Stephen, You're right about the DC-DC conversion issue, but the more progress is made in this respect notably with the use of IGBTs, the more sense it makes to resort to HVDC.
Main advantage over AC I believe is that a given power line, built to a given insulation, can work at a higher voltage by a factor equal to Vpk(AC)/Vrms(AC) = sqrt(2) =~1.5 (e.g. ~300kV DC instead of 200kV RMS), and thus transmit about 50% more power V*I for the same current I and thus the same resistive losses R*I^2. The gain must be even higher if you take into account the savings on dielectric losses (which higher freq AC would increase BTW). Corona losses must be lower too (same sign air ions flowing from the line to the ground offers better space charge screening than mutually cancelling alternating waves of positive and negative ions). Michel ----- Original Message ----- From: "Stephen A. Lawrence" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Sunday, December 09, 2007 11:35 PM Subject: Re: [Vo]:[VO}: Hydrogen as fuel ... >> If sufficient money were put into building a solar infrastructure and HVDC >> power transmission >> system, > > Why HVDC? > > I've been led to believe that the problems in efficient DC-DC conversion > outweigh any advantages > to DC distribution. (Granted, some computer power buses use single-voltage > DC and downconvert at > the board level, but that's all low-current stuff and efficiency isn't such a > big deal in that > case.) > > If we're changing the grid, wouldn't it be more reasonable to switch to > higher frequency AC, which > would be easier to manage than 60 Hz (and maybe less dangerous)? > > Just wondering.
