Biofuels & bioenergy
Biomass is stored photosynthesis, and every route to fuel starts by paying to take its polymer framework apart.
Biomass stores recent carbon in tough polymers, and the whole cluster rests on one fact: before any fuel molecule exists, a toll is paid to take that structure apart. The cluster’s key quantity is lignocellulose recalcitrance — the cost of opening the polymer matrix. It splits every route into two families: biochemical (microbes build molecules selectively, but demand an accessible substrate) and thermochemical (will accept almost any feedstock, but destroys the molecule wholesale).
Three ideas recur from page to page. First, the trade between selectivity and throughput: the more precise the path to a target molecule, the fussier the feedstock. Second, water as the boundary between the families: wet biomass naturally goes to anaerobic digestion, dry biomass to gasification. Third, compatibility with infrastructure: a fuel is valuable not in itself but as a molecule that existing engines, pipelines and standards will accept.
Start with biomass for energy: it sets the route vocabulary and explains why the recalcitrance toll governs the economics of everything after it.
Articles 15
| Biomass for energy Biomass is stored photosynthesis, and every route that extracts energy from it pays the same toll first: opening the lignocellulose matrix. |
| Biogas and anaerobic fermentation Anaerobic digestion is a four-link food chain locked together by hydrogen — and the thermodynamic stinginess that makes the microbes slow is what leaves the energy in the gas. |
| Advanced biofuels: why drop-in compatibility rules the chemistry A jet engine accepts a specification, not a substance — so biofuel chemistry is the art of building molecules that match fossil ones, and each route pays for that in a different currency. |
| Anaerobic digestion of municipal waste The digester consortium is a matched-rate system, and municipal waste attacks both of its balances at once: easily fermented carbon arrives too fast, and protein pushes ammonia toward inhibition. |
| Gasification and Fischer-Tropsch SAF The syngas platform buys feedstock-agnosticism by destroying the molecule first — and then pays twice: once in gas cleanup, once in the chain-growth mathematics that decides what FT may produce. |
| Marine biofuels: biomethanol and bio-LNG A ship chooses its fuel by storage physics long before production chemistry gets a vote — methanol wins as the easiest molecule to synthesize and store, methane as the one an entire engine fleet already burns. |
| Hydrogen fuel from biomass In biomass-to-hydrogen the carbon is not the fuel but the reducing agent that pulls hydrogen out of steam — a route capped by stoichiometry and heat demand, competitive with electrolysis only where cheap waste carbon already flows. |
| Gas fermentation to chemicals Acetogenic bacteria fix CO, CO2 and H2 into ethanol through the only carbon-fixation pathway that spends no ATP — and then the bottleneck moves from metabolism to physics: the gases barely dissolve in water. |
| Microbial electrosynthesis Renewable electricity can push microbes to fix CO2 at a cathode — but most electrons never reach a cell, and the product arrives too dilute to pay for the reactor. |
| Engineered photosynthesis and artificial chloroplasts Photosynthesis is capped by one enzyme's trade-off: RuBisCO fixes oxygen almost as readily as carbon dioxide, and every engineering route is an attempt to dodge that trade-off. |
| Microbial fuel cells Bacteria can hand electrons straight to an electrode — but the biofilm that does it is such a poor conductor that power stays orders of magnitude below chemical fuel cells. |
| Bio-powered IoT charging A bio-source delivers microwatts forever instead of milliwatts for a while — the whole engineering problem is spending that trickle honestly. |
| Bio-based phase-change materials Latent heat is stored in the change of state itself, and fatty acids deliver it well — until supercooling and segregation erode the stock cycle after cycle. |
| Bio-degradation of engine carbon deposits The label promises bio-digestion of carbon deposits, but the chemistry permits only interfacial housekeeping in liquid fuel — no protein survives where deposits form. |
| Microbial enhanced oil recovery Oil stays in the ground because of capillary physics, and microbes can manufacture their own chemicals to beat it — but the price is that the engineer gives up control a kilometre down. |