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Comment: Re:Start spreadin' the rants... (Score 1) 141

by aaarrrgggh (#49628885) Attached to: The World's Most Wasteful Megacity

In terms of the metrics, NYC is penalized for the following: temperature extremes, humidity extremes, tall buildings (plumbing, elevators, etc), and a number of other lesser factors.

NYC is benefitted by the fact that they don't grow anything, or really manufacture much.

NYC should strive to do better. Buildings should be better insulated, HVAC systems should be more efficient, heat recovery should be more widely used, lighting needs to be upgraded with more efficient solutions, and the subway should really try to improve efficiency.

But all these best and worst rankings are bunk without proper context.

Comment: Re:Can't wait to get this installed in my house (Score 1) 512

by aaarrrgggh (#49598081) Attached to: Tesla Announces Home Battery System

It doesn't take this to be off grid; the benefit of the grid is to more transparently accommodate peak loads, and due to the fact that your PV system has to be substantially oversized to generate adequate power on an overcast winter day, relative to cool summer day usage. Being on the grid lets you put that power to use.

Same thing happens with wind.

Comment: Re:Can't wait to get this installed in my house (Score 1) 512

by aaarrrgggh (#49596763) Attached to: Tesla Announces Home Battery System

The long term benefit is stretching the period over which solar power is used; this will reduce the impact of peak pricing. I like the idea; I was actually going to build a 10kWh flooded lead acid system to do the same thing. Effectively you move the cost of peaking directly to the consumer.

The potential down side is you end up with more widespread Critical Peak Pricing schemes, which jack up the cost of electricity on hot summer days to punative rates.

This would be a great solution for a local energy co-op to run low voltage wiring between homes and businesses all trying to be net producers of electricity, but I am not sold on how it works with the current utility grid model.

Comment: Re:Can't wait to get this installed in my house (Score 2) 512

by aaarrrgggh (#49592641) Attached to: Tesla Announces Home Battery System

Assuming you get 2,000 cycles out of the battery, at $350/kWh(B) it is $0.175/kWh shifted. Further assuming 80% round-trip efficiency you are at about $0.22/kWh that needs to be saved to pay for the system. Add in a 5% cost of capital and you need your off-peak energy to be $0.25 less than peak period.

Stated another way, 2,000 cycles is 5.5 years. If you combine a 4kW PV system (roughly $16k) with this, you have an annualized cost of energy of $2,400 (assuming no interest). If you stretch the life to 10 years the cost goes down somewhat, but it is still going to be expensive.

Don't get me wrong; what Tesla is offering is a huge opportunity to make renewable energy viable for the masses, and will likely buy one for my next home. It just requires energy prices to be much higher (or large subsidies) to be economically viable.

Comment: Re:Tesla battery also far larger than needed (Score 2) 329

by aaarrrgggh (#49568467) Attached to: Why Our Antiquated Power Grid Needs Battery Storage

And it's cost is twice what a lead acid solution could be made for. I priced a peak shaving battery for a commercial building, and we were looking at a cost of $300/kWh for the battery, and a savings over the 1,000 cycles of ...$250/kWh(B).

The big challenge for utilities is the 5/6-7/8PM time frame when solar production drops to near zero and lighting consumption goes up. Batteries are a good solution for time shifting noon-3PM production to this window. This will be economical when peak pricing shifts from 12-6PM to 1-7PM. It has already shifted one hour from 5 years ago. Unfortunately, this will make PV a worse payback.

Comment: Re:Curse you, Entropy! (Score 1) 483

Thermodynamics. You are using at least twice the energy to convert the CO2 and H2O to diesel as the chemical energy in the diesel. Factor in efficiency of the engine that is burning said diesel, and you are at best around 15% efficiency, but 8% is much more likely.

In contrast, using the "renewable energy source" directly yields much higher net benefit.

Effectively, this is a battery with terrible efficiency meant to make the oil industry look green.

Now, as I said in my original post, sometimes 8% efficiency isn't bad-- if it is able to use energy that would otherwise be wasted. Usually that is not the case with a process that requires heating something to 800C, but who knows.

Comment: They said the same thing of film (Score 1) 352

by aaarrrgggh (#49557329) Attached to: The Future Deconstruction of the K-12 Teacher

No different than when the "talkie" was expected to revolutionize education. The thing that drives teacher count and pay is the need to adapt the education to individual pupils.

Moreover, if the Tech doesn't have any child skills, it will likely be a 1:20 ratio, and you are right back at $1/student hour just for the tech.

Change needs to happen, but the most economical solution is parent involvement.

Comment: Re:But it does (Score 2) 128

by aaarrrgggh (#49537183) Attached to: POS Vendor Uses Same Short, Numeric Password Non-Stop Since 1990

Ok, how about the fact that credit card numbers are stored in the memory dump of the unit? When encrypted, credit cards storage uses a symmetric key? Servers are regularly stolen, but the drives are not encrypted? The software must be installed as the admin user?

From a security perspective, these units really are a POS and a betrayal of trust by the vendors. Most retailers do not have staff on-property to do IT security, so they out-source it. They have been charged an arm and a leg, but do not get a secure, reliable system.

Comment: ,UDH Worse than just Passwords (Score 1) 128

by aaarrrgggh (#49535973) Attached to: POS Vendor Uses Same Short, Numeric Password Non-Stop Since 1990

The actual presentation is much worse than just passwords.

Really pathetic that "chip and sign" won't do much to fix these issues. Disappointed that they didn't shame the manufacturer, although there are really only 3 left now among the majors.

(And sadly, the link to that presentation's directory is "writeable." Sometimes even security specialists get it wrong...)

Comment: Re:Why not let him know what to do (Score 1) 279

by aaarrrgggh (#49385375) Attached to: Ask Slashdot: Dealing With User Resignation From an IT Perspective?

For what it is worth, I am the employer.

I have had about 12 people resign in the past year. 3 Joined up to start a new company, 3 went to work for one competitor, 2 sought better pay, 2 had similar issues to pay (commute), and the remaining two made quality of life moves.

While only the three were real assholes about it, all twelve were technically disgruntled.

For the record, as a "nerd," I fully understand how to completely invade the privacy of my employees. I consider those actions unethical. They are entitled to be disgruntled, and I need to understand when they are unhappy and do my best to address it. Reality is that people that have a honest need to change, but value their employment handle things differently. They communicate well in advance of two weeks notice, and they provide options for both parties. They are not afraid of being treated like outsiders; they are still invested in mutual success.

Money is the root of all wealth.