index Expo Renew Nonrenew 2source Slowren Factors Recycle Daypr

Growth on a Slowly Renewable Source


A slow inflow from a renewable source runs into a reserve tank. The consumers pump from this reserve tank, which reduces the storage in the reserve tank to a low level.


  • The way resources are supplying our high energy civilisation (reserve tank = storages of oil, gas, wood etc.)
  • Population of fishes in a reservoir behind a new dam that drowns a forest
  • Diagram


    J = inflow of slowly renewable energy
    E = energy stored in the reserve tank
    Q = stored energy
    K0 = decreasing factor of E
    K1 = increasing factor of Q
    K3 = decreasing factor of Q
    K4 = decreasing factor of E


    DE = J - K4*E - K0*E*Q
    DQ = K1*E*Q - K3*Q


    The graph shows the changes of E (blue) and Q(red) over a time period.
    Source code:

    "What if" Experiments:

  • What happens if the reserve tank is initially zero?
  • What would happen if there were no inflow?