James Hansen says renewable energy 'just too expensive' and calls for more nuclear power - agree?

Completely.

Renewables will be able to provide a lot more than they currently do: maybe ~20% of electricity in most developed nations by the 2020s.

That leaves a gaping hole and nuclear is the only sensible way of heard of filling a good chunk of that without massive air pollution and CO2.

You know, it's not so much the entire country's energy needs that should be done in one fell swoop - you need to do bits at a time. Start with wind energy, since that technology is pretty well developed (and also very widespread in mainland Europe, mostly Mid and Southern France). As solar technology becomes more efficient, install those units for government buildings, maybe certain neighbourhoods as a trial basis, free of charge (see how much money they'll actually save). As this takes over more and more, look at how much of the energy needs are covered. What's left can be done through less desirable methods - it doesn't totally get rid of the problem, but it helps. Also see: Japan. North and South America's Western coastline. Chernobyl. y/y?

It's not really an either-or.

We should maximize wind power potential, which is about 6% nationwide, in the aggregate. It's clean, involves no waste, and after the amortized cost to build, it's the cheapest source of electricity. Someday they'll build longer-life turbine blades etc... and it'll be the cheapest source overall. It's also completely domestic - although, so is coal, while natural gas is 90% domestic, 8-9% Canadian. People looking for more govt funding have used a 20% figure but that's misleading - 20% is the upper limit for the proportion of a single grid's power, because wind is not reliable in the short run. But right now only about 1% of US power is generated using wind, so clearly there is room for future investment.

Solar is good on a local level. And clearly we need to keep developing technology because it's used by NASA and the military (satellites).

If you interpret Dr. Hansen's statement to mean that future investment, in terms of quantity of dollars invested and quantity of power produced, should focus on nuclear, then yes, of course I would agree.

I just wouldn't phrase it as an either-or. There are good reasons to invest in renewables. Any viable source of power reduces the cost of power in total, because the grids are designed to switch to the cheapest available source of power.

On that note, the grids themselves are poorly interconnected. The true cost comparison is between maximizing power sources within a given regions and improving the tranmission system. I.e., you have all these regions in the US, and in most of them there is capacity to generate 120%-150% of typical demand. The transmission system among the various regional grids is outmoded. Intuitively, if we want to build capacity for future growth, it makes more sense to improve that transmission system - but that may be more expensive than simply making it 180% capacity within some regions. That's another question though.

I don't think mankind's CO2 emissions are on the verge of causing a climate catastrophe. But I do think that renewable energy is a logical investment of both private and public dollars.

Even with a 20% increase in renewables(2020) "will never happen", it doesn't compensate for population growth. At best one could only have a modest ~1 - 2% gain if any. That's not to mention how long it will actually take for a functional transition to take place.Short of a revolutionary energy break through, there's not any recourse left except to improve efficiency implemented with nuclear growth.

Personally I consider reclamation/reclaiming wasted energy as a better alternative. That's also a slow go, and is mostly seen in the private sector. So until the government actually takes true sponsorship concerning efficiency nothing that amounts to anything is going to happen. Not cap and trade, but something that actually helps.

This is almost entertaining. One of the few things that you can ever get greeners and skeptics to agree on is nuclear power. If greeners were smart, they would ditch the cap and trade and work with the skeptics to pass some serious strategies to push nuclear power forward. They will find it impossible to pass cap and trade without watering it down so much as to have little effect. A severely watered down version of C&T, would be lees effective than a plan to move towards nuclear. A good plan to increase nuclear, however, would meet with bipartisan support and may go a long way to mending fences after the health care debacle (this is not to say the health care plan is bad, just that it certainly was exactly the opposite of bipartisan). You libs entirely certain that you want Obama to be a lame duck and not able to pass any legislation by supporting a bill that will surely anger the repubs to the point of not supporting anything?

I'm living in France, where 80% of electricity comes from nuclear power plants.

One of major problems, except for the nuclear waste, arrives during heat waves, we have to stop power plants.

The water thrown back by nuclear power plants warm rivers, and if rivers temperatures are upper to 28°C ( I think it's around 28°C, not sure ), we do not allow them to reject additional warm water to protect ecosystems unless dispensations.

That already happened few times. We bought electricity from Italians and UK coal power plants...

Both forms of energy are very expensive, which is why we don't do them today. It was cost, not environmental or other concerns, that drove the nuclear industry to a halt in the 1980s, and it is cost that has prevented renewable energy from developing a strong foothold.

I oppose government subsidies for nuclear energy. If it's such a good idea, private financing should be enough. On the other hand, it will take a long time for renewable energy to take care of all our needs.

Such prices don't regard the ultimate waste disposal. And yes, unfortunately uranium (and fossil fuels) won't suffice forever. Renewable energies and processing of new or more efficient technologies (as nuclear fusion) are the only way.

I agree somewhat. Though there are cleaner sources of energy I'm aware that most areas see them as not economically feasible.

I totally agree that nuclear is the clear winner as the bridge gap as we get away from fossil fuels.