The Two Ways of Using Solar Energy for Power Production

imp

Senior Member
It's important to understand that the Sun's energy may be utilized in two distinctly different ways: The Sun's radiant energy, much of it Infrared Radiation, heat, may be used as a source for heating water or other media, in order to lower dependence on traditional heat generating means.

The other use is to generate electric power, using the radiant energy, ALL of it, not just the heat. This usage may be divided into two distinctly differing methods. One is to use "solar cells", which are simply electronic "Solid State" devices which have been around for many decades, to generate electric power. Solar cells do that directly, producing electrical energy as the sunlight falls upon them. They have no mechanically moving parts, but DO require physical movement to "track" the Sun's position across the shy, to obtain most efficiency. Solar cells in theory have unlimited life.

A commercial venture of differing concept to use the Sun's energy, primarily the heat energy, to generate electric power, has been built under the auspices of the United States Department of Energy. This scheme utilizes an enormous number of huge mirrors which reflect and direct the sunlight onto large vertical "chimneys", so called because of their appearance, the concentrated heat within them is used to boil water and produce steam, which is consumed by traditional electric generators to mechanically produce electric power. Here is a bit about that project. The image below is from: http://energy.gov/lpo/ivanpah I tried copying some of the Energy Department hoopla there, but could not. Take a look at it, if you care about our wildlife. Then look further, below.

DOE-LPO_Project-Photos_CSP_Ivanpah_01_0.png



"Emerging solar plants scorch birds in mid-air"
IVANPAH DRY LAKE, Calif. – Workers at a state-of-the-art solar plant in the Mojave Desert have a name for birds that fly through the plant's concentrated sun rays — "streamers," for the smoke plume that comes from birds that ignite in midair.
Federal wildlife investigators who visited the BrightSource Energy plant last year and watched as birds burned and fell, reporting an average of one "streamer" every two minutes, are urging California officials to halt the operator's application to build a still-bigger version. ....."urging California officials to halt the operator's application to build a still-bigger version."
The investigators want the halt until the full extent of the deaths can be assessed. Estimates per year now range from a low of about a thousand by BrightSource to 28,000 by an expert for the Center for Biological Diversity environmental group.

More than 300,000 mirrors, each the size of a garage door, reflect solar rays onto three boiler towers each looming up to 40 stories high. The water inside is heated to produce steam, which turns turbines that generate enough electricity for 140,000 homes.


The above is from: http://www.foxnews.com/us/2014/02/15/world-largest-solar-plant-burning-up-birds-in-nevada-desert/

Now my comment: How can we possibly believe that such idiotic Engineering oversight, could have been allowed to progress from planning to capitalization, to construction, without at least someone "blowing the horn" about the probable effects upon anything entering the paths of the super-heated sunlight? Everyone already knew the effects upon birds by wind generator blades. I am totally disgusted that this effort has proceeded to completion. How do YOU feel? imp
 

It's important to understand that the Sun's energy may be utilized in two distinctly different ways: The Sun's radiant energy, much of it Infrared Radiation, heat, may be used as a source for heating water or other media, in order to lower dependence on traditional heat generating means.

The other use is to generate electric power, using the radiant energy, ALL of it, not just the heat. This usage may be divided into two distinctly differing methods. One is to use "solar cells", which are simply electronic "Solid State" devices which have been around for many decades, to generate electric power. Solar cells do that directly, producing electrical energy as the sunlight falls upon them. They have no mechanically moving parts, but DO require physical movement to "track" the Sun's position across the shy, to obtain most efficiency. Solar cells in theory have unlimited life.

A commercial venture of differing concept to use the Sun's energy, primarily the heat energy, to generate electric power, has been built under the auspices of the United States Department of Energy. This scheme utilizes an enormous number of huge mirrors which reflect and direct the sunlight onto large vertical "chimneys", so called because of their appearance, the concentrated heat within them is used to boil water and produce steam, which is consumed by traditional electric generators to mechanically produce electric power. Here is a bit about that project. The image below is from: http://energy.gov/lpo/ivanpah I tried copying some of the Energy Department hoopla there, but could not. Take a look at it, if you care about our wildlife. Then look further, below.

DOE-LPO_Project-Photos_CSP_Ivanpah_01_0.png



"Emerging solar plants scorch birds in mid-air"
IVANPAH DRY LAKE, Calif. – Workers at a state-of-the-art solar plant in the Mojave Desert have a name for birds that fly through the plant's concentrated sun rays — "streamers," for the smoke plume that comes from birds that ignite in midair.
Federal wildlife investigators who visited the BrightSource Energy plant last year and watched as birds burned and fell, reporting an average of one "streamer" every two minutes, are urging California officials to halt the operator's application to build a still-bigger version. ....."urging California officials to halt the operator's application to build a still-bigger version."
The investigators want the halt until the full extent of the deaths can be assessed. Estimates per year now range from a low of about a thousand by BrightSource to 28,000 by an expert for the Center for Biological Diversity environmental group.

More than 300,000 mirrors, each the size of a garage door, reflect solar rays onto three boiler towers each looming up to 40 stories high. The water inside is heated to produce steam, which turns turbines that generate enough electricity for 140,000 homes.


The above is from: http://www.foxnews.com/us/2014/02/15/world-largest-solar-plant-burning-up-birds-in-nevada-desert/

Now my comment: How can we possibly believe that such idiotic Engineering oversight, could have been allowed to progress from planning to capitalization, to construction, without at least someone "blowing the horn" about the probable effects upon anything entering the paths of the super-heated sunlight? Everyone already knew the effects upon birds by wind generator blades. I am totally disgusted that this effort has proceeded to completion. How do YOU feel? imp

I'm surprised you haven't discussed decentralized solar power. Solar panels on roofs all over the country. Wouldn't it be nice not to be hostage to a national power grid which wastes energy by moving it long distances, costs an enormous amount of money, and is vulnerable to Asian hackers.
 

I'm surprised you haven't discussed decentralized solar power. Solar panels on roofs all over the country. Wouldn't it be nice not to be hostage to a national power grid which wastes energy by moving it long distances, costs an enormous amount of money, and is vulnerable to Asian hackers.

Ah, I guess I hate roof-mounts! No point in arguing the thing, IMO, a roof-mounted solar collector takes precedence over a solar electric array. Hot water can be stored easily, made cheaply using sunlight. Hot electrical energy, not so easy. Now, if the roof-mount produced 120 volts or so, 240 even better, we have solid-state inverters to give us the needed AC (not air conditioning!). All of that's pretty expensive, still, tax credits notwithstanding.

You're right about long distance transmission losses. They are of two types: resistive loss, and "reactive ". Resistive is always present, reactive only when using AC. So, the advent of reliable high-voltage DC to AC solid-state "inversion" has resulted in lots of DC transmission lines lately. In 2007, overall long-distance transmission line losses were about 6.5% (Frequently Asked Questions – Electricity. U.S. Energy Information Administration. November 19, 2009. Retrieved March 29, 2011.).

We are all, and have been, captives of the commercial power system, but all-told, it's pretty hard to justify making your own electric power, after factoring in the capital cost. IMO. Now, that solar-powered electric-driven airplane.....!! imp
 

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