that solar panel manufactures can chose. A lot of new manufactures are suffering from the time it takes UL to start and complete the process if testing them and listing them. Some of them report that ETL is quicker to get, not because the testing and inspecting takes less time but because it is a company that at least for now offers less waiting to start working on the certification.

I guess the issue is still open, though, depending on what the AHJ will decide about “an organization that is acceptable to the authority having jurisdiction”. May be some state or local authorities, or insurance companies will have their own list of organizations that are acceptable.

All trademarks are property of their respective owners and are only displayed here as a reference.

Please, as always, feel free to comment on this. The opinion of people who have experience of going through the inspection process or getting a system insured is especially important.

Lowest Solar Panel Prices Per Watt 2009-10-20

SolarByTheWatt_com — Wed, 21 Oct 2009 02:30:05 +0000

We are continuing our series of articles on lowest prices per watt for solar photovoltaic panels where every time we have changes in the price ranking we will publish a new article with corresponding date in the title.

We list the cheapest panels dollar per watt that we can find on the internet and through direct research. We also include listings of products our readers submit to us through the Contact Us form or in the comments. Representatives of the different vendors are welcome to submit info about their products too. Very differently from other “cheapest solar panels lists” out there we will not charge you for that and we will not tell you the list is already full – yep, this is what some publishers of lowest prices in solar have told some of the vendors of realistically the cheapest panels in certain sizes. Yeah, we had a good laugh listening to the story of one of the vendors here trying to get listed with a web page claiming to be a free survey of the lowest prices. While these vendors were not allowed to be listed their after being asked for money and told that the list is full already there are companies on their list that are listed twice.

We do not claim at all that these are research and results of an absolute character. That is, we realize that there might be products, vendors, pricing structures for certain types of projects and quantities that we are not able to identify through our effort.

That is why nobody should get offended that their product brand or vendor company is not included in our research or they are not ranked correctly because we have not found out about their lowest, low or otherwise competitive prices.

While we maintain that prices as dollar per Watt ($/Wp, dollar per Watt peak) is the number that will take the solar power industry to the stage of playing a major role of resolving the gigantic issues the US and the world have with securing clean, safe and abundant source of energy, we also realize that with many products groups prices reflect many other things than just willingness of the manufactures and the marketers to provide an affordable product.

Namely, different prices may reflect different quality and quality preference of the market – i.e. higher quality products may maintain relatively higher prices given all other factors being equal.

Different prices may reflect different costs to manufacture products of certain type of technology. We are well aware that this is especially true with solar panels. We will try, as effort grows to provide a way for our readers to be able to separate prices listed and researched for different underlying technologies of products.

In this edition of the lowest prices article for example we are separating in different tables the three most popular commercially available cell technologies on which solar photovoltaic modules are based: monocrystalline, polycrystalline and thin-film. That should make it very easy for our readers to get to useful information about the competitors in the different technologies. Also it will give a chance for a vendor who offers a good price in one technology to not to be shadowed by a vendor with low price in the other technology.

We also have tried to include more sizes, that is make the list much longer in order to give chance for vendors that are not necessarily with the lowest price to show in the study. One thing you can expect in future editions is to see the lists broken down in different size ranges which should give even better chance for vendors to appear in their area of strength.

In any case if any reader, buyer or seller of solar products thinks that our best research effort has not presented certain vendors, brand or price – please, feel free to contact us and forward to us details of the the product and price you think we should list. We will add additional level to research to verify that such price is being offered on regular basis and will try to reflect this in our report.

The reason we believe prices in dollar per watt peak with solar photovoltaic modules is so critical for this industry to take off as a major player in resolving the energy issues the world has created for itself is that such price is a major factor in the economic efficiency of a solar power installation. See our article Economics of Solar Power on this.

Have in mind in addition to the very sharply falling prices of solar modules what else is driving the further acceptance of this clean energy technology is the government incentives programs that exist in different places in the world including incentives on federal level in the US in the form of a 30% tax credit on total installation costs and other different state level subsidies and feed in tariffs.

Here is or current ranking:

Monocrystalline

($/Wp, $ per module, Wp of the module, technology, Model, Brand,Vendor, URL to the vendor’s page)

$2.25 / Wp, $416.25, 185W, Mono-crystalline, SMD185M, SolarMaxDirect, SolarMaxDirect.com, http://SolarMaxDirect.com

$2.25 / Wp, $405.00, 180W, Mono-crystalline, SMD180M, SolarMaxDirect, SolarMaxDirect.com, http://SolarMaxDirect.com

$2.25 / Wp, $540.00, 240W, Mono-crystalline, SMD240M, SolarMaxDirect, SolarMaxDirect.com, http://SolarMaxDirect.com (sizes over 190W from SolarMaxDirect.com are not UL listed)
(SolarMaxDirect’s prices for less than a container size of order are $2.70)

$3.20 / Wp, $544.00, 170W, Mono-crystalline, DMSOLAR 170 MONO, BrightWatts, DmSolar, http://www.dmsolar.com

$3.40 / Wp, $594.41, 175W, Mono-crystalline, NT-175U, Sharp, Infinigi, http://www.infinigi.com

$3.57 / Wp, $625.00, 175W, Mono-crystalline, SW175, Solar World, Backwoods Solar, http://www.backwoodssolar.com

Polycrystalline

($/Wp, $ per module, Wp of the module, technology, Model, Brand, Vendor, URL to the vendor’s page)

$2.25 / Wp, $427.50, 190W, Poly-crystalline, SMD190P, SolarMaxDirect, SolarMaxDirect.com, http://SolarMaxDirect.com

$2.25 / Wp, $416.25, 185W, Poly-crystalline, SMD185P, SolarMaxDirect, SolarMaxDirect.com, http://SolarMaxDirect.com

$2.25 / Wp, $405.00, 180W, Poly-crystalline, SMD180P, SolarMaxDirect, SolarMaxDirect.com, http://SolarMaxDirect.com

$2.25 / Wp, $393.75, 175W, Poly-crystalline, SMD175P, SolarMaxDirect, SolarMaxDirect.com, http://SolarMaxDirect.com

$2.25 / Wp, $382.50, 170W, Poly-crystalline, SMD170P, SolarMaxDirect, SolarMaxDirect.com, http://SolarMaxDirect.com
(sizes over 190W from SolarMaxDirect.com are not UL listed)
(SolarMaxDirect’s prices for less than a container size of order are $2.70)

$2.43 / Wp, $509.97, 210W, Poly-crystalline, REC210AE, REC, The Solar Biz, http://www.thesolarbiz.com

$2.43 / Wp, $533.97, 220W, Poly-crystalline, REC220AE, REC, The Solar Biz, http://www.thesolarbiz.com

$2.43 / Wp, $424.97, 175W, Poly-crystalline, BP 175B, BP Solar, The Solar Biz, http://www.thesolarbiz.com

$2.44 / Wp, $549.00, 225W, Poly-crystalline, REC EA US 225, REC, Sun Electronics, http://sunelec.com

$2.54 / Wp, $558.00, 220W, Poly-crystalline, REC EA US 220, REC, Sun Electronics, http://sunelec.com

$2.59 / Wp, $543.90, 210W, Poly-crystalline, REC210AE, REC, BeyondOilSolar, http://www.beyondoilsolar.com
(many REC sizes from BeyondOilSolar are at this price)

$2.60 / Wp, $312.00, 120W, Poly-crystalline, DMSOLAR 120 POLY, BrightWatts, DmSolar, http://www.dmsolar.com

$2.68 / Wp, $522.60, 195W, Poly-crystalline, ES-A-195-fa3b, Evergreen, Sun Electronics, http://sunelec.com

$2.89 / Wp, $635.80, 220W, Poly-crystalline, SCHOTT POLY 220, Schott, Affordable Solar, http://www.affordable-solar.com

$2.99 / Wp, $523.25, 175W, Poly-crystalline, PV-UD175MF5, Mitsubishi Solar, Affordable Solar, http://www.affordable-solar.com

Thin-film

($/Wp, $ per module, Wp of the module, technology, Model, Brand,Vendor, URL to the vendor’s page)

$3.87 / Wp, $232, 60W, Thin-film, Kaneka, GSA-60, Living Off The Grid, http://livingoffthegrid.ecrater.com

$3.97 / Wp, $237.98W, Thin-film, Kaneka, GSA-60, Green Box Usa, http://www.greenboxusa.com

Feel free to send suggestions through comments on our articles or the Contact Us page.

Low prices of solar panels allow investors to build profitable power plants

SolarByTheWatt_com — Tue, 20 Oct 2009 06:48:21 +0000

Low prices of solar photovoltaic panels fighting the $2 per watt range make it possible for investors to build economically efficient, profitable solar power plants and installations.

The prices of solar photovoltaic panels has fallen dramatically in recent months. News about manufactures starting to feel oversupply of production despite the growing activity in solar power plant construction has made many of them lower prices of modules that are commercially available.

While there are rumors and constant news reports about companies especially in the newest of the photovoltaic technologies trying to deal with the $1 per watt barrier the panels that are available commercially are still above $2 per watt peak. By commercially available we mean a purchaser fro a solar power project can pick up a phone a order them with at most a month to two months lead time for delivery, including possible production lead time for orders above a couple of tens of kilowatt (kW).

Recently SolarMaxDirect.com has lowered prices for large orders to $2.25 per watt peak.

With the 30% federal tax credit available for US projects the realistic cost in the project for panels is just $1.575. Having in mind the tax credit can be applied to all the costs for the project currently more than ever investing in solar power is economically efficient.

In addition to the federal tax credit many states offer a direct rebate on certain equipment up to a couple of dollar per watt and also many states offer special feed-in-tariffs (FITs) for the electricity produced by solar power installations.

Price, Dollar Per Watt for Large Solar Photovoltaic Projects

SolarByTheWatt_com — Fri, 16 Oct 2009 03:52:12 +0000

A Review of Total Investment Cost, Dollar per Watt Peak and Euro per Watt Peak for Large Solar Photovoltaic Power Plant Projects.

A reader of SolarByTheWatt.com commented in a letter to us (via the Contact Us page/form) on how important it is for publications when price of solar photovoltaic is discussed – dollar per watt – to point out the difference between cost of solar just for the modules or panels and the cost of completing a whole system.

The price to complete a whole system in addition to the price of panels will include price of mounting, installation hardware, wiring, junction boxes, disconnects, price of the inverter or inverters, wiring and disconnect boxes from inverter to grid switch box, price of installation service (usually specifically trained and certified professionals are involved). In the case of a large scale projects the part of the project involving connection to the grid can be of substantial value too. In these project the price of the land used and all permits for the land and for the utility project also add to the cost.

While the break down of these expenses can be harder to study (one needs to find internal data from different projects) we thought that it is possible for many large project to find the overall costs and get to an indicative price per watt for solar power in terms of complete projects.

We also thought that focusing on as large projects as possible will let us minimize the error of rounding and approximation some of news articles might have made.

We have reviewed different announcements that indicate the price dollar per watt of complete projects.

Thought there is a lot of information about what the largest solar photovoltaic plants in the world are it has been difficult for us to find specific cost, investment information about many of them. The readers are welcome to contribute through comments or on our Contact Us page/form with links to articles specifying cost of projects.

Here is the table of results we have gathered:

Project	Peak Power, MWp	Cost, Euro, millions	Euro / Wp	US$ / Wp
Waldpolenz Solar Park	40	130	3.25	4.23
Amareleja, Moura, Portugal	62	250	4.03	5.24
SinAn Power Plant	24	110	4.58	5.96
Beneixama photovoltaic power plant	30	150	5.00	6.50
Arnedo Solar Plant	34	181	5.32	6.92
Nellis Solar Power Plant	14	77	5.49	7.14

In our results table you can see the name of the project included, peak power or the capacity of the power station in MW (MWp), investment cost in million of Euros – many of the large projects for which capacity and investment cost data was available were in Europe and the articles report the prices in Euros, cost Euro per watt peak, US dollar per watt peak – we used a 1.3 factor (close to the exchange rate at the moment EUR to USD) to get this number which we thought will be useful for anyone used to work in USD as a currency. We ordered the projects in ascending price per watt.

None of the prices we are seeing in the results are very surprising. Different articles mention about a commonly expected price of about US$ 6 – 8 per watt for industrial (utility) size projects. Many specialists involved in the industry, especially in Europe lately talk about bids that projects get in the range of 4 – 5 Euros per watt, approximately US$ 5 – 6.60 per watt.

Lowest Solar Panel Prices Per Watt 2009-02-24

Economics of Solar Power

Solar Energy Land Area Efficiency or How Many Acres per MW, kWp per Acre

A Short Science Lesson for Journalists – Watts, Kilowatts, Megawatts, Kilowatt Hours

Resources used:

http://www.renewableenergyworld.com/rea/news/article/2007/02/phase-one-of-40-mw-german-solar-park-begun-47541

http://en.wikipedia.org/wiki/Moura_photovoltaic_power_station

http://www.xltelenergy.com/PRESS%20RELEASE%20170209.pdf

http://www.conergy.de/en/DesktopDefault.aspx/tabid-181/316_read-9306/

http://www.thinkspain.com/news-spain/12834

http://en.wikipedia.org/wiki/Nellis_Solar_Power_Plant

Lowest Solar Panel Prices Per Watt 2009-04-24

SolarByTheWatt_com — Thu, 23 Apr 2009 17:04:57 +0000

We list the cheapest panels dollar per watt that we can find on the internet and through direct research. We also include listings of products our readers submit to us through or Contact Us form or in the comments. Representatives of the different vendors are welcome to submit info about their products too. Very differently from other “cheapest solar panels lists” out there we will not charge you for that and we will not tell you the list is already full – yep, this is what some publishers of lowest prices in solar have told some of the vendors of realistically the cheapest panels in certain sizes. Yeah, we had a good laugh listening to the story of one of the vendors here trying to get listed with a web page claiming to be a free survey of the lowest prices. While these vendors were not allowed to be listed their after being asked for money and told that the list is full already there are companies on their list that are listed twice.

Namely, different prices may reflect different quality and quality preference of the market – i.e. higher quality products may maintain relatively higher prices given all other factors being equal.

Here is or current ranking:

Monocrystalline

($/Wp, $ per module, Wp of the module, nominal voltage, technology, Brand, Model, Vendor, URL to the vendor’s page)

$3.15 / Wp, $630, 200W, 43.60V, Mono-crystalline, SMD200M, SolarMaxDirect, SolarMaxDirect.com, http://SolarMaxDirect.com

$3.30 / Wp, $726, 220W, 45.2V, Mono-crystalline, SMD220M, SolarMaxDirect, SolarMaxDirect.com, http://SolarMaxDirect.com

$3.30 / Wp, $610.50, 185W, 36V, Mono-crystalline, SMD185M, SolarMaxDirect, SolarMaxDirect.com, http://SolarMaxDirect.com

$5.03 / Wp, $1,005.00, 200W, 42V, Mono-crystalline, HIT-200BA19, Sanyo, atlE Store, http://store.altenergystore.com

$5.16 / Wp, $1,032, 200W, 55.8V, Mono-crystalline, HIP-200BA19, Sanyo, Affordable Solar Group LLC, http://www.affordable-solar.com

$5.52 / Wp, $552, 100W, 18V, Mono-crystalline, SW100C, Sunwize, atlE Store, http://store.altenergystore.com

Polycrystalline

($/Wp, $ per module, Wp of the module, nominal voltage, technology, Brand, Model, Vendor, URL to the vendor’s page)

$2.95 / Wp, $516.25, 175W, 24.2V, Poly-crystalline, SMD175P, SolarMaxDirect, SolarMaxDirect.com, http://SolarMaxDirect.com

$3.30 / Wp, $445.50, 135W, 20.6V, Poly-crystalline, SMD135P, SolarMaxDirect, SolarMaxDirect.com, http://SolarMaxDirect.com

$3.30 / Wp, $594.00, 180W, 24.2V, Poly-crystalline, SMD180P, SolarMaxDirect, SolarMaxDirect.com, http://SolarMaxDirect.com

$3.54 / Wp, $637, 180W, 24V, Poly-crystalline, CSI ECOSENSE CS6P-180, Canadian Solar, Affordable Solar Group LLC, http://www.affordable-solar.com

$3.56 / Wp, $142.49, 40W, 17.3V, Poly-crystalline, BP Solar, Discount Sales Electronics, http://discountsales.com

$3.94 / Wp, $630, 160W, 24.9V, Poly-crystalline, ES-160-A, Evergreen Solar, KULLY Solar, http://kullysolar.com

$4.62 / Wp, $1,016, 220W, 28.7V, Poly-crystalline, SCM220, REC Solar, Affordable Solar Group LLC, http://www.affordable-solar.com

$5.48 / Wp, $328.88, 60W, 12V, Poly-crystalline, CD Tech Solar, RV Fun Products, http://www.rvfunproducts.com

Thin-film

($/Wp, $ per module, Wp of the module, nominal voltage, technology, Brand, Model, Vendor, URL to the vendor’s page)

$3.83 / Wp, $230, 60W, 67V, Thin-film, Kaneka, GSA-60, Living Off The Grid, http://livingoffthegrid.ecrater.com

Feel free to send suggestions through comments on our articles or the Contact Us page.

Physical Area Efficiency of Solar Photovoltaic Panels, or Watt Per Square Foot

SolarByTheWatt_com — Sun, 19 Apr 2009 07:13:14 +0000

A specialist from one of the companies distributing and retailing solar panels brought up a question for discussion that is not usually very specifically talked about but was raised by a client of theirs. The client was looking for the most efficient panels in terms of peak power (rated watts) per square foot of the panel (module) the way it was commercially available.

He was not interested to hear about the comparison between the different technologies in particular because they are usually compared on cell level and the data available is usually from scientific lab test not necessarily directly related to the realistic efficiency of the finished panel. When cells are actually implemented in the configuration of the panel there might be numerous factors additionally affecting the power-to-physical-area efficiency of the panel. Different models of panels are also built on different grade of cells so many time you can have one and the same physical shape, area and cell configuration gaining very different rated power (watt peak). How much space (area) is left between the cells in the panel can also influence the over all watt per square foot performance.

The different solar photovoltaic cell technologies are usually given a percentage physical efficiency number that represent what part of the light energy is turned in to electrical energy. Monocrystalline cells usually are said to be with physical efficiency of about 16 – 17%. Polycrystalline – 14 – 15%. So, often in discussions it is assumed that monocrystalline panels, too, are more area efficient. As we will see our study shows that this does not need to be the case.

Because polycrystalline cell based panes use square (or rectangular) cells they use better the surface area of the panel for light to electricity conversion.

The monocrystalline cells are cut off from round wafers and though they usually have for edges cut off from them for the purpose of not removing too much of the expensive wafer they are not turned in to square cells but in to squares with round edges. When these cells are put in to a panel there are small areas between the edges of the cells that are left unused.

In thin-film panels usually most of the area of the panel is covered by a photovoltaic surface. The configuration of what are effective cells in them may be more complex but there are better opportunities in thin-film panels to use larger part of the surface of the panel efficiently. With thin-film the actual photovoltaic elements are not as physically efficient though – the commercially widely available ones are only know to have 7 – 9 % physical efficiency. So it will be hard for them to compete with the mono- and poly crystalline ones.

You probably already know that SolarByTheWatt.com in general maintains that the economic efficiency of photovoltaic equipment (like panels) is the most important number because this defines the economic efficiency of a whole project.

Surface area efficiency (watt per sq. ft.) can only be critical, or more critical, when there is a limitation of how much area can be used for placing the panels and there is a requirement for the peak power of the whole project. Often this could be the case with residential projects where we intended certain peak power already and the roof area is simply not enough for us to go with the most cost efficient technology (possibly thin film).

Let’s look at the practical numbers for commercially available panels and compare the surface area efficiency they have. We will get the numbers for peak power rating in watts for the panels and the actual physical surface area calculated from the reported dimensions of the panel.

In the following table we have put the number for panels that available at online retailers. If any of the readers know of a model that might show interesting numbers they are welcome to submit data and links through the comments form or the Contact Us page and form on the website.

We were trying to select panels for which we calculated highest watt per square foot efficiency. That is marked in the table as power density.

Model	Techn ology	Rated Power, W	Vmp, V	Imp, A	Peak Power, Wp, W	Surface Size, ft	Surface Area, sq ft	Power Density, W / Sq Ft
SMD190P	Poly-	190	24.48	7.76	190.0	4.34×3.24	14.045	13.53
SMD185M	Mono-	185	35.96	5.15	185.2	5.18×2.65	13.742	13.48
SMD240M	Mono-	240	46.90	5.11	239.7	5.18×3.48	18.027	13.29
SMD185P	Poly-	185	24.48	7.56	185.1	4.34×3.24	14.045	13.18
SMD180M	Mono-	180	35.65	5.05	180.0	5.18×2.65	13.742	13.10
STP-180	Mono-	180	35.60	5.05	179.8	5.18×2.65	13.742	13.08
SMD090M	Mono-	90	18.36	4.90	90.0	3.93×1.78	7.008	12.84
KD205	Poly-	205	26.60	7.71	205.1	4.92×3.25	15.984	12.83
SMD180P	Poly-	180	24.24	7.43	180.1	4.34×3.24	14.045	12.82
PV-UD190	Poly-	190	24.70	7.71	190.4	5.44×2.74	14.884	12.79
SMD230M	Mono-	230	46.40	4.96	230.1	5.18×3.48	18.027	12.77
SMD175M	Mono-	175	35.71	4.90	175.0	5.18×2.65	13.742	12.73
SMD155P	Poly-	155	21.21	7.31	155.0	3.82×3.24	12.366	12.54
NT-175U1	Mono-	175	35.40	4.95	175.2	5.17×2.71	13.993	12.52
SMD175P	Poly-	175	24.24	7.22	175.0	4.34×3.24	14.045	12.46
SW175	Mono-	175	35.70	4.90	174.9	5.28×2.66	14.037	12.46
SMD215P	Poly-	215	30.30	7.10	215.1	5.39×3.25	17.515	12.28
SMD220M	Mono-	220	45.20	4.87	220.1	5.18×3.48	18.027	12.21
KAN60	Thin-Film	60	67.00	0.90	60.3	3.15×3.25	10.230	5.89

This is a key to the different models – how they correspond to a brand name and a website of one possible vendor.

SMD – SolarMaxDirect – http://SolarMaxDirect.com
STP – Suntech Power http://store.solar-electric.com
KAN – Kaneka – http://store.altestore.com
KD – Kyocera – http://store.solar-electric.com
PVUD – Mitsubishi – http://aeesolar.com
SW – Solar Wordl – http://aeesolar.com
NT – Sharp – http://sunwize.com

We reiterate here that we were looking for the data from the specification sheets that come on different product pages of different vendors. Apart from the ordering by power density, or area efficiency – watt per sq ft, we did not have any other criteria for picking the model or the places they can be purchased. Please do feel free to submit your suggestions for us to include other examples.

Economics of Solar Power

SolarByTheWatt.com — Mon, 30 Mar 2009 02:25:22 +0000

One of the most frequently asked questions to consultants and specialists in the solar energy industry is how efficient is the investment in a solar power installation – small or large.

(jump directly to calculation tables)

We want to look at a very simple model of economic efficiency where are we interested in the annual return on investment. A project involving a solar photovoltaic installation requires certain amount of capital to be built and will expect certain amount of annual revenue. The simple indicator of efficiency that we want to study is this annual return on invested capital.

There are more complex models that also include the cost of capital. In a model that studies the cost of the electricity produced for example the cost of capital and factored in return for the investor could be very important factors. Cost of capital on its own can be a complex concept too. Whether the capital is borrowed and the cost will be defined by the interest rate of the loan or is cash participation from the investor and the cost will be defined by other opportunities the investor has to invest in (including risk free investments) or the combination of the two, cost of capital is very significant factor in such models.

We simplify our model to the level of looking at potential return from invested amount of capital. Further investment efficiency study and study on the cost of production of electricity should involve cost of capital.

We will also try to come to tables of calculated efficiency depending on different factors but not the size of the installation. The size of the installation definitely impacts the efficiency of a project. This is the traditional concept of economy if scales. A larger project will be expected to be more efficient over all because of the spread fixed expenses that the project has. But we will be building our model around the idea of dollar per watt, dollar per watt peak, so that it is applicable to different. The efficiency that comes from scale can be reflected in the factors going in to our model – specifically cost to build.

Another factor not included in our model is the maintenance cost of the solar installation. We are hoping that the reader can find resources which will indicate dollar per watt peak what the expected cost to maintain the station are.

The factors that expect to influence our model are: cost to build the power installation, insolation at the geographic location, electricity market price.

The cost to build the power installation includes:

the price of the core photovoltaic components employed: modules, panels, arrays (what exactly list of such components we deal with depends on the design and configuration of the installation),
the price of the mounting equipment (trackers and, or positioning frames) and wiring;
price of inverters and grid connection equipment
service and labor cost to assemble
management and administration costs and costs of permits

The insolation at the geographic location. The insolation is the amount of solar light energy falling on the surface of the earth at a given geographic location per certain amount of area in the span of certain unit of time. More specifically the unit of measure used is watt per square meter (W/m²) or also kilowatt hour per square meter per day (kWh/m²/day). Insolation in Europe, just for reference purposes, approximately, ranges between 1,000 to 2,000 kWh per year per installed kWp, in the continental US – between 800 to 2,100 kWh per year per installed kWp for different regions. Exact numbers can be found in different reference tables and insolation maps on the internet and elsewhere.

In the photovoltaic industry a measure of insolation is employed which helps us more directly figure out how much electricity in kilowatt hours (kWh) we can produced annually from an installed nominal watt (Wp) – that is kilowatt hours annually per installed kWp (kWh/kWp/y).

The market price of the electricity produced. Since we are trying to figure out economic efficiency – annual return on investment we need to involve in the model:

the price of the electricity we produce and sell to the grid

or conversely

the price of the amount of electricity we offset that we were otherwise going to pay for at such market price.

In many places in the world – by country or by specific territory (state, other subdivision) there are financial incentives for investors in photovoltaic power stations in the way of a special feed-in-tariff. These usually are higher price the grid pays to energy producers who utilize photovoltaic power stations. If we have to give some examples these countries have the following feed-in-tariffs (unit of measure is Euros per kWh since classically many of the notable incentives started in Europe and that is the currency used there): Austria 0.57 – 0.59, Germany 0.52 – 0.57, Italy, 0.36 – 0.49, France 0.30 – 0.55, Spain 0.19 – 0.44, Switzerland 0.10 – 0.50, Israel 0.14 – 0.16, Bulgaria 0.40.

The formula.

The annual return on investment in a solar power station will be the annual income from sold (or offset electricity) divided by the amount of the investment.

Annual return on investment = annual income ($) / investment amount ($).

The annual income is the market price of the electricity in dollar ($) per kilowatt hour (kWh) times the amount of energy produced in an year in kilowatt hours (kWh).

Annual income ($) = production per year (kWh) x market price ($/kWh)

The production per year is the solar insolation in kilowatt hours per year per kilowatt peak installed times the installed capacity/power in kilowatt peak (kWp).

Production per year (kWh) = insolation (kWh/y/kWp) x installed capacity (kWp) .

So that we can work on dollar per watt basis we will express the investment amount by the investment cost per watt.

Investment amount ($) = total cost per watt ($/Wp) x installed capacity (kWp) x 1,000

– the 1,000 factor is to adjust the dollar per watt unit to the kWp in which we are measuring the installed power.

So the complete formula for the annual return on investment will be:

Annual return on investment = annual income ($) / investment amount ($)

If we use the formula for the annual income we get:

= production per year (kWh) x market price ($/kWh) / (total cost per watt ($/Wp) x installed capacity (kWp) x 1,000)

If we use the formula for the production per year we come to:

= insolation (kWh/y/kWp) x installed capacity (kW) x market price ($/kWh) / (total cost per watt ($/Wp) x installed capacity (kWp) x 1,000)

Here we can get rid of the installed capacity (kWp) in the numerator and denominator and get to:

Annual return on investment
= insolation (kWh/y/kWp) x market price ($/kWh)
/ ( total cost per watt ($/Wp) x 1,000 )

Let’s use the formula in an example where $7 per watt were spend in the building of the station, the insolation is 1,200 kWh per installed kWp and there is a $0.52 feed-in-tariff for the electricity produced.

Annual return on investment = 1,200 x 0.52 / (7 x 1,000) = 624 / 7,000 = 8.92%.

This calculated rate now can be compared to cost of capital and maintenance cost can be factored in to look for some more complete number of real economic return.

In addition to this formula the following tables can be used to get to approximate numbers:

The first table is given for insolation of 1,000 (this can be easily factored if we know the specific insolation, i.e. for 1,500 we just have to multiply by 1.5, for 2,200 we simply multiply by 2.2, etc.)

The investment cost per watt is given in a very wide range of $3 to $10 per watt but it is not implied that these are possible, practical or easy to obtain prices in reality. Our research shows that large industrial project can reach down to $6 per watt of such cost and smaller commercial and residential projects can go up to $10 and even $15 per watt peak installed.

The price for kWh of electricity is given in a range of $0.05 to $0.60 to reflect different market prices for electric energy and all possible feed in tariffs.

Annual Return on Investment At Insolation of 1,000 kWh/kWp:

	Cost to build, dollar per watt peak ($/Wp)
Price $/kWh	3.00	4.00	5.00	6.00	7.00	8.00	9.00	10.00
0.05	1.67%	1.25%	1.00%	0.83%	0.71%	0.63%	0.56%	0.50%
0.10	3.33%	2.50%	2.00%	1.67%	1.43%	1.25%	1.11%	1.00%
0.15	5.00%	3.75%	3.00%	2.50%	2.14%	1.88%	1.67%	1.50%
0.20	6.67%	5.00%	4.00%	3.33%	2.86%	2.50%	2.22%	2.00%
0.25	8.33%	6.25%	5.00%	4.17%	3.57%	3.13%	2.78%	2.50%
0.30	10.00%	7.50%	6.00%	5.00%	4.29%	3.75%	3.33%	3.00%
0.35	11.67%	8.75%	7.00%	5.83%	5.00%	4.38%	3.89%	3.50%
0.40	13.33%	10.00%	8.00%	6.67%	5.71%	5.00%	4.44%	4.00%
0.45	15.00%	11.25%	9.00%	7.50%	6.43%	5.63%	5.00%	4.50%
0.50	16.67%	12.50%	10.00%	8.33%	7.14%	6.25%	5.56%	5.00%
0.55	18.33%	13.75%	11.00%	9.17%	7.86%	6.88%	6.11%	5.50%
0.60	20.00%	15.00%	12.00%	10.00%	8.57%	7.50%	6.67%	6.00%

Annual Return on Investment At Insolation of 1,500 kWh/kWp:

	Cost to build, dollar per watt peak ($/Wp)
Price $/kWh	3.00	4.00	5.00	6.00	7.00	8.00	9.00	10.00
0.05	2.50%	1.88%	1.50%	1.25%	1.07%	0.94%	0.83%	0.75%
0.10	5.00%	3.75%	3.00%	2.50%	2.14%	1.88%	1.67%	1.50%
0.15	7.50%	5.63%	4.50%	3.75%	3.21%	2.81%	2.50%	2.25%
0.20	10.00%	7.50%	6.00%	5.00%	4.29%	3.75%	3.33%	3.00%
0.25	12.50%	9.38%	7.50%	6.25%	5.36%	4.69%	4.17%	3.75%
0.30	15.00%	11.25%	9.00%	7.50%	6.43%	5.63%	5.00%	4.50%
0.35	17.50%	13.13%	10.50%	8.75%	7.50%	6.56%	5.83%	5.25%
0.40	20.00%	15.00%	12.00%	10.00%	8.57%	7.50%	6.67%	6.00%
0.45	22.50%	16.88%	13.50%	11.25%	9.64%	8.44%	7.50%	6.75%
0.50	25.00%	18.75%	15.00%	12.50%	10.71%	9.38%	8.33%	7.50%
0.55	27.50%	20.63%	16.50%	13.75%	11.79%	10.31%	9.17%	8.25%
0.60	30.00%	22.50%	18.00%	15.00%	12.86%	11.25%	10.00%	9.00%

Annual Return on Investment At Insolation of 2,000 kWh/kWp:

	Cost to build, dollar per watt peak ($/Wp)
Price $/kWh	3.00	4.00	5.00	6.00	7.00	8.00	9.00	10.00
0.05	3.33%	2.50%	2.00%	1.67%	1.43%	1.25%	1.11%	1.00%
0.10	6.67%	5.00%	4.00%	3.33%	2.86%	2.50%	2.22%	2.00%
0.15	10.00%	7.50%	6.00%	5.00%	4.29%	3.75%	3.33%	3.00%
0.20	13.33%	10.00%	8.00%	6.67%	5.71%	5.00%	4.44%	4.00%
0.25	16.67%	12.50%	10.00%	8.33%	7.14%	6.25%	5.56%	5.00%
0.30	20.00%	15.00%	12.00%	10.00%	8.57%	7.50%	6.67%	6.00%
0.35	23.33%	17.50%	14.00%	11.67%	10.00%	8.75%	7.78%	7.00%
0.40	26.67%	20.00%	16.00%	13.33%	11.43%	10.00%	8.89%	8.00%
0.45	30.00%	22.50%	18.00%	15.00%	12.86%	11.25%	10.00%	9.00%
0.50	33.33%	25.00%	20.00%	16.67%	14.29%	12.50%	11.11%	10.00%
0.55	36.67%	27.50%	22.00%	18.33%	15.71%	13.75%	12.22%	11.00%
0.60	40.00%	30.00%	24.00%	20.00%	17.14%	15.00%	13.33%	12.00%

To factor in the cost of capital in the numbers from these tables one needs to subtract the cost of capital as a percentage. For example if the cost of capital is 4% that has to be subtracted from the numbers in the tables above. Similar adjustment can be made for to factor in the maintenance costs.

Configuration efficiency, (performance ratio). We do not know whether this term is discussed in other research in length but we want to mention it for this reason: projects with equal labeled peak power – watt peak (Wp), nominal power, if taken directly from the labeled peak power of the modules involved can have different overall output electricity production – kilowatt hour (kWh) per year at the same geographic location. This could be because of how different modules perform when positioned with trackers or mounted stationary, or how well they perform in different cloud conditions etc. etc. So, realistically the nominal installed power (Wp) that can be used with insolation numbers to figure out annual production can be different for different installations mainly because of the type of modules used a the specific conditions (insolation, cloudiness, positioning etc.) For the different projects this factor has to be specifically researched based on data from similar configuration used in existing projects. By information we can get to such factor can vary between 0.75 and 1.4 – i.e. the electricity produced in a year from the installation in kWh may vary from the above calculation for known insolation from –25% to +40% from the indicated.

Solar Energy Land Area Efficiency or How Many Acres per MW, kWp per Acre

Can Solar Energy Completely Replace Fossil Fuel and Other Sources?

A Short Science Lesson for Journalists – Watts, Kilowatts, Megawatts, Kilowatt Hours

Lowest Solar Panel Prices Per Watt 2009-02-24

Resources:

http://en.wikipedia.org/wiki/Photovoltaic

http://en.wikipedia.org/wiki/Insolation

http://en.wikipedia.org/wiki/Feed-in_Tariff

http://en.wikipedia.org/wiki/PV_financial_incentives

Wind Capacity Needed to Replace Certain Levels of Current Resources Used for Electricty Produciton

SolarByTheWatt.com — Fri, 20 Mar 2009 05:37:01 +0000

Similarly to the analysis we have done for solar we are putting the number together for the capacity needed of to replace coal, oil and natural gas with wind as sources for electricity.

We want to jump here directly to a graph comparing the different levels of electricity capacity currently generated from oil, coal, natural gas and the rest (nuclear, hydro etc) with the capacity wind power fields, farms need, the cost of investment needed and the land area used.

The assumptions are $1.3 per installed watt – much less than solar for now. And 3.8 acres per 1.5MW turbine – this is only the land used by the actual turbines and utility roads etc. not the actual land required for the field in which land can be used for agriculture or other purposes.

Click here or on the image to see full resolution graph.

The highest level displayed is not that important because it already includes renewable energy and nuclear (the argument about how clean it is and it’s safety are a subject of a separate discussion). Natural gas though not renewable is clean and still in abundant quantities in reserves. The more important part of the analysis is the lower levels – oil and coal. Look at how affordable the numbers look. Compare to the money currently the government is spending on trying to jump-start the economy anyway.

The scale is also not impossible to achieve quickly. Wind as solar is an accelerating, fast growing industry. Just to create the correct impression here of how quickly the first level – oil can be covered – it requires about 56 GW of wind power. Only in 2007 the newly installed wind power is 5.3 GW (see resources used at the bottom). So even at the same rate of investment, construction we only need 10 years to replace oil used for electricity. This is not counting the potential of solar, other renewables and the potential for the very likely accelerated addition of new wind capacity every year.

Resources Used

US Department of Energy
Energy Efficiency and Renewable Energy (EERE)
http://www1.eere.energy.gov/windandhydro/pdfs/43025.pdf

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Solar Energy Land Area Efficiency or How Many Acres per MW, kWp per Acre

SolarByTheWatt.com — Mon, 09 Mar 2009 05:28:52 +0000

Solar power alongside the applauding it gets it is also being criticized by the opponents of it especially in terms of the different measures of efficiency – physical, economic (investment) and land area use efficiency. Land area use efficiency is the topic of this study. Let’s look at the definito0ns for the other measures of efficiency just to put our essay in proper context.

Physical efficiency for example is the measure of what portion of the light energy is being transformed to useful electric energy. That currently runs for different types of photovoltaic cell technologies between 8 and 30 and by some reports 38%. We will spare a separate article on the different technologies and their respective efficiency readings.

Economic efficiency or investment efficiency is the dollar cost per nominal generating watt power or simply dollar per watt peak ($/Wp). The investment efficiency can be calculated at the different stage of completeness of a solar photovoltaic system or component – cells, panels, installed systems, power stations. We want to dedicate special studies to the importance of these measures of efficiency. Be prepared to hear our opinion that economic, or investment efficiency is much more important to the useful implementation of this technology than physical efficiency is.

Land area use efficiency is the measure of how much land area is needed for certain capacity of nominal (peak) power of a solar photovoltaic power station (or smaller system). The units of measure used are usually:

acres per megawatt or acres per MW – the land area needed in acres per MW of generation; the way to calculate that is to divide the area used in a project in acres by the peak power of the project in MW;

kilowatt per acre or kW per acre – this is the amount of installed peak power in kW (1 MW = 1,000 kW) divided by the land area needed in acres.

The equivalent units of measure used more often overseas (incl. Europe) are using the derivatives of the metric system for land area – hectares (10,000 sq.meters) and decares (1,000 sq.meters) – hectares per MW, decares per MW and kW or MW per hectare or decare.

We wanted to find out what is the approximate land area efficiency of existing completed and planed projects or ones in progress. We looked first at some of the biggest solar photovoltaic projects around the world, tried to find out quoted figures for their peak capacity and land are used and calculate the land are use efficiency for them.

We also looked at publications discussing proposed project especially for technologies that are just emerging.

This is what we found out.

Some of the largest completed solar photovoltaic power plants, also called solar parks or fields, have area efficiency of about 4.5 to 8 acres per MW. This is when crystalline (mono-crystalline or poly-crystalline) technology cells, modules are used. With thin-film technologies the efficiency is about 10 to 13.5 acres per MW.

For comparison we also looked at data for some solar thermal project and we estimated land area use efficiency of about 5 to 11 acres per MW. The lower values were for projects involving Sterling engines as opposed to the more traditional technology of parabolic mirror throws heating oil in a tube.

Here is a table of our calculations with numbers in the other units of measure and also a list of the resources used.

Project No	Project	Capacity, DC Peak Power, Wp. MW	Land Used, hectares, 10,000 m2	Land Used, decares, 1000 m2
1	Olmedilla Photovoltaic Park	60	108	1,080
2	Puertollano Photovoltaic Park	47	150	1,500
3	Amareleja, Moura, Portugal	62	130	1,300
4	Waldpolenz Solar Park	40	220	2,200
5	Sempra Generation near Boulder City, NV	10	32	320
6	PG&E	6.4	64	640
7	Ivanpah	1,300	4250	42,500
8	Southern Ca. Edison, Stirling Eng. Systems	850	1830	18,300
9	Mojave Solar Park	553	2400	24,000

Project No	kWp/decare	kWp/acre	Acre/MW	Notes
1	55.6	224.83	4.45
2	31.3	126.80	7.89
3	47.7	193.00	5.18
4	18.2	73.58	13.59	Thin-film
5	31.3	80.00	12.50	Thin-film
6	10.0	81.00	12.35	Thin-film
7	30.6	123.79	8.08	Solar thermal
8	46.4	187.97	5.32	Sterling Engine
9	23.0	92.17	10.85	Solar Thermal

Resources used:

http://en.wikipedia.org/wiki/Moura_photovoltaic_power_station

http://www.solarpay.com.au/mega-watts-to-nega-watts.html

http://www.jccm.es/fondosestructurales/fileadmin/user_upload/_temp_/00-NOTICIAS/2008_MARZO/07-03-08_LA_TRIBUNA-Renovalia_invierte_en_parque_solar_Puertollano.pdf

http://www.bizjournals.com/sanjose/stories/2009/02/09/daily59.html?ana=from_rss

http://www.gizmag.com/go/4422/

http://www.renewableenergyworld.com/rea/news/article/2007/07/pg-e-signs-agreement-with-solel-for-553-mw-of-solar-power-49448

http://www.pv-tech.org/news/_a/first_solar_finishes_10_mw_pv_power_plant_for_sempra_pge_to_buy_electricity/

http://www.abengoasolar.es/sites/solar/en/technologies/photovoltaic/concentration/index.html

http://www.energy.ca.gov/reti/steering/2008-06-18_meeting/SOLAR_FS-Utility-Scale_Photovoltai

http://i-r-squared.blogspot.com/2008/08/massive-solar-pv-deal.html

http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel3/60/654/00017907.pdf?arnumber=17907

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SolarByTheWatt.com

Can Solar Energy Completely Replace Fossil Fuel and Other Sources?

SolarByTheWatt.com — Thu, 05 Mar 2009 00:12:48 +0000

Is solar energy capable of providing so much power that to offset the need for use of fossil fuels?

We want to look at the needs of energy of the United States and the world and compare with the practical size installations of solar power stations needed to replace that.

The question of completely replacing all fossil fuel or all other sources of electricity and other energy is much more complex than just looking at the numbers. Probably replacing the other sources in just electricity production is simpler but still in addition to simply adding capacity, changes of large scale are needed in the national grid configuration.

Replacing resources used to produce other energy, other than electricity, is even more complex. That will mean changing how energy is being transported and used. While electricity is a type of energy easy to transport what may need to be changed is the way it is utilized at the end consumer – industrial, residential or transportation. That will involve changes and costs again more than the ones related to replacing the source with solar power stations.

The current electricity generation capacity in the US is about 1TW (1,000,000 MW). About 395 GW (1GW = 1,000 MW) is from natural gas, 315 GW from coal, 100 GW from nuclear, 100 GW from hydroelectric 56GW from oil products, 30 GW from renewables other than hydro, and other small components.

We will look at these numbers separately to see what it will take to replace the more urgent ones of them – coal, oil etc.

The US total energy consumption, not just electricity is 3.5 TW. Most of the difference between just electricity and this number is made up of energy produced from oil so we are not going to try to break this down. We will look at this as one of our theoretical targets.

The world total energy consumption is at around 16 TW of which 4.5TW is electricity.

So, lets build a scale of the different stages that theoretically can be achieved in solar replacing other energy sources.

For our calculations we will assume installation / construction cost for one 1MW of $5m. This is a number ($5/Wp) we think smaller than the recent historic numbers for cost to install solar capacity. But we want to factor for future falling prices of solar modules and other components and overall improving efficiency in the industry. Anyone is free to factor the $ numbers we have if they believe $7/Wp or $10Wp is a better number.

For surface area needs we will assume 200 kW per acre. With different design and technology 800kW per acre is possible but we will go with the low number on this to be on the safe side. Since 1 sq mile is 640 acres, with our assumption we will have 128 MW per sq mile.

To Replace	We Need Solar Capacity, GW	That May Cost, $bn	Will Take Approximately Surface Area, sq miles	Approximately the area size of (examples)
Oil used for electricity production in the US	56	280 (notice this is less than the stimulus package!) like GDP of Ireland, 2% of GDP of USA	438	Guam, Cairo, half the size of Luxemburg or simply area 20×20 miles
Oil and coal used for electricity production in the US	371	1,855 like GDP of Spain or Italy, 13% of GDP of USA	2,900	Sao Paulo, Puerto Rico, Cyprus or Lebanon or simply area 55×55 miles
Oil, coal and natural gas used for electricity production in the US	766	3,830 like GDP of Germany or Japan, 28% of GDP of USA	6,000	Connecticut, less than New Jersey, New York City, Swaziland, Kuwait, Fiji, New Caledonia or simply area 80×80 miles
Total electric generation capacity of the US	1,000	5,000 like GDP of Japan, 36% of GDP of USA	7,800	Belize, Djibouti, Macedonia (Republic of), less than New Jersey, or simply area 90×90 miles
Total US Energy Consumption not just Electricity	3,500	17,500 like GDP of the European Union, 32% of GDP of the world	27,300	UAE, Austria, Serbia, less than South Carolina, 10% of Texas or simply area 165×165 miles
Total Electricity Generation Capacity in the World	4,500	22,500 1.3 times the GDP of the European Union, 41% of GDP of the world	35,000	Hungary, South Korea, Cuba, Bulgaria, Maine, 13% of Texas, 30% of Arizona or simply area 190×190 miles
Total Energy Consumption in the World not just Electricity	16,000	80,000 1.5 times the GDP of the world	125,000	Norway, Malaysia, Finland, Germany, a bit less than Japan, a bit more than New Mexico or simply area 350×350 miles

We tried to display this comparison between energy currently produced by different sources and capacity needed in solar in gigawatts (GW), cost of installation in billion dollars ($bn), land area needed in sq. miles, marks of different countries GDP, and land areas of different geographic locations (certain US states in this case).

Click here or on the graph below to see it in full scale.

On the above diagram, since it uses a linear scale for the capacity, cost and land and the large values (world energy needs) are much larger than the smaller ones (oil and coal for electricity in the US), the small values are not given a good presentation. So here we put the same numbers on a logarithmic scale for the solar capacity, cost and land requirements. We have much better clarity on the comparisons now for the smaller values.

Click here or on the graph below to see it in full scale.

We think in general our study is much more important in reference to the smaller values. They deal with some levels of scale of capacity that are practically easier to achieve in terms of replacing with solar. We are talking about the unquestionably very polluting coal and oil burning for electricity. Again – look at the numbers to replace oil products used for electricity generation in the US we only need $280b and spending that will create jobs, help growth in technology and give all sorts of other economic and social benefits.

The numbers given in our study in reference to the higher levels – world electricity and total energy consumption are simply for getting a better view of the comparative size of all levels.