Energy Systems Categorized

Sandy, 

Air-transport is much more dependent on energy storage density than personal cars, because the distances involved are much higher, the weight sensitivity greater, and the energy use per passenger-mile is somewhat worse.  We are seeing a few applications for battery powered airplanes today which involve travelling less than a few dozen miles (i.e. less even than a typical car): flight training, especially take-offs/landings and self-launched motor-gliders.  The range limitation comes from the weight of the batteries.  It would be great if batteries improved ten-fold; but why do you think this will happen?  We have already changed from using lead to nickel to lithium, the lightest metal; we may well see future improvements in cost effectiveness, but energy/mass ratio improvements will likely slow to a stop.

"I think complete denuclearization of the grid is possible + actually underway."

Of course the grid worked fine before nuclear (except that the resulting air pollution substantially shortened the lives of the people it served and increased the CO2 in the environment).  Returning to that would be a tragedy. 

The claims by anti-nuclear activists that it would somehow make us safer are based on emotions & ideology, rather than science (the actual science says nuclear is the safest source of energy).   

The claims that renewables can do the same job are untrue as well; the variability of solar and wind increase the benefit of using fossil gas to the point that fossil fuel gets locked in (once the renewable penetration exceeds the capacity factor).  The dilute nature of sunlight and wind mean that renewables will increase humanity's environmental footprint.

Decades into the renewables era, there are zero grids which have deeply decarbonized using solar & wind, but France, Sweden, and Switzerland have all deeply decarbonized using nuclear+hydro (by grid, I mean the whole "balancing area", so small towns that export huge amounts of windpower for hours at a time, then import a little coal power when the wind stops don't count; it's the whole grid that matters). 

As to nuclear costs: the amount of concrete and steel involved is much less than for renewables for the same energy production, so there is plenty of opportunity for improvement.

"... nuclear ... a very protracted discussion." Yep, scientific discussions are much simpler than ideological ones.  But Ideological discussions matter too.

Sandy, you can't measure the torque on a screw unless that screw is turning; similarly, you can't measure the volume cost of something if that something is not in volume production.  Any complex item is going to be expensive the first few times you try to build it; that is equally true of windpower, solar, airplanes, rockets, or nuclear reactors. 

To make predictions of how low nuclear costs could go in the future, we should use the normal construction industry practice of basing the estimate on the amount of concrete and steel required.  For large nuclear plants, that's around an order of magnitude less than is required for renewables, for the plant's lifetime energy output.

SMRs are promising in that we'll move down the learning curve faster, since we'll build more units per GWatt of capacity built.  However, I would note that to decarbonize our US grid in a timely fashion, we need to add clean electric generation at a rate over 20 GWatt_avg per year; that is plenty fast enough to drive costs down in even large reactors such as the AP-1000.  In fact, China is building their nuclear fleet primarily around 1-1.4 GW reactors, even though they are also developing a smaller reactor for export; the bigger units use less material and cost less per unit energy produced.

One may think that because America has built 100 GWatt's of nuclear reactors in the past, we should already know how to do it well.  It's easy for an inactive industry to forget that sort of thing, particularly after having gone through a period during which making the product _more_ expensive was the most profitable approach (locked-in contracts, dim prospects for future projects, cost-plus contracts, government regulators who help restrict competition, etc).

As to why existing nuclear plants are being closed down:  

- Overly rigid government regulations, lack of competition, and excessive fear of accidents and radiation releases block operating cost reductions.

- Utilities and the fossil fuel industry benefit from closing nuclear plants because reduced supply causes wholesale prices to go up (bad for consumers, good for producers).

Why should we make the investment to bring the industry back in the face of seemingly less expensive competition?  For the same reason given by advocates of renewables 20 years ago: the superficially cheap fossil fuel competition is not paying for their external costs (pollution, CO2 emissions, and oil wars); that's not a level playing field.  Also one new reason: variable renewables are unlikely to free us from dependence on fossil fuel because they make only variable electricity, but what customers want is electricity-on-demand, which comes only from grids which are dominated by dispatchable generation.