Engineering challenges for the 21st century

The National Academy of Engineering asked a panel of very interesting and thoughtful people to come up with a list of the most important engineering challenges for this century. The group is really impresive. Here are some of the members:

• J. Craig Venter (human genome decoding, first artificial chromosome...).
• Dean Kamen (mobile dialysis machine, insulin pumps, Segway...).
  
• Ray Kurzweil (OCR, text-to-speech...)
  
• Larry Page (Google)
  

So, this group of engineering titans produced a list of general technology fields instead of trying to ascertain the need for any particular specific devices. These are the fourteen challenges proposed with my comment for each:

1. Make solar energy economical: right, but economical in this context means reaching efficiencies above 70%
   
2. Provide energy from fusion: it'll be ready in 25 years! (as it's been the case during the last 40)
   
3. Develop carbon sequestration methods: here's my candidate! (biochar)
4. Manage the Nitrogen cycle: we're going to need a lot of Mr. Venter talent for this one; and a lot less of the European GMO fearmongering than we have right now
5. Provide access to clean water: the way I see it this is mainly an economic challenge
6. Restore and improve urban infraestructure: upwards, please!
7. Advance health informatics: yes, but it won't be the silver bullet many people expect
   
8. Engineer better medicines: this one, on the other hand...
9. Reverse-engineer the brain: I'm afraid we won't be able to
10. Prevent nuclear terror: yes, please. Or even better, prevent terror. Period
11. Secure cyberspace: from splits? from rogues? from thieves? from governments?
    
12. Enhance virtual reality: c'mon Ray, you had to sneak this one?
13. Advance personal learning: and this one too?
14. Engineer the tools of scientific discovery: this more of an ongoing concern than solving a specific incoming challenge

It's a good list, if only a bit too politically correct. However, I miss a very important challenge not addressed there that is much more pressing than a few of the ones that got into the list (like 2, 6, 11, 12 and 13): advance energy storage technology.