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On The Cost of Wind Energy, Part I
"... the best achieved by wind to date is 28% in Denmark."
And I wouldn't make too much of such national figures. Denmark isn't an island. Last year, Denmark generated 10.3 TW-h from wind. It also imported 15.9 TW-h (mostly from Sweden) and exported 10.7 TW-h (mostly to Germany). So Danish wind was really a smaller fraction of the larger, regional electricity supply for northern Europe.
On Offshore Wind vs Nuclear Energy for Mid-Atlantic
Well, plants in China are being built for about $2/W. The Korean plant in the UAE is $3.6/W.
But yeah, in the West $4/W is a bit low. In the US, Summer is $4.5/W and Vogtle is $6.8/W. I believe the difference is because the Vogtle project includes a lot of transmission spending in addition to the two reactors. With their massive cost overruns, Areva's projects in Finland and France are $6.5 and $6.9 /W respectively.
On Offshore Wind vs Nuclear Energy for Mid-Atlantic
That's pretty easy to guarantee, since you can see hurricanes coming days ahead of impact, and prepare for them. As a matter of fact, several plants were hit by Sandy.
http://www.world-nuclear-news.org/RS-Keeping_the_lights_on_as_Sandy_strikes-3010127.html
On German Coal and Solar Energy: A Self Defeating Scenario
Changes in generation, in TW-h, from 2011 to 2012:
High C: 231 + 18 = 249
lignite: 134 + 9 = 143
hard coal: 97 + 9 = 106
Medium C:
gas: 60 - 11 = 49
Low C: 185 + 0 = 185
nuclear: 103 - 9 = 94
wind: 48.9 - 3.0 = 45.9
solar: 19.3 + 8.6 = 27.9
Run/river: 14 + 3 = 17
from pp. 8-9
http://www.ise.fraunhofer.de/en/downloads-englisch/pdf-files-englisch/news/electricity-production-from-solar-and-wind-in-germany-in-2012.pdf
On Two Energy Revolutions Vie Across the Atlantic
Just that '30 TW-h' underrates the potential for German solar power. I expect it will reach that level this year. And I wouldn't be surprised if by 2022 it reached 50 TW-h per year. Of course, a large fraction of that would have to be stored, exported, ... or simply discarded.
On Energy Innovation: Massive Solar Downdraft Tower Proposed in Arizona
As I said before, that 435 MW-h per day figure is dubious. But taking it at face value, that's 159,000 MW-h per year.
On Two Energy Revolutions Vie Across the Atlantic
"... all those panels wont even produce 30TWh annually."
Well, they'll probably reach that level. In 2012, they produced 27.9 TW-h; over the course of the year capacity grew from 24 to 32 GW.
http://www.ise.fraunhofer.de/en/downloads-englisch/pdf-files-englisch/news/electricity-production-from-solar-and-wind-in-germany-in-2012.pdf
On Energy Innovation: Massive Solar Downdraft Tower Proposed in Arizona
"Under the most recent design specifications, the first San Luis Tower has a design capacity on an hourly basis, of up to 1250 megawatt hours, gross. Using a 60% capacity factor, the Tower’s potential hourly yield would be 600 megawatt hours from which approximately 18.5% will be used to power its operations, yielding approximately 500 megawatt hours available for sale to the power grid. Due to lower capacities during winter days, the average daily output for sale to the grid for the entire year is approximately 435 megawatt hours." http://www.cleanwindenergytower.com/the-tower.html
This is a bit of a mess, possibly from some confusion between megawatts (power) and megawatt-hours (energy). Is the gross capacity 1250 MW, or 600 MW, or what?
An average daily output of 435 MW-h would be an average power of 435 MW-h / 24 h = 18 MW. Which is absurdly small.
'... about 750 permanent employees will be needed to maintain the tower and its 25 “generating plants.”'
That seems like an unreasonably large number. Conventional wind farms' employees number in the dozens.
In the linked interview with the CEO http://thestockradio.com/ceo-ron-pickett-of-clean-wind-energy-tower-inc/1766
~2:20: 'Turbines *in series* capture 90% of the energy of the air', would seem to leave a lot of air piling up around the base of the tower.
~3:30: 'An all-in cost for the average wind farm of 18.5¢/kW-h' is a considerable overestimate.
On Wind vs. Nuclear Energy in the UK: A Question of Scale
Yes, I had the same ratio:
London Array (UK) : = 2.2 W/m^2 = 2.2 MW/km^2 = 220 MW / 100 km^2
--> 2.6 GW / 1180 km^2
From context, I'd guess Ivor miswrote, and meant '... to make wind look bad.'
Of course, cost is a more important metric.
Cape Wind (US) : 2.5 e9 USD / (454 e6 W * 0.37) = 14.7 USD/W
London Array (UK) : 1.8 e9 GBP / (630 e6 W * [0.35]) = 12.4 USD/W
Greater Gabbard (UK): 1.5 e9 GBP / (504 e6 W * 0.4 ) = 11.3 USD/W
Clyde (UK) : 500 e6 GBP / (350 e6 W * 0.3 ) = 7.2 USD/W
Shepherds Flat (US) : 2 e9 USD / (845 e6 W * 0.27) = 8.8 USD/W
Bald Hills (Aus) : 250 e6 AUD / (104 e6 W * 0.36) = 6.9 USD/W
Olkiluoto (Fin) : 8 e9 EUR / (1.6 e9 W * 0.85) = 7.6 USD/W
Flamanville (Fr) : 8.5 e9 EUR / (1.6 e9 W * 0.8 ) = 8.6 USD/W
Hinkley Point C : 14 e9 GBP / (3.2 e9 W * 0.8 ) = 8.3 USD/W
Vogtle (US) : 15 e9 USD / (2.2 e9 W * 0.85) = 8.0 USD/W
Summer (US) : 10 e9 USD / (2.2 e9 W * 0.85) = 5.3 USD/W
For reasons Willem lists, that understates the relative value of nuclear vs. wind. On the other hand nuclear has a fuel cost.
On Wind vs. Nuclear Energy in the UK: A Question of Scale
A not-guaranteed-to-be-typical sampling of wind farms suggests that your '4 MW per 4 acres' is out of line.
offshore:
London Array (UK) : 630 e6 W * [0.35] / 100 e6 m^2 = 2.2 W/m^2
Greater Gabbard (UK) : 504 e6 W * 0.4 / 146 e6 m^2 = 1.4 W/m^2
Onshore:
Clyde (UK) : 350 e6 W * 0.3 / 47 e6 m^2 = 2.2 W/m^2
Shepherds Flat (US) : 845 e6 W * 0.27 / 78 e6 m^2 = 2.9 W/m^2
Bald Hills (Aus) : 104 e6 W * 0.36 / 17.5 e6 m^2 = 2.1 W/m^2
your hypothetical : 4 e6 W * 0.35 / 4*4047 m^2 = 86 W/m^2
Hinkley Point C : 3.2 e9 W * 0.8 / 1.7 e6 m^2 = 1500 W/m^2
On Deaths from Nuclear Energy Compared with Other Causes
"Renewables produced 155 TWh last year. Nukes 150 TWh."
In what country? Worldwide, nuclear power produces more than 2,500 TW-h per year.
http://www.iaea.org/PRIS/WorldStatistics/WorldTrendinElectricalProduction.aspx
On Energy Finance: German Solar Four Times Higher Than Finnish Nuclear Energy
At the current cost of PV, the difference isn't quite as stark.
Olkiluoto (Fin) : 8 e9 EUR / 1.6 e9 W = 6.5 USD/Wp; @ 0.85 CF = 7.6 USD/Wave
Flamanville (Fr): 8.5 e9 EUR / 1.6 e9 W = 6.9 USD/Wp; @ 0.8 CF = 8.6 USD/Wave
German PV : 1.5 EUR/W = 2 USD/Wp; @ ~0.11 CF = 18 USD/Wave
U.S. PV : ~3 USD/Wpeak; @ ~0.25 CF = 12 USD/Waverage