Comment by trompetenaccoun | Hacker News Reader

Comment by trompetenaccoun | Hacker News Reader

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trompetenaccoun

And keep in mind it's to store energy from renewables (minus hydropower), i.e. mainly solar and wind. Solar is nonexistent at night. And although it varies, wind is generally strongest during the day and delivers less energy at night. But night-time is exactly when the vehicles are charged in people's homes, at least currently that's the situation and it would necessitate a ton of new infrastructure to change that. High voltage charging everywhere - ideally even DC charging and the necessary transformers, power cables etc. Even for street parking, because that's where a lot of cars are parked. So assuming there will be more EVs and we want to reach those net zero goals politicians always talk about we'd need charging stations everywhere.

Meanwhile in the real world, here is the result when the green revolution doesn't go as imagined, due to failures in planning and mismanagement. Case study Germany:

https://www.euractiv.com/section/energy-environment/news/gro...

> But night-time is exactly when the vehicles are charged in people's homes

Average wind production over the last 2 years in the UK is 5.8GW, with the peak (>6GW) between 1400 and 2200, and trough (<5.7GW) between 0200 and 0800, a total of 140GWh a day

But that's only a 5% variation between high and low.

Total demand though is lower at night than in the day. It's 25% down on the low at 0300-0400 and 17% up on average from 1800-1900, which more than offsets the daily variation in wind.

Throw in grid solar and sure, more renewables during the day (domestic solar isn't measured aside from a drop in demand) and you get an average 24% of current UK electricity driven by renewables, with a peak of 33% at midday and trough of 18% from 1900-2100.

But if you doubled wind that average peak would be 52% at 1200 for renewables, and a trough of 36%.

Assuming an infinite capacity grid (as the data isn't readily available), doubling wind+solar energy would save 40TWh of gas a year even with current demand. Tripling would save 60TWh, increasing 5-fold would save 76TWh, reducing Gas usage from 88TWh a year to 11TWh a year.

Those savings are based on real world generation and demand data from 2021.

Sure wind and solar can't entirely replace gas on its own, but it can knock usage down by 90% quite easily by putting up more strings between areas of the grid and simply building more.

You don't need to eliminate fossil fuels completely to make a difference.

The real issue is hidden in the title: it’s short term storage, ie the daily cycle. Mid-northern Europe has much more of a seasonal supply problem.

That said, smoothing out the daily cycle would help a lot too, even in cold winter days. But Germany and friends have decided to phase out nuclear before alternatives are actually deployed, which has led to like the worst winter… so far.

Charging at work seems like the thing to do. Not only is there excess solar energy at that time, but workplaces are more concentrated than homes so the installation costs for chargers should be less.

Even with US levels of 11,000 miles of driving per vehicle per year, or 30 miles a day, that's about 10kWh a day.

Why can't you charge that with a 1kWh draw over 10 hours you park the car overnight?

Yeah, I mean if you really think about it, this sort of concept would still work very well.

If everyone has an electric car and that car is always plugged in when not in use, regardless of where you are, then car batteries are only out of grid use while they're being driven.

The electrical grid must be such a difficult thing to manage, even with cars acting as local grid storage we'd need supplemental neighbourhood/regional storage units as well as a way to handle any unexpected peaks.

I mean I know there's the whole "Coronation Street finishes and everyone turns their kettles on" thing but imagine if at x time on x day everyone collectively did turn their kettles on - literally everyone, every single household. It would blow the grid no matter what the operators tried to do.

In a way we need grid storage in the form of batteries to enable better use of green/local energy sources, but I think it would be smart to include some sort of chemical based generation capacity with that local storage, some way for us to store energy in a solid form say, then never use it apart from very unexpected peaks where the system needs to scrabble to find more juice.

Unfortunately a lot of potential fuels are also flammable, not really the best thing to have a huge stockpile of in your neighbourhood. Maybe a huge flow battery fed by massive underground tanks, if we ever manage to improve that technology...

It's a complex problem but there are fairly obvious strategies that longer term can address most of the points you raise.

The company I work for in the main strategy is to facilitate AC charging points in places you are naturally stopped for enough time to top up charge. So home, work, shopping areas being the most obvious.

So small frequent incremental opportunities to top up or in the case of this article contribute to the grid.

There are definitely lots of solvable problems in this space that underpinned by the correct financial models will contribute a lot positively to climate change.

Topping up from solar during the day and from wind during the night along with predictive (per driver) charging models will go a long way. Whilst complex the challenges feel very much in the realms of scheduling and loading cargo onto ships Vs autonomous driving from a software side. For hardware (chargers) it's really down to plentiful supply in the main.

Any major change is going to have problems. The green revolution isn't just one event that has failed in Germany is a progressive change.

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