In a long piece, its hard to work out what you are referring to. The potential for daytime peak CSP power from North Africa is substantial ... due to the latitude, its a better resource than the American Southwest where CSP is already being installed.
HVDC is what you would use for distances on the order of 1,000km, because of the higher line losses for HVAC, and because of the freedom from grid frequency.
On that map, that is taken from The e-Parliament initiative (pdf), you don't think that there is a coastal wind resource in NW or SE England, or you don't think that with a guaranteed round the clock market for the power harvested that the wind resource would be commercially viable? I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.
Traditional low voltage AC lines lose large amounts of electricity in long distance transmission, because electricity is dissipated as heat due to the resistance of the conductors. High voltage lines require less surface area for transmission, which results in less heat being created, and therefore less transmission loss. [Howerver] High Voltage Alternating Current (HVAC) lines remain inefficient over long distances.
I'm sure it sounds convincing, but it's drivel. Not that it matters cos he doesn't explain why DC transmission over a thousand km is so much more efficient and I know nothing about DC transmission. I'm prepared to accept it because the commercial case seems compelling. But the description of how conductor loss works with AC is just wrong, in fact it's closer to the DC case than the AC one far as I remember (dredges up 30 year old memories of transmission line theory, blows dust off page, page is blank).
There is nothing wrong with the commercial case for building windfarms in the UK, except that nimbyism and the nuclear lobby who back them will never allow it. keep to the Fen Causeway
AFAIU, the main technological advances are in materials science in the conductor, which is decades back, and in the solid state power electronics for the voltage conversion, since the 1970's.
The big limit on HVDC is that its for point to point transmission ... AFAIU, multi-terminal is a headache with DC, requiring active management. So HVAC would continue to be used the distribution grid because one line for each local substation would be a dramatic increase in capital costs, as would a HVDC to AC inverter at each local substation.
But HVDC requires fewer conductors, has lower losses over long distances (it has higher transmission losses are at the origin and terminal, but lower over the line), and does not require synchronization between origin and terminal.
So for the application of long-haul point-to-point transmission, its the choice, for distances of 800km+ ... the Inga Dam to Shaba copper mine in the Democratic Republic of Congo is a line of 1700km. I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.
