11-CS-3 Engineering Management · May 2013
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
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.
The table below summarizes the comparison. The question asks for values for cost and for how long the resource will last, and high/medium/low ratings with an explanation for the remaining categories. Costs are given as indicative levelized costs of electricity (LCOE) in Canadian cents per kilowatt-hour at the time of the examination; resource duration is the reserves-to-production life at present rates of consumption. Exact figures vary between textbook editions, so the ranges below should be read as order-of-magnitude values and the ranking they produce is what matters.
| Method | Relative cost | Resource duration | Local air pollution | Hazardous waste | Global-warming potential |
|---|---|---|---|---|---|
| Coal | ~6–10 ¢/kWh (low–medium) | ~110–200 yr of proven reserves (finite) | High | Medium (ash, heavy metals) | High |
| Nuclear fission | ~9–14 ¢/kWh (medium–high) | ~80–100 yr of conventional uranium reserves; centuries to millennia with reprocessing/breeding | Low | High (radioactive waste) | Low |
| Photovoltaic solar | ~15–25 ¢/kWh in 2013, falling rapidly (medium–high) | Effectively unlimited (renewable); panel service life ~25–30 yr | Low | Medium (manufacturing solvents, end-of-life panels) | Low |
| Hydroelectric | ~4–9 ¢/kWh, very low once built (low) | Effectively unlimited (renewable); dam life 50–100+ yr, limited by remaining sites rather than by fuel | Low | Low | Low |
| Wind | ~7–12 ¢/kWh (low–medium) | Effectively unlimited (renewable); turbine service life ~20–25 yr | Low | Low | Low |
Coal: historically cheap fuel but a finite fossil resource lasting on the order of one to two centuries at present consumption. Local air pollution is high—it emits SOₓ, NOₓ, particulates, and mercury. Hazardous waste is medium: large volumes of fly ash and bottom ash containing heavy metals. Global-warming potential is high: it is the most carbon-intensive major source, emitting roughly 1 kg CO₂ per kWh.
Nuclear fission: high capital cost but a long-lasting fuel resource. Local air pollution is low (no combustion products). Hazardous waste is high—spent fuel is intensely radioactive and requires isolation for thousands of years. Global-warming potential is low: essentially no operational CO₂.
Photovoltaic solar: higher unit cost (falling rapidly) but an unlimited renewable resource. Local air pollution is low in operation. Hazardous waste is medium: cell manufacturing uses toxic solvents and some panels contain trace hazardous elements, and end-of-life panel disposal is a growing concern. Global-warming potential is low (small manufacturing footprint only).
Hydroelectric: low operating cost after the dam is built and a renewable resource. Local air pollution is low; hazardous waste is low. Global-warming potential is low, though reservoir flooding can release some methane and has significant ecological and land-use impacts not captured in these five columns.
Wind: increasingly low cost and an unlimited renewable resource, with low air pollution, low hazardous waste, and low global-warming potential; its main drawbacks are intermittency and land/visual/wildlife impacts.
