Tom Brown Profile picture
energy system modeller | professor @TUBerlin | https://t.co/aQkOid3MlA | https://t.co/bWdJySq7D7 | @openmod ally | migrating to @nworbmot@mastodon.social | he/him
Sep 21 7 tweets 2 min read
future renewable German power system with today's weather 🌬️🌞

last few days got through without touching backup, just good ol' wind, solar, pumped hydro and batteries Image the hydrogen storage is full, ready for those nasty kalte Dunkelflauten

will we make it through the winter? 🤔 Image
Aug 30 11 tweets 5 min read
What flexibility do we need from biogas?🌱

Shifting baseload generation by a few hours with small storage helps, but what we really need is seasonal flex by upgrading to biomethane/ol (and using most of it in other sectors).

A few thoughts on scaling, grids, liquids. 🧵 Image "Flexibility from biogas" often means switching from baseload to only feeding in at peak hours of the day, which requires a larger generator and biogas storage of 12-24 hours, like this oft-cited example in the Schwarzwald



zdf.de/nachrichten/wi…
fnr.de/presse/pressem…
Jan 23 14 tweets 6 min read
🚨 new web app 🚨

future renewable power systems running on today's market data 🌬️☀️, scaled up



- updated each day 🕰️
- wind, solar, hydro, batteries, hydrogen storage 🔋
- Germany as an island 🏝️
- coming soon: interconnectors, new electric demands 🚗 model.energy/future/
Image How does it work?

We take the current day's demand, wind, solar and hydro time series from (left graphic).

Then we divide generation by current capacities and scale them up to the future capacities (right graphic).

All code and data is open (obvs). SMARD.de

Image
Image
Oct 31, 2023 21 tweets 10 min read
A renewable power system that is reliable whatever the weather? 🌬️⛅️

The case for e-methanol with carbon cycling ♻️:
liquid storage that can be built anywhere

🚨 New impulse paper🚨 in @Joule_CP with @euronion42

Paper:

Slides: doi.org/10.1016/j.joul…
nworbmot.org/energy/brown-i…
Image For a very fine overview check out @pfairley's article in @IEEESpectrum or read on for my two pennies 🧵

spectrum.ieee.org/methanol-energ…
Oct 3, 2023 17 tweets 6 min read
All your carbon shall be methanol

Arguments for mopping up all carbon in wastes and residues into methanol; use it to supply sectors that can't be electrified

TL,DR: methanol is liquid; easier to transport/store than CH4/H2/CO2; costs scale down nicely to multi-MW size Image We need carbonaceous fuels for big chunks of shipping, aviation and chemicals

Methanol can serve all of these

Flexible, distributed synthesis from wastes and residues (topped up with green H2, "bio-e-methanol")

=> minimise direct air capture, and transport of fiddly gases Image
Jun 8, 2023 11 tweets 4 min read
The US is not the EU 🇺🇸🚫🇪🇺

For green hydrogen, the US should consider stricter rules because:

- EU has other guardrails in place (ETS, RES targets)

- US needs to comply with EU rules if it wants to export there

- initial volumes in US could be v. high (3 $/kg...)

Thread! Image The EU has loosened its rules for green hydrogen to require hourly matching only from 2030 (without grandfathering), and additionality by 2028

energy.ec.europa.eu/publications/d…
Dec 20, 2022 19 tweets 8 min read
Hourly or annual matching for green hydrogen?

Our new preprint shows: it depends.

Hourly matching has low system emissions impact across all scenarios.

Annual matching raises emissions if electrolysis is inflexible and the grid is not clean, otherwise it can lower emissions. You can read more in our preprint (not yet peer-reviewed) here:

doi.org/10.5281/zenodo…

The modelling work was led by @lisazeyen_lz, with support from me and Iegor Riepin.

🧵 below
Oct 11, 2022 27 tweets 12 min read
🚨 New 24/7 report for Europe! 🚨

Companies moving from *annual* to *hourly* clean power matching get:

- lower emissions for them *and* system

- reduced backup needs for system

- only small cost premium for 90-95% hourly matching

- stimulation of new tech for final 5-10%

🧵 Image Today we published a report on the first results from an ongoing project between @TUBerlin and @Google:

doi.org/10.5281/zenodo…
Mar 16, 2022 7 tweets 2 min read
Nice paper shows that including decades of weather data reveals longer periods of wind and solar than typical years contain (dreaded D-word)

=> more long-term storage needed for VRE systems

Extreme events and inter-annual variability need to be considered!

few comments... The study assumes Germany is isolated and considers electricity system only => caveats
- most hydrogen likely to be used for dense fuels / industry, so long-duration storage you get as "side-effect"
- benefits of electricity interconnection => less storage needed
Mar 15, 2022 14 tweets 6 min read
- Renovating buildings to make them more efficient doesn't just reduce energy use

- It also reduces demand peaks in electrified system

- Critical for the kalte Dunkelflaute! (cold, electric heat, low wind, low sun)

- Strategies for heat demand in zero-CO2 Europe in a new paper New(ish) paper from 2021 led by researcher @lisazeyen_lz

"Mitigating heat demand peaks in buildings in a highly renewable European energy system"

Open access in Energy:

doi.org/10.1016/j.ener…

Also on arXiv:

arxiv.org/abs/2012.01831
Feb 23, 2022 7 tweets 3 min read
Ever wanted to run an energy system model with your own assumptions?

We've made a simplified version of our 45-node European sector-coupled model available to run online.

It includes renewables, CCS, nuclear, power, hydrogen, biomass, industry, etc.

model.energy/scenarios/ You can ask it questions like:

i) At what cost does nuclear take over (around 3-4000 EUR/kW)

ii) What happens if we restrict power or hydrogen grid (costs go up!)

iii) What happens if we relax restriction on carbon sequestration from 200 MtCO2/a (costs go down!)
Dec 9, 2021 6 tweets 3 min read
a learning curve for silicon solar cells...from 1972

when cumulative capacity was just 600 kW (today it is more than a million times higher)

most capacity back then was in space industry

if I read this right, they fit a learning rate of 31% or 21% depending on point selection Most solar learning curves start much later, so it's nice to back-fill to the beginning, see e.g. this example

Jun 17, 2021 30 tweets 11 min read
how to avoid (panic about) declining market value of wind and solar

OR

how I learned to stop worrying about market value & love shadow prices

a DUAL perspective on a primal problem

new paper by @ReichenbergLina and me:

doi.org/10.1016/j.enec… summary:

traditional "primal" view says low-marginal-cost wind and solar push down market prices when they produce a lot, suppressing revenue

we present another "dual" point of view: it is subsidies that suppress revenue, not variability

both are correct, but framing matters!
May 22, 2021 13 tweets 4 min read
- Learning effects lead to path dependency

- Including learning in your model => many distinct local optima

=> Diverse choice of low-cost future energy systems

- Can't just look at one

Conclusions from Niclas Mattsson's pioneering work in 1990s:

research.chalmers.se/en/publication…

1/12 (above graphic is from @MichaelGrubb9's fabulous book "Planetary Economics", downloadable here: climatestrategies.org/publication/pl…)
Mar 30, 2021 5 tweets 2 min read
Great to see this paper on long-duration electricity storage:

- Storage energy cost & efficiency critical

- Needs <= 50 USD/kWh to be relevant next to VRE, batteries, "firm" gen

- Needs <= 1 USD/kWh (e.g. salt cavern for hydrogen storage) to make serious dents in "firm" gen I'd also be interested in the question posed the other way round: what is the value of "firm" clean generation in the presence of VRE, batteries and long-term storage?

E.g. how much does system cost reduce by adding nuclear/CCS etc. to wind+solar+batteries+hydrogen.
Oct 22, 2020 6 tweets 3 min read
C. Darwin: an "admirable speech"

In 1863, William Armstrong advocates:

- end of coal
- efficiency
- electrification
- renewables (he developed first hydro power)
- open data
- technological learning ("tendency of progress is to quicken progress")

vimeo.com/75975295 You can read more about him here:

en.wikipedia.org/wiki/William_A…

williamarmstrong.info

And in @henrietta999's biography "Magician of the North".

Don't know if there is a transcript of the speech floating around anywhere (if not, we should transcribe one!).

Oct 17, 2020 11 tweets 5 min read
Last thread on history of renewables + hydrogen (promise):

TL;DR:

- Idea of using electrolysis of water & storing hydrogen is almost as old as electrolysis (1789)

- Already a lively debate in *1863* about combining variable renewables with electrolytic hydrogen to replace coal The above quotation is from Jevons' (he of paradox fame) marvellous 1865 treatise "The Coal Question":

oll.libertyfund.org/titles/317#Jev…

(h/t @physicspod)

and refers to an exchange in The Times of London in 1863, started by this letter on page 10 of the 2nd Sep 1863 edition:
Jul 31, 2020 9 tweets 4 min read
Despite the current hype, there's nothing new about electrolytic hydrogen.

- 100 MW electrolysers since late 1920s for fertiliser and heavy water

- 100 GWh salt cavern storage since 1960s

- 4500 km hydrogen pipelines today

What was missing was abundant low cost power. From 1920s-1970s, 100+ MW water electrolysers were built across world to meet demand for ammonia for fertiliser.

Prerequisite: cheap power from hydro dams.

All were dismantled as other power demand grew and fossil gas became available to make ammonia.

books.google.de/books?id=bf3lB…
Feb 17, 2020 29 tweets 8 min read
"wind and solar will always cannibalize their own market revenue"

"market value decline is an inevitable consequence of variability"

"market integration of wind and solar is impossible"

WRONG, WRONG & WRONG

THREAD! (1/infinity) ...based on a preprint (not through peer review yet) by Lina Reichenberg of @chalmersuniv and me:

arxiv.org/abs/2002.05209

@flexibledragnet's pithy summary:

"VRE cannibalisation is a policy artefact, not a physical system constraint"
Dec 5, 2019 24 tweets 11 min read
Build your own clean energy system!

- wind, solar, storage + others optimized live while you wait

- works for any region in the world

- you choose your own technology assumptions

model.energy

thread with examples

reward at end This toy model meets a constant demand over a year of weather data

The default setting is to use wind, solar, batteries and hydrogen storage only; further technologies can be added, as can H2 demand (for heavy transport and industry)
Nov 26, 2019 10 tweets 3 min read
In Oct 2019 @Equinor and @OpenGridEurope presented a feasibility study to produce blue hydrogen in Germany (from natural gas with CCS)

Aims for blue H2 at a cost of 2-3 EUR/kg (50-80 EUR/MWh), competitive at a CO2 price of 50-70 EUR/tCO2

Short thread

open-grid-europe.com/cps/rde/oge-in… H2morrow would supply industry with H2 in west of Germany (NRW), importing natural gas from Norway.

Uses autothermal reforming (ATR) to produce H2. CO2 is captured, liquified, then shipped on Rhine down to Rotterdam and onwards to Norway, where it will be sequestered offshore.