The game calculates the total net energy used or produced by the players by using a life-cycle assessment approach that accounts for all the inputs and outputs based on their in-game decisions. The players have access to four variables on each field which reflect their energy production: crop yield, energy produced, energy expended, and net energy.

 

Crop Yield

The growth of switchgrass and corn in the midwest is largely limited by the availability of inorganic forms of nitrogen in the soil. To reflect this, the game models the yield of grass and corn as a function of the amount of available (inorganic) nitrogen.

 

 

Alfalfa is a legume, and as such forms a symbiotic relationship with nitrogen-fixing bacteria that remove nitrogen from the air and provide it to the alfalfa. For this reason, alfalfa growth is not limited by nitrogen availability, and is modeled differently than corn and grass.

 

 

Energy In

There are three primary aspects of crop production reflected in the game that require energy inputs; production, transportation, and refinement.

production

Production refers to the phase in which the crops are planted, grown and harvested, and is calculated using a combination of fixed and variable cost inputs.

NEED TABLE

transportation

Transportation costs are variable, and dependant on the yield of the crops you grow. It is assumed that whatever crop you grow, transporting the harvested crop to market requires 0.256 MJ of energy per kg of crop.

refinement

Refining the crop to ethanol requires some energy input as well. The game model assumes that alfalfa is not used for fuel, and therefore requires no refinement energy. Corn is assumed to require 12.58^† MJ of energy to produce 1 liter of ethanol, while switchgrass is produced at a rate of 3.1^† MJ/liter.

 

Energy Out

 

Net Energy

 

†Values obtained from the EBAMM 1.1 model

 

 

 

 

Field Level

At the field level, the player will have access to four energy calculations. These are: crop yield, energy produced, energy expended, and net energy. Each number, its unit, and its calculation function will be explained in a corresponding section below.

Crop Yield:

(Crop Yield content)

Energy Produced:

(Energy Produced content)

Energy Expended:

(Energy Expended content)

Net Energy:

(Net Energy content)

Farm Level

At the farm level, the player will have access to two energy graphs. The first of these charts the farm's yield for each crop, and the second charts the net energy produced via each crop. Each graph, its units, and its calculation function will be explained in a corresponding section below.

Crop Yield:

(Crop Yield content)

Net Energy:

(Net Energy content)