Hacker News Reader

Comment by Reason077 | Hacker News Reader

> "100MW in storage capacity"

Sigh. A MW is not a measure of storage capacity, it's a measure of momentary power. Do they mean it can store 100 MWh of energy? Or do they mean it can generate up to 100 MW of power?

Journalists always seem to get confused by this[1], but it's surprising to see "Recharge News", of all people, making such a mistake!

[1] The Times once famously published an entire headline anti-EV article that claimed the UK would need to build dozens of new nuclear power plants to power them. But it quickly turned out they had just gotten GW and GWh confused!

View on HN

Most here probably won't need this but: the Watt is a unit of power. Power is the rate of energy consumption. An amount of energy, over an amount of time. 1 Watt is 1 Joule per second. The "over time" is literal: 1 W = 1 J/s = 1 V*A/s. 1 watt, is 1 joule per second, is 1 volt-ampere per second.

An analogy to motion: joules are distance, watts are speed, and watt-hours are like light-years.

The amount of energy consumed, if you have one watt of power for a certain amount of time, is the confusingly-named Watt-hour, or Watt-year, etc. 1 Watt-second is 1 Joule. 1 Watt-minute is 60 J. 1 Watt-hour is 3600 J.

I'm not really sure why the Wh exists, other than to let you easily estimate how much it costs to run an appliance for once hour. It tends to confuse.

> I'm not really sure why the Wh exists

It never really clicked for me how silly this is until you said it, so I went and looked it up.

It turns out it's kind of the other way around; the watt came first: It was originally defined as "the power conveyed by a current of an Ampère through the difference of potential of a Volt".

Watt-hour seems to come around in the 1890s as utilities explore ways to bill customers for electricity use, originally "ampere-hour meters" and then "watt-hour meters".

Joule shows up about the same time, in like 1880 or so, and was defined in terms of the watt, rather than the watt defined in terms of the joule, if I skim Wikipedia correctly.. So that'd mean Joule and Wh are both kind of competing units of energy - one used by GE and Westinghouse and all those people, and the other used by scientists(?)

The watt then gets redefined in terms of a joule much later, in 1948.

> Watt-hour seems to come around in the 1890s as utilities explore ways to bill customers for electricity use

Makes sense kwh is an accounting unit of energy not a science unit. I feel that's 'fine'. Tell the accountant that the pump that drains the east shaft runs 12 hours a day at 53kw and they can figure the monthly cost using a ten key.

Hat tip the parent. It's really annoying that Journalists understand neither science nor accounting.

it's a nice human scale unit - a bit like some countries still cling to inches as a length measure.

> 1 W = 1 J/s = 1 V*A/s

That last "/s" should not be there.

Either way, "building dozens of nuclear power plants" is something that should have been done decades ago. Yes, waste handling is a concern for the local environment of a specific area and needs to be taken seriously. But given that climate change is a GLOBAL concern, how much better off would we as a planet have been doing prudent risk management and pressing forward with nuclear power as opposed to listening to the hysterical FUD of people who call themselves "environmentalists?"

> Either way, "building dozens of nuclear power plants" is something that should have been done decades ago.

Great idea. How?

Even China, which regularly builds new nuclear power plants, can't do it at a pace sufficient to keep up with wind power, not to mention renewables as a whole.

I talking here in terms of reported TWh delivered.

> Great idea. How?

Small modular reactors https://www.rolls-royce.com/innovation/small-modular-reactor...

"The Nuclear Fallacy: Why Small Modular Reactors Can’t Compete With Renewable Energy":

https://cleantechnica.com/2023/01/18/the-nuclear-fallacy-why...

> "“Small modular reactors won't achieve economies of manufacturing scale, won't be faster to construct, forego efficiency of vertical scaling, won't be cheaper, aren't suitable for remote or brownfield coal sites, still face very large security costs, will still be costly and slow to decommission, and still require liability insurance caps. They don’t solve any of the problems that they purport to while intentionally choosing to be less efficient than they could be. They’ve existed since the 1950s and they aren’t any better now than they were then.”

Hinkley Point C is still not finished.

The problem is not so much the waste, but the "black swan": each plant has a failure probability that's low - perhaps 1/10,000 or less - of a disaster that contaminates a very large area around it. The UK was tracking after effects of Chernobyl, two thousand miles away, for two decades after the incident. That has a negative effect on people's willingness to build new plants.

1607 Bristol Channel Flood

https://en.m.wikipedia.org/wiki/1607_Bristol_Channel_floods

Your chosen scapegoat isn't plausible. If the issue was just "people who call themselves environmentalists", we'd be awash in nuclear power plants, because societies globally are pretty notorious for not paying much attention to environmentalists.

The real issues are quite different. Environmentalists may have pointed out some of them, but they're just the messenger in that case.

Waste handling is only a problem because of non proliferation laws it’s not a mandatory outcome

Assuming they accurately reported that it is an olympic swimming pool sized resevoir and a height differential of 100 meters, that would only be 1.7 MWh of storage capacity with perfect efficiency.

I think it is talking about power capacity, not the discharge rate.

A watt has dimensions of energy over time. It cannot be used to express a measure of energy unless you multiply it by time, as in a watt-hour.

I work in energy storage. This is not totally wrong, its just omitting the duration. 100MW only describes the rate at which the battery can discharge. The duration would be expressed in MWhours (mwh) so a 100MW/200MWh system would be able to discharge its full tank in 2 hours. You need to know the MWh to know how physically large the system is.

Came here to say the same

Reply on news.ycombinator.com