energy "payback" of PV's [RE-wrenches]

[Joel Davidson]

Dear Todd,

The issue is not ugly. Rather, PV nay-sayers have an ugly attitude -
probably from the pollution that they produce and the shame and guilt they
feel for polluting. The short answer is their argument has no merit. I
recommend not wasting time talking to anti-PV people that could be better
spent selling and installing PV systems.

The http://dieoff.com/ web site is pretty pessimistic.

I like the idea that a BTU of sunlight is fundamentally different (better)
than a BTU of fossil fuel, but, alas, BTUs are pretty apolitical. A million
BTU of any flavor = 252 calories = heat needed to raise 1 pound of water
from 60 to 61 degrees F.

For an optimistic vision of the future that goes far beyond just PV breeder
plants, here is some interesting information about the Genesis Project.

http://www.atip.or.jp/ATIP/public/atip.reports.97/atip97.030r.html
The Genesis Project is the brainchild of Dr. Yukinori Kuwano, Sanyo director
and general manager of the Group's R&D Headquarters. Here's a synopsis of
his thoughts:

The major drawback of solar cells is their inability to generate power at
night, and that their output fluctuates dramatically depending on the
sunlight conditions. These problems give some concern to those who feel that

solar energy is unstable as a prime-energy source.

A Global Energy Network Equipped with Solar cells and International
Superconductor grids (GENESIS) would resolve these problems. A look at earth
from space shows that rainy and cloudy areas cover less than 30%
of the total land mass, and that it is always daylight on one side of the
globe. A worldwide PV power generating system connected by superconducting
cables with no transmission losses (until these are available, high-voltage
DC transmission technology could be used) would enable daylight areas to
provide clean solar energy around-the-clock to those areas where it is
night, rainy or cloudy.

Forecasts are that in the year 2000, energy demands will be the equivalent
of 14 billion barrels of crude oil per year. To meet this requirement, 800
km square of solar cells would be needed, assuming a conversion efficiency
of 10%. Barely 4% of the world's desert area would suffice.

Implementing this plan is not so unrealistic. When a large number of people
install PV  power generation systems in their homes and in factories, and
these are connected to the electric power grid, all of Japan will be made
into a network through PV power generation power lines. If the same pattern
is repeated in several countries, PV power generation networks will be
created in each of these countries. Country networks could then be
connected.

For example, South Korea and Japan (Kyushu) are separated by 200km - their
transmission lines could be connected. In Europe, electric power grids of
some countries are already interconnected. As a next step, a
plan called "Silk Road GENESIS has been proposed by the Tokyu Construction
Co., Ltd. to construct PV power generating systems along the ancient trade
road. It will include Sanyo and four other companies. The project envisages
the building of a total of 139 100,000KW solar plants between 2001 and 2030.
The combined power generation capacity is expected to reach 100 million kw.

Between 1996 and 2020, when the market size reaches between 10,000 MW and
100,000mW per year and integrated solar cell module cost drops to $1/W or
less, the use of solar cells will find wider application in
private homes, apartment blocks, factories, industrial facilities, and power
stations. Finally, sometime after 2020, the Genesis Project - a global solar
power network - might be realized.

Also http://www.geni.org/geni97/coldwar.html
Sanyo Electric has proposed Project GENESIS for the mid 21st Century.
GENESIS stands for Global Energy Network Equipped with Solar Cells and
International Superconducting Grids. Even though superconducting power
transmission is still a research dream, Sanyo figures that solar cells
covering just 4% of the worlds deserts would supply the energy needs of
everyone on the planet.

A few years ago Dr Shinya Tsuda, Sanyo, "My final target is the Genesis
project, a global energy system using photo-voltaic cells. All of us
involved with the Genesis project think a step by step approach is very
important. At the initial stage, we want to make some products which will
connect to the conventional grid network of the electric power companies so
we can establish a local area network of photovoltaic systems. Then we'll
expand it all over the country and connect such a system to the neighboring
country. Eventually, we can expand such a system into a global system in the
same way the telecommunications industry grew."

Happy Independence Day!
Joel Davidson



"Todd Cory, Mt. Shasta Energy Services" wrote:

> Sorry to raise this ugly issue again, but I am dialoguing with some
> folks that insist that PV's never recoup their embedded energy. Can this
> possible have merit?
>
> Pasted text follows.
>
> Todd
>
> RENEWABLE ENERGY SYSTEMS
>
> So-called "renewable" energy systems are evaluated differently
> than "non-renewable" energy systems. In order to be "renewable",
> an energy system must produce enough net energy to reproduce
> itself.
>
> A BTU of sunlight is fundamentally different than a BTU of fossil
> fuel. Directly and indirectly it takes about 1,000 kilocal of
> sunlight to make a kilocalorie of organic matter, about 40,000 to
> make a kilocalorie of coal, about 170,000 kilocal to make a
> kilocalorie of electrical power, and 10 million or more to support
> a typical kilocalorie of human service. So when renewable energy
> systems are evaluated, both inputs and outputs must be converted
> to solar eMjoules (or "sej") and compared. (There are ten
> different sets of equations to convert energy to sej:
> http://dieoff.com/emergy.pdf ) The difference between the sej
> input and sej output is known as the "net sej".
>
> Calculations show that solar cells consume twice as much sej as
> they produce. http://dieoff.com/pv.htm So even if all the energy
> produced were put back into production, then one could build only
> half as many cells each generation -- they are not sustainable.
> Even if the sej efficiency of solar cells doubled, ALL of the
> energy produced would have to be used to manufacture new cells,
> which still leaves a zero net benefit to society!
>
> Traditional measures of "net energy" for solar cells may be
> improving but "net sej" may be getting worse because there are ten
> different sets of equations to convert energy to sej. The only way
> to know is to DO THE MATH. http://dieoff.com/emergy.pdf

[Non-text portions of this message have been removed]

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