Energy Conservation in Industry Questions and Answers

Answer: A

Correct answer: output of product

Specific energy consumption is energy per unit of output, and it is that ratio rather than the absolute figure that measures efficiency. Dividing by capacity, headcount or turnover would give a number that moves with things having nothing to do with how well energy is used - which is why the denominator must be physical product.

Answer: B

Fixed loads such as lighting, ventilation and idling plant continue whatever the output, so cutting production spreads them over fewer tonnes. It is the commonest reason a recession appears to make a plant less efficient.

Answer: C

A different grade of product or a lower loading changes the figure without any change in how well the plant is run. The scheme that regulates designated consumers builds normalisation factors in for exactly this reason.

Answer: D

Weighting each grade by its energy requirement and expressing the total against a nominal standard grade removes the product mix from the comparison. Without it a shift toward a heavy grade reads as a loss of efficiency.

Answer: A

Definitions of the boundary, the product and the energy included differ from company to company, so a published figure may not mean what it appears to. Sector studies exist precisely to place everyone on the same basis.

Answer: B

It is the standard against which a replacement decision is judged, and the gap between it and the present plant is the ceiling on what any retrofit could deliver. The thermodynamic minimum is lower still and unreachable.

Answer: C

The threshold is set separately for each notified sector in units of oil equivalent, so a large cement works and a large textile mill are caught at different consumptions. Designation brings reporting and target obligations with it.

Answer: D

Correct answer: at the intervals the regulations prescribe

The audit obligation is periodic and stated in the rules, so it does not wait on a missed target or an inspector’s order. The purpose is to keep the plant’s own understanding of its consumption current, and an audit carried out only after a failure would come too late to prevent one.

Answer: A

The target is expressed per unit of output, so a plant that grows its production is not penalised and one that shrinks gains nothing. Targets differ between plants according to how far each already is from the sector's best.

Answer: B

Correct answer: the plants furthest from best practice must improve most

Targets are differentiated by how far each plant already stands from the sector’s best practice, so an efficient plant is asked for little and an inefficient one for a great deal. A uniform percentage would penalise the plant that had already invested and let the laggard continue, which is the opposite of what the scheme is for.