News for hackers. Stuff that matters.

snowwindwaves

Re:Practical Transformer Winding (2010) on Monday December 27, 2021 @03:53PM (#29706656)
Large power transformers have efficiencies in the 98-99.75% range.

I don't doubt switch mode could be smaller and cheaper up to some size, but I am struggling to see transformers larger than about 5 mva being replaced with power electronics.

Solar farms etc have inverters in modules I believe 500 kva each - and of course the power electronics are necessary there, there is no substitute.

I have a 20 MVA transformer that is nearly at end of life and would be open to cheaper replacements.

Re:Practical Transformer Winding (2010) on Monday December 27, 2021 @01:58PM (#29705552)
Are you saying large Transformers 1 mva, 10 mva, 100 mva, 500 mva are obsolete and should be replaced by switched mode power supplies? What mva is the threshold?
like you I hope I'm as present in my senior years! Female friends have entertaining stories about encounters with him from 17 years ago when he was 77!
what else have envy and greed driven? What would the world look like without those inate human emotions? It might be a simpler place but potentially the worst of history could have been avoided.
Wannabe's is pretty harsh for a group of people that started first and achieved their goals second.

Wannabe's never do the thing. They don't seriously try to do it. I have no reason to defend bezos but people made a serious effort there and they would not be wannabes even if they failed

I'm a wannabe for launching weather balloons and model rockets with my kids from the comfort and security of my well paying public sector job

You'll be a manager one day
Are there cities with land that isn't expensive?
In desireable locations the land cost is often more than the construction cost, so splitting that land cost across multiple dwellings makes them more affordable. Sure the cost per sq ft is higher when you are putting in three dwellings under one roof than for a McMansion, but you are getting three dwellings that in aggregate should be worth more than one McMansion.
I'm looking to sell my f150 in to these high used car prices and get an electric pickup for hauling my snowmobile. Self driving doesn't interest me at all. Cyber truck delivery is mid 2022. Hopefully it is cheaper than the long range f150 lightning.
Re:NetBSD Explained: The Unix System That Can Run on Anything on Thursday August 19, 2021 @01:54AM (#28230790)
Just to be clear vxworks is not bsd based that I could tell from Wikipedia. I work with Schneider electric plcs and sometimes vxworks errors bubble up.
Re:Hydrogen: The middle east's next black gold on Monday August 16, 2021 @12:53AM (#28195045)
I didn't realize that hydrogen is/will be commonly transported as NH3 ammonia before its end-use. I'm starting to see lots of articles about Ammonia as the transportable energy dense fuel of the future that could soon be flowing in pipelines.
Re:The Case for Optimism on Sunday August 15, 2021 @11:17PM (#28194634)
It becomes an easy decision to get an electric f150 when gas costs $8 a gallon because of carbon taxes and a full charge is only a couple bucks
Both you and and animats are describing the same thing, brushless synchronous machine, which exists for long time.
Re:Activists who embrace nuclear power on Wednesday February 24, 2021 @01:42AM (#26247285)
Thanks for the great posts.

Have you seen any numbers for the life expectancy of grid connected batteries? I heard A solar project in Hawaii expects to replace the batteries every 5 years with daily cycles. So for California it would be $111 million /yr in battery costs. Manageable, but not a trivial amount to be factoring in to the cost of firming up the capacity of wind/solar.

Re:Activists who embrace nuclear power on Wednesday February 24, 2021 @12:48AM (#26247024)
Nuclear + renewables = 0 carbon and a consistent reliable base load ... sounds ideal?
Re:The Texas power outage is a nation-wide problem on Thursday February 18, 2021 @11:30PM (#26189748)
People are attacking texas' less interconnected system for being "independent" and others are pointing out more interconnections from places with no power to spare would not have helped.
Re:The Texas power outage is a nation-wide problem on Thursday February 18, 2021 @11:25PM (#26189707)
Underground costs about 10x as much as overhead.
Re:Electricity over $900/MWh in most of Western US now on Thursday February 18, 2021 @02:22AM (#26176965)
The intertie from BC to Washington is 3150 MW from north to south.
Re:Electricity over $900/MWh in most of Western US now on Thursday February 18, 2021 @02:15AM (#26176927)
Put the food outside?
Re:Electricity over $900/MWh in most of Western US now on Thursday February 18, 2021 @02:12AM (#26176909)
The paper suggests solar thermal and wind plus gas peakers. So the overbuilt point from the parent stands.
Re:What went wrong with the Texas power grid? on Wednesday February 17, 2021 @01:43AM (#26163445)
So bringing up battery storage on an article about a blackout caused by a multi day storm might lead some people to believe that batteries would make a difference in this situation, when they wouldn't, regardless of the GW.
Re:What went wrong with the Texas power grid? on Wednesday February 17, 2021 @12:46AM (#26163146)
Electrical engineers wouldn't build a power line to Texas with a capacity of 5000 MW and then put intertie hardware such as phase shifters or ac-dc-ac converter with capacity of 1000 MW on the end of it. So it is likely that the transmission capacity and intertie capacity are exactly the same!
Re:What went wrong with the Texas power grid? on Tuesday February 16, 2021 @11:01PM (#26162509)
Not for batteries since a battery that can deliver 17 GW for an hour is much smaller than one that can deliver 17 GW for a week. Usually grid connections are measured in power since you could use it at 100% indefinitely - not so with a battery , so hours matter.
Re:What went wrong with the Texas power grid? on Tuesday February 16, 2021 @10:58PM (#26162489)
Or somebody cheaper can generate since they didn't bother building their plants to withstand low temperatures so the more expensive plants to run go out of business or lose that expensive to maintain ability and then here we are
Re:What went wrong with the Texas power grid? on Tuesday February 16, 2021 @10:50PM (#26162430)
it isn't that big a deal to run a fridge and some led lights on solar pAnels. As you identified heating and cooling are the big energy users.
Re:What went wrong with the Texas power grid? on Tuesday February 16, 2021 @10:39PM (#26162358)
Plus they are not really screwed, they lost 5 days revenue from not being able to pump/generate, surely at elevated prices - but these businesses will not feel this event in a negative way on their annual report
Re:What went wrong with the Texas power grid? on Tuesday February 16, 2021 @10:35PM (#26162335)
70 GWh of battery storage would have kept the lights on for an extra 2 hours during this event - assuming the batteries themselves aren't affected by temperature. While battery storage might be nice to increase the capacity factor of a solar or wind farm it isn't going to make a difference in an event like this where a weather system moves in for a week.
Re:What went wrong with the Texas power grid? on Tuesday February 16, 2021 @10:17PM (#26162226)
The parent said there is not enough transmission capacity not generation capacity. Generation needs to be near loads. If not then transmission lines are required to bring current from generators to loads. Transmission lines have fixed capacities, like your internet connection can only transmit so much data/s, they can only transmit so much power.
Re:How to SSH into a Self-driving Vehicle (2020) on Saturday February 13, 2021 @01:41AM (#26121875)
For remote interrogation of meters?

Older »