Subject: Re: Selling energy via the grid

From: [email-masked] (Nick Pine)
Date: 19 Sep 1995 16:06:28 -0400

Mr. Nice Guy <[email-masked]> wrote:
>[email-masked] (Will Stewart ) wrote:
>>In <[email-masked]> [email-masked] (Stephen Lajoie) writes: 

>>...Today's converters no longer create a square wave, but a sine wave.

>No they don't produce a true sine wave, they produce a digital 
>approximation of a sine wave with additional higher harmonics.

I think that's true.

>If a user intends to sell power back to the grid they will have to 
>purchase a larger inverter than they would otherwise have needed, 

I think that's false. What do you mean by that? "Synchronous inverters"
connected to the grid can be a lot simpler and cheaper than stand-alone
inverters. Think of a backwards lamp dimmer, with a full wave triac bridge
in series with a choke, with the triacs triggering on for part of the
60 Hz cycle, when the DC source voltage is effectively at a higher
potential than the line. To vary the power delivered, vary the firing
angle. Pretty simple. These don't even need a 60 Hz frequency reference
That can come from the line. 

>inverters are expensive.  The big question is why anyone with 
>access to the grid would select solar power in the first place?

For fun, I guess. And to avoid having a houseful of batteries.

Nick

---

From: [email-masked] (Nick Pine)
Date: 29 Sep 1995 03:51:24 -0400

Stephen Lajoie <[email-masked]> wrote:

>Solar energy dates back to the 1970s when it became popular politically. 

It does? I thought the sun was much older than that :-)

Edward Morse patented what is now known as the Trombe wall in 1881.

I have an old book about "it" called _The Source and Mode of Solar Energy
Throughout the Universe_, by I. W. Heysinger, M.A., M.D, published by
J. B Lippincott in 1895.

Dr. Heysinger begins:

   In endeavoring to present a new and rational interpretation of the
   source and mode of solar energy, based upon the established
   principles of recent science, it becomes necessary to briefly cite
   the facts bearing upon the problem to be solved and the authorities
   for their support, as well as to describe concisely the different
   hypotheses at present in vogue, and to point out the well-established
   insufficiency of these theories, one and all, to account for or explain
   the difficulties encountered, and which so far have remained as an
   unsolved enigma. And this problem of solar energy is the grandest and
   most important problem of all physics, for upon the light and heat of
   the sun depend all physical life and its consequences, animal and
   vegetable, past, present and future. If within finite time, and relatively,
   compared with the enormous vistas of the past, a very brief time, this
   source of energy is to cease, and our whole system be involved in darkness
   and death, such darkness and death must be eternal; for the dead sun
   in his final stage of condensation will be as fixed and unchangeable
   as the operation of eternal laws can make it, and henceforth there can be
   no revival or reversals, no turning back of the hand upon the dial,
   while the laws of nature continue; and outside the uniform operation
   of the laws of nature there is no source, or mode, or continuance of
   solar energy conceivable. It is true that when our system shall have
   run down to its culmination in death, other present systems may continue
   for a time to exist and new ones spring into being; but these, too,
   must inevitably follow the same course, and likewise end in eternal
   darkness, until finally the great experiment of creation shall have
   ended in eternal failure.

Nick