Before doing the integrated writing below, complete this matching exercise
legitimate
electrolysers
curtailed power
cradle-to-gate footprint
a use-phase basis
combusted CO₂
residues
corn stover
wheat straw
sawdust
cropland
cap removal rates
biochar
cover-cropping
manure
landfills
venting
seals
RNG
SCR
particulate filters
cuts NOx
PM
tailpipe NOx
modular CO₂ capture
the hardest-to-abate
near-term
valid, reasonable, justified
Devices that split water into hydrogen and oxygen using electricity.
surplus renewable electricity that would otherwise be wasted
impact from resource extraction up to the factory gate
measured during the stage when the fuel is actually used
carbon dioxide released when burning fuel
leftover by-products from crops, forestry, or processing
Leaves and stalks of maize left after harvest.
Stems of wheat plants remaining after grain harvest.
Fine wood particles produced when cutting or sawing.
land used to grow crops
limits on how much material can be removed to protect soil
Carbon-rich material made by heating biomass in low oxygen.
planting crops mainly to protect and enrich the soil
Animal waste used as natural fertilizer.
Sites where waste is buried and managed.
release of gas (like methane) directly into the air
Closures or gaskets that prevent leaks in pipes or equipment.
renewable natural gas (biogas upgraded to pipeline quality)
Selective Catalytic Reduction system to reduce NOx in exhaust.
Devices that trap fine particles (PM) from exhaust gases.
reduces nitrogen oxide pollutants
particulate matter, very small solid particles in air pollution
nitrogen oxides released from a vehicle’s exhaust pipe
carbon capture units built in scalable, compact modules
industries where cutting emissions is most difficult
happening in the short future
2. Integrated writing.
Step 1. Read the text below.
Reading Time — 3 minutes
Read & take down 3 main ideas: 3:00
Reading Passage:
Proponents of “green fuels” often claim substantial environmental benefits, yet a closer look suggests these claims may be overstated. Three commonly promoted options—green hydrogen, advanced biofuels, and synthetic e-fuels—face practical limits that undermine their alleged climate advantages.
First, lifecycle emissions are frequently higher than advertised once upstream energy inputs are counted. Electrolytic hydrogen can be “green” only if powered by surplus renewable electricity, which is scarce and intermittent in many regions; using mixed grids with fossil generation pushes its carbon intensity upward. Similarly, synthetic e-fuels require large amounts of electricity for CO2 capture and fuel synthesis; when that electricity is not strictly renewable, the resulting fuel can approach or even exceed the emissions of conventional fuels.
Second, feedstock and land constraints call the “sustainability” of biofuels into question. Even second-generation (cellulosic) biofuels must be sourced, collected, and transported, which can disturb soils, reduce carbon in agricultural residues, and compete with other uses (e.g., animal bedding, soil cover). Expanded energy cropping risks indirect land-use change, biodiversity loss, and higher water stress in already arid zones.
Third, local environmental externalities persist. Biogas systems can leak methane—a potent greenhouse gas—during collection and upgrading. Burning e-fuels still produces NOx and ultrafine particles in cities, so air-quality gains may be limited. Finally, building out hydrogen pipelines, electrolysers, and carbon capture facilities entails considerable material footprints, raising questions about the true speed and scale at which these fuels can deliver net benefits.
In sum, while green hydrogen, advanced biofuels, and synthetic e-fuels sound promising, real-world constraints on electricity supply, land, and infrastructure suggest their environmental payoffs are narrower and slower than advocates imply.
Step 2. Listen to part of a lecture below and take notes.
While some specialists highlight legitimate implementation challenges, contemporary lifecycle evidence shows that the three fuels discussed—green hydrogen, advanced biofuels, and synthetic e-fuels—can be decisively cleaner when produced and used in the ways they were designed.
First, on lifecycle emissions: When electrolysers run on dedicated wind and solar or on curtailed power, green hydrogen’s cradle-to-gate footprint drops dramatically, enabling 70–100% CO2 reductions in applications that replace grey hydrogen or diesel in heavy transport. Likewise, synthetic e-diesel and e-kerosene synthesized with renewable electricity and captured CO2 (from biogenic sources or direct air capture) become nearly carbon-neutral on a use-phase basis, since combusted CO2 was previously removed from the atmosphere. Energy intensity is real, but it is precisely why these fuels are targeted to sectors that cannot electrify directly (long-haul aviation, shipping, high-temperature process heat).
Second, on feedstocks and land: Advanced biofuels today prioritize residues and wastes—corn stover, wheat straw, sawdust, municipal organics—materials that do not require new cropland. Modern soil-management guidelines cap removal rates to maintain soil carbon and prevent erosion, and many projects pair feedstock collection with biochar or cover-cropping to restore soil health. Biogas from manure and landfills prevents methane from venting; even modest leak-control—tight seals, continuous monitoring, and upgrading to RNG—turns a super-pollutant into a low-carbon substitute for fossil gas.
Third, on local air quality and infrastructure: After-treatment (SCR, particulate filters) paired with clean e-fuels cuts NOx and PM well below legacy levels, improving urban air relative to conventional fuels. Hydrogen use in fuel-cell trucks removes tailpipe NOx altogether. As for infrastructure, electrolyser manufacturing is scaling quickly, pipelines are being repurposed for hydrogen blends or converted to carrier molecules like ammonia, and modular CO2 capture is reducing material intensity per tonne. These are not theoretical trends; they are happening along real supply chains that prioritize the hardest-to-abate niches.
In short, when we match the right fuel to the right job and enforce renewable electricity, verified feedstocks, and leak-controlled operations, these pathways deliver substantial and near-term climate and air-quality benefits rather than the marginal gains suggested in the reading.
Summarize the three main claims in the reading that question the environmental value of green hydrogen, advanced biofuels, and synthetic e-fuels. Then explain how the lecture challenges each claim with specific lifecycle examples (renewable electricity sourcing, residue-based feedstocks and methane capture, modern after-treatment and infrastructure scale-up).
Reading time – 2 minutes, writing time – 8 minutes
Step 1. Read the academic discussion
Read the post carefully: 2:00
Professor’s Post (Environmental Policy Course):
This week, let’s consider the role of universities in the global energy transition. Some argue that higher education institutions should direct their resources toward developing new renewable energy technologies (for example, advanced solar panels, offshore wind, or hydrogen). Others suggest that universities should focus on improving traditional energy systems (such as coal, oil, and natural gas) to make them less polluting and more efficient.
What do you think is the most effective direction for universities to take, and why?
Student 1 — Maya (Supportive of Renewables)
I believe universities should prioritize research on renewable energy. Fossil fuels are finite, and investing in cleaner versions only delays the inevitable. By pushing the boundaries of solar, wind, and hydrogen now, universities can accelerate the transition to a sustainable future. Also, students themselves are motivated by purpose-driven projects, which helps attract talent and funding.
Student 2 — Daniel (Supportive of Cleaner Fossil Fuels)
I disagree. Renewable energy is important, but fossil fuels still dominate the world’s supply. If universities can make coal or natural gas plants capture more carbon and run more efficiently, the global impact will be immediate. Billions of people still depend on these energy sources every day. It seems practical to improve what we already rely on, while renewables scale up more gradually.
Step 2. Write a response
Tip: State your opinion clearly, connect to the professor’s post, and refer to the students’ ideas.
Say whether you agree more with Student 1 or Student 2 (or partly both).
Support your view with reasons and examples (economic, environmental, social, etc.).
Explain why the other viewpoint is less convincing in your opinion.
This is a challenging topic, but I think that …. I strongly agree with Emily’s//James' idea that …. I’d add that …………. WhileJames/Emily raised the relevant point that …, he didn’t mention that ….. As a result, ….
While I appreciate the points mentioned by James and Emily, I think that ……………….
Remember that …, so …. Some people may feel that …., but I think …….. .
