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“Green Energy” Ain’t That Green
Part I
Solar Energy
By: David Deschesne, P.h.D.
& special guest, Paul Philbrick
Fort Fairfield Journal, October 20, 2021
With Joe Biden and Maine’s Democrat governor, Janet “Big Sister” Mills conspiring to shut down Maine’s lobster industry in order to make room for off-shore wind electrical generation, it behooves us to look closer at so-called “Green Energy” to see if it is in fact as environmentally-friendly as politicians claim it to be. Since politicians are, by their nature, liars, we have to suspect their claim about “Green Energy” is also a lie.
In this multi-part series, we will examine the politically correct sources of “Green Energy” to see just how Green they really are.
Maine uses 8 Trillion Watthours (TWh) of combustible-derived (i.e. coal, petroleum, natural gas, biomass) electricity per year. An additional 3.7 TWh is derived from hydroelectricity, mostly from Canada for a total of 11.7 TWh.1
The goal of politicians, mostly in the Democrat party, but some misled Republicans, too, appears to be replacing that 8 trillion watt-hours per year, which averages out to 913,242,009 watt-hours per hour, with so-called “Green Energy.” But is Green Energy really all that environmentally friendly? No, it isn't.
The big fad today is photovoltaic (PV) panels - also known as “solar panels” - as the Green Energy solution. While both of these writers do have PV installations at our homes and support their use at a local level for home use and backup power, we must caution that the public, and electrically-ignorant politicians, do not try to employ them for more than they are designed to do.
After doing the math, it will be shown herein that it would take over 2 billion 100 watt PV panels, covering more than 500 square miles, to replace Maine’s combustible-derived electricity alone. Then, there’s the mining and refining of millions of tons of quartz, coal, and hardwood trees, as well as steel, silver and aluminum to produce those panels and install them (yes, thousands of cords of hardwood are required in the production of the silicon for PV panels, keep reading). Not to mention all the diesel fuel required in the heavy earthmoving and transportation systems that are necessarily part of the process. At the end of the day, the industry has to burn a lot of coal, trees and fossil fuels to produce “green energy” PV solar panels.
At best, a typical 100 watt PV panel only converts no more than 20 percent of the total energy that hits it into electricity. The remaining energy is simply dissipated as heat. In reality, the actual solar module component itself, has an efficiency of only 12-17% (electrical energy produced at DC output voltage), vs. the solar energy deposited onto it (the solar energy which is immensely greater, as one could expect) by the suns rays. PV systems only output at 80-85% of their rated power, under normal conditions. However, that is a very generalized statement and further explanations, or just a choice few carefully placed words, are needed for clarification.
Very generally speaking, for a commercially sized (economies of scale fully leveraged) grid connected PV system, consisting primarily of solar modules (PV panels) and DC to AC inverters, the OVERALL 'efficiency' CONSTANT is 80-85% (for engineering design purposes, we always apply 80% in the formula for efficiency, which more technically is the 'derating factor' applied to the DC rating of the DC solar module nameplate rating), This constant, when applied to the DC RATING of the sum total of all modules in a system yields us a realistic derating factor for the electrical output of an overall grid connected PV system, based upon DC nameplate rating of the modules. This Efficiency Constant of 0.80 (the lower of the 80-85%), also covers and includes the corresponding derating factor of the inverter, as well as the DC solar modules (not just the solar modules only).
For Example:
100 modules x 100 watt nameplate rated = 10,000 watts
10,000 watts x 0.80 derating (efficiency) = 8,000 watts (or 8 KW)
But that is best case scenario - at 12 volts DC. Now, things get a little more complicated here, as well.
In actuality, the voltage output of the typical solar module, is one of the primary challenges when engineering a PV system. Mathematically, in the engineering design process for each PV system, based upon varying commercially available products (with the modules primarily), one has to take into consideration the DC output voltage rating.
So yes, generally speaking, the voltage output ratings of the module in theory can be said to be rated at 'around' 12VDC, or rated 'around' other DC voltages, commonly 24VDC. But then, the panels are connected in series to one another into loops, to add the 12VDC from module 1 to module 2, and module 3, and 4, etc. An inverter can accept several series loops of modules. The DC output voltage of each module actually varies widely, depending upon the intensity of the sun's rays hitting the module, and the ambient temperature of the module. One gets to the highest DC voltage output in very cold weather because the silicon wafers create and conduct electricity much more efficiently when they are cold. So, the trick is to put the correct number of modules in series with one another, to get to the combined module optimum voltage DC output (of each loop) to the inverter, while keeping that combined module output voltage to the inverter within the range which the inverter can accept and still produce a sine wave. If the DC voltage ever becomes too high, or too low, (as a result of temperature and/or solar energy deposited on the face of the module) the inverter simply 'drops out' (in other words, stops supplying AC power on the output of the inverter) in in order to protect itself. Obviously, if this happens at all or often, one must derate the 80% even further. The AC output of the inverter is a constant and regulated 120/240 volt AC sine wave output. However, the combined series connected module loop input DC voltage to the inverter, from the several loops connected onto one inverter, will vary broadly in DC voltage over the course of a day, and a year with the rising and falling of the sun, the changing height of the sun in the sky, and from summer to winter temperatures.
And too, we're now starting to compare apples and oranges…'grid connected' (AC) PV systems, with 'off-grid' (DC only) systems with storage batteries. Off grid systems, in their truest sense, are designed to provide entirely DC output to every electrical load possible. In the challenge to convert one's life to entirely DC, therein becomes a problem for which Hybrid PV systems are born (some small inverter insertions into the DC only system).
Now for some simple math. For clarification, this math is going to be done using "perfect world" conditions with the sun directly overhead hitting the panel surface at exactly 90 degrees angle and the panel cooled to around -20 F, as it would be in the middle of winter (unfortunately when the sun is at its weakest point in the sky). The warmer a panel is, or the more obliquely the sun hits it, the less energy it produces. So, for the rest of this exercise we will be using "perfect world" conditions. The actual number of panels required for "real world" conditions may be significantly higher.
To get the required 913,242,009 watt-hours per hour out of PV systems you would need:
913,242,009 ÷ 85 watts = 10,744,023 PV panels operating at 12 Volts DC.
In order to create 120 volts you would need to multiply that number by 10, which gives you 107,440,230 PV panels. For those who can't envision numbers directly, that's over 107 million panels.
Most people think PV panels only produce their peak energy roughly 4 hours a day - 2 hours before noon and 2 hours after noon. But that is a very generalized statement based upon our human-to-sun interaction during the course of a day. In reality, the electrical peak of a PV panel is much shorter. First, the peak occurs only for a few minutes, not for hours. The AC output on the load side of the inverter (on a perfect day) is the classic 'bell' shaped curve.
In order to keep the math simple, we'll go with the severely underrated 4 hour window to figure extra panels to create (and store in batteries) enough electricity for the full day's requirements, multiply the current amount of PV panels by 6 (4 hours x 6 = 24 hours). While this still might not be enough, it's a good starting point for this academic exercise we are undertaking. In reality, you may need many times more panels especially given our latitude above the equator and the decreased amount of solar energy hitting our state in the course of a year.
107,440,230 PV panels x 6 = 644,641,380 PV panels
This is what would be needed to - in theory - produce and store (in external batteries) 913,242,009 watt-hours of electricity to cover a 24 hour period when there is direct sunlight overhead for a 4 hour time period in a day. Again, this is very generalized for the purposes of this exercise. In reality, many times more panels will be needed for real world use.
Since the sun doesn't shine every day, or is intermittently partially occluded by clouds on most partially cloudy days, you will need at least 3 times as many PV panels to create and store electricity to compensate for energy lost during cloud cover.
644,641,380 PV panels x 3 = 1,933,924,140 PV panels (That's 1.9 Billion panels)
Since the process of inverting DC to AC is only around 85% efficient (approximately 15% of energy is lost in heat), add an additional 15% to the total number of PV panels to compensate:
1,933,924,140 PV panels + 15% = 2,224,012,761 (2.2 Billion) PV panels to generate 8 TWh of electricity per year.
While PV modules vary widely in size and density of semiconductor substrate quality (output power), it is possible to get quite a bit more DC watts on a nameplate rating in a module with given dimensions. So, under pain of having to choose a panel for the purposes of this math exercise, we will go with a typical 100 watt PV panel which measures around 40" x 26" or 7.2 square feet.
2,224,012,761 PV panels x 7.2 square feet = 16,012,891,879 total square feet of PV panels.
That's 16 billion square feet. To convert that into square miles to more easily envision, you do this math:
16,012,891,879 square feet ÷ 27,878,400 sq feet per square mile = 574.4 square miles of PV panels.
Think of a swath of panels 10 miles wide extending from Caribou, down Route 1 to Houlton and you'll start to get a picture of what would be needed here.
But that 574 square miles measurement is for the area of the PV panels only. The true area used would be much greater. Vacant space must be allowed for expansion and contraction, and cooling. These modules get rather hot in the summer. Typical spacing is 1 to 2 inches all around, not to mention all of the space which must be allocated in front of the modules to prevent shadows from obstructing any of the surface of the row of modules in behind on the next row of modules. I'm thinking that with our snow totals (bottom height) and height the modules have to be tilted up vertically for maximum production all year round in Northern Maine, spacing between rows has to be a minimum of 20' (plus) to avoid further derating for shadowing. Another characteristic, even the slightest shadow of a leafless twig from a tree onto the face of a single module, will nearly kill the DC output of the entire module. So these panels would have to be in wide open fields with no trees around. That means we either sacrifice our potato fields for solar energy (which produces much less economic gain than the potato) or we have to cut down hundreds of square miles of forest. PV panels don't sound so "Green" now, do they? But cheer up, it gets worse.
Approximately 2 pounds of Metallurgical-grade silicon (MG-Si) is used to create a single 100 watt PV panel. Therefore;
2,224,012,761 PV panels x 2 lbs = 4,448,025,522 pounds of MG-Si
4,448,025,522 lbs ÷ 2,000 lbs in a ton = 2.2 million tons of MG-Si
This is what’s required for our hypothetical 2 billion panel array of 8 TWh annual production using PV panels. Remember, this is just for Maine's fossil-fuel derived electrical energy to be replaced with solar.
Kato Institute research2 has shown that to create 1 ton of MG-Si you need the following raw materials:
Quartz: 2.4 tons
Coal: .606 tons
Oil coke (coal "charcoal") : .22 tons
wood charcoal: .661 tons
hardwood chips: .33 tons
So, to create the necessary 2.2 million tons of MG-Si for our hypothetical 8 TWh PV system, we would need to mine/harvest/process:
5.28 million tons of quartz
1.33 million tons of coal
484 thousand tons of oil coke
1.45 million tons of wood charcoal
726 thousand tons of hardwood chips
But that's just to created the PV panels only. The mounting system contributes to over 33% of the cost of any 'Fixed' (non-tracking) ground mounted PV system. Mounting structures are primarily made of aluminum or steel, and concrete for below the base plates.
In a 2015 study, the U.S. Dept. of Energy estimated it takes about 15,800 tons of steel, glass, concrete/cement, and other miscellaneous materials to construct a 1 TWh PV energy system.3 For an 8TW PV system as described above, that would be 126,400 tons of material. Contrast that with around 8,000 tons of the same material to construct a similarly-sized 8 TWh natural gas-burning electrical generation facility.
So, to convert to a solar-based electrical generation system will require around 16 times the cost of conventional systems. These costs are not just in dollars and raw materials, but also the unmonetized costs of damage to the environment caused by mining all of those millions of additional tons of raw materials to produce a PV system large enough to replace combustible forms of energy production.
We do not have solar powered excavators and dump trucks so all of the above raw materials are mined, harvested and processed with diesel-burning heavy equipment and processed in factories that derive from either coal or fuel oil the necessary energy required for the process. The quartz and coal have to be smelted together in huge furnaces at high temperatures along with the coal, oil coke, wood charcoal and wood chips to create the metallurgical-grade silicon. After the silicon is produced, still more energy is needed to turn the silicon into ingots, then into wafer cells that can be used in the PV panels. Fossil fuels are used to create the plastics that compose the backing of the PV panels and still more fossil fuels are then burned to ship the PV panels to their destination and install them. The amount of additional fossil fuels required to do all of the above is outside of the scope of this research. Most Mg-Si production is now done in China where environmental and pollution standards are much more lax than the U.S. and other Western countries.
The raw materials of quartz and coal do not sit on top of the ground, there is oft-times a significant amount of dirt (overburden) that must first be moved to reach the ore that needs to be extracted. The amount of additional fossil fuels required to do this work is outside of the scope of this research.
But, all of this work, mining and refining raw materials would simply produce and install the panels. The raw materials required to produce the necessary amount of batteries to store electricity when the sun is not shining will be addressed in another section of this research. While it's easy to build battery banks and inverter systems for homes and small commercial business locations, there is no storage system in existence on the scale required for us to function reliably on solar or wind as a primary source of electrical energy.
Until we get back to nuclear electricity production, Natural Gas (the only fossil fuel presently being developed, or was at least, under Trump) is where the money should be spent. The big electrical energy power producer-money is not going into much else besides the 'politically deemed green' alternatives. Due to Green Energy's dismal efficiency and a decommissioning of the more energy-dense fossil fuel generating plants, electricity rationing and brownouts are coming.
There is no scientific logic to government subsidy propping up solar and wind, neither of which can exist, if it were not for fossil fuels or nuclear for reliability of energy generation for their mining and construction. But, when did government ever use scientific logic?
Writing in cooperation with FFJ editor, David Deschesne, Paul Philbrick is originally from Fort Fairfield. He is owner of Elco Electric in Bangor, Maine and has been designing/installing PV systems for years.
notes:
1.https:// www.energy.gov/sites/prod/files/2015/05/f22/ME-Energy%20Sector%20Risk%20Profile.pdf