[KickAssClown]

Question: How much power is produced, on average, by square meter of PV?

Question: How much power would be produced if 1/4 of the roof tops of america were converted to PV?

[CraigD]

Originally Posted by KickAssClown

Question: How much power is produced, on average, by square meter of PV?

A high-quality, clean-surfaced silicon photovoltaic cell has an efficiency of about 12%, generating about 120 W/m^2 at the equator. For estimating purposes, then, 100 W/m^2 is a good, round number. The world consumes about 10^13 W. So, to supply all of the worlds power, about 10^11 m^2 – a square about 320 km on each side, or about the area of an average-sized state, such as Virginia - of PV needs to always be pointed directly at the unobscured sun.

Question: How much power would be produced if 1/4 of the roof tops of america were converted to PV?

There are about 10^8 households in the US. Assume each household averages a modest 100 m^2 (This may be overstated – I’m currently sitting in a typical suburban single family home beneath about 200 m^2 of roof, but many Americans live in multi-unit homes with much less roof per houshold). The total rooftop area of America is – very roughly – 10^10 m^2, only 1/10th what’s needed to supply the world’s energy needs.

The practical details of how to do this – keep the panels clean, have sufficient are pointing Sunward at all times, distribute power halfway around the world during the night, or store energy, and how to satisfy all of the worlds requirements with electricity only, are very complicated. I seriously doubt that PV panels are a viable approach to the problem. However, these estimates give a rough idea of the requirements for a 100% solar world energy system, illustrating that some sort of near 100% solar world energy system is not beyond the realm of the likely. Many promising approaches in this direction are under serious development – hypography’s own Kayra comes to mind as having done a substantial amount of research in this area.

[KickAssClown]

No but they are part of the solution that I seek. We need many sources to make viable renewable power. So now, how about Hydro? Also what about the Sahara Desert (PV)? Wind? In a bit we will see about a few other (more esoteric) sources, of course one is not good enough, but many will suffice, and each can compensate for the draw backs of the other.

I think that Storing our power into Hydrogen fuel cells or other such would be good, as we can renew them.

Remember it is: Reduce, Reuse, Recycle. In that order.

[cwes99_03]

Originally Posted by Mercedes Benzene

I'm back! yay. lol.

Anyway, I was watching a show on the science channel a while back.... I think it was about a trans-atlantic tunnel (which I do not think will happen for a long time [if ever]), but it introduced some interesting points.

Trains can be very efficient if we actually worked towards a more advanced system.
For instance, if you build a mag-lev system inside of a sealed tunnel, very quick transportation can be attained.
Since the train would be based on a mag-lev system, all train-to-track friction would be eliminated.
Now, mag-lev systems obviously exist and can achieve comprably magnificant speeds. Here's the fun part though.
If you pump all of the air out of the tunnel, extreme speeds can be reached because almost all friction has been eliminated! (both train-to-track, and train-to-air friction) Air locks at the train "stations" will allow people to board the trains safely.
One could theoretically board a train in D.C., and go to work in L.A.

This could be very interesting.

Evacuating the tunnel would be nearly impossible as the costs to produce such a sealed tunnel and train cars would be prohibitive in my sense of the situation. Instead blowing air through the tunnel in the direction of travel of the train would reduce the air friction to extremely negligible, but I think that tunnel itself would reduce the friction to negligible.

Now since you propose building a tunnel, would you build it underground? Who would tunnel this earth away? What happens in the case of an emergency in the tunnel (another good reason why evacuating the tunnel would be bad)?

If you have a tunnel why not have a metal tube which can allow mag tracks below and above and on the sides of trains to stabilize it's motion through the world. Better still, why not above and below tracks and forgo the tunnel. Then you only need a system of stringers to suspend the upper mag track so that the train can run on it and the people on the train still have a view.