- Energy source & Energy content & Renewability & Environmental impacts of extraction & Environmental impacts of combustion & Key combustion equation/s \\ \hline
- Coal (brown/black) & Low (black: 34 kJ/g, brown: 16 kJ/g) & Very low - produced by fossilised plant material (thousands of years) & Destruction of vegetation, pollution due to mine waste (tailings etc), greenhouse emmissions from transport \& mining machinery & Acid rain (\ce{SO2}), greenhouse gas emmission & \\ \hline
- Crude oil & & & Transport by road \& sea releases greenhouse gases.
- & Toxic \ce{CO} with incomplete combustion, & Complete: \ce{2C16H34(l) + 49O2(g) -> 32CO2(g) + 34H2O(g)} Incomplete: \ce{2C16H34(l) + 17O2(g) -> 32C(s) + 34H2O(g)} \\ \hline
- Petroleum gas & 48 kJ/g & Refinement causes hydrocarbon pollution of air. & & Uncombusted hydrocarbons may be released (\ce{CO}), causing photochemical smog.
- & Complete: \hspace{2em} \ce{2C8H18(l) + 25O2(g) -> 16CO2(g) + 18H2O(g)} Incomplete: \ce{2C8H18(l) + 17O2(g) -> 16CO(g) + 18H2O(g)}\\ \hline
- Coal seam gas & $\approx$ 54 kJ/g (nat. gas)& & Destruction of vegetation \& geology (drilling), pollution of aquifers & Greenhouse gas emmissions & Methane: \hspace{4em}\ce{CH4(g) + 2O2(g) -> CO2(g) + 2H2O(g)} \\ \hline
- Biogas & Relatively inefficient & & & & \\ \hline
- Bioethanol & & & & & \\ \hline
- Biodiesel & & Very renewable – sourced from used cooking oil, tallow, oil seed crops & Consumption of waste (landfill reduction). Less space for agriculture \& forests. Biodegradable. Byproducts (glycerol) can be used elsewhere. & & \begin{align*}\ce{\\C17H29COOCH3(l) + 26O2(g)\\ -> 19CO2(g) + 16H2O(g)}\end{align*} \\ \hline
+ \textbf{Energy source} & \textbf{Energy content} & \textbf{Renewability} & \textbf{Environmental impacts of extraction} & \textbf{Environmental impacts of combustion} & \textbf{Key combustion equation/s} \\ \hline
+ Coal (brown/black) & Black: 34 kJ/g; Brown: 16 kJ/g & Non-renewable - produced by fossilised plant material (millions of years) & Destruction of vegetation, pollution due to mine waste, greenhouse emissions from transport \& mining machinery & Acid rain (\ce{SO2}), greenhouse gas emissions (accelerates climate change), air pollution (e.g. smog) & Complete: \ce{C(s) + O2(g) -> CO2(g)} \newline Incomplete: \ce{2C(s) + O2(g) -> 2CO(g)}\\ \hline
+ Crude oil & 30 kJ/g& Non-renewable - organisms fossilised over millions of years. Limited worldwide supply& Transport by road \& sea releases greenhouse gases.
+ & Toxic \ce{CO} with incomplete combustion, produces \ce{CO2} contributing to climate change. & Complete: \ce{2C16H34(l) + 49O2(g) -> 32CO2(g) + 34H2O(g)} \newline Incomplete: \ce{2C16H34(l) + 17O2(g) -> 32C(s) + 34H2O(g)} \\ \hline
+ Petroleum gas & 48 kJ/g & Non-renewable (derived from crude oil) & Refinement causes hydrocarbon pollution of air & Uncombusted hydrocarbons may be released (\ce{CO(g)}), causing photochemical smog.
+ & Complete: \ce{2C8H18(l) + 25O2(g) -> 16CO2(g) + 18H2O(g)}; $\Delta H = 5.51$ MJ/mol octane \newline Incomplete: \ce{2C8H18(l) + 17O2(g) -> 16CO(g) + 18H2O(g)}\\ \hline
+ Coal seam gas & $\approx54$ kJ/g (nat. gas)& Non-renewable (byproduct of natural coal production) & Destruction of vegetation \& geology (drilling), pollution of aquifers & Greenhouse gas emissions & Methane (complete): \hspace{4em}\ce{CH4(g) + 2O2(g) -> CO2(g) + 2H2O(g)} \\ \hline
+ Biogas & 26 kJ/g & Very renewable - sourced from anaerobically decaying organic waste (e.g. manure). Currently low worldwide supply. & Relief of landfill. Reduces air pollution from waste. May require damaging boring \& trenching. & Low odour \& smoke. Produces greenhouse gases like other methane-based fuels. & Methane (complete): \hspace{4em}\ce{CH4(g) + 2O2(g) -> CO2(g) + 2H2O(g)} \\ \hline
+ Bioethanol & 30 kJ/g& Very renewable - sourced from fermented sugars (e.g. wheat starch, molasses). Combining with E10 reduces renewability. & Comsumption of agricultural waste (landfill reduction). More land dedicated to bioethanol sources, less for food agriculture. & Produces \ce{CO(g)} and hydrocarbons (greenhouse gases) without E10. Produces \ce{CO2(g)} with E10. Can corrode engines (high water retention).& \ce{C2H5OH(l) + 3O2(g) -> 2CO2(g) + 3H2O(l)}; $\Delta H = 1370$ kJ/mol \\ \hline
+ Biodiesel & 42 kJ/g& Very renewable - sourced from used cooking oil, tallow, oil seed crops & Consumption of waste (landfill reduction). Less space for agriculture \& forests. Biodegradable. Byproducts (glycerol) can be used elsewhere. & Similar to petrodiesel - produces \ce{CO2(g)} (greenhouse gas), contributing to air pollution \& climate change & \ce{C17H29COOCH3(l) + 26O2(g) -> 19CO2(g) + 16H2O(g)} \\ \hline