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Comment by scottLobster | Hacker News Reader

At the end of the day it's a matter of infrastructure. BEVs benefit from a pre-established electric grid, end of story. Sure that grid might need improvements/hardening/modernization as BEVs become more popular, but the fundamental infrastructure exists.

Hydrogen needs entirely separate refineries/production facilities, specialized transport vehicles and fuel stations, all of which must be built entirely from scratch and negate many of its efficiency benefits. A viable hydrogen vehicle market would likely need tens if not hundreds of billions in initial capital just to get off the ground and be self-sustaining; and even if such an effort was politically feasible why not put that money into BEVs where it will arguably do more good?

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Theoretically you could just electrolyze water on site using power from existing grid. It wouldn't be that much more difficult infrastructure wise than building charging facilities for EV. However according to the diagram included on this article[1] the pipeline from AC power to usable thrust is 3x more efficient for battery vehicles currently.

EDIT: forgot to link the article but I'm on my phone now. Some clever googling will find it for you if you're interested.

And they’ll have to deal with the pesky fact that hydrogen gas from natural gas is cheaper than H2 from electricity.

So it’s either:

1) more nuclear plants in Germany (lol)

2) increased German dependence on Russian natural gas (lol)

What happens to the carbon from natural gas once the hydrogen is extracted?

Ultimately becomes CO2. Because it's produced centrally, you could collect it and do something with it or store it.

It's possible to just leave it as carbon. The energy needed to convert methane to carbon + H2 is much less (per unit H2) than that needed to convert water to O2 + H2.

There are experiments (currently underway in Germany) to extract hydrogen from natural gas without burning the resulting carbon, leaving behind graphite powder which can then be either buried or fed into carbon-composite manufacturing.

If you buy electricity on the spot market it can be extremely cheap or even negative-priced. But the downside of that strategy is that you can only operate your facility for some times of the day.

That's an interesting point, in aggregate.

As we move towards more intermittent renewables, assuming the market remains intermittent, there's an entire new class of demand that's feasible.

Essentially anything that "only needs power sometime in the next week, can soak up a semi-arbitrary amount of power, and can start/stop quickly (ideally grid-controlled)."

I also think we haven't fully exploited interrmittent/responsive demand.

I'd have no issues if a household or building's HVAC system, hot water system, electric car chargers ebbed and flowed their demand in response to supply.

E.g. when I turn on my dishwasher, I don't care if it holds for 2 hours and then runs because the winds are calm now, but expected to pickup in 2 hours.

I don't care if my hot water heater superheats water now because it's especially sunny or windy out.

I don't care if my electric car chargers over the course of 8 hours in the evening, instead of charging quickly now.

I don't care if my AC system makes the building a couple of degrees cooler now to thermal bank the excess supply before rates increase later.

The issue seems to be that energy markets are a long way from achieving financial market levels of responsiveness.

You're essentially increasing the number of market participants a couple orders of magnitude, and the system and existing players semi-understandably balk.

On the other hand, without exposure to end users, the utility-driven pace of change is going to be glacial (by which I mean, we won't have glaciers anymore either).

We already have "smart-meters" that enable time-of-day billing. They just need to monitor usage on a per 5-minute basis (and I suspect they do). They don't necessarily need to report it every 5 mins (otherwise how does the current system know how to respond to demand?).

I do feel like we should start billing on per-5-minute increments, then the responsiveness will come.

I think overnight we'll have a thousand startups selling devices that turn on/off your HVAC or car charger accordingly and save you money overall. Possibly even with a warmer home in winter or cooler home in summer, by being strategic.

> They don't necessarily need to report it every 5 mins (otherwise how does the current system know how to respond to demand?).

Supply is managed at the ISO level (a grid subsection, like the entire California grid), not the individual consumer level. The ISO monitors the AC frequency of the grid, which varies with the imbalance of supply and demand. The ISO contracts with "spinning reserve" generators who supply power to the grid at low latencies when needed to meet demand, a service known as frequency regulation.

There are efforts underway to provide frequency regulation via demand control and battery storage instead of spinning reserves, which are typically Nat gas turbine powered.

Right, but why not let my electric car or water heater take part in that market?

Instead of spinning up a natgas turbine, why not let my water heater or car charger take a break as a part of the market?

There are some grid level implementations of this (install our thermostat that we can remotely turn off to get a 5% rebate), but these seem to work around the primary problem: we pay an average price for electricity, not the actual price.

And if it all works based on grid frequency, the system could even work offline: water heater sees frequency drop and takes a random break between 1 and 60 minutes.

Or variable-frequency drive AC drops 10% in intensity, or increases by x% when frequency is getting a little high.

> Right, but why not let my electric car or water heater take part in that market? Instead of spinning up a natgas turbine, why not let my water heater or car charger take a break as a part of the market?

Indeed, that's precisely what I meant by frequency regulation via demand control and batteries.

(I'm not an electrical engineer)

The problem I was thinking about was demand harmonics.

It's not unreasonable to envision a scenario where a large number of independent devices, acting in their own self interest, end up oscillating between on and off together. E.g. by using the same logic.

It seems like you need something approaching a parallelism primative to coordinate behavior. E.g. bid two steps in advance, find out if your bid was accepted one step in advance, then act.

Or is bidding in energy markets already complex enough to avoid that outcome?

Such harmonics can be avoided by injecting some random delays

You can imagine a system where loads with the ability to vary their draw do so automatically in response to grid frequency changes, without even needing a centralized bidding system.

Frequency regulation is, however, a relatively small amount of power, and the grid itself needing to run at a particular frequency is more the result of loads that rely on the grid frequency for timing (i.e. A/C electric motors in fans).

In the future the grid frequency could be allowed to vary much more if loads become resilient to frequency variations.

The bigger (in terms of total energy) issue is shifting load to match supply, or vice versa. That can be achieved with appliances that store energy in one form or another. One of the most interesting examples of this is generating ice with wind energy at night to be used for cooling during the day.

In Austria and recently (since April?) there is a provider called Awattar. They sell energy with a flexible price model that's based on the energy spot market. They claim "you might even get paid to consume power".

My car charger can interface with them, and do exactly what you suggest. In theory you "just" need smart controllers for the systems.

The idea is similar to 1980s "Storage heaters", which would use cheaper nighttime power; but using fossile electricity this is very inefficient and thus bad for the environment - when exclusively using excess regenerative energy that's different though. Same for AC. The problem is when there is no excess energy for a long time; so I'd personally go with a hybrid system for heating (regenerative energy when available for a heat pump, local solar thermal energy for "base load" heating/warm water - not sure if fossil fuel for winter is necessary with that, but that depends on your climate).

One very interesting example of this is high temperature storage of heat for industrial use.

http://news.mit.edu/2017/firebricks-low-cost-storage-carbon-...

In the heating season, it would make sense if we could just have strategic resistive heating to soak it up the supply and offset natural gas use.

I feel that electricity prices being cheap or negative is because very few actually get those prices (e.g. residential/commercial customers paying averaged rates when they shouldn't). Or transmission/distribution prices being averaged (which should also rise/lower with demand because capex upgrades are driven by peak users)

If you periodically have a lot of excess electricity because you installed a lot of wind/solar; using that to create hydrogen is not the strangest plan. Germany has a lot of clean energy capacity already and plans to install more seem popular.

From what I've seen on current hydrogen fuelling stations having the capacity to actually refuel a significant amount of cars are limited (because tanks have to be repressurised), if you add electrolysis to this I imagine the fuelling rate is even more limited.

The title of the article is unclear, they mostly talk about increasing the mix of hydrogen with methane on the natural gas grid. This requires new ways of production but is re-entering the existing gas infrastructure for transport.

Most boilers and gas hobs are fine up to 10% hydrogen instead of 100% methane.

It's a good way to reduce the carbon footprint of heating by 10% (edit: after reading the message from aurelwu, this doesn't make sense, it won't reduce by 10, but by less than that), assuming the hydrogen has been produced in a reasonable way (excess solar and wind for instance).

> At the end of the day it's a matter of infrastructure.

No, in the end of the day it is a matter of efficiency, i.e. money. Hydrogen is just really inefficient in production, storage, and converting it back to energy. Unless this is solved (which I don't see) it cannot compete with batteries.

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