23-CS-3 Sustainability, Engineering and the Environment · December 2013
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams — December 2013 — 11-CS-3 Sustainability, Engineering and the Environment. Open book; non-communicating calculator permitted. Any four questions constitute a complete paper; all questions are of equal value (25 marks each).
Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.
| Technology | Land requirement | Cost | Noise | Emissions | Safety concerns |
|---|---|---|---|---|---|
| Solar PV | Medium–high | Medium | Low | Very low (operation) | Low; electrical, some toxic manufacturing materials |
| Wind | Low (footprint)/High (spacing) | Low–medium | Medium | Very low (operation) | Blade throw, ice, bird/bat strikes |
| Hydroelectric | High (reservoir) | Low (after build) | Low | Low (some reservoir methane) | Dam failure/flooding risk |
| Geothermal (heating) | Low | Medium (drilling) | Low | Very low | Low; drilling, minor gas release |
| Biofuel (liquid) | High (cropland) | Medium | Low | Moderate (combustion + farming) | Flammability; food-vs-fuel land use |
Solar PV: needs a medium-to-high area of panels for utility scale (though rooftops use existing space); moderate cost (falling); essentially silent; near-zero operating emissions but some toxic solvents and end-of-life panel waste; low safety risk beyond electrical hazards. Wind: turbines themselves occupy little ground (land between them remains usable) but require wide spacing; low-to-moderate and falling cost; audible aerodynamic and mechanical noise (a medium concern near homes); near-zero operating emissions; safety concerns include ice/blade throw and wildlife (bird and bat) strikes. Hydroelectric: reservoirs flood large land areas (high); very low operating cost once built; quiet; low emissions though flooded vegetation can release methane; the dominant safety concern is catastrophic dam failure. Geothermal for building heating: a small surface footprint (ground loops or wells); medium cost driven by drilling; quiet; very low emissions; low risk aside from drilling and occasional gas release. Liquid biofuel: demands large areas of cropland (high) and competes with food production; medium cost; low noise; only moderately "clean"—combustion emits CO₂ (nominally offset by crop uptake) and farming adds fertilizer and fuel emissions; safety concerns are fuel flammability and the food-versus-fuel land-use dilemma.
