Demand Side Management Questions and Answers

Answer: A

Correct answer: a saving of 8000

The peak rate is three times four, or twelve, so shifting a unit saves the difference: \[ 1000 \times (12 - 4) = 8{,}000. \] The saving is the difference between the rates rather than the peak rate itself - the energy is still bought, merely at the cheaper time, which is why 12,000 is wrong.

Answer: B

The first two are correct and the second is the objective that surprises people. A diversity factor exceeds one because the sum of the individual peaks always exceeds the group peak; it is the coincidence factor that is below one.

Answer: C

The load curve says when the system is short, the avoided cost says what relief is worth, that budget determines what programme and incentive can be afforded, and the evaluation establishes what was actually delivered.

Answer: D

Correct answer: reducing the losses in the transmission network

The recognised load shape objectives are peak clipping, valley filling, load shifting, strategic conservation, strategic load growth and flexible load shape - all of them changes to the shape of the load curve. Loss reduction is a network measure achieved by other means and is not a load shape objective.

Answer: A

Correct answer: a new industrial load operating only during the afternoon peak

A load falling entirely in the peak hour raises the peak and the average by the same amount in energy terms, but the peak is the denominator of the load factor, so the ratio falls. The other three either fill the valley or clip the peak, and both raise the load factor.

Answer: B

Correct answer: loss of diversity as every controlled load switches together

A tariff beginning at a fixed hour causes every timer and every controller to act at that instant, so loads which had been naturally spread now coincide exactly. The remedy is randomisation - staggering the start times across the population - which restores the diversity the tariff destroyed.

Answer: C

Correct answer: free riders who would have acted without the incentive

The gap between gross and net is the saving that would have occurred anyway, and here it amounts to 40 per cent - a high but not unusual free rider rate for a measure consumers had reason to take in any case. Reducing it means targeting the incentive at those who would not otherwise act.

Answer: D

A megawatt of peak relief avoids the station, the lines and the substation capacity together, and the sum of those is what a programme is compared against. That breadth of avoided cost is exactly why the comparison so often favours the demand side.

Answer: A

Consumers do respond to price, which is what the reason states, but shifting moves the consumption to another hour rather than removing it, so the units sold are very nearly unchanged. It is conservation that reduces sales.

Answer: B

A generator built for fifty hours a year carries its capital cost for all 8760, whereas the contract is paid a retainer and an energy rate only when used. Its reliability is generally lower than a generator's, which is the trade.