Map of solar energy received across the USA on average day during 12 months. U.S. Dept. of Energy NREL, 2010.

Possible locations for solar panels on U.S. government-owned Bureau of Land Management lands.

The United States consumes enormous amounts of energy annually. Here is the breakdown of our ability to manufacture energy for electrical power use, listed from the largest to the smallest kind of generator or electricity source. As you can see from the table below, Natural Gas is the largest single source of power, while solar energy is the smallest. Figures are from the U.S. Department of Energy, for 2008.

Simple arithmetic calculation suggests that we would need to produce 2,304 times more solar generating capacity than we currently have, if solar was to provide 100% of our electrical energy needs.

Another way to look at the solar solution would be to calculate how many 200watt 4′x10′ solar panels it would take to generate 100% of the total electrical power for the USA. Since the USA currently uses about 1,048,313 Megawatts of capacity per year, the calculation would be:

1,048,313,000,000 / 200 = 5,241,565,000 200watt solar panels (measuring 4 by 10 feet each)

A rule of thumb is that the amount of land required to plan a usable solar panel array is roughly 3 times the actual square footage of the panels themselves. For these calculations, we could end up with about 22,500 square miles of total solar panel installations. That’s an area equal to a rectangle 70 miles by 220 miles in size. This area would occupy most of the total Southwest corner of Arizona, from metro Phoenix to the Colorado River, and from the Mexican border to the middle of the State… a huge region almost totally devoted to solar panels. Naturally, this one single installation would be impracticable. There would doubtlessly be a dozen or more smaller installations, but each one would be huge by today’s standards. This would be the largest engineering project in the history of the human race!

These panels now cost about $500.00 each.

But, there’s a flaw in this logic. The sun only shines about 12 hours a day, and provides about 10 hours of usable light for solar cells, even at the best location in the Southwest USA. That means that we would need to generate and store for nighttime use enough power during the day to also meet the nighttime needs, or about 2.4 times more power during any one average hour during the day than the above figure shows.

This produces 6,289,878,000,000 dollars in total cost to build solar panels to meet our total electric needs.

That’s roughly 6.3 Trillion dollars to build enough solar panels to meet USA needs at present prices for solar panels.

And the final cost might actually be several times that figure.

That cost assumes that the cost of manufacturing solar panels would not increase during this manufacturing process. However, in the last 3 years alone, the cost of many solar cell materials like Indium, Platinum, Gallium, Germanium, and other similarly rare elements have increased tremendously. At least some of these rare materials are required to manufacture almost every conceivable solar cell now being produced. Costs of materials are increasing at anywhere from 200% to 300% per year in some cases.

Further, no matter the cost, it may impossible to find enough of several very rare component materials like Gallium and Indium or Platinum to make enough solar cells to meet our total energy needs over the next few years. The Earth may not contain enough of these materials.

Another problem yet to be solved — at present we know of no way to efficiently store the energy that solar panels generate during the day for use during nighttime when solar panels don’t produce power. Among methods being considered are batteries, pumping water up a hill to run downhill at night to power hydroelectric generators like a dam does, storing unused power as heat for use in steam generators at night, and so on. All of these methods suffer from some serious problems — they are expensive to build and maintain, and they also lose at least 40% or so of the total power stored during the re-generation process. The storage/regeneration losses would mean that we would have to produce yet another 50% or so of total electrical power during the day in order to compensate for losses during the storage and regeration period at night.

These costs seem totally out-of-bounds, and make the idea of using solar panels for all of our electrical energy needs completely unworkable.

Total 2008 Electricity Generating Capacity* by Type of Source

*Energy Capacity Shown in Megawatts per Year

[1] Anthracite, bituminous coal, subbituminous coal, lignite, and waste coal.
[2] Distillate fuel oil (all diesel and No. 1, No. 2, and No. 4 fuel oils), residual fuel oil (No. 5 and No. 6 fuel oils and bunker C fuel oil), jet fuel, kerosene, petroleum coke (converted to liquid petroleum, see Technical Notes for conversion methodology), and waste oil.
[3] Includes a small number of generators for which waste heat is the primary energy source.
[4] Blast furnace gas, propane gas, and other manufactured and waste gases derived from fossil fuels.
[5] The net summer capacity and/or the net winter capacity may exceed nameplate capacity due to upgrades to and overload capability of hydroelectric generators.
[6] Wood/wood waste solids (including paper pellets, railroad ties, utility poles, wood chips, bark, and wood waste solids), wood waste liquids (red liquor, sludge wood, spent sulfite liquor, and other wood-based liquids), and black liquor.
[7] Municipal solid waste, landfill gas, sludge waste, agricultural byproducts, other biomass solids, other biomass liquids, and other biomass gases (including digester gases, methane, and other biomass gases).
[8] Batteries, chemicals, hydrogen, pitch, purchased steam, sulfur, tire-derived fuels and miscellaneous technologies.

Notes:
• Capacity by energy source is based on the capacity associated with the energy source reported as the most predominant (primary) one, where more than one energy source is associated with a generator.
• Totals may not equal sum of components because of independent rounding.
• In some reporting of capacity data, such as for wind, solar and wave energy sites, the capacity for multiple generators is reported in a single generator record and is presented as a single generator in the count of number of generators.

Source: U.S. Energy Information Administration, Form EIA-860, “Annual Electric Generator Report.”

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Multi-Junction Solar Cells respond to a wider range of photo energy than single layer cells, resulting in more electrical power and higher efficiency.

Spectrolab announced recently that new improvements in their multijunction concentrated sunlight solar cells have produced a world-record efficiency of 41.6%. This means that 41.6% of the incoming sunlight energy is converted by the cell into usable electricity.

The achievement was independently confirmed by the U.S. National Renewable Energy Laboratory, which tested the new Spectrolab photovoltaic cells and released test results proving the new cells have in fact broken a previous record efficiency of 41.1, held by the Fraunhofer Institute in Germany.

Spectrolab is a wholly owned subsidiary of Boeing. It has been the leading provider of solar cell panels to power U.S. military, civilian and NASA satellites since the beginnings of the space program, back in 1958.

Dr. David Lillington, President of Spectrolab, a division of Boeing.

“This latest record asserts Spectrolab’s leadership position in high efficiency multijunction solar cells and brings the industry one step closer to achieving affordable solar electricity,” remarked Dr. David Lillington, president of Spectrolab. “This cell is an advanced version of our lattice-matched cell technology that will be incorporated quickly and successfully into our production line. This milestone underscores our emphasis on realizing the highest efficiency cells in high-volume production. Over the past decade, Spectrolab’s efforts developing terrestrial solar cell efficiency have achieved an average improvement of approximately one percentage point per year, and we expect to continue that pace,” Lillington concluded.

A wide range of solar cell types are presently offered in the renewable solar energy market. Designs vary from several design considerations, single layer designs, thin film cells, single junction and multiple junction varieties. Some cells use just the normal sunlight, while others use concentrated sunlight. A wide range of rare earths, metals, ceramics and semiconductors are used in the manufacture of the panels.

Until recently, many of these materials were expensive and quite rare. However, increases in efficiency and experimentation with completely new kinds of structures and materials have produced a much less expensive initial range of costs. These new designs may in fact be so affordable that solar cells may begin to compete against fossil fuels like coal or petroleum as major energy sources in coming decades.

How Single Layer Silicon Solar Cells Work

Typical single-layer silicon solar cells work by absorbing photons from sunlight. When an atom of the silicon absorbs a photon of a particular energy level, that atom releases its lowest energy electron into the surrounding medium as a “free electron” with an energy level corresponding to the absorbed sunlight photon. The photons coming from the sun with less energy than the required releasing energy level do not produce electricity, but instead simply produce heat. Also, photons of a higher energy level than is required lose their excess energy as heat. Since only a small band of incoming photons are exactly of the right energy to produce electricity, silicon solar cells can produce only a limited range of power from sunlight — usually from 6% to 15% of the total sunlight energy available to the solar cell.

How Multijunction Gallium Solar Cells Work

By stacking several different materials in thin layers on top of each other in a single cell, scientists can produce a cell that is capable of absorbing almost half the total sunlight energy hitting the cell. A cell can be constructed from 3, 4 or even more layers. Each layer can have a medium that responds to different energy levels of incoming photons so that a much wider range of photons are absorbed to produce electricity. Most of these multi-junction or multi-layer cells are based on Gallium — either Gallium Arsenide or Gallium Indium Phosphorus. Other materials can also be used to treat or dope the final layers so that they respond more efficiently to photons and end up producing higher levels of sustained electrical power for longer lifetimes.

World-record 40.7% efficiency triple-junction solar cell developed by Spectrolab. Newer models have now reached 41.6% efficiency.

Older solar cell designs relied on silicon as the primary material. Silicon produces electricity ranging in efficiencies from 6% to 15% for most silicon-based cells. By contrast, so-called “group III-V” solar cells usually are built around Gallium Arsenide GaAs material instead of silicon. These cells can achieve solar conversion efficiencies ranging from 25% to 41%, depending on various doping recipes and whether they use concentrated sunlight or “one sun” un-concentrated sunlight.

The main reason that the higher efficiency cells are not used in most solar panels at present is that they have been very expensive to manufacture. Doping materials used in these designs are becoming increasingly rare. The costs for Gallium, Indium, and many other of the “group III, IV and V” materials has doubled or tripled in the last few years, and were already expensive to begin with compared to silicon and its related materials. As a result, the cost of generating a kilowatt with silicon cells has remained cheaper than generating a kilowatt using more efficient Gallium Arsenide based cells.

This cost-vs-efficiency curve has produced a constant drive toward looking at other materials which might be effective and efficient producers of solar electricity, other than silicon and gallium or similar products. The quest continues.

Sources: American Solar Energy Society, Kanoda Group

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Michael Gratzel, inventor of the Dye Sensitive Solar Cell and winner of the 2010 Millennium Technology Prize.

How the Dye Sensitized Solar Cell Works -- Sunlight enters the cell through a platinum or cobalt sulfide cathode at the top, then travels down to dye-coated Titanium-Oxide particles to release electrons into the electrolytic get or liquid, then free electrons are collected by an Anode at the bottom.

A new kind of solar cell that is based on cheap light-absorbing dyes and low cost titanium-dioxide promises to revolutionize the way electrical power is generated over the next 10 years.

Back in 1991, two chemical research scientists working in Switzerland developed a completely different approach to getting electricity from the sun that uses very cheap and easy-to-manufacture solar cells made from common materials. They called their new technology Dye Sensitized Solar Cells (DSSC).

The new affordable solar cells use a metal electrode top layer over a liquid gel middle layer with particles of titanium-oxide that are each coated with a light-absorbing dye to generate electrons in the titanium that overflow out into the electrolytic fluid, and then another metal layer on the bottom to collect the light-produced electrons.

Dyes from raspberries, blackberries, currants and blueberries could collect photons to start the electron flow in new solar cell technology.

New research reports that these dark blackish-blue-brown dyes covering the titanium bits could even be coloring agents from natural products including raspberries, blackberries, blueberries or black currants. These dyes will do the work of absorbing the sunlight photons, just like chlorophyll does in green plants. Imagine, your house or car powered by blueberries!

The researchers, Michael Grätzel and Brian O’Regan of the École Polytechnique Fédérale de Lausanne (Switzerland), made their announcement in a paper they published in 1991. Brian O’Regan, Michael Grätzel (24 October 1991). “A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films”. Nature 353 (6346): 737–740.

Two Big DSSC Problems Are Now Solved

UQAM Professor Benoît Marsan

From the beginning, Gratzel’s cells had two basic problems that have now been solved after almost 20 years of work on the technology. In the Spring of this year (2010), Professor Benoît Marsan and his team at the Université du Québec à Montréal (UQAM) Chemistry Department announced solutions to the 2 main problems that the Gratzell Solar Cells have faced:

1. Problems in Materials for the Cathode and Electrolyte — The design of the Gratzel Cell requires sunlight to pass through a platinum metal cathode, then down through a liquid electrolyte chemical where it frees electrons from particles of photosensitive dye-coated titanium dioxide suspended in the electrolyte.

Dr. Brian Regan, Imperial College London, Assistant researcher to Dr. Gratzel, co-inventor of the Dye Sensitized Solar Cell.

The light photons free electrons from the titanium-oxide into the electrolyte, after which they are collected at the bottom of the cell into an anode wire to provide the positive contact for the “solar battery”. As the cells are used, the original electrolyte darkens and becomes opaque, which lets much less light pass, vastly reducing the efficiency of the cell.

Further, the electrolytic fluid was originally very corrosive, gradually eating away at the dye-coated titanium particles and platinum cathode. Another problem was that platinum is itself completely opaque, requiring a mesh-type design for the cathode that further reduced light passage efficiency from the very start.

UQAM Professor Livain Breau

2. The Solutions — Professor Livain Breau, also of the Chemistry Department at the Université du Québec à Montréal, has invented a new electrolytic gel that is still transparent, but is not corrosive and provides a more dense resource for generation of free electrons than less viscous liquids did.

This results in a longer lasting cell and one that has higher voltage and current output than earlier designs. Breau also invented a new cathode that replaces expensive platinum metal with much less costly cobalt sulfide.

All of these design considerations use materials that are relatively common and affordable, when you compare them to today’s conventional silicon wafer solar cells.

Today’s silicon cells are costly to produce due to the need to bake them at high temperatures during the doping and curing process.

Also today’s silicon cell panels are heavy, brittle and easy to break by wind, hail, or vibration damage.

Another big disadvantage of silicon technology is that it uses very hard to find materials such as bisphthalocyanine complexes, indium, platinum, tantalum, ytterbium oxide, alumina, zirconia, gallium arsenide, boron, germanium and/or yttrium. Other thin-film solar cell materials include cells made from CIGS, a combination of very common copper, indium (not so common), relatively common gallium and selenide.

Some new photovoltaics are being designed made from very common elements like copper, zinc, tin, sulfur, and selenium, but those “non rare-earth” materials are just now entering the market, and offer solar electric power efficiencies of only 9% or so at their best. This compares to efficiencies from DSSC Gratzel Cells of well over 12% — and even more efficiency is expected in coming years of DSSC development.

The resulting “improved DSSC” solar cell product using this new improved design promises to enable DSSC technology to enter the market at affordable prices and power capacity.

They offer low cost affordability, power output levels, ruggedness and 12%-15% efficiencies that make them a real competitor against today’s fossil fueled economy.

The first new cells using this system may begin to show sometime over the next 2 years, perhaps as early as the Spring of 2012 to 2013. Factory production of low-cost Gratzel DSSC solar panels for the mass market could be running at full steam by 2020, according to some projections.

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Ford has your car: The beautiful and fuel efficient Lincoln Mark Z Hybrid — but Ford wants you to call it the MKZ Hybrid of course.

Starting at a reasonable $34,330 MSRP, the MKZ Hybrid boasts an official 41 City, 36 Highway fuel economy MPG rating. A wide range of options can raise that price by several thousand dollars — all up to you. Ford begins their lease offers as low as $399 /month (39 months long, with $4,512 due at signing, price may vary by your zip code and date offered).

At only  41 MPG compared to the Toyota Prius 50 MPG, Ford’s new entry won’t actually win the gas-saving race, but it certainly leads in style and grace.

This new Ford Lincoln is a real winner that delivers both eco-friendly economics and a low carbon footprint, while cruising around the city at up to 47 miles per hour in all-electric power mode.

That speed is hard to beat or even match in other hybrids in their own electric mode.

And, after the 47mph limit, the new MKZ’s powerful 2.5 liter gas engine kicks in to provide a combined 191 horsepower for true highway acceleration, uphill and passing performance.

You’re not likely to miss much in highway or city street performance while driving this new beauty.

Luxury Cars: Nowadays, it seems as though everyone is jumping on the green bandwagon, making a conscious effort to lead an eco-friendly lifestyle.

With an influx of “green” vehicles hitting the market, consumers no longer have to sacrifice luxury in order to reduce their carbon footprint.

As the latest eco-friendly vehicle to hit the streets, the 2011 MKZ Hybrid comes equipped with all the luxuries one would expect to make its way out of the Lincoln garage.

The all-new MKZ Hybrid was first unveiled at the 2010 New York Auto Show, where everyone there seemed impressed by this top-of-the-line hybrid.

The new MKZ features a new 2.5-liter Atkinson-cycle, 4-cylinder gas/electric powertrain system that also spins the wheels for the Ford Fusion and Ford Milan hybrids.

However, the MKZ has styling and beauty that is unique to the famous Lincoln logo.

Ford has endeavored to use 100% sustainable materials in their new ecologically-conscious vehicle. This includes both their Bridge of Weir leather interior and wood highlights from ecologically sustainable, carefully managed forests.

Ford introduces in this model a new power/economy gauge cluster called SmartGauge(tm) with EcoGuide, a novel approach to give the driver improved instant information on how the car and his/her driving is managing fuel economy and driving performance.

Want more luxury?

How about a 10-way power seating for each occupant, memory controls for each seat, and effective front and side window acoustical insulation to reduce wind and road noise to a whisper, providing an almost silent, relaxing ride — especially in the full-electric mode around town at speeds under 47mph. This Lincoln also features SIRIUS satellite radio, with integrated SIRIUS Travel-Link(tm) navigation and a voice-activated communications system to stay in touch with friends, business associates and so on. Other gadgets include a voice activated MP3 player, Bluetooth enabled phone, and 911 Assist(tm) with the Ford Vehicle Health Report.

Quite impressive electronics! And overall, Ford’s new luxury sedan offers a powerfully attractive combination of gorgeous styling and ecological engineering to ensure it a leading role in the automotive panaroma for 2011.

The new Ford MKZ Lincoln Hybrid for 2011 -- The most fuel efficient luxury sedan in America, at 41MPG City, all electric at up to 47mph, and 191 combined horsepower!

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Economics of sustainable energy: Cost of producing the energy compared to amount of energy generated.

In life, things are often much simpler than we make them. The economics of sustainable energy, are also simpler than they are made to appear by many authorities — including world girdling corporate giants, government agencies, and think tanks.

OVER UNITY COST OF PRODUCTION VS. YIELD COSTS

The main goal of any energy resource management program is to get more out of any particular resource, energy-wise, than it costs to produce it.

Let’s take a look an an example: The cost of producing energy from coal.

Coal is the easiest to mine or obtain, most abundant in terms of the amount of it that we can prove exists, and therefore the most economical energy resource in the world.

Since coal is the cheapest and most available energy resource, why aren’t we planning to use it over the coming hundred years or so?

Because it coal, like petroleum and natural gas, or biomass and biofuels, must be burned to produce energy. When we burn coal, gas, plant cuttings, alcohol made from plant products, or bio-diesels made from plant oils, we produce three things:

1. Ash – Sludge, Carbon, Phosphorus, Sulfur, etc.
2. Water – H2O
3. Carbon Dioxide – CO2

Strip mining coal is the easiest, least expensive way to produce coal. The problem is that it destroys the local environment, while producing burning end-products that include airborne sulfur, acid rain, and CO2.

Burning always produces at least water and carbon dioxide, even if it is merely burning pure alcohol, or hydrogen, which are the cleanest fuels.

Burning petroleum products, plant cuttings or plant oils also leaves “ash” products that are themselves dangerous and pollution products.

So far, studies of burning alcohol and hydrogen have demonstrated that these processes always tend to USE more energy than they ultimately produce. More energy is required to gather, store, transport, purify, and clean up the waste from burning these products than is ultimately generated during the final burning in our cars, trucks, or generator stations. As a result, these processes are considered “unsustainable.”

Burning petroleum distillates such as diesel or gasoline usually produces more energy than is used to mine the raw oil from the earth, transport it, store it, purify it, and transport it to be pumped into our cars or trucks or generating stations for burning.

Petroleum not only produces undesired by-products like airborn sulfur, CO2 and water-born pollution -- we are simply running out of it.

The problem is that we are simply running out of easy-to-find and easy-to-mine petroleum sources on this planet.

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