11-CS-3 Engineering Management · December 2014
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams — December 2014 — 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.
| Technology | Geographic availability | Land requirement | Emissions | Cost | Safety concerns |
|---|---|---|---|---|---|
| High-head hydro | Low (needs terrain/rivers) | High (reservoir) | Low | Low (after build) | Medium–high (dam failure) |
| Geothermal (electricity) | Low (needs hot resource) | Low | Low | Medium–high | Low (gas release, induced seismicity) |
| Solar PV | High (sunlight widespread) | Medium–high | Low | Medium | Low (electrical) |
| Wind | Medium (needs windy sites) | Low footprint / high spacing | Low | Low–medium | Medium (blade/ice, birds) |
| Biofuel (wood pellets) | Medium (needs biomass) | High (forestry) | Medium | Medium | Medium (combustion, dust/fire) |
High-head hydro: limited to mountainous river sites (low availability); floods large reservoirs; low emissions; cheap once built; dam-failure risk. Geothermal electricity: restricted to regions with accessible high-temperature resources (low availability); compact; low emissions; costly deep drilling; minor gas-release and induced-seismicity concerns. Solar PV: sunlight is widely available (high); needs significant panel area; low operating emissions; medium (falling) cost; low electrical risk. Wind: needs consistently windy sites (medium availability); small footprint but wide spacing; low emissions; low–medium cost; blade/ice-throw and wildlife risks. Biofuel (wood pellets): depends on local biomass supply (medium); needs large forested land; combustion emits CO₂ and particulates (medium; nominally offset by regrowth); medium cost; combustion, dust-explosion, and fire hazards. The comparison highlights that hydro and geothermal are geographically constrained, while solar and wind are widely available but diffuse and intermittent.
Reading the table as a whole: no technology scores “low” on every heading, so the choice is a trade-off. Hydro, geothermal and wind have the lowest life-cycle emissions (a few to a few tens of g CO₂e/kWh, mostly embodied in construction), while wood-pellet heating has the highest stack emissions of particulates and CO and is only carbon-neutral if the harvested forest regrows. Solar PV and wind are variable, so their system-level cost rises once storage or backup is counted; reservoir hydro and geothermal are dispatchable, which is why British Columbia’s hydro-dominated grid can firm new wind and solar. In a Canadian context the dominant safety concern for large hydro is dam safety (the Canadian Dam Association guidelines), while pellet heating plants need attention to CO build-up in pellet storage and to dust-explosion control.
