Which according to thermo, is about as much as we got out of burning them, assuming 100% efficiency. I think there's a little bit of wiggle room if you can find a low energy compound to turn it into, but it's still going to be a lot. And it can't be a neutralized acid like formate or bicarbonate. Maybe add H2 and do some electrochem to make oxalic acid? It's a powder, which would be a bonus for disposal.