Store Your Own Juice

sfeinstein writes "Power companies using dynamic pricing models to charge more for electricity during hours of peak usage is nothing new. Now, however, one company has decided to take advantage of this by using technology to buy (and store) capacity when rates are low and use that capacity when rates are at their highest." From the article: "The device, called GridPoint Protect, is the size of a small file cabinet and connects to the circuitbreaker panel. (The company also offers a lower-capacity version designed for homes, which costs $10,000.) A built-in computer powered by a Pentium chip will make intelligent purchase decisions, buying when prices are low, then storing the electricity for later use. That will make it possible to run your company during the workday with cheaper electricity that you purchased at 3 A.M."

Greenies have had this choice for a while.

[Myself]

Anyone running a grid-intertied home power system [homepower.com][PDF] (typically photovoltaic, but wind and hydro also apply) with battery storage has had this ability for years. If they're not producing enough of their own power to meet demand, they buy from the grid. Since the process of rectifying, storing, retrieving, and reinverting the power has some efficiency losses, buying power at off-peak times isn't always a no-brainer, but it's frequently economical to do so.

And of course, even if you don't have a battery-based storage system, scheduling your laundry to run in the middle of the night is smart. You get cheaper electricity (assuming your utility meters it that way), and you ease the burden on the wastewater treatment system by not dumping your effluent into it during peak demand periods.

Re:Nice idea, but the cost...

[toetagger1]

The summary is wrong! The $10,000 unit is targeted at small businesses with an electricity bill of $2500 a month. Also, would this count as a UPS and surge protector as well? Then this might work well for a small data center, maybe?

Re:Nice idea, but the cost...

[LunaticTippy]

You're right about the purchase price not being worth it for home users.

About the chip, you can use cheap p2 chips that take 10 watts. It's actually not completely stupid. Maybe have the controller monitor prices to take advantage of on-the-fly pricing. The plant I work at pays continually variable pricing. Intel even has info [intel.com] for embedded systems.

Re:How does it know?

[celardore]

In the UK there is a rate called "economy seven", which if I remember rightly is low rate at 0000 to 0700. And has been for the last ten+ years, and will be for the forseeable future. While the prices may change, the times don't.

When your schedule agrees with the power company's

[Mr. Protocol]

It's nice when your own schedule coincides with the power company's.

I'm a customer of the Los Angeles Dept. of Water & Power. They don't advertise the fact very widely but they have a three-tier time-sensitive rate structure for residences, which is optional. I signed up for it. They came out, replaced my electro-mechanical power meter with a computerized model, and I was off and running.

No one's home during the day. That's key. From 1-5pm my electric rate is about double what it is from 8pm-10am. But since no one's home then, I make out like a bandit. My electric bill fell by one-third while everyone else's was going up.

If your place is empty during the day you should see if you have such a rate where you live. No need for power-storing file cabinets if so.

Re:With intel inside

[Anonymous Coward]

Even where it's available not everyone participates. Part of the signup is getting a new meter installed which is capable of time metering. Keep in mind this isn't meant to save people money, that's just the mechanism. The goal is to flatten peak demand to avoid costly upgrades in the infrastructure as well as brownouts and blackouts. To accomplish that you only need a portion of your users to adjust their usage patterns (if everyone did, you'd just shift the peaks, not flatten them out).

Gridpoint in a gridlock

[dinther]

What a stupid way to sell a big UPS. As they already comment you need a power bill in the thousands $ before you save money but the specs tell me that this thing can only supply 1KW for 7 - 10 hours. Therefore it is only capable to run 2 PC's (oh make that one because it already has one itself) and a few lights. I consider that nothing compared to what you normally use if you have a thousand + power bill.

Let's run some numbers:

Say you save 50% on a power unit (1 unit = 1Kwh). Assume a unit costs $0.20

The unit can store 7 Kwh which is worth in savings a massive $0.70 per day.

I am going to be generous and allow these savings to run through the weekend thus saving $4.90 per week or $255 per year.

Based on $10000 that is a return on investment of 2.5% per annum

CNN Money reported: "The company features an all-star board of advisors, including tech guru Esther Dyson and Bill Bradley, the former presidential candidate and longtime member of the Senate Energy Committee."

Whoooaaaaa ha ha ha ha, these clowns can't even count. Yeah, I'll have the stainless steel door upgrade. Ha ha ha, this thing is a stupid investment that will have no practical benefit unless you want a UPS or solar power solution in which case there are much better and cheaper alternatives.

No wonder sensible USA energy policies are non existent. What a morons.

Re:With intel inside

[tomhudson]

We've been scammed.

I went to their web site, and your $10,000 doesn't include batteries.

All you get is a rectifier and switch, that will, if you connect enough betteries to it, give you 1 kw for 10 hours. So you can only expect to run a couple of computers off this. Nothing else. For less than $2,000 you can get a 5000 watt inverter that will put out 230 volts. Connect that to the same set of batteries. Plug your computers into it. Charge it up at night. Run your boxes off it during the day. You've now saved $8,000 + the cost of an installation into your mains box, and its a lot easier to maintain.

Re:Savings?

[rcw-home]

based on the footprint, I would assume they have a 10kW inverter and 16-22 hours of battery run-time.

I don't see how you can squeeze 576 megajoules (16*3600*10000) into something the size of a filing cabinet using lead-acid batteries. According to Wikipedia [wikipedia.org], the batteries alone would weigh 5333kg.

One other critical thing is that for every joule you pump into a lead-acid battery, you can only get about 0.7 joules out. In addition, rectifiers/inverters for that power range are usually only about 90% efficient. If the difference between peak and non-peak power in your area is less than 50%, this device couldn't save you money if they gave it to you.

Speaking of Wikipedia, they have a good writeup on how to store energy. [wikipedia.org] If it was as cheap or easy as they'd like you to believe, the power companies would do more of it for you and pocket the savings of not maintaining standby generators.

this is a home solar PV system...

[Anonymous Coward]

..without the solar PV panels part! 10 to 15 grand! It's a charger/inverter and a few gel cell batteries. Charge at night, run during the day. You might have to flip one switch twice daily to do this. And that's it! Stuck in a cabinet. You are paying thousand$ for the box and an on off blade switch! How many batts can they fit in there, three maybe?? Most of the newer charger/inverters ARE programmable, got nice screens to look at, nice buttons to mash, nifty little engrish handbooks for instructions, they HAVE a "magical" "CPU" chip thingee in there, and are designed to be grid tied. Save yourself well over half what these things cost and get thee to your nearest solar dealer, they will fix you right up, if that is all you want. For the same thing these guys charge you can have BOTH what they offer PLUS the ability to get some additional juice from the sun, later pon if you want to, you DON'T need to add the solar panels to the initial installation. BUT, if you do it right (and cheaper) the first time you CAN add the panels and the charge controller later on if you feel like it. You can get a spiffy new programmable Xantrex (old Trace brand) programmable charger/inverter for ~ 2500 clams. this is considered industry standard top shelf. "Good enough" brand 6 volt gel cell storage batteries are around 150$. top of the line amazing brand (like rolls/surrettes) are 300$, last 20 years.

Not trying to really rain on what these guys have,I think everyone should have a setup like this (I have a small one, neat), but this is serious wheel reinventing here, for a lot of money.

I guess for the technically disinclined with some spare change to burn, it would be OK. You would still most likely and legally need an electrician to do the installation to the panel or sub panel, and *maybe* the local e inspector "permit-ission"

It's still better to give your local alternative energy guy the business, and you will wind up with a lot more stored amps for the buck, and will be lots more easier to upgrade the set up.

Exploding flywheels

[sshore]

Someone's covered that. From Wikipedia's Flywheel energy storage [wikipedia.org] article:

Soviet engineer Nourbey Gulia had been working on flywheel energy storage. His work resulted in many original solutions for wheel suspension, sealing the vacuum chamber, rotation rate decline compensator and hydraulic transmission. However, the primary advance was the composite flywheel capable of rotation rates exceeding 40,000 rpm, running for up to a week when not loaded, and resistant to explosive destruction. Gulia's "super flywheels" were tightly wound of metal or plastic tape. These had tensile strength higher than that of molded steel, and in the case of failure simply unwound inside the chamber, filling it and grinding to a stop. Gulia's first wheels were made of steel tape, but the latest models used Kevlar filament, wound not unlike a bobbin of thread.

Re:Storing juice?

[Flashbck]

The long term problems with this type of system should be obvious to everyone. The power companies have a different rate schedule for a reason. Their prices are based off of demand. If enough people start using this system, then the peak times will alter and therefore the prices will become essentially a flat-fee.

Down here in the oven(New Orleans) our power bills skyrocket during the summer because of added cooling costs from the AC and fridge. As a consequence, the price of power is actually lowered to allow people to survive. There are even laws in place that prevent the power company from cutting off power due to unpaid bills because people can die without AC(it's a sad world we live in that people depend on this so heavily). During the winter months our power costs more because of lowered usage. This past winter, our rates actually were lowered a bit because it was such a hot winter. I know this seems counter-intuitive but it is in fact the case. Supposing that the end user had the capability to store very substantial amounts of power during the summer, when rates are lower and therefore used less power during the winter(a very hypothetical case), then the prices during the winter would increase because of the lowered usage. So this system seems highly worthless to me.

Re:Wastes energy?

[swelke]

I wonder if the off peak electricity is generated with a more efficient power source than the peak electricity.. which might make the the system as a whole (from generation to consumption) more energy efficient, thus using less energy (not less electricity) in total.

Usually the main power supply is a big plant with cheap fuel like nuclear or coal (usually with a touch of solar and wind thrown in). At peak times, that power source is often supplemented by another power plant with more expensive fuel, like oil-fired or natural gas turbines. So yes, the system does gain something by converting off-peak power into peak power.

That doesn't mean the whole thing is necessarily a good idea. It just means that there are arguments for it as well as against it.

Especially nukes

[ScottBob]

Nuclear power plants are the hardest to throttle back when the demand is lower. It takes days to ramp a nuke up to its rated output, therefore, once up, they are left running full blast year round as a baseline energy load. They are usually shut down during the spring or fall for maintenance and refueling because the electricity demand for heating or cooling is less. Fossil fired steam electric plants can be brought up and down quicker, but it still takes the better part of a day to bring one online. Gas turbines are the quickest to bring online, taking only minutes to spool up, and are often used for peak load times (i.e. the afternoons of hot sunny days).

A while back I remembered seeing proposals for storing excess electricity during off-peak hours in huge supercooled superconducting storage rings, but I haven't heard any more about it in years, and don't even know how such a scheme would work.

Re:Especially nukes

[david.given]

Gas turbines are the quickest to bring online, taking only minutes to spool up, and are often used for peak load times (i.e. the afternoons of hot sunny days).

It's possible to bring up a gas turbine in seconds if you're prepared for it; you leave the turbine spinning but with no actual load.

There's also a special type of hydroelectric plant called a pumped storage power station. What you do is to connect two lakes at different levels via a set of turbines. When you have excess power on the grid, you pump water uphill; when you need power, you let it run downhill. They don't have a great deal of capacity, but you can bring them online from cold in only a slightly longer time than a hot gas turbine. The one I've visited, the Ben Cruachan power station [wikipedia.org], can generate 440MW for 22 hours and can come online in two minutes.

A while back I remembered seeing proposals for storing excess electricity during off-peak hours in huge supercooled superconducting storage rings, but I haven't heard any more about it in years, and don't even know how such a scheme would work.

The problem with superconducting storage rings is that if anything goes wrong all the energy gets liberated as heat... very, very suddenly. If you had a storage ring the size of the pumped storage station described above, you'd end up dissapating 6x10^11 joules of energy... about the equivalent of 150 kilotonnes. Yum!