and «For the mining and retort process, the net energy return (NER) is very low if total energy inputs are counted (NER < 1.5)(Brandt 2006, 2007)... EROI for shale oil ranges above and below the break even point» (theoildrum.com)
In the third year, the fertilizer energy accounted for 84.6 percent of the total energy inputs, 8.57 times more than in the non-organic system. (fao.org)
In the second year, energy from organic fertilizers equalled 84.3 percent of the total energy inputs in the organic system, 5.64 times the fertilizer energy for the non-organic system. (fao.org)