// We have to ensure that there are enough batteries to
// support the shift schedule. There must be at least enough batteries to
// supply the two largest adjacent shifts, and there must also be enough
// to power the two largest adjacent shifts, in case a single battery
// cannot power an entire shift.
void validateBatteries() {
int minBatteries = 0;
Shift s1 = null;
Shift s2 = null;
for (int i = 0; i < shiftSchedule.length; i++) {
Shift s = shiftSchedule[i];
if (null == s) {
s1 = s2;
} else if (s2 != s) {
s1 = s2;
s2 = s;
if (null != s1) {
int n1 = s1.getTrucks();
int d1 = s1.getDuration();
int n2 = s2.getTrucks();
int d2 = s2.getDuration();
double neededBatteries = (n1 * d1 + n2 * d2) * truckKW / getBatteryCapacity();
minBatteries = (int) Math.max(minBatteries, (n1 + n2));
minBatteries = (int) Math.max(minBatteries, Math.ceil(neededBatteries));
}
}
}
int neededBatteries = minBatteries - nBatteries;
if (neededBatteries > 0) {
log.error("Not enough batteries (" + nBatteries + ") for " + getName());
// Add discharged batteries to fill out battery complement
log.warn("Adding " + neededBatteries + " batteries for " + getName());
setNBatteries(getNBatteries() + neededBatteries);
}
}
// ======== per-timeslot activities ========
@Override
public void step() {
// check for end-of-shift
Shift newShift = shiftSchedule[indexOfShift(getNowInstant())];
if (newShift != currentShift) {
log.info(getName() + " start of shift");
// Take all batteries out of service
double totalEnergy = getEnergyCharging() + getEnergyInUse();
setEnergyCharging(getEnergyCharging() + getEnergyInUse());
setCapacityInUse(0.0);
setEnergyInUse(0.0);
// Put the strongest batteries in trucks for the next shift
if (null != newShift) {
setCapacityInUse(newShift.getTrucks() * batteryCapacity);
setEnergyInUse(Math.min(getCapacityInUse(), totalEnergy));
setEnergyCharging(totalEnergy - getEnergyInUse());
}
log.info(
getName()
+ ": new shift cInUse "
+ capacityInUse
+ ", eInUse "
+ energyInUse
+ ", eCharging "
+ energyCharging);
currentShift = newShift;
}
// discharge batteries on active trucks
if (null != currentShift) {
double usage = Math.max(0.0, normal.sample() * truckStd + truckKW * currentShift.getTrucks());
double deficit = usage - getEnergyInUse();
log.debug(getName() + ": trucks use " + usage + " kWh");
if (deficit > 0.0) {
log.warn(getName() + ": trucks use more energy than available by " + deficit + " kWh");
addEnergyInUse(deficit);
addEnergyCharging(-deficit);
}
addEnergyInUse(-usage);
}
// use energy on chargers, accounting for regulation
double regulation = getSubscription().getRegulation();
log.info(getName() + ": regulation " + regulation);
double energyUsed = useEnergy(regulation);
// Record energy used
getSubscription().usePower(energyUsed);
log.info(
getName()
+ " cInUse "
+ capacityInUse
+ ", eInUse "
+ energyInUse
+ ", eCharging "
+ energyCharging);
}
ShiftEnergy(Instant start, int end, int duration) {
super();
this.start = start;
this.endIndex = end;
Shift next = shiftSchedule[end];
if (null != next) {
energyNeeded = next.getTrucks() * next.getDuration() * getTruckKW();
}
this.duration = duration;
}
// Computes constraints on future energy needs
// Amounts are energy needed to run the chargers. Energy input to trucks
// will be smaller due to charge efficiency.
ShiftEnergy[] getFutureEnergyNeeds(Instant start, int horizon, double initialCharging) {
Instant seStart = start;
int index = indexOfShift(start);
// current time is likely to be partway into first shift
Shift currentShift = shiftSchedule[index]; // might be null
int duration = 0;
while (shiftSchedule[index] == currentShift) {
duration += 1;
index = nextShiftIndex(index);
}
Shift nextShift = shiftSchedule[index];
// this gives us the info we need to start the sequence
ArrayList<ShiftEnergy> data = new ArrayList<ShiftEnergy>();
data.add(new ShiftEnergy(seStart, index, duration));
seStart = seStart.plus(duration * TimeService.HOUR);
int elapsed = duration;
// add shifts until we run off the end of the horizon
// keep in mind that a shift can be null
while (elapsed < horizon) {
duration = 0;
while (nextShift == shiftSchedule[index]) {
index = nextShiftIndex(index);
duration += 1;
}
nextShift = shiftSchedule[index];
data.add(new ShiftEnergy(seStart, index, duration));
elapsed += duration;
seStart = seStart.plus(duration * TimeService.HOUR);
}
// now we convert to array, then walk backward and fill in energy needs
ShiftEnergy[] result = data.toArray(new ShiftEnergy[data.size()]);
double shortage = 0.0;
for (int i = result.length - 1; i >= 0; i--) {
int endx = result[i].endIndex;
int prev = previousShiftIndex(endx);
currentShift = shiftSchedule[prev];
Shift end = shiftSchedule[endx];
double needed = 0.0;
if (null != end) {
// Assume we need, at the end of each shift, enough energy to
// run the next shift
needed = (end.getTrucks() * end.getDuration() * getTruckKW()) / getChargeEfficiency();
}
// chargers is min of charger capacity and battery availability
int chargers = getNChargers();
int availableBatteries = nBatteries;
if (null != currentShift) {
availableBatteries -= currentShift.getTrucks();
}
chargers = (int) Math.min(chargers, availableBatteries);
double available =
getMaxChargeKW() * result[i].getDuration() * chargers / getChargeEfficiency();
double surplus = available - needed - shortage;
shortage = Math.max(0.0, -(available - needed - shortage));
result[i].setEnergyNeeded(needed);
result[i].setMaxSurplus(surplus);
}
// finally, we need to update the first element with
// the current battery charge.
double finalSurplus = result[0].getMaxSurplus();
if (finalSurplus > 0.0) {
result[0].setMaxSurplus(finalSurplus + initialCharging);
} else if (shortage > 0.0) {
result[0].setMaxSurplus(initialCharging - shortage);
}
return result;
}
// make sure we have enough charging capacity to support
// the shift schedule
void validateChargers() {
// ToDo -- A single charging should be able to charge a truck worth
// of batteries in a single shift
// The total output of the availableChargers should be at least enough
// to power the trucks over a 24-hour period. Note that the shift schedule
// starts at midnight, which may not be the start of the current shift.
double maxNeeded = 0.0;
int offset = 0;
while (null == shiftSchedule[offset]) {
offset += 1;
}
Shift currentShift = shiftSchedule[offset];
int remainingDuration = 0;
int hoursInShift = (HOURS_DAY - currentShift.getStart()) % HOURS_DAY;
remainingDuration = currentShift.getDuration() - hoursInShift;
for (int i = offset; i < (shiftSchedule.length - HOURS_DAY); i++) {
double totalEnergy = 0.0;
Shift thisShift = shiftSchedule[i];
if (thisShift != currentShift) {
currentShift = thisShift;
if (null != currentShift) {
// first block of energy in 24h window starting at i
remainingDuration = currentShift.getDuration();
}
}
if (null != currentShift) {
totalEnergy += currentShift.getTrucks() * remainingDuration * truckKW;
}
// now run fwd 24h and add energy from future shifts
Shift current = currentShift;
// int shiftStart = i;
for (int j = i + 1; j < (i + HOURS_DAY); j++) {
Shift newShift = shiftSchedule[j];
if (null != newShift && current != newShift) {
int durationInWindow = (int) Math.min((i + HOURS_DAY - j), newShift.getDuration());
totalEnergy += newShift.getTrucks() * durationInWindow * truckKW;
current = newShift;
}
}
maxNeeded = Math.max(maxNeeded, totalEnergy);
remainingDuration -= 1;
}
double chargeEnergy = nChargers * maxChargeKW * HOURS_DAY;
if (maxNeeded > chargeEnergy) {
double need = (maxNeeded - chargeEnergy) / (maxChargeKW * HOURS_DAY);
int add = (int) Math.ceil(need);
log.error(
"Insufficient charging capacity for "
+ getName()
+ ": have "
+ chargeEnergy
+ ", need "
+ maxNeeded
+ ". Adding "
+ add
+ " availableChargers.");
setNChargers(getNChargers() + add);
}
}
