it doesn't matter if cars get better fuel economy; or if you did want to avoid some of the oil-co2, the problem is to decrease mileage and number of cars so that conceivably some oil would be left in the ground....

If stopping coal is the priority, is there some reason Hansen is not interested in solar/wind technology?

Solar power and wind power can not scale fast enough.  Oil and gas should be conserved, if possible, to make the coal-free bridge into the future.  Gas can be used to displace coal.  Existing fuel industries scale quickly.  

Most important is to focus on coal.  Stop expansion then retire old coal plants.  Solar, wind, etc. will rush into the vacuum and grow organically as gas prices go up.

...nudge nudge, wink wink?

Can't concentrated solar power be scaled more easily than PV or wind turbines?  Or what is holding up the scaling of PV or wind turbines?

It takes careful engineering to make renewable energy cost competitive (3 year payback).  Making solar power is both the least efficient and most expensive use of solar energy, especially when that solar energy has a nexus with liquid fuels.

Existing passive architecture and active solar heat collectors could scale quickly.  But the big public stump is that solar energy is rooftop pv, which makes difficulty for James Hansen to use the words 'solar energy' when talking about coal.  Wind is experiencing some difficult scale-up problems i.e. no supply of wind turbines for existing customers.

gotta go.

<blcoquote>And mirrors?...
...nudge nudge, wink wink?
Can't concentrated solar power be scaled more easily than PV or wind turbines?  Or what is holding up the scaling of PV or wind turbines?

Gremlins.

What many people overlook is that Renewables actually can scale quite quickly, if not more quickly than Coal.

Catch being, incrementatlly it's a matter of questioning, which is better.

250MW installed every years.
Or 2500MW installed every 10 years?

The answer is the 250MW, since it would be incrementally generating that whole time.

So obviously rather than a few gigantic power stations, lots of smaller, quickbuild, installations is better.

Problem is, we need data on manufacturing all of those wind turbines and PVs and Concentrated solar power installations -- not that I'm asking you to do it, it's part of a larger  -- a very large project -- that needs to be undertaken.

..that the first wind installations could be used to build the next generation, etc. -- that's the power of self-reproduction, it can lead to exponential increase in production, which has been the key to growth throughout the industrial era.  But we still have to figure out where all the materials will come from, it's not just a problem of energy supply.