I've just recently released the final update to the National Renewable Ammonia Architecture
If you're not up on this chemical, the U.S. uses some twenty million tons a year, 90% of that for agriculture, and estimates are that half of the protein humans consumes has its roots in ammonia and successor chemicals made from fossil fuels. I'd like to see less in the way of pesticides and herbicides used in food production, but the protein thing is a fundamental mass balance problem - if you don't have the inputs needed for protein you don't get the protein. And there's no natural source for biologically available nitrogen that meets our needs, either - the Atacama desert nitrate deposits are largely worked out and they wouldn't do the job when the population was a third of what it was now, which is what drove the development of synthetic ammonia in the first place.
Ammonia is a fertilizer, it's a good hydrogen bearing fuel, and it can be used to drive plant based carbon sequestration if we're making more than we need for food production. Getting a renewable foundation under this vital substance could dramatically redraw the landscape of our energy market.