The German FDP (supposedly free market liberals) party likes the word “Technologieoffenheit” - openness to new technologies

This is all very well in theory, but the practice is more questionable

It is most often used when trying to justify the use of hydrogen in decarbonisation efforts, rather than using something else

So let's use two different transport cases and explain it

This thread will look at passenger rail, and buses - and how to decarbonise them

A 🧵

The NEED is easy enough to understand

A bunch of passenger trains, and a bunch of buses, run on diesel. Burning it emits CO2. Capturing that is next to impossible. So you need an alternative power source

What alternative technologies have you got?
Directly electrify with an overhead wire ⚡️
Use a battery (or possibly supercapacitor) 🔋
Use hydrogen

Each of these alternatives has pros and cons

If I believe in “Technologieoffenheit" then I should assess the pros and cons of each, and opt for the technology that's the best bet - according to the criteria for each

So passenger rail, electrification
✅ Technology proven over more than 130 years
✅ Once installed has the highest efficiency of all, as power source is external to the vehicle - no dead weight to haul around
❌ High one off cost to install overhead wires above track

Buses, electrification - essentially a trolley bus
✅ Technology proven over more than 100 years
✅ Once installed has the highest efficiency of all, as power source is external to the vehicle - no dead weight to haul around
❌ High one off cost to install overhead wires above roads
❌ Advantage to buses is flexibility, and overhead wires limits that - especially in countryside

Passenger rail, batteries
✅ One-off investment cost is lower than overhead electrification - no new wires needed
✅ Energy efficiency - while higher than hydrogen - is lower than an overhead wire
✅ Can be used with partially electrified lines - batteries can charge on these sections
❌ Dead weight of batteries to shift around, limits distance that can be travelled on the battery

Buses, batteries
✅ One-off investment cost is lower than overhead electrification - no new wires needed
✅ Energy efficiency - while higher than hydrogen - is lower than an overhead wire
✅ Can be used with partially electrified lines or chargers at bus stops
❌ Dead weight of batteries to shift around, limits distance that can be travelled on the battery

Passenger rail, hydrogen
✅ One-off investment cost is lower than overhead electrification - no new wires needed. But currently higher than for battery trains
❌ Energy efficiency is lower than a battery, and much lower than an overhead wire
❌ No use for partially electrified lines - cannot be charged when under a wire
✅ Dead weight of fuel cells to shift around is lower than the weight of a battery, giving greater range than a battery

Buses, hydrogen
✅ One-off investment cost is lower than overhead electrification - no new wires needed. But currently higher than for battery buses
❌ Energy efficiency is lower than a battery, and much lower than an overhead wire
❌ No use for partially electrified lines - cannot be charged when under a wire
✅ Dead weight of fuel cells to shift around is lower than the weight of a battery, giving greater range than a battery