In order to "dispatch" power as-needed, you need buy in from municipal power companies to grid-connect the supply (or generation). As we're seeing (eg. in Hawaii), the power company becomes less-and-less incentivized to permit grid-connections as the rate of decentralized supply (or generation) increases.
What I'd really like to know: How will the power companies adapt to new, decentralized generation (or storage) on a massive scale? Or alternatively: The municipal power companies budgeted their massive expenditures over decades; does this analysis account for all the expenses municipal power companies will necessarily incur (and pass to consumers) if the status quo shifts?
Homeowners in Hawaii are using batteries to go completely off the grid, so as to not be required to get permission from the utility for their solar grid tie connection.
The upside is, once the utility comes around to investing in their transmission infrastructure, they can receive power from those houses.
“I’ve actually taken people right off the grid,” he said, including a couple who got tired of waiting for Hawaiian Electric to approve their solar system and expressed no interest in returning to utility service. “The lumbering big utilities that are so used to taking three months to study this and then six months to do that — what they don’t understand is that things are moving at the speed of business. Like with digital photography — this is inevitable.”
Well, right now many of the Independant System Operators (ISO's) have specific markets for frequency support which are theoretically separate from the market for energy supply. So as distributed renewable dump-as-much-as-available style generation gets added to the grid, in principle the price for frequency support increases. In the same vein, distributed energy storage works very well for frequency support, which can drive the price for that service downwards.
That still leaves the wires themselves. At the residential level, you typically pay a flat connection fee for the wires (and distribution and maintenance thereof). Commercial sites pay a Demand Charge for their peak total power consumption at any time during the billing period. So that's how the interconnect infrastructure gets paid for - the commercial demand and residential interconnect charges.
Power is currently dispatched according to the most efficient units run most frequently. Peaking units run only when it is most cost effective, i.e. power is needed and there are not cheaper options. Yes it is possible to store the energy (one method is pumped storage) for peak shaving, but different methods have different break even points.
Also of interest is the Clean Power Plan and how it will change the generation mixture.
A battery is not available 24 hours as the article indicates. There is the time to charge and the time to discharge. There is also the time for maintenance activities on the batteries.
If a battery system or solar system is installed then it breaks and power is wanted from the local utility, the utility has the costs associated with supplying that power with less time in use although it is expected to be available at need and at the peak demand for all customers. Will end users be willing to pay for the emergency back up or will another solution be found? How long will it take to repair battery or solar when it breaks? And what do you do for power until is repaired (if you don't use the utility)?
Using more energy efficient building technologies, e.g. ICF or something like enteria.com; will probably be useful in combination with batteries. And using a chest fridge as a refrigerator can also help: http://newlifeonahomestead.com/convert-chest-freezer-to-frid... (one example from the google search results).
It is an interesting time as energy use and supply are modified. 30-50 years ago, a 15-50 minute outage wasn't that big of deal, but today it is expected that power is always available. Interesting how our perspective changes.
Arbitrage. The price of power changes every few minutes (wholesale) to a utility. They shield you from this with flat rates per kwh or tiers. With battery arbitrage, you switch to a time of day metering scheme where you're exposed to dynamic pricing. The benefit, of course, is that you can charge when power is cheap, and run off your battery when power is expensive.
A great example: I reside in Illinois for part of the year. My utility provides power from nuclear plants, which cannot be idled. That means, at night, I can get power between midnight and 5am for about 1 cent/kwh. If batteries get cheap enough, cheap power + batteries means I save money.
Most electric vehicle charge controllers are already "smart" in this regard, and can charge when power drops below a certain price.
The only problem with this is that this will be a zero sum game.
If peak power consumption drops electric companies will start charging higher rates for off-peak hours or drop the off-peak rate completely.
Anything that will eventually lower the revenue of the electrical companies won't really be supported by them, however if they can employ batteries to "flatten" their peaks they might be contempt with keeping the current rates as long as is financially beneficial for them.
The peak hours are when electricity is most expensive to generate. And transmission lines etc. need to be sized to the peak.
That's one of the reasons that rooftop solar actually makes a lot of economic sense anywhere that aircon is used. However, the people who generate that electricity receive no direct reward and will probably be accused, by the very utility that benefits, of being subsidy junkies or parasites.
When utilities have calculated the "value of solar" its come out as much higher than the price currently paid to homeowners.
Personally, I love the idea of neighborhood-level collection and distribution. If everyone is collecting throughout the high-output times, when the high demand times come, less has to come from the overall grid. Also, when power is cut/damaged for an area, systems could be smart enough to prioritize across the neighborhood.
Imagine a system that keeps the refrigerators and freezers running - to protect food - but doesn't run the AC or dishwasher or lights. Not perfect but way better than losing food.
It's a zero sum game from the point of the consumer, if you "exploit" the current day/night difference and the electric companies start to lose money they'll increase the tariffs to compensate.
> The only problem with this is that this will be a zero sum game. If peak power consumption drops electric companies will start charging higher rates for off-peak hours or drop the off-peak rate completely.
Which will push those who can to local rooftop solar generation. We've already entered what the utilities refer to as a "death spiral" [+].
> Anything that will eventually lower the revenue of the electrical companies won't really be supported by them, however if they can employ batteries to "flatten" their peaks they might be contempt with keeping the current rates as long as is financially beneficial for them.
Solar is still very expensive at around 10K$ an upwards in the US and considerably more expensive in Europe, solar is also not an option for the majority of residents in the big cities where electrical supply is usually a bigger issue.
I'm personally not a big believer in residential solar, it can't be as efficient as dedicated solar installations and the cost overhead for so many small scale installations pretty much outweigh the benefits in the long run. I do however believe that many smaller communities should be powered with renewable energy where possible. It can allow you to build much bigger and more efficient installations of wind and solar, won't require you to convert it to high voltage in order to connect it back to the grid/transfer it along large distances and your energy storage is also much easier.
> Solar is still very expensive at around 10K$ an upwards in the US and considerably more expensive in Europe, solar is also not an option for the majority of residents in the big cities where electrical supply is usually a bigger issue.
It's $3.50/watt fully installed in the US currently. There is a 30% tax credit that expires at the end of 2016 (drops to 10%). That's a great deal for a system that will generate power (warrantied) for 25+ years. If you're in the city or someplace you can't get rooftop solar, you can usually purchase wind or solar specifically from your utility (depending on local utility regulations and laws).
> I'm personally not a big believer in residential solar, it can't be as efficient as dedicated solar installations and the cost overhead for so many small scale installations pretty much outweigh the benefits in the long run. I do however believe that many smaller communities should be powered with renewable energy where possible. It can allow you to build much bigger and more efficient installations of wind and solar, won't require you to convert it to high voltage in order to connect it back to the grid/transfer it along large distances and your energy storage is also much easier.
Renewables should be installed wherever feasible, whether on rooftops or at utility installations. We need every clean watt we can get.
Yeah you can purchase solar/wind from your utility provider usually at a huge premium, that combined with usually less efficient power infrastructure, single rate meters, and apartments which tend to be less energy efficient than private houses means that you either need to be quite well off or very dedicated to pay it.
Yes renewables should be installed where feasible, but actually feasible not feasible because it's cool, good PR, or under the current tax credits efficient. Small installations are costly, you spend quite a bit of energy in installing individual setups, and maintaining them in terms of efficiency you are better off centralizing your efforts if you really care about the environmental foot print.
> Yeah you can purchase solar/wind from your utility provider usually at a huge premium, that combined with usually less efficient power infrastructure, single rate meters, and apartments which tend to be less energy efficient than private houses means that you either need to be quite well off or very dedicated to pay it.
It's only about 2-4 cents more per kwh to get 100% renewables. I don't find that to be a "huge premium", nor do you need to be "well to do" to afford that. If we properly priced the cost of coal and other dirty fuels into their per kwh costs, renewables would win by default.
> Yes renewables should be installed where feasible, but actually feasible not feasible because it's cool, good PR, or under the current tax credits efficient. Small installations are costly, you spend quite a bit of energy in installing individual setups, and maintaining them in terms of efficiency you are better off centralizing your efforts if you really care about the environmental foot print.
We'll agree to disagree! I'm not worried, as tax credits will be around for another 14-15 months, at which point solar and wind will be even cheaper than they are now.
Not everyone lives in the states, if I use a "green only" supplier where I live in the UK I pay 25-30% more and that's without counting the night rate loss.
For me that almost doubles the electrical bill, that's a huge premium I can pay but i rather not spend another 800 GBP on a "green supplier".
Not to mention that it's not like I would get my energy from a renewable source, I get it from the grid, yes the green energy company will get some of that money but It's not that straight forward.
Especially considering that those "green providers" are allowed to buy electricity from other suppliers while technically remaining 100% green, most of them are running at a "power deficit" and cannot cover the energy that they should be putting into the system with their current production.
I think they were referring to the fact if you pay for your own solar system you can generate electricity for $0.06/kWh over the life of your panels. Where your electric company wants to be the ones to buy the panels for themselves and charge you $0.17-$0.32/kWh - a huge profit for them.
That's why you see utilities in California pushing for 50% renewable energy source requirements while at the same time fighting to end net metering for consumers. They are fighting to protect their own profits in the face of cheap solar panel availability.
That's over the life time of the panels, which for most installation is quoted at 25 years.
The 0.06$ figure only works if you actually keep them for the 25 years, most people do not live in a single home for 25 years these days.
The figured also does not include potential maintenance that needs to be conducted on the system, as well as part replacements for most installations I've seen only the panels were insured for 25 years and again only against an internal catastrophic failure, which usually only kicks in after 50% drop in efficiency.
Other parts like the inverter, wiring, mounting frame, regulator bank, power storage might very well fail within those 25 years, and most importantly 25 years is more than the life time of most composite roof tiles these days, depending on the environment you live and your roofing in you might need to do roof maintenance every 5-10 years and usually replace the roof every 20-30 years.
And this is without taking into effect environmental affects on the system like salts in the air if you live on the coast line, hail and frost damage, and the potential very likely obsolescence of the panels them selves.
I'm a huge supporter of solar, but I'm not a supporter of residential solar, not at this time for sure, if the panels become very cheap to make to the point of becoming carbon neutral and breaking even say within a year (heck i would even take 2-3) sure, but even then it's still most likely be much more efficient and so environmentally sound to have them in a central location where hybrid PV and Thermal solar panels can maximize the amount of energy gained per surface area while providing a system which is easier to maintain and upgrade.
Actually 25 years is a pretty good match between roof and panel lifetimes.
It doesn't matter who lives in the house, or for how long, for payback costs. Solar panels are no different from the rest of the roof in that department. When you sell the house, its value is estimated from the age of the fixtures, and that all comes out in the price.
But I'm with you on the central-solar issue. Its got to be vastly more efficient to create a planned installation, than to slap solar on every roof in the neighborhood.
It's jargon, it just means using the energy, with some implication of centralized management. So as an example, natural gas peak load plants are dispatched when there is a sudden increase in demand.
There always is sense in self-renewing energy sources. Especially, when it comes to saving our environment and lives. Implementing of such batteries would be beneficial for everyone. And it would finally let the mankind get rid of petroleum fever, which is now a source of all evils and the main cause of all wars.
If we could get in-house/building DC power (not to replace but to complement AC power) and get industries to make digital products work with this we could get another substantial savings in energy efficiency. Plus digital products would cost less b/c they wouldn't all need AC to DC adapters.
Unfortunately, unplugging DC power plugs under load tends to damage them much more than the equivalent AC plugs. Similarly, DC rated circuit breakers and fuses are much larger than their AC counterparts. The reason is that the zero-crossing of the AC voltage waveform naturally allows the developed arc an opportunity to be extinguished. DC current/voltage has no such zero crossing.
I doubt that anyone would be running space heaters or ovens off the DC part of the system. The idea is more to prevent having to do a zillion high voltage AC to low voltage DC conversions.
The problem with low voltage DC wiring is that it requires much more metal to prevent serious losses in the lines. You could switch to higher in the lines and then a converter in the wall but then you're back to the same circuit breaker problem. AC deals with this by the fact that zero crossing gives a great way to break arcs and you can convert it to DC really efficiently.
I believe the idea is probably to have one large switchmode converter running off the mains at the POE that supplies, say, dual rail 20VDC / 5VDC throughout the building, replacing the umpteen smaller converters in the average house.
That's the point, if you don't do the conversion to low voltage at the source you lose a lot in losses from the resistance in the lines.
Let's say you're using the normal 14 gauge solid core wire commonly found in houses right now for a 5V supply. A 200ft run of that in the house (both ways) isn't out of the question if there's a central supply in a 2 story building. That's about 1 ohm [1], which doesn't sound like much at first until we look at what it ends up meaning.
A phone might take an 1 Amp to charge at it's fast rate (tablets 2 or more), so we've got 1 Amp, with a 1 Ohm resistance. That means we're going to have a 1 Volt drop to that outlet, which means the phone is likely not going to charge at the correct current since it'll only see 4 Volts at the outlet. It also means you've just had a 20% loss in the power line in order to have a larger central power supply.
Combine that with the fact that most Switch-Mode Power Supplies aren't actually that efficient when not under load (part of the problem) then it might not be unreasonable to have it running at 80% efficiency to begin with. At this point you're down to 64% total efficiency instead of the 80-90% that the small wall warts end up getting you.
You could use a higher voltage, 48V isn't uncommon because of the telephone industry, but then you need conversion at the outlet again and end up with the same problem you've got with wall warts.
The other option is to use more copper to carry the current, say 10 gauge, which brings the losses to 0.4V and about 10% losses, but you need 150% more copper than 14 gauge.
Trying to regulate 5V across 14Ga wiring isn't anything anyone would do. If 48V became some sort of DC standard then devices would work off 48V. That might not make sense of course and how much sense it might make could depend on line voltage (120V vs 240V).
There is a cultural thing here too. If you live in a place where all heating is done with combustion then there is no particular reason so not do everything with low voltage DC. Now that lighting is LED based there wouldn't be anything that would need the higher voltage and power.
No it's absolutely not what someone would do, but it is what the grandparent proposed, that's why I addressed it. I'd love to see it used for more efficient lighting, as if it was done correctly I think you could get some pretty nicely efficient and long lasting lights that way with a bigger better current driver for the leds. This might be a good idea to move Track lighting to since they'll have more freedom on the sockets and interfaces.
As far as other devices needing the AC power, you've got hair dryers, kettles, vacuum cleaners, air conditioners, water pumps, etc that all need more power than would be reasonable with low voltage DC (some might need 25-50 amps to run at the same power they currently use). All of that just means you'll still have the AC running through the house for a very long time anyway, so you'll end up with nothing changing.
Yes, I imagine if you have a large 2 story house with 30 metre cable runs you would need to use a backbone of solid bus bars, with shorter runs of cable to the outlets.
As I said, I have my doubts it would be a win anyway - for much the same reasons: I^2R losses and because I'm not sure that large switchmodes are significantly more efficient than smaller ones anyway.
however within substations, or perhaps subdivision localized power storage facilities, or lets go even further, charging stations for cars, I can see it.
Utility setup and managed charging stations replete with a lot of battery storage soaking up wind, sun, and base line power when off peak usage times, providing both a source to recharge EVs and serve peak power usage times. To insure adequate power on hand they could charge EVs based on time of day to move people off peak.
because honestly, the last thing I want in six hundred to thousand pounds of lithium batteries in my home.
I've got pressurized natural gas lines into my basement and running to my hot water heater, to my furnace, and to my stove. These appliances actually release and burn that gas, sometimes only a foot or two away from me.
It's kind of crazy, if you think about it. I barely know a thing about how these work and why they are safe. I just pay professionals to show up and install or maintain the things--and that happens very rarely. No one has looked at my stove or water heater since the home inspection years ago.
My point is, there are seemingly risky technologies all around us, which we ignore out of familiarity. I'm not going to buy the very first Tesla battery--I'm not an early adopter in general--but I see no reason to reject lithium-ion battery technology entirely. I mean, I press a small lithium-ion battery directly against my head on a regular basis, with only a thin sheet of glass to protect me.
the last thing I want in six hundred to thousand pounds of lithium batteries in my home.
Think for a second.
If there was danger to the batteries then like a propane tank or similar thing, a home battery would be in an enclosure some distance from one's house.
What I'd really like to know: How will the power companies adapt to new, decentralized generation (or storage) on a massive scale? Or alternatively: The municipal power companies budgeted their massive expenditures over decades; does this analysis account for all the expenses municipal power companies will necessarily incur (and pass to consumers) if the status quo shifts?