Energy Conservation in Industry Questions and Answers

Answer: A

Correct answer: both the assertion and the reason are true and the reason explains the assertion

Both are true and the reason gives the necessity. A plant running at part load or making a different product mix will show a different specific consumption without any change in how well it uses energy, so an unnormalised comparison against a benchmark measures the circumstances rather than the performance. Normalisation removes those effects before the comparison is made.

Answer: B

Correct answer: the assertion is false although the reason offered is a true statement in itself

The reason is true - the plant does pay for the absolute quantity - but it does not support the assertion. Efficiency is energy per unit of output, and absolute consumption can fall because production fell or rise because production rose, in neither case saying anything about how well energy was used.

Answer: C

Correct answer: delivers sooner but needs continuing discipline

Housekeeping - switching off idle machines, repairing leaks, correcting set points - costs little and delivers almost at once, but every one of those savings can be lost again by inattention. A capital project delivers more slowly and requires sanction, but once the equipment is installed the saving persists without anyone having to remember it.

Answer: D

Correct answer: appointing a certified energy manager

A designated consumer must appoint a certified energy manager, have periodic audits carried out, report its consumption and meet its target. Buying renewable certificates and self-generating a share of its electricity are obligations under other schemes entirely, and publishing the specific consumption in the annual report is not among the requirements.

Answer: C

The objectives of energy management are to minimise energy wastage, to minimise environmental effects of energy use, and to achieve and maintain optimum energy utilisation at the lowest possible cost. So maximising the cost of energy is the opposite of an objective, since good management aims to reduce the cost of energy for a given output. The answer is option C.

Answer: B

Energy used is power times time. The heater has a rating of 5 kW at the rated voltage of 230 V, so running for one hour at the rated voltage

\[ \begin{aligned} E = P \times t = 5\ \text{kW} \times 1\ \text{h} \\ &= 5\ \text{kWh} \end{aligned} \]

The voltage rating does not change the answer when the heater is run at its rated voltage. The value 2.5 kWh would be for half an hour, and 1 kWh and 0.5 kWh have no basis. The answer is option B.

Answer: B

Using maximum daylight, switching off appliances when they are not in use and getting an energy audit done all reduce the consumption of energy. An LED bulb gives the same light for about one fifth to one eighth of the power of an incandescent bulb, so replacing LED bulbs with incandescent bulbs would waste energy and does not support conservation. The answer is option B.

Answer: D

The key gives rubber as the production unit that does not produce a substantial waste product. Paper mills (black liquor and sludge), aluminium smelting (red mud and spent pot lining) and glass making (cullet and dust) are all taken to have large waste streams, while rubber processing is considered a lesser waste producer here, since scrap rubber is mostly reused or recycled. This is a matter of the setter's classification and I could not confirm it from an independent source. The explanation follows the key, option D.

Answer: A

The key gives wood as the sector that does not have the potential to raise energy savings by more than 10 per cent through recycling. Recycling aluminium saves about 95 per cent of the energy needed to make it from ore, steel recycling saves about 60 to 75 per cent, and recycling plastics also saves a large share of the energy of making it from raw materials, so all three offer more than 10 per cent. Recycled wood products do not give such a large saving in the energy audit figures that the setter has in mind, so wood is the exception. The explanation follows the key, option A.

Answer: A

The barriers to implementing industrial end use energy efficiency that an energy audit lists are economic and financial (the cost of the investment), regulatory (rules and tariffs that discourage savings) and informational (a lack of data and awareness). The key gives technical as the one that is not a barrier, since the efficiency technologies are mostly available and proven, so the difficulty is not that the technology does not exist. This is the setter's view and not a fixed rule, and the explanation follows the key, option A.