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Another Step Forward In Small Scale Electrical Generators

timothy posted more than 2 years ago | from the still-won't-let-you-take-it-on-the-plane dept.

Power 137

NicknamesAreStupid writes "Product Design & Development reports another breakthrough in small scale solid oxide fuel cells. This methane-fueled cell achieves about 50% efficiency at around 2kW, enough to power an average home. It does so by efficiently recycling its heat to perpetuate the process. Of course, this is not practical for most homes, which only have natural gas that contains nearly one fifth impurities. However, that could change if gas suppliers refined their product."

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How small is small? (3, Interesting)

fahrbot-bot (874524) | more than 2 years ago | (#40202595)

Could it be used on board an electric vehicle to provide power in lieu of a battery?

Re:How small is small? (5, Informative)

Anonymous Coward | more than 2 years ago | (#40202645)

Could it be used on board an electric vehicle to provide power in lieu of a battery?

No. Even though solid oxide fuel cells work and are commercially available (in larger sizes), they have problems for automobile applications - to run efficiently, they operate close to 1000 degrees C, and they don't like being bounced around. Dealing with that kind of temperature in a car is a problem.

For mobile applications, PEM fuel cells [wikipedia.org] are far more likely to be practical.

Re:How small is small? (1)

Anonymous Coward | more than 2 years ago | (#40202761)

Yeah, but you need a lot of platinum for those (though it has been reduced in recent years). Hmm. Who can we invade? Zimbabwe has lots of platinum. We could even say that we're doing it to give them freedom!

Re:How small is small? (1)

Anonymous Coward | more than 2 years ago | (#40203029)

Asteroids anyone?

Re:How small is small? (3, Funny)

mfnickster (182520) | more than 2 years ago | (#40204863)

No, I don't think giving them Asteroids will please them either. Pac-Man or Galaga, maybe.

Re:How small is small? (1)

barv (1382797) | more than 2 years ago | (#40203503)

"they operate close to 1000 degrees C, and they don't like being bounced around. Dealing with that kind of temperature in a car is a problem."

Gosh. You mean my diesel cycle runs at less than 1000 deg C?

Re:How small is small? (1)

Anonymous Coward | more than 2 years ago | (#40203655)

Yes, but your diesel engine can start making power at 20 C or 0 C and sometimes -20 C. The fuel cell will not make power until it is over 500 C. And due to its mechanics and design, it would take an hour heat up to that temperature and longer to its peak efficiency. It might be plausible for a semi-truck, but for most vehicles this delay would be too long.

Re:How small is small? (2)

Amouth (879122) | more than 2 years ago | (#40203677)

Your diesel runs significantly less than 1000 deg C. most run at ~550C or less.

Utter Crap (2)

barv (1382797) | more than 2 years ago | (#40204059)

"Your diesel runs significantly less than 1000 deg C. most run at ~550C or less."

For instance look at figures 5 and 6. http://www.engineering-4e.com/diesel.pdf [engineering-4e.com]

Maximum cycle temperatures for a diesel are shown as between 1500K and 2100K which is 1200C to 1800C

On a theoretic basis, that is what gives a diesel such a high thermal efficiency.

Re:Utter Crap (2)

Amouth (879122) | more than 2 years ago | (#40204581)

You do realize that that document is talking about pure theory and theoretical maximums? In reality the operational temperature of you diesel engine is far lower, the 550C is the ignition temp while the actual motor temp is closer to 100-150C.

Also note that isn't why diesel has a higher thermal efficiency in an ICE environment, but rather it's increased efficiency is because of how and when the fuel is added to the cylinder and the ignition mechanism which enables much higher compression ratios than are possible with gasoline fuel mixture spark systems.

Re:Utter Crap (1)

barv (1382797) | more than 2 years ago | (#40205233)

Working from memories a few decades old...

Carnot applies. Max.Eth = 1 - Tlow/Thi

Where Max.Eth = maximum theoretical thermal efficiency.
Tlow = sink temperature (exhaust temp in K or R.)
Thi. = Max cycle temp (just after explosion/injection finishes)

So what you are saying is a mechanics explanation. There is nothing theoretical in my figures. The temperature inside the cylinder easily exceeds 1000C. What I have stated is the physical law that governs the theoretical maximum efficiency. Carnot applies to all heat engines. In a diesel, because of its design, the maximum theoretical thermal efficiency is higher than any other heat engine, including the solid oxide Fuel cell (unless it is chemical electricity). And that is only because no other engine (at least, of which I am aware) has a higher cycle temperature.

Interestingly, this (Carnot) is the reason that a diesel has a higher thermal efficiency than a coal fired power station. That is because the maximum continuous temperature at which creep is not a problem is around 700C. And steam boilers and turbines, unlike a diesel cylinder, must tolerate that temperature on a continuous basis.

Re:Utter Crap (0)

Anonymous Coward | more than 2 years ago | (#40205415)

What are you talking about? There is no logical way to go from Carnot efficiency to saying that a non-Carnot engine is more efficient than another non-Carnot engine because of Carnot efficiency (again). You have to analyze the actual heat cycle. A diesel engine runs under a Diesel cycle and a coal plant operates under a Rankine cycle. You have to compare the thermodynamic cycles and then come to a conclusion.

Btw, gasoline burns at a higher temperature than diesel fuel, but a diesel engine typically is more efficient. How do you explain that? Not with Carnot efficiency, I would reckon. Carnot efficiency only tells you the max efficiency. It doesn't tell you what you will actually get.

Some conclusions you might reach: a large coal plant will operate at a higher efficiency than a small diesel engine. A large diesel engine will operate at a higher efficiency than a large coal plant. A gas turbine generator could beat both depending upon how its used.

Re:Utter Crap (1)

barv (1382797) | more than 2 years ago | (#40205859)

Dear Anonymous Coward: When a heat engine operates between given temperatures, Carnot is the most efficient possible cycle. End of story. Otto, Diesel, Rankine, Stirling, the various gas turbines etc are all less efficient than Carnot. Easily seen from T-S (Temperature-Entropy) diagrams.

"gasoline burns at a higher temperature than diesel fuel" A meaningless statement. Gasoline has a higher CV than diesel, but the temperature after combustion (burning) depends on both the starting temperature and the CV of the fuel. Before combustion in the Diesel cycle the fuel/air mix is hotter than that in the Otto cycle. After combustion, the burnt gases in the Diesel are hotter than those in the Otto cycle.

"a large coal plant will operate at a higher efficiency than a small diesel engine". Yes. Well anyhow maybe more efficient than my 4HP "firefighter". But not much more efficient.

The various gas turbines are nice cycles. But I suspect the maximum operating temperature of any of them is too low to beat a large Diesel.

Re:Utter Crap (1)

Amouth (879122) | more than 2 years ago | (#40205425)

I understand what you are saying but, if we are going to start calling peek temperature in the chamber as operating temp then i'd like to point out that the temperature of the spark from the plug is ~50-60,000C.

Why is this argument important? because while sure you might reach 1000C for a moment inside your diesel cylinder the overall operating temperature of the diesel engine is significantly lower than that. But for a fuel cell application the operational temperature is the actual continuous temperature of the device, in which case 1000C is extremely hard to manage in something the size of a normal motor.

I know you where trying to be witty but in reality your not comparing apples to apples here.

Re:Utter Crap (1)

barv (1382797) | more than 2 years ago | (#40205773)

Maximum spark temperature is about 500C not 50,000C
see e.g. http://rb-aa.bosch.com/aa-th/en/static/produkte/zuendkerzen/zuendkerzenkunde/waermewerte.htm [bosch.com]

"in which case 1000C is extremely hard to manage in something the size of a normal motor."

I have not seen details of the size and weight (power density) of this electric generator. And it will also need an electric motor if it's going into an automobile. OTOH a temperature of 1000C is not so hard to manage (with e.g. ceramics) if the stresses are not high.

"your(sic) not comparing apples to apples here". Good point.

Re:Utter Crap (1)

Amouth (879122) | more than 2 years ago | (#40205855)

Again your link is to something different than what i said, that temperature is for the operating (think constant) temperature of the plug it's self, not the spark it creates. Just like the operating temperature (think constant) for your diesel motor is a lot less than the burn temp of the vapor.

Again "Operating" temperature is constant a "cycle" temperature is just that, a cycle and not constant.

For fuel sell Operating and Cycle temperature are the same as it is one continuous long cycle while it is operating, where your ICE is not by any means constant.

Re:How small is small? (0)

Anonymous Coward | more than 2 years ago | (#40205403)

"Gosh. You mean my diesel cycle runs at less than 1000 deg C?"

Continuously? Of course not. You know very well that this is not comparable.

Offtopic (0)

Anonymous Coward | more than 2 years ago | (#40202615)

We need to focus on storing energy. We can easily obtain energy from renewable sources but they aren't reliable enough.
I'd rather have a small battery rather then a small generator.

Re:Offtopic (1)

HiThere (15173) | more than 2 years ago | (#40203839)

A decent point, but lots of renewable energy sources readily produce methane. Which can be easily stored, if you don't mind a heavy pressure tank. (Think propane tank. So it's not all *that* heavy, but it sure isn't light.)

Re:Offtopic (1)

SuricouRaven (1897204) | more than 2 years ago | (#40204073)

Methane-and-stuff. You need some rather bulky equipment to purify it for cells. It'd mean your remote country house would need someone to bring a tanker around from time to time, just like is the case with oil- or gas-heating already.

Re:Offtopic (1)

slippyblade (962288) | more than 2 years ago | (#40205035)

Yeah! Someone needs to invent Shipstones!

Re:Offtopic (1)

Eyeball97 (816684) | more than 2 years ago | (#40205081)

I didn't think that comment was particularly offtopic. I've been saying for years that storage and not generation, is a bigger problem.

Solar panels are getting pretty cheap - although it pisses me off that they keep pumping money into making them more efficient rather than making them cheaper. While I'd love to have super-efficient panels that mean I never have to plug in my phone or laptop again, I'd sooner have "normal" dirt cheap panels I can replace the tiles on my roof with.

I'm still waiting for my Sodium Sulfur Battery - 50kWh storage in a fridge sized unit with a 10 year life cycle @$4k...

Of course, once we've figured out how to store free power cheaply, it doesn't take a genius to figure out who's holding us back from that...

2 kW enough? (1)

Anonymous Coward | more than 2 years ago | (#40202655)

Hold the phone, 2kW enough for an average home? Well, i'm sorry but i have an average home but 2kW isn't enough for me. I mean, 2000W is just enough power for a small heater.

Re:2 kW enough? (2)

AvitarX (172628) | more than 2 years ago | (#40202697)

Seriously, that's essentially one circuit.

It's 1/2 of a dryer.

Re:2 kW enough? (1)

AvitarX (172628) | more than 2 years ago | (#40202713)

Though, I suppose if it requires gas, the dryer is not an issue, it's still not much. certainly no AC is going to happen on that.

It'd be doable, but it'd suck, and using central heat instead of space heaters would drive up overall energy usage for me at least.

Re:2 kW enough? (4, Insightful)

newcastlejon (1483695) | more than 2 years ago | (#40202703)

If there's already a gas supply in place, why use electricity for heating?

Re:2 kW enough? (2)

Dan East (318230) | more than 2 years ago | (#40202747)

Good point. Gas furnaces are already over 98% efficient. That is so efficient that the exhaust gas is cool enough to simply vent via a PVC pipe, and a drain is required because water condenses out of the exhaust gases.

Re:2 kW enough? (3, Informative)

fa2k (881632) | more than 2 years ago | (#40203161)

Electricity can be more than 100 % efficient if you use a heat pump ( http://en.wikipedia.org/wiki/Heat_pump [wikipedia.org] ).

Re:2 kW enough? (5, Interesting)

fgouget (925644) | more than 2 years ago | (#40203775)

Electricity can be more than 100 % efficient if you use a heat pump ( http://en.wikipedia.org/wiki/Heat_pump [wikipedia.org] ).

You're forgetting that power plants have efficiencies of 30% or less. So add a heat pump with a typical COP of 3 and the overall cycle is no better than burning the gas directly. Now if the 50% efficiency figure quoted for this fuel cell is really just for the electricity generation side (i.e. does not take into account heat generation), then that may be more interesting. It would actually be a step up from standard power plants too so if it can be scaled up it should be.

Re:2 kW enough? (1)

cheater512 (783349) | more than 2 years ago | (#40203975)

How efficient is the production of natural gas and pumping it to houses?

Re:2 kW enough? (1)

fgouget (925644) | more than 2 years ago | (#40204189)

How efficient is the production of natural gas and pumping it to houses?

That's irrelevant since you incur the same costs whether you directly burn the gas for heating or use it in the fuel cell and then use electric heating. Now in the absolute conventional gas has an EROI somewhere between 20 [theoildrum.com] and 100 [bnet.com] . I doubt distribution uses much energy but I could not find any figure so if you find any please post them.

Re:2 kW enough? (2)

Dare nMc (468959) | more than 2 years ago | (#40205777)

Based on cost, more efficient than electric. IE compare production cost of electric ($.03 to $.08 per kwhr) to the cost at my house $.25, net cost of Ng per BTU is less than the delivery cost of electric, where I live.

Re:2 kW enough? (0)

Anonymous Coward | more than 2 years ago | (#40204617)

You're forgetting that not all electricity generated around the world is of the type ( and efficiency ) that you state. In the country I live, we have only one nautral gas power plant, the majority of generation of electricity is hydro, the rest geothermal and wind, with a small fraction of coal and gas.

In that case, using a heatpump is far better on the environment and in total efficiency ( including transmissin losses/costs ) than directly burning natural gas ( and getting it to your house), and then venting CO2 into the atmosphere. Running costs per kW of heat is better for heatpumps.

This was an exercise to remind you that Slashdot readers are not all American and living in the USA. A big chunk of Slashdot's demographics are (dirty/socalist) foreigners.

Re:2 kW enough? (0)

Anonymous Coward | more than 2 years ago | (#40205443)

"You're forgetting that power plants have efficiencies of 30% or less."

Umm, the damn article is about 50% efficient power generation? With a typical real world heat pump, this still beats a 98% furnace.

So can gas. (2)

cnaumann (466328) | more than 2 years ago | (#40205667)

Gas powered heat pumps can be more than 100% efficient as well. The natural gas to runs an ICE that provides mechanical power for a compressor. You recover exhaust heat and your overall exhaust is actually colder than ambient. Current efficiency's range from about 120 to 150%. A small generator can be attached to the shaft as well and provide enough power for control and to possibly operate a blower. It is a neat system, but they are not catching on.

Re:2 kW enough? (0)

zzyzyx (1382375) | more than 2 years ago | (#40203453)

A drain is required because the combustion gases contain water (CnH2n+2 + 2n+1 O2 -> n CO2 + n+1 H2O). I don't even think condensing vapor from ambient air would be thermodynamically possible.

Re:2 kW enough? (1)

SuricouRaven (1897204) | more than 2 years ago | (#40204121)

Condensing water from ambient air is easy. Happens every time your car window gets fogged up. There is just no point in doing so.

Re:2 kW enough? (1)

History's Coming To (1059484) | more than 2 years ago | (#40204579)

Contrails.

Re:2 kW enough? (0)

Anonymous Coward | more than 2 years ago | (#40205489)

It's not just heating the Home. It's Heating the home and providing for all of its electrical needs. If this was used on a large scale, it would solve a major drawback of the electrical grid. That being, the fact that we don't have a way to efficantly store electrical energy. All electicity that a powerplant produces today must imediately be transmitied and used. On top of that there is the mater of the inharently dangerous, expensive and difficult work that goes into building, maintaining, and repairing the electrical inferstructure. Imaging if all of that inferstructure could be replaced by an underground gas line that is more reliable, can't be knock out by inclemant weather, and is less likely to instantainiously kill people who are working on them or just happen to be in the wrong place at the wrong time.

Re:2 kW enough? (2, Informative)

JimCanuck (2474366) | more than 2 years ago | (#40202705)


Averaging it out, yes 2kW is probably typical in most homes. As gas furnaces are typical, and if you eliminate your stove, and instead use a natural gas stove, 2kW as a ceiling would be easy to maintain.

Personally for my own uses, 2kW/h nearly excessive, due to my gas furnace, gas water heater and gas stove, I'm averaging out approximately 1.25kW to 1.5kW per hour with a ceiling of 2kW. That includes running 2 TV's, a PC I set up as a file server, 2 other PC's, 2 fridges in the home and the Microwave running for me to hit that 2kW ceiling.

Re:2 kW enough? (4, Funny)

NoNonAlphaCharsHere (2201864) | more than 2 years ago | (#40202749)

I can just picture explaining to my wife that she has to unplug the refridgerator before she can turn on her haid dryer.

Re:2 kW enough? (4, Funny)

redneckmother (1664119) | more than 2 years ago | (#40202845)

I can just picture explaining to my wife that she has to unplug the refridgerator before she can turn on her haid dryer.

Green Acres is the place to be...

Re:2 kW enough? (2)

DamonHD (794830) | more than 2 years ago | (#40202851)

Astonishingly, lots of people without grid connections manage situations like this without their heads exploding.

Even the servants understand the necessity to live within means, if you are patient enough.

Rgds

Damon

Re:2 kW enough? (0)

Anonymous Coward | more than 2 years ago | (#40202941)

Smart circuitry. The fridge won't be hurt if it's off a few minutes while your wife dry her hair.

Solutions like that are easy.

Re:2 kW enough? (3, Informative)

houstonbofh (602064) | more than 2 years ago | (#40202943)

Unfortunately, air conditioning does not work as well off natural gas as a heater. My boat needed more than 2.5kw for the air conditioners. In Houston, most of the standby generators in case of hurricanes are 5kw to 7.5kw, and some larger houses have 15kw.

Re:2 kW enough? (4, Informative)

michael_cain (66650) | more than 2 years ago | (#40203549)

The standard numbers that are tossed around for the average US suburban home (where a bit over 50% of the population lives these days), is 30 kWh per day, with a peak hour usage as high as 6 kWh, depending on location. IIRC, the peak hour tends to occur in the late afternoon and early evening, and varies somewhat between households: people coming home from school/work and turning on lights and A/C, parents firing up the washer/dryer, electric cooking, etc. We looked at converting to NG for cooking at one point; current code requires venting to the outside, which would in turn require some structural work. A contemporary single-family house in the US suburbs will be equipped with at least the equivalent of 125-amp 120-volt service (supports 15 kWh per hour max); the equivalent of 200-amp 120-volt service (24 kWh per hour) is not unusual.

Obligatory "Get off my lawn you damned kids!" anecdote. When my kids were in their early teens, I swear they could come through the front door and within 60 seconds, turn on 500 watts worth of assorted load each. Ever since, and after comparing notes with colleagues, I've claimed that one of the defining characteristic of dads who've had teenagers is a compulsive urge to turn things off and sit quietly in the dark.

Re:2 kW enough? (1)

FrankieBaby1986 (1035596) | more than 2 years ago | (#40204025)

Check your units. kWh per hour would be an accelerating rate of energy usage.

Re:2 kW enough? (2, Informative)

Anonymous Coward | more than 2 years ago | (#40204063)

Haha, no. kWh/hour = kilowatt, so it's power.

Re:2 kW enough? (1)

SuricouRaven (1897204) | more than 2 years ago | (#40204161)

The electricity industry insists on using these strange units of energy that are used no-where else. It's annoying.

Re:2 kW enough? (1)

CrimsonAvenger (580665) | more than 2 years ago | (#40204615)

Check your units. kWh per hour would be an accelerating rate of energy usage.

Might want to check your units too. The hour in KWh and in hour cancel, leaving KW.

Re:2 kW enough? (0)

Anonymous Coward | more than 2 years ago | (#40204723)

This must make you a dinosaur, because at least until the past 3ish years, just turning on the PC would hit your 500w mark (monitor+computer=300-600W) and I bet you upper-middle class kids are kicking on 1000-1500W every time they fire up their alienware with dual water cooled GPUs.

Re:2 kW enough? (0)

Anonymous Coward | more than 2 years ago | (#40205851)

The late Australian playwright Alex Buzo was well known for observations such as "The oldest person in the house always turns off the lights".

Re:2 kW enough? (1)

JoeMerchant (803320) | more than 2 years ago | (#40203995)

Depends on your "lifestyle":

PS3 + 50" plasma screen > 0.5kW/h

Fancy bitcoin mining parallel GPU setup can be > 1kW/h

4 ton A/C unit running full tilt > 2kW/h

Re:2 kW enough? Not quite (1)

confused one (671304) | more than 2 years ago | (#40204773)

2kW average may do the job for the most part... You can argue that the heating system, stove and hot water heater should run on gas... but in the South, we like our air conditioning. 2kW won't even kick over the compressor in my home's system. I recently did the calculation for what I need, in terms of a backup generator. It was on the order of 10-12 kW to handle the peak load (HVAC startup).

Re:2 kW enough? (1)

stanlyb (1839382) | more than 2 years ago | (#40202717)

They mean AVERAGE, not maximum output. And if you have batteries in place, and transformers, and actually one little small el.central....

Re:2 kW enough? (1)

houstonbofh (602064) | more than 2 years ago | (#40202961)

They mean AVERAGE, not maximum output. And if you have batteries in place, and transformers, and actually one little small el.central....

Really?

"This methane-fueled cell achieves about 50% efficiency at around 2kW, enough to power an average home."

So it is not enough to power an "average" home for peak use. And it is not enough to power an average home for average use in a very warm climate. AC uses a lot of power.

Re:2 kW enough? (5, Interesting)

funwithBSD (245349) | more than 2 years ago | (#40203109)

I have a 2.9Kw solar, so let me explain how this works.

My bet is that this device does not switch on and off real fast, nor does it modify it's out put much.

And for most systems, like the solar, that produce DC, you need an AC converter. The most efficient ones take the "heartbeat" of the grid to time themselves and makes sure you are not out of sync with the grid power.

That means while you are using .5 or 1Kw steady, you are pumping power out to the grid, running the meter backwards.

When it comes time for a peak surge, you draw from the grid to provide the peak.

So my solar that puts out 22 to 26KW a day during the peak months of May to September roughly half that energy goes back on the grid, I pull some back for peak usage, and pull the rest back at night.

The GRID is my battery, and it is better than free, I get 3.2c credit for producing at peak and pulling at night.

Re:2 kW enough? (0)

Anonymous Coward | more than 2 years ago | (#40203923)

3.2c OMFG

Re:2 kW enough? (1)

SuricouRaven (1897204) | more than 2 years ago | (#40204195)

The power output is DC. So all you need to do is stick a great big battery bank in there. Problem solved.

Re:2 kW enough? (1)

Anonymous Coward | more than 2 years ago | (#40203465)

They mean AVERAGE, not maximum output. And if you have batteries in place, and transformers, and actually one little small el.central....

No. They mean peak. Average usage is measured in kilowatt hours(kWh). Generator output is an instantaneous measure of continuous or peak current output, usually kilowatts(kW).

A gasoline powered portable generator from a large department store is typically 5kW advertised peak. In reality you'll get a constant draw of 4 to 4.5kW Take it from someone who has lived off of a 5kW generator for two weeks, post hurricane. You cannot run an entire house off of it. You can run the fridge/freezer(1.2kW), a few lights and a radio or television. Or, if you shut everything else down you could possibly run three burners on the stove(4kW). But, turn the microwave(1kW) on at the same time and pop! The washer will work on it's own, but forget the dryer(4.5kW). A portable A/C or window unit(1.4kW) is possible, but central air needs more than 5kW to start the average sized unit.

2kW is not nearly enough to run a very small home in my area.

Re:2 kW enough? (1)

kanweg (771128) | more than 2 years ago | (#40202881)

It's 2012. Time to switch to a heat pump then.

Bert

Re:2 kW enough? (1)

mehrotra.akash (1539473) | more than 2 years ago | (#40202901)

Well, once you move water heating to a solar heater or gas heater and if you live in an area without need for Air conditioning, 2kW is much more then enough
my home uses less than 1kW after excluding AC and water heating

Re:2 kW enough? (1)

houstonbofh (602064) | more than 2 years ago | (#40202973)

I think about 60% to 75% of my power use is AC, and I leave multiple computers on 24/7. But AC is not an option in Houston.

Re:2 kW enough? (3, Insightful)

HiThere (15173) | more than 2 years ago | (#40203925)

You may "need" air conditioning, but there are ways and ways. With decent insulation, you need a lot less air conditioning. I don't know what your understory is like, but in many places you can store heat there in summer, and withdraw it in winter (using some sort of heat pump). That's not enough on it's own, but combined with decent insulation, it get's you quite close to reasonable. Then you need only a quite small amount of either air conditioning or heating.

That said, I'd expect that in Houston the most reasonable alternative would be solar. (And since you're in town, it's not reasonable to even try to get off the grid.)

But the first step is GOOD insulation. With good enough insulation, you could overheat a house just by living in it, even during a blizzard, but that much is unreasonable. It does, however, imply that you'll need some air condition, and air circulation, too, but the air circulation system could go via a heat exchanger, so not too much heat transferred via that pathway.

OTOH ... you won't see me investing in that kind of system. Yes, it would work, but it's too complex, and would probably require lots of maintenance. But with proper design, 2 KW should be plenty. It's just that proper design is quite rare. (FWIW, my wife thinks that we have good insulation. It is to laugh. The wind blows through the house, even with the doors closed. But it suffices for our environment [SF Bay]. Elsewhere I'd be much more interested in better insulation.)

Re:2 kW enough? NOT! (0)

Anonymous Coward | more than 2 years ago | (#40203133)

I'd say that 2kW was WAY below average in my area. An electric stove or oven is more than 2kW. Even a microwave oven alone is 1kW. Add a wife with a hair dryer(1.5kW and you're overloaded. Electric clothes dryer, water heater, air conditioner...

My 3,000 SqFt home uses 2kW at idle. When the A/C comes on and we're cooking dinner, I can peak at 15kW.

Re:2 kW enough? (0)

malx (7723) | more than 2 years ago | (#40203613)

2kW is an "average home"? Seriously?

My induction cooktop has a rated load of 11kW!

Rated loads on some other devices:
PC power supply: 800W
Plasma TV: 420W
Home cinema amp: 870W
Stereo amp: 800W

I also have an electric oven (two actually), a washer-dryer and a dishwasher. It is by no means inconceivable that all these devices would be running simultaneously. And that's without counting the multiplicity of relatively low power devices, which will all add up.

In common with most British people I don't have air-con. The heating is gas powered, but for many people in apartments it will be electric.

Now I know a lot of people will cook with gas, and my entertainment system is more than many people may have (although I imagine it's not unusual amongst slashdotters). And of course this gear won't draw the full rated load in normal use. Nonetheless, it seems pretty clear that a 2kW supply certainly couldn't power my home. Am I so atypical?

Re:2 kW enough? (0)

Sponge Bath (413667) | more than 2 years ago | (#40203805)

My induction cooktop has a rated load of 11kW!
Rated loads on some other devices:
PC power supply: 800W
Plasma TV: 420W
Home cinema amp: 870W
Stereo amp: 800W

Am I so atypical?

Honestly, that sounds like a premium setup. Not excessive, but not average. 2kW is just a starting point and will be coupled with efficiencies in consumption and supplemented by the grid for peak consumption. As another poster pointed out, if you have a supply of natural gas then a gas cooker could be part of that solution.

Re:2 kW enough? (1)

tragedy (27079) | more than 2 years ago | (#40203623)

Presumably this would need to be coupled with a storage bank of batteries, or something like that to meet peaks of demand.

Re:2 kW enough? (1)

SuricouRaven (1897204) | more than 2 years ago | (#40204107)

That's probably averaging out. 2KW averaged over a few days, but with peaks much greater when the electric shower is on or someone is drying their hair. You could use an inverter to help with that. It also can safely ignore heating and cooking, as that'd just run off burning the gas and thus use negligable electricity.

What's the cost of refining the gas? (1)

hackertourist (2202674) | more than 2 years ago | (#40202665)

That should be part of the efficiency calculations as well.

Re:What's the cost of refining the gas? (1)

King_of_Prussia (741355) | more than 2 years ago | (#40204005)

The answer to that is: extremely expensive. And that's probably why they didn't present any of the figures. The compression, material and heating costs to remove all the CO2 from the gas would likely make the total cycle efficiency terrible.

Re:What's the cost of refining the gas? (0)

Anonymous Coward | more than 2 years ago | (#40204041)

I used to work in oil and gas, and the reason NatGas is so cheap is because they don't spend the money to develop "pure" methane. There's a bit of propane and even some butane in natural gas, along with CO2, Nitrogen, and some inerts.

removing these to provide pure CH4 for methane-based fuel cells would increase the cost by about 3 times.

The obsession with efficiency (3, Interesting)

fustakrakich (1673220) | more than 2 years ago | (#40202681)

It makes all the machinery frail and brittle. I'll settle for a few percent less with a Stirling engine running off the natural gas we have now. And most likely it will run on anything I throw into the 'boiler'.

Re:The obsession with efficiency (1)

houstonbofh (602064) | more than 2 years ago | (#40202979)

If the cost of replacing or rebuilding machines is less than the cost savings in fuel efficiency, you loose.

Re:The obsession with efficiency (0)

Anonymous Coward | more than 2 years ago | (#40203707)

If the cost of replacing or rebuilding machines is less than the cost savings in fuel efficiency, you loose.

But in this case it isn't, so you lose.

Classic problem with fuel cells (5, Informative)

Animats (122034) | more than 2 years ago | (#40202727)

A classic problem with fuel cells is extreme intolerance to contaminants. [sciencedirect.com] Even trace amounts of contaminants tend to damage fuel cells. Hydrogen fuel cells need cleaner hydrogen than is normally available commercially. Research continues on making fuel cells more tolerant of contaminants, but it's hard. Fuel cells are surface chemistry systems. 40 years of research hasn't solved this problem.

Reverse osmosis water purification systems once had the same problem. Today they routinely take in raw seawater and pump out clear water. They just need a backflush cycle once in a while to flush the crud off the membranes. Fuel cells aren't there yet.

Re:Classic problem with fuel cells (-1)

Anonymous Coward | more than 2 years ago | (#40202817)

I am a methane producing fuel cell. If you smelled the emission that came out of my ass a few hours ago you'd realize that contamination is hardly a problem. Reeking of sulphur with a consistency tantamount to oatmeal, the event was a bowl splattering cacophony that left the bowl stuccoed in fecal matter. Had to wipe and get the hell out of there quickly, before I was overcome by the smell. Someone is going to have a mess to clean up.

Re:Classic problem with fuel cells (1)

jklovanc (1603149) | more than 2 years ago | (#40203227)

You have hit the mail on the head. Reverse osmosis membranes can be easily cleaned by reversing the pressure so that a small amount of fresh water will flush the built up salt. There is no such mechanism with fuel cells. When natural gas is used the impurities coat the reaction plate and decrease the reaction. There is no way to reverse the process to clean the plates. It is very difficult to create perfectly clean natural gas. Even a small amount of impurities will coat the plates creating an insulation layer. The cleaner the gas the longer it takes but since it is impracticable to create perfectly clean natural gas it is only a matter of time before the plates are coated.

Interesting if you don't need heating (1)

hackertourist (2202674) | more than 2 years ago | (#40202739)

Until now, the most efficient electric generators for home use I've seen are heat-power coupling devices: natural gas-powered engines that have their coolant loop linked to the house central heating system. They can reach a combined efficiency of near 100%, if you can use the heating. In the summer, they get expensive to use.
60% efficiency for electricity alone is pretty good.

Source of methane (4, Funny)

Skapare (16644) | more than 2 years ago | (#40202769)

I already have a home source of methane. I just need a nice way to capture it.

Re:Source of methane (0)

Anonymous Coward | more than 2 years ago | (#40203071)

Taco Bell as a fueling station???

Can it power my grow op? (1)

future assassin (639396) | more than 2 years ago | (#40202789)

Make it run reliably for 2+ years and you got a market. 2KW is small for Canada as if you pull 1lb out of a 100W light thats only about 2K every 8 weeks. Now in the US you're looking at 3000-4000K for that same lb.

Re:Can it power my grow op? (1)

future assassin (639396) | more than 2 years ago | (#40202805)

3-4K not 3000-4000K

Re:Can it power my grow op? (0)

Anonymous Coward | more than 2 years ago | (#40203047)

What has kelvin-watts to do with this?

Silly question I know... (0)

Anonymous Coward | more than 2 years ago | (#40202915)

But if the problem is that natural gas piped into homes is 1/5 impurities, why not add a filter to remove them? If it runs at a peak efficiency of 2kW, you could mate this to a battery pack and inverter, so that the house is essentially a hybrid. Are its emissions as clean as commercial power, though?

what about building them at sub stations? (1)

Joe_Dragon (2206452) | more than 2 years ago | (#40202965)

what about building them at sub stations?

Farms? (1)

Midnight Thunder (17205) | more than 2 years ago | (#40203165)

How effective would methane generators be in small farming communities, which already produce methane as a by-product? If they work well, then they may be able to be off-grid completely?

Re:Farms? (0)

Anonymous Coward | more than 2 years ago | (#40203713)

There are several pig farms in Denmark that collect the methane gasses from the manure and burn it to create heat/electricity. The build permitting for this has hampered their expansion for the last decade.

Re:Farms? (1)

compro01 (777531) | more than 2 years ago | (#40204659)

Impractical at present. Fuel cells require extremely high purity methane and the equipment to purify random natural gas or decomposition gas is expensive.

Just burning the stuff in an ordinary generator is way better in terms of return on investment.

Bull (1)

pubwvj (1045960) | more than 2 years ago | (#40203427)

Bullshit
Or pig shit.

Keep livestock,
gather the manure,
make methane.

In our case though the animals spread the manure out in the fields which is far more efficient.

Houses Need 5KW (3, Informative)

Doc Ruby (173196) | more than 2 years ago | (#40203477)

The average American house consumes about 1.5KW electricity average across the days (and nights) through the weeks of a year. But they not infrequently peak demand in spikes over 2KW. A hairdryer or space heater draws about 1.5KW. A dishwasher (especially with extra washing or drying heat boost) will draw 1.5KW. An electric stove/oven can draw 4KW or even 7KW as it heats up. A vacuum cleaner can draw up to 1.5KW, especially if it's a strong one that gets jammed.

And all of those could happen at once. A couple happening at once is pretty likely at least once a year. Plus the rest of the 1KW regular demand, which is closer to 2KW max, averaged against quiet times closer to 0.1KW.

A home power supply should be close to half the 100A 120VAC panel, which is 6KW. A 5KW max supply is probably just fine. A 2KW fuelcell would need a battery that can output 5KW for at least a few minutes, perhaps while an alarm goes off warning the battery will drain down shortly and circuit breakers will snap.

Really all the residential fuelcells I've seen talked about are 5KW. A 2KW fuelcell seems like a good device for a yacht.

Re:Houses Need 5KW (0)

Anonymous Coward | more than 2 years ago | (#40203957)

I love these misconception busting threads.

My 3,000SqFt Heated living area home on the 28th parallel(average to slightly above average for this area) has drawn an average of 68kWh per day for the past 12 months. The peak month for that period was last August/September where the 30 day average was 101kWh per day.

My friend's boat, 43 sport fisherman, has a 5kW generator that can easily peak with everything on(dual A/C, microwave, hot water heater, a few AC lights, battery chargers).

Does not fit with the image (1, Insightful)

Gonoff (88518) | more than 2 years ago | (#40203575)

The image I have of the US does not include 2KW covering the average home. It might do for the 96% of the planet outside the USA though...

Re:Does not fit with the image (0)

compro01 (777531) | more than 2 years ago | (#40204667)

That's 2KW averaged throughout the day, including the ~1/3rd of the day when everyone is asleep.

You'd need a sizable capacitor or battery to handle peaking.

AU being promoted bt German fuel cell vendor(s) (0)

Anonymous Coward | more than 2 years ago | (#40204363)

We heard a radio interview [on ABC Local Radio?] with a rep from an Aussie-based company (from the company name, it is linked with a German fuel cell maker or marketer)... ...in which the benefits of a small (the size of a bar fridge or washing machine?) fuel cell were promoted.

"If only we can get the price of our unit down to $20 or better $10K, this would suit home owners." (or similar) was heard.

Interestingly, NO mention was heard of the need to have high-quality (better filtered?) gas fuel for these units.

Is that because these costly models -include- a continuous filter?

Or, perhaps, is Aussie gas -already- of a sufficiently high quality to work in these fuel cells?

(Of was it an after-sale -surprise- eg, after an [intermittent] unit failure? "Oh, your unit failed because of [intermittently present] impurities in your gas service. We'll have to install our -optional- gax filter...")

Pants? (1)

ksandom (718283) | more than 2 years ago | (#40204513)

This could evolve to underwear that powers your phone!

only 50% ? get with the program! CFCL is @ 60% (0)

Anonymous Coward | more than 2 years ago | (#40204873)

You may want to check out the Australian company, ceramic fuel cells, who have the blue gen product available already.
cfcl.com.au
These guys have been doing this for years.

Whimsey (0)

Anonymous Coward | more than 2 years ago | (#40205131)

2KW enough to power the average home? Where, in Somalia? What crap ...

Bloom Energy (0)

Anonymous Coward | more than 2 years ago | (#40205375)

Why is everybody dismissing the highly touted vaporware fuel cell manufacturer Bloom Energy [slashdot.org] ?

We simply cannot allow big energy to quash into obscurity our most promising vaporware manufacturers like this.

Why are people debating the logistics? (0)

Anonymous Coward | more than 2 years ago | (#40206255)

It's so silly to be debating the logistics of this device. Everyone should be burning down the laboratory in protest.

People hang around debating whether this fossil fuel consuming electrical generator is better than a slightly different fossil fuel consuming electric generator. The US government is still busy researching how to tie people to fossil fuels for another 50 years. That's the story.

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