Vehicle-to-Grid Technology Project From Idea to Viva

import numpy as np
rng = np.random.default_rng(7)
N, CAP, P_AC = 500, 40.0, 7.0                    # fleet size, kWh, kW per charger
RESERVE, SOC_MIN, ETA = 0.30, 0.20, 0.95         # driver reserve, floor, one-way efficiency
HOURS = np.arange(24)

# --- synthetic residential fleet: evening arrival, morning departure --------------------
arr = np.clip(rng.normal(18.5, 1.6, N), 15, 23).astype(int)
dep = np.clip(rng.normal(7.5, 1.0, N), 5, 10).astype(int)
soc_arr = np.clip(rng.normal(0.45, 0.15, N), 0.15, 0.85)
plug_prob = 0.85                                  # not every car is plugged in
plugged = rng.random(N) < plug_prob

def present(h, a, d):                             # plugged-in window wraps past midnight
    return (h >= a) | (h < d)

up, down, n_on = np.zeros(24), np.zeros(24), np.zeros(24, int)
for h in HOURS:
    mask = plugged & present(h, arr, dep)
    n_on[h] = mask.sum()
    # SOC at hour h if the car charged from arrival at P_AC (simple baseline)
    hrs_plugged = np.where(h >= arr, h - arr, h + 24 - arr)
    soc = np.minimum(0.95, soc_arr + ETA * P_AC * hrs_plugged / CAP)
    can_dis = mask & (soc > RESERVE + 0.05)       # export only above reserve
    can_chg = mask & (soc < 0.90)
    up[h]   = can_dis.sum() * P_AC                # kW the fleet can inject
    down[h] = can_chg.sum() * P_AC                # kW the fleet can absorb

print(f"{&#x27;hour':>4} {'plugged':>8} {'V2G up (kW)':>12} {'absorb (kW)':>12}")
for h in [0, 3, 6, 9, 12, 15, 18, 19, 20, 21, 22, 23]:
    print(f"{h:04d} {n_on[h]:8d} {up[h]:12.0f} {down[h]:12.0f}")
print(f"\nPeak injectable power : {up.max():.0f} kW at {up.argmax():02d}:00  ({up.max()/(N*P_AC):.0%} of nameplate)")
print(f"Energy exportable 18-22h (at 20 % participation): {0.2*up[18:22].sum():.0f} kWh")
print(f"Average availability   : {n_on.mean():.0f} of {N} vehicles plugged in")

hour  plugged  V2G up (kW)  absorb (kW)
0000      429         3003           91
0003      429         3003            0
0006      303         2121            0
0009        2           14            0
0012        0            0            0
0015       27          112          189
0018      297         1820         1827
0019      373         2450         2044
0020      415         2814         1799
0021      426         2919         1169
0022      429         3003          553
0023      429         3003          252

Peak injectable power : 3003 kW at 00:00  (86% of nameplate)
Energy exportable 18-22h (at 20 % participation): 2001 kWh
Average availability   : 236 of 500 vehicles plugged in