Intro

• Biofuels are oft heralded as the bringers of a new era in green energy

  • (but are really just an excuse to keep using internal combustion engines)

• In the USA, bioethanol makes up 10% of gasoline in cars¹

• Norway has introduced regulation requiring airlines to make 0.5% of their fuel biofuels²

• How it works³:

  • Corn is used as a feedstock for yeast
  • Yeast respire anaerobically to produce ethanol

• Biofuels can generally work in engines just like normal fuel, with no retrofitting required

  The composition of ethanol is different to that of a crude oil based fossil fuel such as petrol. Higher blends of ethanol can cause corrosion of some rubbers and alloys used in the engine and fuel systems of some older vehicles.

  • E10 petrol - what is it and can I use it in my Toyota? - Toyota UK Magazine

  • E.g. new E10 UK petrol (10% bioethanol)
    • Supposed to reduce emissions... but not really
      • However still better than petrol if cannot be replaced by EVs
  • E.g. use of bioethanol in Brazil for automotive purposes (cars)

• E-fuels⁴ use renewable energy to make hydrogen, and then combine this with carbon dioxide to make replacements for fossil fuels

  • More synthetic than biofuels, as they are manufactured from their basic elements to form "drop-in" hydrocarbons.

Problems

• Inefficient

  • Explain theoretical cycle

  <aside> 🔻 Energy negative process

  • (carbon) Plant → car → atmosphere → plant </aside>

  • Huge land usage

    • 8.8%⁵ of US farmland used to grow corn for ethanol
    • With goal of 20%⁶ of gasoline being ethanol, 17.6% of US farmland would be used to grow corn for ethanol

  • Photosynthesis is generally less than 1% efficient for extracting energy from the sunn

    • Photosynthesis has huge water requirement (and only ~5% efficiency WRT water use), so if biofuel crops require artificial irrigation, this rapidly becomes unsustainable.
    • Corn is 0.25%⁷ efficient at this
    • By contrast, solar panels are 12-20%⁸ efficient

  • Seriously inefficient from sun to kinetic energy

    • EVs use solar panels (12%)
    • And from that electricity are 72%⁹ efficient at moving
    • E-fuel powered cars, on the other hand (which use electricity to make hydrocarbons), are only 16%⁹ efficient
    • Biofuels are probably even worse given the 0.25% efficiency of corn, and the dismal efficiency of internal combustion engines

• Wasteful

  • Water wastage
    • 240x water usage compared to solar energy; 72x¹⁰ compared to fossil fuels
  • Waste of farmland; destroying ecosystems
    • Most new farmland is used to grow corn
    • Price of corn has risen due to biofuels¹¹
    • This drives up prices for other products such as milk and meat, which are fed on corn
    • Palm oil used as feedstock! In 🇪🇺 initiative.¹²

• Actually quite polluting at times:

  • Particularly wood-burning stoves! (wood is a biofuel insofar as trees capture carbon dioxide to grow, supposedly making it carbon neutral. This ignores, however, other problems with its use:)
    • Highly popular in modern interior design on the grounds that they look nice and are very efficient (admittedly this is essentially true insofar as an open fire is about 20% efficient whereas a wood stove is ~80% - but is there a need for a fire in the first place!?).
      • We still don't have our heaters on 🥶. We have fireplaces but I don't think they actually work - quite common IME, esp. in Victorian/Edwardian English terraced housing. Blocked up for insulation reasons, generally.
    • Burning wood releases large amounts of particulate matter, which has led to the introduction of a ban¹³ on wood-stove fuel purchases:
      • We use eco-friendly wood in our pizza oven which we use only once a week, and our chimenea which we use very rarely.
      • In Malawi we would fire our pizza oven with wood from a tree that fell over and these seed pod things that littered the garden in certain seasons.
        • That's a good example of a biofuel with no transport overhead - something which often increases the carbon footprint of things like bioethanol
          • Plus we new where it was coming from
  • Charcoal is quite a good example of another widely-used polluting biofuel (ultimately wood - popular in BBQs!)
    • This doesn't necessarily need to be removed completely, but it should be regarded as a treat for a couple times a year at most. And investigate briquettes/other more eco-friendly grilling options.
      • Yes - probably better than gas-fired BBQs from POV of avoiding fossil fuels
      • Also from a health perspective! Meats grilled over a BBQ tend to have harmful substances on them incl. carcinogens¹⁴ from the burning... maybe stick to the hob?
  • Normal petrol-based biofuels also create non-carbon emissions such as harmful nitrous oxides.

• Purely a product of the corn industry

  • Maize shortages in Mexico brought about by it being channelled for biofuel use¹⁵
  • Pushed by pro-corn lobby groups
  • It's not actually good for the environment
    • It's like another fossil fuel industry

• It just makes no sense

  "Growing plants for food is a necessity, growing food for power is completely and utterly irrational" - Real Engineering

  • If we could eat electricity... we would
  • We can't make enough biofuels to "decarbonise" all of the transport energy - we need to electrify where possible

Problematic solutions

• There are plenty of alternatives to corn-based bioethanol, but they all have their problems
• Sugarcane ethanol¹⁶
  • Energy positive
  • Destroying Brazilian rainforests to grow it
  • Imported overseas mainly to USA
    • Links forward to renewable imperialism which we will mention in 18.
• Cellulosic ethanol¹⁷
  • Made using grasses which are abundant and efficient
  • Very energy intensive and expensive...
• Algae¹⁸ ¹⁹ ²⁰ ²¹
  • Quite promising for a large number of reasons
    • Widely available
    • Reproduce quickly
    • Can use waste- or salt-water
    • Very efficient at photosynthesis
      • 40%²² of carbon sequestration worldwide
  • Currently unsustainable and unprofitable
    • But quite promising
  • Produces bio-crude-oil²³ with high energy density
    • Useful for some specific applications
• Waste cooking oil²⁴
  • Oils (such as, controversially, palm oil), can be used as a feedstock for biofuels
  • An idea is to use waste cooking oil
  • Seems genius, but practicalities get in the way
    • Would need an entire new supply chain and infrastructure
    • Little incentive for people to collect; difficult and waste of time
    • Need a lot!
    • Waste cooking oils would likely require purification before they could be used as genuinely clean-burning fuel.
    • Possibly problematic if cooking oils are actually palm oil in the first place!
• Aviation fuels have complicated needs