He means that solar and wind power (and other renewable energy sources) represent only a tiny fraction of power generation in the US. Therefore, using them as a justification for the "clean" generation of hydrogen just doesn't make the case.

He is right that they are indeed "rounding errors." The DOE's own data shows that "Wood, black liquor, other wood waste, biogenic municipal solid waste, landfill gas, sludge waste, agriculture byproducts, other biomass, geothermal, solar thermal, photovoltaic energy, and wind" contributed to only 3% of total energy production in the US in 2008. [1]

[1] http://www.eia.doe.gov/cneaf/electricity/epm/table1_1.html

Precisely. (Thank you for chiming in. I'm the author of the presentation in question, and am completely surprised to find it here on Hacker News nearly two years after publication!)

Thanks for the presentation. If hydrogen is not the answer. What other technologies have potential?

The best solution seems to be plug-in hybrid cars with batteries. They move the power generation problem from cars to power plants, where nuclear, solar or some unforeseen future technology can handle it. More importantly, you can actually buy them today, and they can fall back on gasoline when exceeding the range of their batteries, so drivers don't have to worry about getting stuck like they do with all-electric cars. If the US automotive fleet were entirely converted to plug-in hybrids, then the remaining demand for gasoline would be small enough to supply with synthetic fuel, which can in principle be made carbon-neutral as well.

In the near term, plug-in hybrids with flex-fuel engines, plus lots and lots of nuclear power plants, followed by space-based solar power satellites in the medium term. Fusion in the long term (defined as "after I'm dead, dammit").

I can't speak for the author - but there is some evidence that, to produce our power needs via wind/tidal means on a large scale (i.e. an appreciable portion of total production) would cause as of yet hard to predict ecological impact. You sap the energy out of your tide and wind and bad juju will happen to your environment.

"Hard to predict" is an understatement. For all we know, extracting energy from wind and waves could counter the recent perceived increase in hurricanes and tropical storms, or it could restore weather patterns to what they were prior to deforestation.

> For all we know, extracting energy from wind and waves could counter the recent perceived increase in hurricanes and tropical storms

The recent trend in hurricanes has been a decrease. (We can spot storms in places that we couldn't look before, but if we look just where we could look before, there's a decrease.)

The middle of the 20th century was far worse.