Natural Resources & Energy — Science
- Grade 9 — Natural Resources: Renewable & Nonrenewable
- Grade 12 — Nonrenewable Energy & Fossil Fuels
- Grade 12 — Renewable Energy
- Grade 12 — Water & Land Resources
- Grade 12 — Mineral & Soil Resources
Apply it in a new setting
Problem 1
Hints
Capacity factor = average actual output ÷ maximum possible output.
Divide 45 MW by 150 MW.
Convert the decimal to a percent by multiplying by 100.
Answer and explanation
30 %
Capacity factor = average output ÷ nameplate capacity = 45 MW ÷ 150 MW.
45 ÷ 150 = 0.30.
0.30 × 100 = 30% (low because wind is intermittent).
Problem 2
Hints
Find the CO_2 saved per kWh first, then scale up to the whole year.
Per kWh saved = 2.2 − 0.9 = 1.3 lb.
Multiply that saving by 3,000,000 kWh.
Answer and explanation
3900000 lb
CO_2 avoided per kWh = 2.2 − 0.9 = 1.3 lb.
Over the year: 1.3 lb/kWh × 3,000,000 kWh.
1.3 × 3,000,000 = 3,900,000 lb of CO_2 avoided (though methane leaks can erode some of this gain).
Problem 3
- A large hydroelectric dam, since dams carry no environmental drawbacks
- A coal plant, because fossil fuels are renewable on a human timescale
- Solar panels with no storage, which would guarantee power right through the night
- Wind turbines paired with battery storage: the steady wind gives a high capacity factor, the turbines emit no CO_2 while running, and storage covers the calm spells
Hints
Match the resource to the island's conditions: steady wind, little land, no big rivers.
Watch for false claims in the distractors (dams with 'no drawbacks', coal as 'renewable', solar 'through the night').
Intermittency is handled by adding storage.
Answer and explanation
Wind turbines paired with battery storage: the steady wind gives a high capacity factor, the turbines emit no CO_2 while running, and storage covers the calm spells
No large rivers rules out hydro (and dams do have real drawbacks); coal is a nonrenewable fossil fuel, not renewable; solar makes nothing at night without storage.
Strong steady wind gives turbines a high capacity factor with zero operating CO_2, and batteries bridge the calm periods.
Wind plus storage is the best fit — D.
Problem 4
- Groundwater is renewable in principle, but withdrawing it faster than it recharges makes it behave like a nonrenewable resource that can run dry
- Because groundwater is renewable, it can never be depleted no matter how fast it is pumped
- Groundwater is strictly nonrenewable, so the pumping rate makes no difference to how long it lasts
- Pumping the water faster actually speeds up the aquifer's natural recharge
Hints
'Renewable' does not automatically mean unlimited — it depends on how fast you use it versus how fast it refills.
Compare the withdrawal rate to the recharge rate.
If you spend faster than the account refills, it drains.
Answer and explanation
Groundwater is renewable in principle, but withdrawing it faster than it recharges makes it behave like a nonrenewable resource that can run dry
An aquifer recharges slowly, so it is renewable only if withdrawals stay within that recharge rate.
Pumping faster than recharge drains it like a nonrenewable resource — pumping never speeds up recharge, and 'can never be depleted' is false.
Renewable in principle but drainable in practice is correct — A.
Problem 5
- Oil is actually spread evenly worldwide; the second country simply hasn't drilled deeply enough
- Ocean currents redeposit the world's oil into different countries every year
- The geologic history of each site — where ancient sediments were buried and heated just right — set where oil formed, long before any borders existed
- Governments decide where underground oil deposits appear
Hints
Oil forms only where specific geologic conditions occurred in the deep past.
Resource distribution is a fingerprint of ancient geology, not of modern borders.
It is neither even worldwide nor set by human choice.
Answer and explanation
The geologic history of each site — where ancient sediments were buried and heated just right — set where oil formed, long before any borders existed
Oil forms only where ancient organic-rich sediments were buried and heated to the right degree over millions of years.
That geologic history — not even global spread, ocean currents, or government decree — determines where deposits sit, regardless of where borders were later drawn.
The ancient-geology explanation is correct — C.
Problem 6
- Soil is renewable and reforms within a single growing season, so erosion is not a real concern
- On a human timescale soil is effectively nonrenewable, so practices like cover crops and no-till farming are needed to keep it from eroding faster than it forms
- Soil is a fossil fuel formed from ancient plankton, so it should be burned for energy
- Eroded topsoil instantly regrows to full depth after each rainfall
Hints
Compare how fast soil FORMS with how fast it can be LOST.
If it is lost far faster than it forms, it behaves like a nonrenewable resource on our timescale.
The right response is conservation that slows erosion.
Answer and explanation
On a human timescale soil is effectively nonrenewable, so practices like cover crops and no-till farming are needed to keep it from eroding faster than it forms
Soil forms far slower (centuries per centimeter) than it can erode (decades), so on a human timescale it is effectively nonrenewable.
That makes conservation — cover crops, no-till — essential to keep loss below the formation rate; soil is not a fuel and does not regrow in a season or after one rain.
Effectively nonrenewable, needing conservation, is correct — B.