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Solar power is catching on. Along with it, other things are changing. Selling back to grid only gets you credit towards your power bill which you need to use up in 6-12 months or you lose it (someone who recently got solar told me this is how it works for him).

I would like to see ways for customers to sell power among themselves (if possible) in this case. If I generate some extra power and someone needs it to charge their car, i'd rather sell it to him. Instead of the shady power company. But maybe it doesn't work like this.

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Ignoring the time limit you mention, I fail to see the difference? Electricity isn't tangible. In the case of AC, they're just wiggling the electrons in your appliances back and forth. Any promise that your power goes to your neighbour, via the grid, would be a lie.

In financial terms, letting anyone sell electricity to the "shady power company" at the same price they buy it at is only possible as a government-mandated subsidy paid by all customers, intended to promote clean energy. It effectively makes the grid your free, unlimited, zero-loss battery.

If you want to sell it to your neighbour at the same price they and you pay to have the grid wiggle your electrons, there's no difference. If you want, for unfathomable reason, to set a different price, you can just walk over and hand them some money whenever you feel like it. But currently, there are no circumstances under which it would make sense to not sell as much as you can to the power company: if you're producing at costs above grid prices (still likely in most locations), your neighbour could always get his power cheaper from the grid. If you're producing below grid prices, selling as much as possible at the subsidised rates is your best choice.

> In financial terms, it's extremely generous to let anyone sell electricity to the "shady power company" at the same price they buy it at.

In some countries, it's even a better deal, because the "shady power company" has to buy it for more than they sell electricity for. (I don't know if it's still true, but it was the case in France)

I think the previous commentator's point is that distributing power between neighbors is a theoretical way to avoid the time limit imposed by the power company. Of course, with current infrastructure I assume the power company would still need to support this model by doing some simple math with everyone's meters in a neighborhood or region.

If the time limit is 6 months as he say and you have excess panels to cover average winter needs, summer surpluses are lost

More importantly it was left unspecified if the discount given was dollar for dollar electricity. If it's less than that suddenly your ideal, infinite battery becomes less than perfect

But I agree selling to the neighboor is not gonna work - a feasible alternative would be to have the resources pooled for building a larger panels with a larger battery

"they're just wiggling the electrons in your appliances back and forth"

Sorry for highjacking your comment, but are there any physicists here who can comment on whether this is accurate? More in particular, does electricity have mass? Is 'current' electrons moving across a wire, or wiggling without 'moving'?

I've asked this years ago on the physics stack exchange, but I never got an answer I actually understood. The context for my question was a legal paper I was reading whose core argument relied on 'current' having mass, or rather, the consumption of electrical energy requiring the transfer of mass, however small. Note that there is an important precedent in my jurisdiction (the Netherlands) that sort of assumed this back in the 1930's, but in this particular argument (on ownership of virtual goods, like a sword in World of Warcraft), the issue of the mass was even more pertinent.

(note that I'm not interested in debating whether that matters re: ownerships of virtual goods; in my legal context it does. And yes I have a law degree. I'm just putting this in because I've asked several times in several places over the years, and there are always people who like to go 'XY problem!' and then make ridiculously wrong pseudo-legal arguments.)

The comment is accurate, and electricity should not be considered as having mass.

In a direct current (DC) setup, electrons will be moving continuously though the wires in a big loop. But the displacement of the electrons is not the electrical energy we are interested in.

It is instructive to think about alternating current (AC). In this case, electrons will be moving a bit forward, and then a bit back. So, basically wiggling more or less in place. There is still a lot of energy transferred.

A metaphor is a chain, like in a bicycle. You can use the chain to transfer energy, but it is not the chain links that are the energy. The movement is the energy. This is similar to electricity; it is not the electrons that move that is the electrical energy, instead the electrical energy is the movement itself.

(Due to Einstein's theory of relativity, we know that E=mc^2, which can be summarized as "all forms of energy are also mass". Considering this, all transfer of energy is transfer of mass. But it is miniscule. A small nuclear power plant could produce 4450 GWh in one year. The relativistic mass of this is 180g. All the energy produced in one full year of this plant has a total mass of 180g. So you should not consider electricity to be transfer of mass, even though it technically is :P )

(Also, since you asked for a physicist: I am not a physicist)

No worries, I'm using a loose definition of 'physicist' - anyone knowing about physics is fine :)

Thanks for your contribution; as I mentioned below, I've gotten some different answers, e.g. on http://physics.stackexchange.com/questions/2188/does-electri... where I asked the first time. Essentially, are you saying that with DC current, there is transfer of 'mass', but with AC, there isn't? In the case such as I've explained it elsewhere in this thread, this might mean that it matters how a computer is build to decide on whether the virtual sword can be stolen or not... (maybe, I haven't really looked hard at it in a few years, so I'm probably forgetting some details of it).

[Similar disclaimers about not being a physicist go here]

Something that's going to be a bit tricky here is that electrons are really, really slow when we're talking about electricity through a wire. The electrons will bounce around very quickly at random, but the average flow caused by a current is slow. Really, really slow.

https://en.wikipedia.org/wiki/Drift_velocity

For a specific but not unreasonable example:

> Therefore in this wire the electrons are flowing at the rate of −0.000023 m/s. At 60 Hz alternating current, this means that within half a cycle the electrons drift less than 0.2 μm. In other words, electrons flowing across the contact point in a switch will never actually leave the switch.

That kind of speed means that any messages sent over a copper wire are not going to be sending electrons all the way for that message. The electrons that 'carry' the message "I AM A VIRTUAL SWORD" will not go from my machine to yours as a rushing block. Instead all I'll be doing is tapping the end of a very long pole connecting our two properties, so you can read the message by the patterns of the end of the pole in your house moving ever-so-slightly.

So, I guess I am transferring mass, but nothing that comes from me goes to you.

This also assumes a very particular direction. There's nothing, as far as I'd understand, that requires me to be pushing electrons at you. I could be pulling on the pole slightly rather than pushing.

I'd love any corrections or additions to this, purely my lay understanding of the topic.

Even ignoring the speed of the electrons, this ignores that several steps of that route will almost certainly be done over fibre anyway, and at that point there is clearly no transfer or electrons from the "seller" to the "buyer". Although I have no idea whether or not this is relevant to the legal question at hand…

https://en.wikipedia.org/wiki/Effective_mass_(solid-state_ph...

Water is another good analogy. When you turn on a tap/faucet, the water that comes out is the water that was just sitting there in that last few inches of pipe, it didn't come all the way from the city's dam in that time.

Also with waves in water; put a ball floating at the beach and it'll mostly stay put bobbing up and down. (It's only when the waves actually break that there is substantial movement of actual "bits" of water.)

Ah, I apologize, but I have to join the unhelpful choir ;)

It seems to me that the question of whether or not electricity has mass is a proxy for whether or not information is tangible. This is the same interpretation that "Greg Graviton" at stackexchange has. And it is hard to meaningfully answer by yes or no; information needs material in order to exist, but by itself it is not tangible. Both yes and no are misleading.

My advice, which is completely ignorant of how law is practiced, is to find another way to settle the original question of whether or not the coerced obtaining of the virtual sword could be named "stealing". When taking intuitive notions such as "is this a _thing_ or not?" to the fundamental levels, the questions often stop making sense, as it has in this case, because the intuition is dependent on another level of abstraction. At this point it is no longer constructive to attempt obtaining answers to the questions as posed, and maybe this is why you have struggled to find a good answer. That's probably not helpful to you, but it is my best attempt at resolving this question :)

(About DC: It is more accurate to say that there is an exchange of mass. The same count of electrons go down the wire as up the other wire. There is no net transfer of mass. See also https://news.ycombinator.com/item?id=14087221 )

The "big loop" concept is fundamental: the power lines we use to move energy around are all closed loops, so, even with DC, the mass of electrons that flow in one direction is the same as the mass that flows in the opposite direction. There is no transfer of mass.

This is different from ectrostatic generators: there, AFAIK, there should be an actual transfer of mass. https://en.wikipedia.org/wiki/Van_de_Graaff_generator

Can you elaborate on the legal details of that 1930s case in The Netherlands please and how electricity being massless would change it.

First, note that that wouldn't change with electricity being massless; the argument in the paper I mentioned would.

Turns out it was in 1921, but either way: there was a dentist who blocked his electricity meter by putting a pen in it (it was one of those that turned to take the measurement). The question was: did this qualify as 'theft', because, according to Dutch penal code, theft requires the 'appropriation of any good'. The argument was that electricity is not a 'good' (Dutch civil law has a particular concept of a 'good', and being physical is one of the criteria. Note also that I'm not writing a paper here, and that I'm using loose translations for terms that are well-known concepts, so I'm probably making several technical mistakes here). The Supreme Court however decided that electricity was still a 'good' because it represented economic value (that was one line of reasoning, they didn't actually say 'electricity has mass, hence it's physical, hence it's a good'). The paper I mentioned then concluded from this that the Supreme Court had decided that electricity has mass (because it was considered a 'good', and 'goods' need to be physical - which is why e.g. what we now call intellectual property is not a 'good'. This has far-reaching consequences.)

So the paper went on to qualify virtual swords as goods, and then proceeded from there. There are more criteria for being a 'good', like something has to be uniquely identifiable; so the author couldn't make a straight analogy to the electricity case to make his case for virtual swords being 'goods'; I don't recall the details exactly but in the end, his qualification of virtual swords as 'goods' came down to electricity having mass. He said, essentially, that the 'sword' is the movement of electrons through systems, and that therefore it could be qualified as 'theft'. There was a separate argument about intellectual property as well of course, I don't recall either, but there was a reason that wasn't material in the precise question being asked. The whole point was of looking at the case of some people (physically) forcing a boy to transfer his virtual sword to them in some online game, and whether that constituted 'theft' or 'robbery' (which requires some aspects of the 'theft' aspect).

(Edit: also, the paper was written by an engineer who also had a law degree (maybe this paper was part of his degree, I forgot.) This is not some case of 'haha idiot lawyer'.)

See https://en.m.wikipedia.org/wiki/Electric_current#Drift_speed

I think a decent analogy is a pneumatic air power distribution system. Air particles move randomly in the pipe, but if the air is flowing, they tend to pass through the customer in a given direction and get work done. Alternating current is akin to switching the direction of air pressure twice a day, from (say) 1.5 atm to 0.5 atm.

Well, when I asked before, people said that hydraulic or pneumatic systems are not apt analogies; because there is water, oil or water actually flowing. Now it's not the water that is the energy, it's the movement thereof, or the pressure. That's where the analogy starts to break down.

For reference, the first time I asked was here: http://physics.stackexchange.com/questions/2188/does-electri... (7 years ago - time does fly). There is a bunch of discussion there (also going into at what point a water analogy breaks down), and I'm not sure they agree with each other. I mean, another way of looking at it: you can encode n bits by charging (or not charging) capacitors. Does a series of capacitors encoding '0' have a lower mass than a series encoding '255'?

So yeah I don't really understand, still not after all those years. It's probably (in part) because I have not formulated one single yes/no question that is unambiguous or does not need any interpretation to be answered. Or maybe I'm just stupid.

There is also electrons actually flowing. As far as movement of mass goes, the pneumatic system analogy is a good one. It is not a mathematically identical system.

Look, you can just look at how this stuff works. Electrons move randomly, and when there's a current they move on average in a certain direction because the electric field leans that way. That's it. See my link I pasted above, it describes what happens when a current is flowing.

A capacitor encoding '0' will have the same number of electrons as when it encodes '1' because that's the way capacitors work. You can read about it at https://en.m.wikipedia.org/wiki/Capacitor

Disclaimer: I am not a physicist.

> the consumption of electrical energy requiring the transfer of mass, however small

Does precedent talk about transferring mass of electrons? Otherwise the transferred energy also has mass, via mass-energy equivalence.

> but in this particular argument (on ownership of virtual goods, like a sword in World of Warcraft), the issue of the mass was even more pertinent.

This on the other hand is on a bit more tenuous grounds. In theory you don't actually have to move energy (and thus mass) around to move information if you use physically reversible operations. But all practical computers use irreversible operations, which means information is sent by expending some energy, this is obvious in sending photons down a fiber or radio waves being able to power a lightbulb.

https://en.wikipedia.org/wiki/Landauer%27s_principle

This question, or variants of it, comes up on electronics.stackexchange a LOT. It's rather hard to explain in a compact way. You can either start with metaphors (which collapse under examination) or the maths (which most readers find impenetrable).

Current is measured in amperes, which have two definitions:

"a unit of electric current equal to a flow of one coulomb per second"

"that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross section, and placed 1 meter apart in vacuum, would produce between these conductors a force equal to 2 x 10-7 newton per meter of length"

Right away one of those definitions mentions charge (coulombs) and the other one doesn't. This is actually a better approach because while charge is usually carried by electrons, this is not always the case. Charge in semiconductors may be carried by "holes". Charge in batteries is carried by ions. Capacitors are usually considered to have a "displacement current" flow between the plates that has no carrier at all.

HOWEVER! For the purposes of the question here, we can skip all that and focus on the electrons in your appliances. Specifically, we can see that there's a complete loop between them and the substation/pole transformer feeding your house. You have no direct connection to the HV lines.

Perhaps you could say "the power company causes a magnetic force which moves the electrons in their transformer back and forth, which by electrostatics pushes the full loop of electrons in their and your wiring back and forth, which does useful work in your house".

Simple.

You're overlooking the value of off-grid power storage, severing reliance on the grid.

> Electricity isn't tangible.

Quibble. Electricity is tangible. Use your finger to complete a circuit. My bet you will perceive it by touch.

I guess you could contract with your neighbor and run your own lines to their batteries?

A scheme used here in Australia is to sign up your PV+battery to a virtual power plant, then sell electricity on the wholesale market when it is profitable to do so.

e.g.: Reposit Power http://www.repositpower.com

Tesla will be doing the same with their vehicles and Solar City's tech team: distributed virtual generators and demand. ISO operators will be able to issue price signals, and Tesla will be able to supply to or draw power from the grid (in accordance with their customer's wishes of course) in aggregate

It's probably why Tesla wants to sell people the power wall despite its own shortcomings. Why give that power back to the grid operators who are going to screw you over? Just get a battery storage solution that also charges your car and maybe covers some of the power consumption in the home? I think in the long term this is the only viable option or until the grid operators and other concerns outlaw usage of battery tech that stores power in advance of daily usage.

Grid operators would love it if you leveled out your energy usage in that way. They see the duck neck coming: https://www.caiso.com/Documents/FlexibleResourcesHelpRenewab...

Solar power is catching on but it does not work on all roofs in all locations and I am curious if companies pushing home roof top installations are upfront with their numbers.

I know our local energy co-op lets you "invest" into a facility they have constructed where they are adding panels as demand increases. The logic here is, not outlay of funds by the home owners, maintenance needs are consolidated to one location, and it can be ideally situated.

Until panel installs become near maintenance free and service technicians are common where inspections are fast and cheap its not going to solve our problems.

I am hoping TESLA's previous announcement related to solar shingles and such plays out well. It needs to become cheap enough that even if your system is not ideally situated its cheap enough to be economical.

I'm sure you could, but you'd have to lay your own cable to your neighbor. If you want the power company to transmit the power and handle load balancing, you will end up paying for it.

A Powerwall helps with being able to store charge for yourself.

It'd be awesome to share power directly with neighbors, too. You could always install your own cable, right? Doesn't seem like the power company would even need to be involved.

In Australia at least, there are regulations against installing power cabling that goes between premises (unless you're a power company, of course).

Same in California. The rule is that the cabling can't cross a street. So actually you could provide power to neighbors within in the block but not the next one.

We're not even allowed to run cable between two adjacent properties owned by the same company. (A former employer of mine got around this with a "temporary" 3-phase cable going between the two, but it was regarded as a bit dubious.)

In many places the streets form a grid, it's true. You would possibly have only a dozen homes that could be connected. In other places, the streets are arranged as a tree with cul-de-sacs as the leaves. An island of acreage could emerge in such developments where you could visit dozens of homes without crossing a street.

Yep, they're so strict that the National Broadband Network was worried that simply powering distribution point units for Fibre-to-the-Curb internet would break those rules.

I suppose that it's a good idea to take precautions against accidentally running multiple AC devices in the same room that might be connected to very different branches of the AC distribution network. An AC connection is not the internet, where you can safely make any independent topology change as long as you set up the right routing metrics.

So you would need wireless transmission. Hmm, the spectrum is regulated, but there are bands with more freedom...

It's funny how power companies quickly moved away from the pay you cash for your power to credits to now fixed rates for life. Solar is a huge disruptor.

It was obvious that pay you for power was not scalable. Eventually you'll see people disconnecting from grid altogether to avoid fixed rates.

There's an interesting project called Solar Coin[0] attempting to do this. I'm not too sure how it relates to crypto-currency, though. [0] https://solarcoin.org/en/front-page/

What about Folding@Home or other high energy computing tasks.

If you have your PS4, XBOX, home desktop, SO's laptop, etc running high intensity tasks how much energy would that be?

The biggest power consumer is things like Geysers, kettles, stoves and so on. A desktop running at 100% uses like 200W whereas a geyser uses like 2kw.

The biggest power consumer is electric heat/ac.

http://www.torontohydro.com/sites/electricsystem/residential...

My high end gaming PC would push over 500W when mining Bitcoin (actually Lite coin) back in the day.

Side note: Swype keyboard will not allow me to write Litecoin as one word with a bracket after it, no matter how much I correct it.

When autocorrect refuses to cooperate I find that spacing things out between normal words then deleting the spacers usually works. Correction usually only occurs after typing punctuation, not for deletion.

Litecoin and []

Litecoin []

Yeah, that seems to be the only way to do it.

(Litecoin)... Strange, it's changed its policy now.

I mined Ethereum last summer on a 6 GPU, dual-PSU rig. Each GPU consumed roughly 220W-250W IIRC, so the heat and noise was considerable.

That's one panel worth of power, theoretically.

The heat from that would be horrendous. A typical space heater consumes about the same as that.

Even at just 500W my machine would heat the room considerably over a few hours.

> Geysers

For those wondering, that term means hot water heater.

If your hot water heater resembles a geyser, you need to call a plumber ASAP.

Electric hot water heater. For those with too much money in their bank account.

2kW when the faucet is running, about zero when it isn't. With a duty cycle of 1% (= running hot water for 15 minutes a day), that desktop could beat your geyser, even when running at 10% throughout the day.

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