23-CS-3 Sustainability, Engineering and the Environment · May 2015
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams — May 2015 — 11-CS-3 Sustainability, Engineering and the Environment. Closed book; approved 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.
Rating convention: each cell rates the magnitude of the heading as worded — H for geographic availability means the resource is widely available (favourable); H for land requirement, life-cycle emissions, cost or safety concerns means a large requirement, emission, cost or concern (unfavourable). Where a technology genuinely spans two bands (e.g. wind: small physical footprint but wide turbine spacing) both are shown.
| Technology | Geographic availability | Land requirement | Life-cycle emissions | Cost | Safety concerns |
|---|---|---|---|---|---|
| High-head hydro | L (needs terrain) | H (reservoir) | L | L (after build) | M–H (dam failure) |
| Geothermal (electricity) | L (needs hot resource) | L | L | M–H | L (gas, seismicity) |
| Solar PV | H (sunlight widespread) | M–H | L–M (manufacturing) | M | L (electrical) |
| Wind | M (needs windy sites) | L footprint / H spacing | L | L–M | M (blade/ice, birds) |
| Biofuel (wood pellets) | M (needs biomass) | H (forestry) | M | M | M (combustion, dust/fire) |
High-head hydro: restricted to mountainous river sites; floods large reservoirs; low life-cycle emissions; cheap once built; dam-failure risk. Geothermal electricity: limited to high-temperature resource areas; compact; low emissions; costly deep drilling; minor gas/seismicity concerns. Solar PV: sunlight widely available; needs panel area; low emissions with some manufacturing footprint; medium cost; low electrical risk. Wind: needs windy sites; small footprint but wide spacing; low emissions; low–medium cost; blade/ice and wildlife risks. Biofuel pellets: depends on biomass supply; large forestry land; combustion emits CO₂ and particulates (nominally offset by regrowth); medium cost; combustion, dust-explosion, and fire hazards. Hydro and geothermal are geographically constrained; solar and wind are widely available but diffuse and intermittent. In a Canadian setting the pattern is visible directly: large high-head hydro dominates in B.C. and Québec where the terrain allows it, high-temperature geothermal is confined to a few volcanic-belt prospects in western B.C. and the Yukon, and wood-pellet heating is most attractive in forested regions with sawmill residue. Overall, wind and solar PV score best across the five headings (low emissions, low-to-moderate safety concern, falling cost), hydro is excellent where sites exist but carries the largest land and dam-safety burden, and biomass heating is the weakest on land use and local air quality.
