Understanding how fossil fuel consumption has changed over time — and why it cannot continue indefinitely — is central to evaluating the need for a sustainable energy transition.
| Era | Key Trend |
|---|---|
| Pre-Industrial (<1800) | Energy from biomass, wind, water, animal power |
| Industrial Revolution (1800–1900) | Coal becomes dominant — powers steam engines, manufacturing |
| Early 20th century (1900–1950) | Oil rises — internal combustion engine; petrol era begins |
| Post-WWII boom (1950–2000) | Rapid growth in all fossil fuels; electrification; natural gas expansion |
| 2000–present | Continued fossil fuel use; renewable growth accelerating; global CO$_2$ still rising |
Peak oil is the point in time when global (or regional) oil extraction reaches its maximum rate, after which it inevitably declines as reserves are depleted.
American geologist M. King Hubbert (1956) proposed that oil production from any given region follows a bell-shaped curve:
$$\text{Production}(t) = P_{max} \cdot \text{sech}^2\left(\frac{t - t_{peak}}{k}\right)$$
(A bell-shaped logistic curve)
Historical application: Hubbert correctly predicted that US lower-48 oil production would peak around 1970 (it did). However, he did not anticipate unconventional oil (tight oil, oil sands, deep-water drilling) extending production.
| Type | Description | Energy Return on Investment (EROI) |
|---|---|---|
| Conventional oil | Easily extracted; flows under own pressure or simple pumping | ~20:1 historically; declining |
| Tight oil (fracking) | Hydraulically fractured shale formations | ~5–10:1 |
| Oil sands (tar sands) | Bitumen extracted from sands; energy-intensive processing | ~3–5:1 |
| Deep-water oil | Deep ocean wells; high technology cost | ~10–15:1 |
EROI (Energy Return on Investment): Ratio of energy produced to energy consumed in extraction. As EROI declines, more energy must be invested to get less energy out — economically and environmentally less favourable.
This remains debated:
- Conventional oil production peaked around 2005–2006
- Unconventional sources (US tight oil boom from fracking, ca. 2010–2015) pushed global production to new highs
- Some analysts argue demand peak oil (demand falling due to electric vehicles and renewable energy) is a greater constraint than supply
Key principle regardless of timing: Oil is a finite resource — a peak and eventual decline is inevitable. The question is not if, but when, and what the world does in the transition period.
| Impact | Description |
|---|---|
| Price volatility | As remaining reserves become harder to extract, prices increase |
| Energy security | Nations dependent on imports face strategic vulnerability |
| Economic disruption | Industries built around cheap fossil fuels face structural change |
| Environmental | Accessing more marginal reserves involves greater ecological risk (deep-water drilling, Arctic extraction) |
| Climate urgency | A fossil fuel supply peak may come too late to prevent dangerous climate change — demand reduction through policy is needed sooner |
VCAA FOCUS: ‘Peak oil’ refers specifically to the maximum rate of production, not the total quantity remaining. It does not mean oil is ‘running out tomorrow’ — it means the rate of extraction cannot increase indefinitely. Draw and annotate a Hubbert curve to demonstrate understanding.
