An impulse.

There seems to be a kind of quiet certainty among Solar Investors.

There's not alot of fear, but there's also not alot of dangerous exuberance. Those old-timers that are still in, are in with solid confidence. Newbies that have come in have quietly been growing value since the trend reversed. It's just a matter of when the next move is going to come.

Thoughts on Solar Materials - Thin Film - 6/3/09

I hear the arguments on future domination of the Solar Industry by Thin Film Technologies, but I would suggest that this is far from certain.

What particularly gets me is when people talk about how they're going to come up with solar paint or some such thing, and all of our problems will be solved, just like that; like a snap of the fingers. The argument goes that there's little point in spending all the time and effort on the massive industrialization of Silicon, because some futuristic technology will simply come along to make it obsolete.

Ok, so maybe it's true that some revolution will come along that will completely change how we see Solar Energy. Maybe one day you'll be wearing Solar Clothing to charge your remote devices, and cars and homes will wear coats of Solar Paint to provide for their Energy needs.

Even if this Solar future is to be the case, though, we know that it will have to meet certain requirements, particularly in terms of Scalability / Material Availability, and Cost Efficiency.

Remember that only 1000 Watts of Power strike the surface of the earth per Square Meter on average in the middle of a clear day. That's it. No matter the wonderful technology that you develop, you can't generate more energy than what's available. To generate the incredible amounts of Energy that will be required of the future Solar niche will require a mind-dizzyingly vast array of "panels" distributed around the Planet. That's miles upon miles of glass and aluminum frames housing some kind of protected PV material, whether Wafer-based or Thin Film; or else unhoused, or lightly-housed thin films of various types, even potentially including "painted" Solar surfaces.

The main point that I want to mention at this point is on the value of Cell Longevity.

Note that when you invest in a Solar Panel, you are actually paying upfront for the entire future energy production of that panel. Normally, Solar Panels are rated in Cost per Watt Peak, or Peak Power, which is an indication of the amount of Energy that the Panel would produce at an instantaneous moment of time in ideal midday conditions. Peak Power, however, is no indication of how much Energy that the Panel will actually produce over its lifetime. Two different kinds of panels may cost the same number of Dollars per Watt, but if one lasts only half as long as the other, then ultimately it is twice as costly in terms of its total Energy Production over its lifetime.

This is where the Levelized Cost of Energy (LCOE) comes in. When you Calculate the Levelized Cost of Energy of a Solar System, you are basically determining the overall cost of the System per unit Energy over the Entire expected Life of the System. I did a rough version of this kind of calculation here. Sunpower Corp provides this nice description of the factors involved.

There are a several reasons why a Solar Cell might stop working. One reason that a cell could fail would be from molecular damage to the PV material simply by the bombardment of Solar Energy (including various cosmic rays). This could slowly degrade any kind of Solar Cell. Other types of Solar Cell may be chemically susceptible to degradation, such as today's Organic and Plastic Cells. These materials degrade quickly under common exposed conditions, and at this stage of the game, a lifespan of five years or so seems to be the cutting edge. Finally, of course, smashing a Solar Cell by way of storm debris or a baseball can destroy a panel, and dirt and grime can cover the surface and degrade its performance.

Solidly encasing the PV material in an aluminum and glass (or possibly plastic) module will, in most cases, help to protect the cells from physical damage, but that housing will certainly add to the cost of manufacturing the module. For a thin film product aiming to compete on very low manufacturing cost, this added expense is going to be a killer. In fact, during First Solar's Q1 '09 Conference Call, Jesse Pichel of PJC suggested that Glass was actually FSLR's largest cost. First Solar didn't disagree, and nobody mentioned Tellurium.

Now, if glass is actually even a significant portion of the cost per watt for a thin film, then it sets a kind of a lower limit on the potential cost to manufacture Thin Film Cells housed in glass (adjustable by efficiency). So, to some extent, the decision is whether to go for extreme affordability (or flexibility) and avoid a robust enclosure, but lower the operating lifetime of the cells; or else go for a longer lifespan, but adding significantly to the total cost of the module. First Solar, for example, is targeting a production cost of $.65 per Watt.

Though I'm certain that nanotech of various sorts will be able to make headway in durable exposed thin film cells, I can't help but think that it's going to have its limits. For comparison's sake, a tarp is made of very tough stuff, yet I've seen my share of tarps shredded by fall winds, and a tarp doesn't depend on the same kind of exacting chemical structure that a PV cell does. You can beat the crap out of a tarp, and it will still keep the rain off of your stuff. I'll be very impressed if I see a thin film material that you can roll into a ball, peat with a stick, and still use to generate electricity. I can't wait to see the infomercial.

There are numerous conclusions that I could follow with, but for now, I'm going to leave this with a simple idea for the consumer. Don't just buy solely based on Cost per Watt, or one day you're going to be led astray. Know what you're buying, and make sure that it has a solid warrantee over a time period to assure your expected payback. If you're offered a deal too good to be true on a cost per watt basis, it could simply be that the product you're buying is going to crap out long before it pays itself off.

So, you want to buy a solar plant.

A Scenario.

Note: A follow-up scenario includes accounting for system degradation and inverter losses.

The cost of the install + Interest will equal some amount of money to be paid out per month. I'll call this Outgoing$Monthly.

Power generated per month will be sold on the market for some amount of money. I'll call this Incoming$Monthly.

Set Incoming$Monthly = Outgoing$Monthly.

This would be the point at which your investment broke even on a monthly basis (not including maintenance cost at the moment, this is just to include interest expense into the equation). It's not going to be quite right, because of seasonal variation, as mentioned below, but I'm not looking for anything exact, just a rough way to start gauging cost / benefits.

The end result will be a relationship between the Installation Cost per Watt, Interest Rate, and Required Sales Price of Energy produced in order to break even.

I'll skip to the chase, for those that don't want to read through the whole thing.

Cost/kWp ($/Wp) = Rate ($/kWh) * C2/C1

Note that the assumed interest rate (5%) for purposes of this post has been set and absorbed by C1, and the Insolation Ratio has been absorbed into C2.. Other assumptions are pointed out below.

To give an example of what this tries to point out, let's say you can sell the energy produced by the power plant for $.25/kWh (equal to the low range of this estimate of costs for future nuclear power plants).

Cost/kWp ($/Wp) = $.25/kWh * 146 Hours/Year / .0066 = $5,530/kWp, or $5.53/Wp.

So, if you can sell your power for $.25/kWh, then you break even (roughly) if you can complete the installation for $5.53/Wp or less. Note that the equations below DO NOT include the existing 30% Federal Tax Credit for Solar Installation. That's icing (of course, it also doesn't include lifetime performance degradation or inverter losses).

Fact: this is very much in the range of possibility in TODAY's market. Particularly in the case of mid-large scale installations.

The basis follows.

If there's one thing that I've learned being on the Internet this many years, it's that if you're wrong, somebody will point it out. Have at it with my thanks!

Here goes:



First, find the Monthly Payment required to make the loan payment for an installation of some total cost.


(1) Outgoing$Monthly = (Principle * i) / (1 - (1+ i)^-n) See http://en.wikipedia.org/wiki/Amortization_calculator.

This is the Monthly Payment on the loan for the power plant with the below assumptions.

Principle = Total Original Loan amount used to finance the entire plant = the Total Peak Power of the plant * the overall Cost per Watt of the system.
i = periodic interest rate (Monthly. Assume 5% APR, so i = .05 / 12 = .0042).
n = total number of payments (Months. Assume 20 Year Loan, so n = 240).


(2) Principle = TotalPeakPower * Cost/Wp

The Principle is the amount of the loan, where the total cost of the installation is given by the Total Peak Power * Cost per Watt. Substituting for "Principle," from (2) into (1) gives:


(3) Outgoing$Monthly = (TotalPeakPower * Cost/Wp * i) / (1 - (1+ i)^-n)

For simplicity, and ease of double-checking results, I'm going to treat n and i as constants (they are part of the assumptions above), and will pull a constant out of the above equation (3):


(4) Set C1 = i / (1 - (1+ i)^-n) and substitute into (3).


(5) Outgoing$Monthly = TotalPeakPower * Cost/Wp * C1



Now, to figure out what's coming in every month on the sale of the Energy.


This doesn't include seasonal variations. On thinking about it, though, in an Energy market where consumers are paying based on momentary supply and demand, wintertime prices could actually go up based on decreased supply, and so help to balance out the annual cycle for the energy supplier. Then, in the summer where supplies were higher, the prices to the consumer would decrease to offset some winter costs.

In any case, following similar logic to my note on Insolation, the Annual Energy output of the plant can be written as below.


(6) Annual Energy (kWh) = TotalPeakPower (kW) * 20% * 8760 Hours/Year * 1 Year

Start by writing down an equation to relate the Installation's Total Peak Power, to it's Annual Energy Output. I'm plugging in an assumption of a 20% Insolation Ratio, which would include a broad swath of non-sunbelt States. The Insolation Ratio Assumption for this post applies to such shady states as Tennessee, Missouri, and even North Dakota.


(7) Incoming$Yearly = Annual Energy (kWh) * Rate ($/kWh)

Multiplying the Annual Energy Output by the Rate at which it sells for, gives the Total Income for the year. Divide by 12 (below) and you have the Average Monthly Income.


(8) Incoming$Monthly = Incoming$Yearly / 12 Months


(9) Set C2 = .2 * 365 * 24 / 12

Once again, I'm going to pull all of the Constants out of the equation (6) to come up with C2.


(10)Incoming$Monthly = TotalPeakPower (kW) * Rate ($/kWh) * C2


Ok, so now we have the Monthly Outlay required for loan payments, and we have the Monthly Income from energy sales.


To break even - let's set them equal to each other.


(11) Set Outgoing$Monthly = Incoming$Monthly


(12) TotalPeakPower (kW) * Cost/kWp * C1 = TotalPeakPower (kW) * Rate ($/kWh) * C2 (Hours/Year)


(13) Cost/kWp ($/kWp) * C1 = Rate ($/kWh) * C2


Canceling out TotalPeakPower (kW) from both sides of the equation, gives a very simple equation relating the Rate at which the energy is sold, to the Cost/kWp of the initial plant installation.

Neat.



Ok, so to an example and a factcheck.


First, Calculate out C1 and C2.

(14) C1 = i / (1 - (1+ i)^-n) = .0066 (i = .0042, n = 240)

(15) C2 = .20 * 8760 Hours/Year / 12 Months/Year = 146 Hours/Month

Then, pick a target Sale Price for the power that is produced by the Installation, and solve (13) for Cost/kWp. I'm using $.25 in this case, so:

(16) Cost/kWp = Rate * C2/C1 = $.25/kWh * 146 Hours/Month / .0066 = $5,530/kW

Now to check it, or at least check the Interest Calculations:

Since TotalPeakPower was canceled out of the above equation, I'll pick a value to use for the factcheck, say, 1000kW.

So, using (3), Outgoing$Monthly = (TotalPeakPower * Cost/Wp * i) / (1 - (1+ i)^-n) = 1000kW * $5,530/kW * .0042 / (1 - (1+ .0042)^-240) = $36,617/Month.

Then, using (6), Annual Energy (kWh) = TotalPeakPower (kW) * 20% * 8760 Hours/Year * 1 Year = 1,752,000kWh/Year and Dividing by 12 to get a monthly Energy Output, gives 146,000kWh/Month.

Multiplying this by $.25/kWh gives $36,500/Month

Pretty Close. Exponentials are subject to rounding errors. Another way to check would be to put the total cost, or Principle (in this case, $5,530,000) into any number of online mortgage calculators.


Fin

Part II : Percentage Land Area required for 100% Replacement of 2006 Energy Demand.

Yesterday I posted a chart showing a rough estimate of how much land area would be required by each State in order for that State to replace 100% of its Energy Demand (per DOE numbers).

I posted it at DailyKos, and on the LDK board for comments.

Apsmith of DailyKos makes a good point that there are generator losses, etc., which should be used to reduce the overall total energy required to be replaced, and China_s2 of Yahoo agrees, and points out a different set of data, which is based on retail electricity use, so should closely represent actual electricity delivered, as opposed to total Energy Input.

So, I copied over the old data to a new sheet, plugged in the new data, and came up with a rough estimate of the total land are required to replace 100% of US 2007 Electricity demand.

Percentage Land Area required for 100% Replacement of 2006 Energy Demand.

The following chart represents the percentage of land for each State, and the USA as a whole (without Alaska), that would be required to replace 100% of that State's Annual Energy Demand.

Make no mistake, the numbers are huge. Then again, nobody is actually talking about 100% replacement by Solar, Ever. This is just to give an idea that it is physically possible, at all.

Assumptions and references follow.




here's the spreadsheet.


References:


State Energy Data.
State Land Area Data.
State Insolation Estimates.
Sunpower Power/Area Claim.


Assumptions / Notes:


The percentages reflected in the Graph are based on a Stationary system, though the value for Power/Area is based on a Sunpower claim related to their tracking system. This should be irrelevant, as Power is independent of whether the system tracks or not. Since these are Sunpower numbers, the Panel's Conversion Efficiency should be around 22%.

The Demand cited is irrespective of source, and so includes existing production of renewables such as Hydropower. Here's a very interesting page from the DOE giving detailed map-based information on US Energy sources. There's a "Select a State" dropdown that will take you to a close-up of the individual State including facts and demographics.

In order to work out an the Area, I used the equation:

Annual Energy Output = 1 Year * Power/UnitArea * Insolation Ratio * TotalSolarArea * 8760.

For more info, see A Note on Units of Energy and Insolation. Solve for TotalSolarArea, and divide by the State's Total Land Area, and you will get the percentage. Most of the trouble here is just in the conversion of units. On a political note, can we just all go metric please?

The Insolation values were eyeballed from the map. If anybody's got some better data on State Average Insolations, I'd love to see!

The base data does not seem to include Transportation Energy, though it didn't specify.

Of course, this assumes nice flat areas of land, on which to set up installations, and it also assumes that each state takes care of its own needs irrespective of local conditions or capacity. It's a brief look from 1000 miles up above. It's not exhaustive, but it's fun, and maybe interesting.

By all means, if my basic math is way off, let me know.

This post is followed by Part II, which calculates the same area percentage, but only for the replacement of Electricity End Use.

For the Survivalists: How much gasoline is one Solar Panel worth?

Ok, first, what is the Kilowatt*Hour equivalent of a gallon of gas?

A Gallon of gas contains 114,000 BTU/gallon per Wikipedia (and other sources).

So, 1kWh is ideally equal to 3412 BTU, but no Generator is ideal. The generator's conversion efficiency is measured by its "heat rate," and the common range seems to be centered around 8,000-11,000 BTU/kWh. For this estimation I took a very efficient generator and used 8000 BTU/kWh (about 43% Efficiency).

Using these numbers gives a Total Energy Output/Gallon of 114,000 BTU/Gallon * 1kWh/8000BTU, or 14.25 kWh/Gallon.

Cost: $2.50/Gallon. This gives Cost/kWh = $2.5/14.25kWh = $.18/kWh


Now, let's look at a single 200Wp Solar Panel over one year at a 17% Insolation location (like in Massachusetts).

200Wp * .17 * 1Year = 34W*Year = 34W*Year*365Days/Year*24Hours/Day = 297.8kWh
Cost: $800/Panel. This gives Cost / kWh = $800/297.8kWh = $2.68/kWh


Woah! Ok, so obviously the Solar System doesn't pay off in a year. Going out 25 years, though, (assuming 10% average degradation over that time) gives a total of 6700.5kWh produced over that time for a total 25 Year Cost/kWh of $0.12/kWh.
For another comparison, over 25 years this single solar panel will produce the equivalent of 470 Gallons of Gas, or at this rate, 19 Solar Panels (3800Wp) will produce the equivalent of a gallon of gas per day.


Of course, this isn't exhaustive. I didn't compare costs of the generator involved, or of the installation and inverter costs for the Solar (this will at least double the cost for Solar Energy, but Government Incentives will bring it back down quite a bit). The focus here is a comparison between energy output over time. The point being, it's a potentially valid hedge for those that might be worried about future disruptions in such things like the supply of gasoline for generators. Prior to such a time, there are choices to be made, and in the case of a very long term potential outage, Solar Panels will provide much more energy than a person could even safely store in the form of Gas for an extended period of time. I also didn't account for such things as Interest on debt, because a Survivalist isn't necessarily going to care about that. If the time comes that they are preparing for, they know that money just might not worth what it is at the moment, and a working light bulb may be worth alot more.

Of course, remember that if you're one of these people, the neighbors will know that you have Solar Panels (or a Generator), and they'll want in on it. Therefore, the best thing we can all do now, is to do everything possible to make sure that not just "we" have a system, but to make sure that as many of our neighbors have them, too. Desperate people are dangerous.

Converting Energy to Peak Watts.

I put this out on the LDK board today. I figured I'd keep it here for posterity.

The debate starts with a claim that a company's product can put out 500MWh / acre / year, and that this is a good thing.
Well, it may be a good thing, but I can't really compare it to anything without converting it to Peak Power. So, that's what I do.


500MWh is energy, not power. So, we need to convert to Peak Power in order to compare to other systems.

Energy = Power * Time, so Power = Energy / Time.

Average Power per Acre = 500,000kWh/Year/Acre / Time (1 Year) = 500,000kWh*1day/24h*1year/365days*1/acres*1/year.

Do some cancelling and division:

The Average Power required to produce 500,000kWh in a year per acre is 57kW/acre.

Ok, so the company didn't give any idea of what assumed insolation ratio they are using here, but if it were set up in, say Arizona, and was on a dual axis tracker, 33% insolation would be a reasonable guess.

Start with Peak Power * Insolation Ratio = Actual Average Power.

Solve for Peak Power = Actual Average Power / Insolation Ratio = 57kW / .33 = 173kWp

This is the Peak Power Rating of their 500MWh/acre/year system assuming dual axis tracking, and 33% Insolation Ratio.

Comparing to a real world scenario (see).

Per Sunpower Tracker Advertising, their system works out to 161kWp/acre, which is just slightly less peak power than this reflecting system, which makes sense if the reflecting system gets a 28% conversion efficiency.

Heck of a day today in Solar.

More Mathematical Mumbo Jumbo.

The other day I pointed out the diminishing retrurns of increasing a Module's Conversion Efficiency. The folks on Daily Kos nicely pointed out how trivial the results really were. Well, I can live with that. I think the post still serves to make very clear that the percentage change in output Energy is, in fact, proportional to the percentage change in Conversion Efficiency (I don't know, I guess I just had to see it for myself).

As usual, if there are errors, please let me have it; though please point out a specific or two rather than just saying "check your math."

So, turned into a simple equation, increasing a module's Conversion Efficiency increases the total energy panel output per unit time and per unit area by (Conversion_Efficiency_final / Conversion_Efficiency_initial - 1) * 100%.

For example, the percentage difference between the Annual Energy Output of a 16% Efficient Panel and a 20% Efficient Panel would be (20/16 - 1) * 100% = 25% (assuming constant Area).


Following from this, I'd like to get a few more bits of information from these variables.


Effects on Surface Area of Improving Conversion Efficiency:


It could be said that Power_Peak (W) = Insolation_Peak (W/m2) * Area (m2) * Conversion_Efficiency (%).

Setting Power_Peak and Insolation_Peak as Constants, then we can say that C = Area * Conversion_Efficiency.

Take two scenarios, say, Case 1 and Case 2.

C1 = Area1 * Conversion_Efficiency1.

C2 = Area2 * Conversion_Efficiency2.

C1 = C2

Area2 / Area1 = Conversion_Efficiency1/Conversion_Efficiency2

Let's imagine a Solar Manufacturer and set today's average Conversion Efficiency at 16%, and let's say that by 2012 the average Conversion Efficiency will be 22% for some company.

Area2 / Area1 = .16/.22 = .72 = 72%

So, in order to generate the same amount of Peak Power at 22% Conversion Efficiency vs. 16% Conversion Efficiency, the manufacturer need produce only 72% as much area of PV material. Nice.


I'm not sure how "deep" this thought is, but I'm putting it out here, at the very least as a future resource for myself.

How much is 1% in efficiency worth in Solar?

Ok, so say you start with a Solar Panel that's 15% efficient (like today's low-end Crystalline Silicon Panels). For simplicity's sake, lets say that the panel has an area of 1 M^2.

So, at 1000W/m^2 Insolation, the panel will produce 150W, so this would be called its Peak Power Rating.

Let's say that you set that panel in an area with an Insolation Ratio of 20%.

In one year, that panel will produce 30W*Year = 262.8kWh [150W * .20 * 1Year * 365 Days/Year * 24 Hours/Day]



Now, say that the solar panel is 16% efficient.

At 1000W/m^2, the panel will produce 160W, so this is its peak rating.

You set that panel in an area with an Insolation Ratio of 20%.

In one year, that panel will produce 32W*Year = 280.3kWh



What is the percentage difference in the Energy Produced by the two panels in one year?


280.3kWh/262.8kWh = 1.067, so the 16% efficient panel will produce 6.7% more energy in a year than a 15% efficient panel.



Now, say that the solar panel is 22% efficient.

At 1000W/m^2, the panel will produce 220W, so this is its peak rating.

You set that panel in an area with an Insolation Ratio of 20%.

In one year, that panel will produce 44W*Year = 385.44kWh

This panel prouces 46.7% more energy in a year than the 15% panel.


See http://spreadsheets.google.com/pub?key=pNlmSU6te4mhtvbGWKl6KCA for a Spreadsheet that shows the interesting, but maybe obvious results.


So, let's say I have a choice between a 14% Module and a 15% Module. Well, the 15% module produces 7.14% more Energy per year than the 14% one. So, I had better look at the prices, and if the 15% module is more that 7.14% more costly, then you're better off sticking with the 14% one. This is assuming that space, quality, etc, aren't factors, of course. This is "all things being the same."

What if I has a choice between a 45% module and a 46% module? Well, the 46% Efficient Panel will produce just 2.22% more Energy per year than the 45% Efficient one. So, once again assuming that space isn't a factor, the 46% efficient panel had better be no more than 2.22% more costly.


I'm thinking that this is something that manufacturers have to be thinking about, too. Of course, there could be marketing reasons why a panel of a higher percentage efficiency might sell for more, and there are certainly applications that put surface area at a premium, but from a basic cost perspective at the very least, if a manufacturer of 50% efficient modules thinks that they have some technology that will take that efficiency up to 51%, then they'd better be able to manufacture those panels for less than 2% more than it costs them to make their 50% Modules. If the additional materials and manufacturing operations are going to add more than 2% to the cost of manufacture, then they very well might not have gained anything by the "breakthough."


As usual, if my thinking is wrong, by all means, let me have it.

Does Solar Tracking make sense?

I want to know, so I'm going to try to work out a rough scenario.


Looking at Wattsun Tracker Datasheets, I've decided to use 12 175W Suntech Panels. See http://www.wattsun.com/prices/Wattsun_Tracker_Prices.pdf

Cost of Tracker Equipment: $6250.

Additional Installation Costs (Rough Guess): $3000-$4000 (lower costs if you can put together an out-of-work electrician, welder, and some laborers).

Panel Total cost at $4.50/W = $9450; Total Peak Watts: 2100W

Inverter Cost: $2500 (small inverter, for just this application).


Cost of Tracking System:

Using these rough estimates, the total cost of the Tracking System with Panels would range from $21,200 - $22,200. Just to assume the worst, I'll stick with $22,200, or $10.57/Watt.

The cost of JUST the Tracker and Installation ($4000), runs $10,250, or $4.88/Watt.


Cost of Stationary System:

Calculating a rough cost of an Installed Stationary System, I'll go with the above Panel Cost of $4.50/Watt, and using the Solarbuzz estimation, which suggests that the total installed cost of the system will be twice the cost of the panels (I believe that this would include the Inverter). So, for comparison purposes, I'll set the Installed Stationary system at a total of $18,900, or $9/Watt.


Insolation Comparison:

In a normal stationary scenario, the Installation would produce energy according to the usual local Insolation values. However, the fact that it's a tracker, leads to an INCREASE in the effective Insolation value. Using a US Government Insolation Reference, it looks safe to say that for at least a very large portion of the US, there's a 2 kWh/M2 difference in Annual Insolation between a "Flat Plate Tilted South at Latitude," and a "Two Axis Tracking Flat Plate." I know from previous calculations that 2 kWh/m2 is equivalent to an insolation ratio of 8.33%.

Let's put this percentage in terms of our original 2.1 kW System. Assume that the Stationary Installation is on a roof angled at latitude, in a region that recieves an average of 20% Insolation over the course of the year. In ideal conditions, this system will produce 2.1 kW*Year * 20% = 0.42 kW*Year = 3679kWh.

Now, let's put that same system on a tracker, thus increasing the effective Insolation Value by 8.33%. This system will produce 2.1 kW*Year * 28.33% = 0.59 kW*Year = 5212kWh.

We can see that an 8.33% increase of in the effective Insolation Ratio has increased the total Annual Energy Output by 29.5%!


Does the Tracker pay off?

To start out with, let's find out how much Energy each system will produce in 25 years. To be a bit more accurate to the real World, I'll take off 25% from each value to reflect Inverter losses, efficiency degredation over the 25 year lifespan, and variation from the Manufacturers Test Conditions that went into the initial rating of the Panels.

Stationary: 3679kWh/Year * 25 Years * .75 = 68,961kWh.

Tracking: 5212kWh/Year * 25 Years * .75 = 97,725kWh.

So, over the course of 25 Years, the Tracking System produces 28764kWh more than the Stationary System.

Since the Tracking System cost $3300 more than the Stationary System, this is our target to beat.

Taking the difference between the two outputs, and multiplying by a reasonable energy selling price ($.12/kWh) gives 28,764kWh * $.12/kWh = $3451, which, compared to the additional cost of the Tracking System ($3300) is a win over 25 Years, just barely.


Conclusion:

Yes, the tracker pays off slightly over 25 years, using rough estimations. Much would depend on the specific local conditions, and the Electricity Costs.


Final Comparison:

The Stationary Roof Installation had a Total Cost of $18900, or $9/Wp, and produced 68,961kWh over 25 Years.

$18900 / 68,961kWh = $.27 / kWh.

The Tracking Installation had a Total Cost of $22,200, or $10.57/Wp, and produced 97,725kWh over 25 Years.

$22,200 / 97,725kWh = $.23 / kWh.

From this, we can see quite clearly how, though the price per Peak Watt for a Tracking System is higher than for a Stationary System, the actual cost per unit of Energy of a Tracking System is lower.


Note:
Of course, there are many variables unaccounted for in these basic Calculations, including Government Subsidies, Interest on Loans, and Insurance Considerations. More detailed Calculations would have to be done on a specific case-by-case basis. I think this is good for a start.

Lots of good news Lately...

Check the left-hand sidebar. Lots of RSS Feeds there. Keep coming back, it's changing all the time.

Real World Estimation of Land Use per Watt - Sunpower

Sunpower gives us an idea of a realistic value for Land Area per Watt of 2-3 Hectares per MW.

Convert Units:

2.5 hectare = 6.2 acres per MW.

Determine Total Peak Power Output:

1.5 Million Acres / 6.2 Acres/MWp = 241935 MWp = 241,935,000,000 Wp = 242 GWp

Calculate Average Annual Energy Output:

242 GWp * 18.75% Average Annual Insolation = 45.4 GW*Year = 3974 GWh = 397 Billion kWh

This is about 4 times less than the ideal number calculated in this Ideal Situation. Not a problem at all, IMO, considering that you don't actually want to cover every square inch of a chunk of land with flat panels. Tracking is sure a nice option.

Follows: Solar vs Coal, Land Area Comparison.

Great Solar article from Triplepundit.

Solar Stocks: Wall Street Heavyweight or Punching Bag?

Kudos on the find to mgraffis of Yahoo.

Note on CEC Ratings for Modules.

Here's a list of CEC ratings from California.

Here's a description of "derating" of Energy Output. In other words, the panels aren't perfect, here's how to estimate actual output to AC from DC.

What a Market this could be.

Forget Large-scale Energy Production for a moment. Turn your eyes from the rooftops, fields, and deserts where you could put PV or Concentrating Solar. For a moment, look around your house and think of all of the possibilities for very Small-scale Solar.

Somebody at Yahoo joked about giving someone a Solar Powered Flashlight, as if, I suppose, you waited until you needed it before you decided to try and charge it up. Thinking about it, though, who wouldn't want a solar powered flashlight for an emergency (with LED lighting). I have a flashlight sitting at my desk, and for the few hours of actual emergency light it's provided, I've changed the batteries numerous times (my Son likes to play with it). Rather than going hit and miss with a flashlight that may or may not have charge in its batteries for an emergency, why not have a flashlight that is constantly charging, as long as light is present?

Another example that's come up is based on the smoke detector that is currently sitting on my kitchen counter. The Smoke Detector is dependent on the tiniest flow of charge to trigger the alarm, and yet, they come with batteries that just might not be there when you need them. The smallest solar chip or thin-film coating could keep a very small battery charged up for a very very long time.

The list goes on. Remote Controls, MP3 Players, Cell Phones, Game Controllers, ... remote devices in general. Sure, depending on your amount of time talking on the phone, or listening to music, you might need a way to plug in the device to give the batteries a boost, but it seems to me that if you could bake a durable thin film onto the surface, you'd be set for rather a much longer time between charges, at the very least.


BTW: Googling "solar flashlight" does turn up solar flashlights. On the other hand, I just did a bunch of calculations, and I have a hard time believing that the quality of these things, based on today's common batteries, solar collectors, and manufacturing scale, is terribly high. It will take some time, and some good combinations of technological advancement before quality solar remote items become commonplace.

Great News from Congress, Markey to take Energy and Air Quality Subcommittee Chairmanship.

Rep Markey possible to take Energy and Air Quality Subcommittee Chairmanship...

This is great news! Boucher is from Virginia, which is a Coal State. He'll have over the Telecommunications and the Internet Subcommittee, while Markey from MA will be very influencial in Climate Change / Energy Policy.

I've seen Markey talk about Energy, and he's a Solar Warrior. This is good.

Happy New Year part 1. Tax Credits are Effective Today!

Here's a short article on the Credits.

Here's a good article on Inverters by the same author

I'm starting to think that a good way for to go for a self-starter, or one with limited funds upfront, would be to buy an Inverter, and a minimal number of Panels ASAP. This would make the home Solar-Ready, with the inverter reflecting the greatest single-item cost, and would allow for expansion in production over time.

I'm going to go to the Bank soon, and start looking into financing. They WANT to lend money, but they want to lend money safely. What's a safer bet these days than lending money on a system with a potential immediate payback of 30% in Tax Credits, which not only adds real value to the home, and provides for immediate and long term payback in in the form of free electricity.

Solar Investing on CNBC

Solar Set to Shine Again

Looking forward to 2020.

Per Wikipedia, Total World Consumption of Energy in 2005 was somewhere in the area of 15TW. It's suggested that 86.5% of this total is derived from Fossil Fuels, which amounts to a total World rate of Energy Consumption of 13TW. Note, this value includes the energy content of Oil and Liquid Fuels, so is not just the Electricity component.

Using 2005 as a rough basis:

The Total Energy Consumed over the whole Year could be written as 13TW*1Year.

There is a growing consensus in the World that the first International Targets will be in the area of 20% production of Energy from Renewables by 2020. Let's be conservative, and suggest that this target will be missed, at least on a Worldwide scale. There are several major Economies that might not play along, particularly among the heavy coal users.

We'll go with just a 15% target. 15% of 13TW*1Year = 1.95TW*1Year of renewables needed for, say, the year 2020.

Pulling a number out of my butt, let's say that Solar PV will provide just 10% of this amount of Energy by 2020. That makes for a Solar PV contribution of 195GW*1Year in 2020.

Since a Solar Panel doesn't provide constant Energy, we can take some averages, and assume that over an entire year, the panel will have provided a total Energy of about about 20% of its Peak Power Rating, so in order to provide 195GW*1Year, you'd need to install 971GWp of Solar Panels.

Hmm, 971GW of installed Solar Panels by 2020. Sounds crazy.

2007 Total Installation was in the area of 8.7 GWp. That leaves 962GWp to produce over the next 12 years.

What would this look like?

Photon Consulting put out some numbers quite some time ago suggesting what the growth curve in Solar would look like up to 2012. I took 10% off of the top from each of their yearly estimates to reflect the effects of the present slowdown, and came up with the following path to 962GWp by 2020.

The Spreadsheet is here.

For sake of completeness, I also made a more conservative scenario where the present downturn caused the Photon Numbers to be slashed by 30% over the next 3 Years. See the "Scenario 2" tab.

In the end, it makes little difference whether we slow down a bit for the moment, as the long term goal is largely set, and will almost certainly be acted on with great vigor by the Obama Administration.

Is it any wonder that I look with some scorn at the short-sighted calculations regularly drawn up by Yahoo bashers who suggest that today's Solar Manufacturers will wither due to lack of future demand for their products? The market that we're talking about is simply larger by orders of magnitude than most people can visualize, and it follows that so is the opportunity at a time when wholesale replacement of Existing Technology and Energy Sources are the order of the day.