Battery Technology

[moldyoldy]

For those of you with an interest in battery technology, a recent article in "Der Spiegel" issue 2007-48 (A German weekly) gave some remarkable datapoints on energy efficiency. For those of you who wish to read the original article in German, check out http://www.spiegel.de/spiegel/0,1518,519773,00.html.



For my own use, I am slowly making the switch from NiMh to Lithium-Ion rechargeable technology. slow because of the investment in Ni-Mh chargers and cells.

The essence of the opinion expressed in the article is that electric drive is the future of vehicle drive systems, not any piston-driven system, be it diesel or gasoline. Some interesting data points roughly in order of appearance in the article. ((parentheses indicate my input))

- A diesel engine converts about 1/3 of the available (hydrocarbon) energy into drive power. ((gasoline engines are less efficient)).
- An electric drive converts a very high percentage of the provided electrical energy into drive power. ((and with high torque))
- the primary failure of electric cars in the current market is due to the short range, currently only about 50 km, and a charge time of hours.
- many firms have been working for over 10 years on a roundabout method of generating electricity with hydrogen as the energy carrier. A hydrogen fuel cell drive system can achieve several hundred km range.
- The primary inadequacy of the fuel-cell drive system is due to the excessive energy expended in generating hydrogen to be converted back to electricity. With a hydrogen fuel cell system, only about ¼ of the original electrical energy is delivered to the drive wheels. Half of the original electric energy is lost in creating hydrogen. Half of the resulting hydrogen energy is lost in the reverse conversion of hydrogen back to electricity on board a vehicle. worse still, the storage and transport of hydrogen is expensive due to the storage characteristics of hydrogen.
- The efficiency of a modern coal-fired power plant is about 45%. ((steam turbine systems))
- Natural gas-fired power plants with heat recovery systems can reach 90% efficiency.
- Losses in charging and discharging "modern" batteries lies in the single digit region. ((unspecified which battery type))
- Lithium-Ion batteries are taking over in many areas be it mobile telephones, laptops, model airplanes.
- For upcoming electric cars, VW is planning on it's "up!", a longer version called "space up!". Mercedes will bring out an electric "SMART". GM is planning on a compact car already shown as an Opel by the name of "Flextreme".
- Nevertheless the current data shows the limits of batteries. The GM vehicle has 180 kilograms of Lithium-Ion batteries which generate 16KWH of electricity. That is corresponds to the energy in 2 liters of gasoline. However in an electric car, that 16KWh gives a range of about 150km when driving moderately with a top speed of about 120km/h (75mph). Unfortunately the electric power required is more than a standard house mains outlet can provide. The researchers are trying for a cycle life of 3000 cycles corresponding to a 10yr lifetime. For the time being in current prototype autos from VW and GM, an internal combustion engine provides the necessary current for long distance driving. In normal commuter traffic, the current available in a normal house is sufficient to keep the batteries charged
- Li-Ion batteries cost about 1000 Euro per KWH with a price drop expected for production quantities
- German household electric costs are about Euro 0.18 per KWH. ((In Minnesota, it is about $0.08/KWH)). The resultant electric car operational costs for 100km would be about 1.5 Euro or about 10x less than a gasoline or diesel motor system costs in operation.
- Safety is still of great concern for use of Li-Ion cells with their large energy content. The plastic separator between the anode and cathode melts at about 140 deg C and then the battery gives off its energy in flame. If this event occurs with a 16KWH Li-Ion battery, there is a serious life danger for several meters around. Because of this danger, the use of Li-Ion batteries in cars is being delayed. Most manufacturers are considering the use of small Li-Ion battery packs. Tesla uses 7000 laptop-cells to drive its' E-sports car although that is a bit daring and not ready for large serial production.
- overcharging is a still a problem as many owners of small devices have found out.
- A breakthrough is possible ((for Li-Ion cells)). Chemists have developed a flexible ceramic separator which withstands up to 450deg C. Overcharging this cell leads only to venting. Another test was to drive a nail thru the cell. In a normal Li-Ion cell, it would have exploded in flame w/in seconds. With the ceramic separator it only lost its' charge.

Notes from an earlier Spiegel magazine article:
- the efficiency of the German train system with electric drives results in an equivalent efficiency of about 2.5 liters of "fuel" per 100 km. Most European cars are still hoping to consume less than 5 liters of fuel per 100km. ((47.5 mpg or so)).

 

[65535]

Sounds to me like natural gas is the way to go, have POU (point of Use, your house) natural gas generators, and use them with load control to run your house and charge you electric car, with A123 systems new current cell technology, I think most problems with venting have gone away.

I would not recommend a natural gas engine for a car simply because there is not enough space to add the required thermal capture equipment to be efficient enough.

BTW this is really great stuff, Al Gore should send this around, this is the real truth.

 

[shadowjk]

Small (personal) powerplants are probably unable to reach the higher efficiencies of large powerplants. A CHP powerplant reaches 90% efficiency, even with coal. Due to public hate against coal powerplants most of them are extremely old and inefficient, and if their filters haven't been upgraded they spew out quite alot of pollution as well (not just co2)...

Both coal and natural gas can be adapter to power internal combustion engines too, but of course as we all know the ICE is horribly inefficient. The issue with both natural gas and coal is that they're fossil fuels that will one day run out, and by burning them the Co2 levels in the atmosphere goes up, which might make this little old blue ball a bit warmer

In general I like the idea of a rechargeable car though, because it means that you can get the power delivered to your own house through the existing powergrid infrastructure, whether that power is then generated with PV, Wind, Hydro, fossils, nuclear or renewables makes no difference for the end user. I don't really understand the "power required" being bigger than mains outlet though. A standard low power outlet (europe) is 10A at 230V, 2.3kW. That'd recharge your 16kWh car overnight when you sleep, if you had driven it empty. Ovens, stoves and water heaters usually have 16A, either 220V or 3 phase power, using that would cut down charging time further. Heck, in Northern Europe the infrastructure is already there, with mains outlets in parking lots to power the electric block heaters that preheat the engine and interior of car during winter (where total consumption of the engine heater and interior heater can exceed 2kW).

 

[65535]

The problem is the power grid was never designed for 100 people in a neighborhood to create a 2.3MW surge for 5 hours.

 

[moldyoldy]

65535 is correct. The impact of many cars charging their main drive batteries would be overwhelming to the present electrical grid system. Nevertheless, the context of the article in that location was referring to the capacity of a single standard mains outlet to supply enough current to charge the 16kwh battery in only a few hours rather than charging all night long assuming nothing else on was connected to that outlet. That is one of the many reasons why some form of internal combustion engine will be present in vehicles for many years. In Europe the leading hybrid design is preferring a diesel-based rather than a benzine-based internal combustion engine.

Most of Europe is relying on time distribution of demand to avoid overload of the electrical mains distribution system. For example, many German/Austrian/et.al. apartments and even some homes have a flash electric water heater located beneath the sink with a very small storage capacity. Turn on the faucet and the electric heater turns on. nothing more. or, in the case of a bathtub, if you want to take a bath, turn on the tank heater above the tub to a desired temperature a couple hours before your bath. The intent is to avoid heating large volumes of water to be stored as found in the US and then piping that hot water to another location in the apartment or house with commensurate heat losses from the tanks and piping. This distributes the demand current over time rather than heating a large tank of water even at night. Of course any homes with hot water heat have access to centralized water heating, storage and distribution. Forced-air heating of homes is not common, at least in my living experience. Electric heating based on a single room is popular. yes, shutting off heat to unused rooms is very common. Again, a very diffuse and distributed demand system.

Although Germany/Austria/Switzerland/Italy seems to favor a lot of electric usage possibilities, the end result is still lower in electric/energy consumption than in the US. For example, nearly all hallway or stairway lights even in private homes in Germany utilize some form of timers or motion sensors.

Why not a much greater consumption of natural gas in lieu of expensive electricity? Natural gas is also quite expensive. And, digging around in the ground for anything is rather dubious considering how many battles were fought all over Europe with unexploded munitions still surfacing. ie: less than a year ago, a highway construction worker on a backhoe hit a WWII bomb - instant end of story for him.

Nevertheless, the future appears to belong more to electricity than any other energy form. For example, I recall that BMW achieved a higher energy efficiency in one car model without hybrid drive than the Toyota Camry with hybrid drive, by, among other changes, replacing the mechanically-driven oil pump with an electrically-driven oil pump. Most cars now have a radiator fan that is electrically driven on thermostatic demand. However, what that electricity is generated from is the subject of many discussions and papers.

 

[Brock]

The problem is the power grid was never designed for 100 people in a neighborhood to create a 2.3MW surge for 5 hours.

Ummm, that is what happens when everyone turns on their AC? So far it seems to work, unless you're in CA and for pollution reasons aren't allowed to build more power plants even though demand keeps increasing...

Most of the automotive chargers would be running at night when the demand is the lowest on the grid and likely less then that of a typical home AC unit, charging from power that is otherwise literally wasted at night.

Even if they have to upgrade the grid (lines and plants) if everyone switched to electric vehicles we would still be way better off, again electric plants are in the 90 percent range for efficiency while gas cars are typically in the mid 20's and diesels in the mid 30's. Not to mention the emission controls you can add to power plants that just are not feasible on a car. Just image a car going from 25 percent efficient to 80 percent (10 percent lost at the plant and 10 percent lost charging the batteries and motor losses). That would be like increasing a cars mileage from 25 to 80, a big difference, no?

 

[Mr Happy]

There's not a huge problem with people drawing 2.3 kW overnight, at least not in Europe. The electricity companies encourage people to do so by offering discounted electricity rates during the hours of darkness when demand is low so people can use night storage heaters for central heating and hot water.

But you have to remember though that 16 kWh translates to 21 hp-hours. That means your electric car can run at 21 hp for an hour, or 10 hp for two hours, or 42 hp for 30 minutes. Compare that to the horsepower of the typical gas-guzzling engine in the average American automobile and you can see why electric cars are not going to be hugely popular any time soon.

Also, I may need to go check my facts, but I don't think the 90% maximum efficiency figure for electric power plants is real. I think it's more like 50-60% converted to electricity for the best combined cycle plants and the rest supplied as low grade heat or steam for other uses.

 

[Darell]

Brock already covered all the good points!

If the grid can't handle the loads of EV charging... then they also can't handly the pool pump and AC loads that we give it today. Oops... the grid DOES handle that. And considering that most commute cars are gone during business hours, and home to recharge AFTER peak times, we have plenty of off-peak power to go around. Funny, but nobody uses the AC at midnight. That's the best time to charge your car, however.

The more battery cars we have on the road, the more efficient our current grid can be (level the load during off-peak hours with EV charging).

The article in the OP is a bit frightening. EVs have a range of 50km? Since when? I had a 1996 EV1 that would go over 100 miles on a charge. I've taken my curren Rav4EV (designed for the 1996 model year also) 135 miles on a charge. Today's cars can go 300 miles. Farther, cheaper and more efficiently than any fuel cell car.

Yes, there are some good points made in the article - and some other important points are missed completely.

 

[Mr Happy]

Again, we have to get the numbers right. The Tesla is a modern electric car with a range of over 200 miles, but it takes a heck of a lot more than 2.3 kW to charge it. It takes something like 25 kW for several hours, and that is vastly more than your average air conditioning or pool load. So much so that Tesla suggest you may need to get a special electric supply provided by your utility company. Make no mistake, if everyone wanted to drive a Tesla the electric grid would be unable to cope.

 

[TorchBoy]

I too wonder where they got that 50km range figure from.

But you have to remember though that 16 kWh translates to 21 hp-hours. That means your electric car can run at 21 hp for an hour, or 10 hp for two hours, or 42 hp for 30 minutes. Compare that to the horsepower of the typical gas-guzzling engine in the average American automobile ...

But that's peak power output, and I'm not using all however-many kilowatts all the time. In fact, I think I've only used that a handful of times since I bought the thing 2.5 years ago. For normal driving I'm using just a tiny portion of the maximum output. How much exactly, I really don't know. :shrug:

... and you can see why electric cars are not going to be hugely popular any time soon.

Actually, the acceleration that can be obtained from them (consider torque curves - ie, where the torque is available - not just power) would make them popular right now if they were available. The Tesla is sold out for years ahead.

But not everyone wants that sort of acceleration. Even a third the acceleration would be OK. But thinking even lower power, Kmart here recently advertised an electric bike. My city is built on 50 extinct volcanoes and it would be great to have one. (And I think our fuel prices are about twice what Americans pay thanks to lots of tax on the stuff.) The main reason I don't buy one straight away is because I consider our roads too dangerous to cycle on. In summary I just don't think technology is the biggest hurdle at present. :sigh:

 

[Mr Happy]

But that's peak power output, and I'm not using all however-many kilowatts all the time. In fact, I think I've only used that a handful of times since I bought the thing 2.5 years ago. For normal driving I'm using just a tiny portion of the maximum output. How much exactly, I really don't know. :shrug:

That's quite true. When you are driving at constant speed on a level road, you only need just enough horsepower to overcome wind resistance. That's about 10 - 40 hp, depending on the size of your car and how fast you are going. But one thing about America which hurts is the huge number of traffic lights that make you brake to a stop and then accelerate again. The amount of power required for acceleration depends on the weight of the car, and big electric batteries, unfortunately, weigh a lot. Driving in England the problem is much less, because over there we have lots of these magic things called "roundabouts"

Here in America, I find my car gets about 50% better mileage on freeway journeys at 70-80 mph than town and city journeys at 30-40 mph. Odd, isn't it? (Odd, when you consider that wind resistance, or aerodynamic drag, varies with the square of the speed, and drag is the biggest problem cars face when traveling fast.)

 

[TorchBoy]

I worked out once that ignoring air resistance, it takes as much energy to accelerate from stationary to 70.7 km/h as it does to go from 70.7 to 100 km/h. My conclusion was that keeping an even speed on the open road is really important. Does that apply to an EV with regenerative braking?

 

[moldyoldy]

Some comments on comments.

50km range for a pure electric vehicle? I myself wondered a bit about that number. However I also know that the average car driven in Europe is definitely smaller than in the US - meaning not a lot of space for batteries in the vehicle. There is also a sensitivity point on price, also equivalent to not a lot of batteries in the vehicle.

Acceleration is a significant factor in determining how far a vehicle can travel on batteries. The Americans are acceleration junkies! as a kid, I enjoyed some of that acceleration. as an old EE, I am far more worried about the energy consumed in the process of normally operating an engine that has the capability for that acceleration. Generally speaking, whether 8, 6, 4, or 3 cylinders, the more cylinders, the greater the fuel consumption. The Geo Metro does quite nicely on a 3 cylinder engine. By comparison, my Honda Civic 5 sp manual transmission achieves 40-42 mpg in the summer to/from work based on a monthly average. My younger daughter has the same vehicle a year newer. On over-the-road trips with no AC turned on and driving the speed limit, we both reach 46-48 mpg. In the winter with cold weather, it drops to 36 mpg. That is very close to a current hybrid vehicle version, Honda Hybrid or Toyota Prius. Per Consumer Reports, the hybrid Honda Accord can nearly out-accelerate a standard Honda Accord. All that the automotive manufacturers have done is discover the wonderful low-speed torque curve of an electric motor which has been powering diesel-electric locomotives for years.

Once upon a time, just for the experiment, I disconnected my car's alternator (took the belt off) and drove on the battery alone. I charged the battery every night. I proved that it was cost effective, meaning that my fuel mileage increased more than my electricity charges increased. It was also a pain to use.

Electric grid loading? The electric grid was not designed to handle the full load of all devices turned on, including AC. Some areas of the country have only a 5-6% theoretical overcapacity, others have 20-25% and higher theoretical overcapacity. Sharing power between parts of the country? A NSP power dispatcher used to live across the street from me. He had tales to tell about something everyone considers to be "expected" and "assumed". On bad days he bought power from the TVA and Canada hydro plants, but it also costs dearly to transport electric power more than, say, a 1000 miles now. At the time (1980's) he indicated a cross-over point of 600-900 miles depending on the specific network and voltage up/down conversion losses. Farther than that and it was worth it to transport the energy in some other fashion.

Load-leveling? Nearly every electric utility has some feature such as being able to shut off residential AC during the day (ie: 15min on, 45min off) when the load gets too high. My current employer is controlled by an "Energy Alert" from Excel Energy. If an Energy Alert is declared (happens often in the summer), the site has to shed a significant portion of the draw from the grid down to 4 MW - most AC is turned off and maybe cycled. They will even run several in-plant diesel generators to achieve that load shedding. Most utilities also offer off-peak electric usage rate decreases during limited night-time hours. What does that mean for electric cars? there is a cross-over between lower electric draw charging a battery all night long, which is evidently considered too slow, and using the unused generated power during low consumption periods.

overnight battery charging? I recall other pertinent articles about efforts to achieve a quicker charge than an all-night battery charge which is considered far too slow for a consumer economy. Look at flashlight battery chargers. How many are being sold that take all night to charge? very few.

 

[jzmtl]

Well the problem with electrical car is still the range and charge time. Sure it's okay for some people's daily commute, but what about longer trips, you'd have to have two cars for that (and I bet most people can't afford that). Even with 100 km range it's not even half way there for weekend ski trips, or even daily commute for a lot of people who live around here. Then there's the time when I take my vehicle to offroad incursion, won't find a place to plug into in the middle of a forest.

Then there's the problem of power, some people like vehicles with decent power, not floor the pedal and read a book before it reaches highway speed.

 

[shadowjk]

But one thing about America which hurts is the huge number of traffic lights that make you brake to a stop and then accelerate again. The amount of power required for acceleration depends on the weight of the car, and big electric batteries, unfortunately, weigh a lot. Driving in England the problem is much less, because over there we have lots of these magic things called "roundabouts"

I always look ahead to see if the lights ahead are going to be green or red when I get there, and adjust speed without braking so that I'll arrive while it's green or if that looks impossible, just take the foot off the pedal so that the car slows down without wasting it's kinetic energy by converting it into heat with the brakes..

There's not a huge problem with people drawing 2.3 kW overnight, at least not in Europe. The electricity companies encourage people to do so by offering discounted electricity rates during the hours of darkness when demand is low so people can use night storage heaters for central heating and hot water.

Indeed, and in northern europe there's already a peak in winter mornings when people's cars start sucking up electricity in order to heat up the oil and coolant, thaw the windows and doors and the interior so that all the plastic details don't crack and break when the driver comes a few hours later to drive to work.

Summertime there's typically reduced demand overall for electricity, though many production facilities are taken down for annual maintenance, which might be a problem, though the grid itself will have a lighter load.

In Europe the leading hybrid design is preferring a diesel-based rather than a benzine-based internal combustion engine.

I believe the governments are also using taxes to encourage diesel based engines over gasoline engines. Diesels are more efficient and cleaner than gasoline engines, though they don't have the same wide RPM range as gasoline engines.

Speaking of efficiency, I wonder how much could be gained by moving towards central heating/cooling in all urban areas. Cogeneration of heat/cold with electricity is just so more efficient than producing electricity alone, not to mention first producing electricity in a non-cogeneration plant and then using that electricity to produce cooling...

 

[Brock]

I would be the first to admit that if everyone switched to EV's the grid would need some serious upgrading, but if it were a slow switch I believe they will keep up, supply and demand, not to mention the extra power we will have from not refining and pumping our current fuel. We do all know the single largest consumer of electricity in the US is the petroleum companies, right?

So for everyone that thinks EV's wont work you would also recommend no one use point of use or instant water heaters, at least not electric ones right? My brother has a whole house instant electric unit (after his solar pre heater). It has a small 2 gallon tank and 24kw of elements, four 30 amp 240v breakers. You want to see lights dim turn on the hot water It does come on in 6kw stage rapidly.

Just looking at the economics of it a gallon of gas has about 124,000 BTU and a gas engine is about 25% efficient so you get 30,000 BTU. To create 30k BTU with electricity you would need 8.8kw of electricity, assuming charging losses lets call it 10 KW. So the gallon of gas is $3.00 and 10 kw is what? For me it's $0.06 so that would be $.60 for the same energy as a gallon of gas. Heck even if your electricity is $.20 kw that's still $2.00 compared to $3.00 for a gallon of gas.

No stopping at gas stations, far less maintenance, heck if your like Darell you can charge your car via solar and add no load to the grid or even supply power during peak times during the day and charge at night. No tanker trucks pulling 1000's of gallons of highly flammable fuel around, all delivered to your house way more efficiently then gas with less danger, noise and way less pollution, but I digress.

 

[Darell]

Load-leveling? Nearly every electric utility has some feature such as being able to shut off residential AC during the day

I'm not sure how you define "nearly every." If you are speaking of mandatory A/C kill switches, then "nearly none" of the utilities in CA have that. It is optional at best, and not even offered at worst (and that last case would be for the largest CA utility that I'm a part of). EVs would help to load-level in a serious way. Both at night and during peak times. You can't get energy back out of an A/C unit. You CAN get energy back out of an EV.

there is a cross-over between lower electric draw charging a battery all night long, which is evidently considered too slow

Who evidently considers overnight charging too slow?

overnight battery charging? I recall other pertinent articles about efforts to achieve a quicker charge than an all-night battery charge which is considered far too slow for a consumer economy.[/quote]
Again, who considers this? Nobody who actually does it, certainly. Fast charging is a reality. It has been used for ground support at airports for 16 years. It is a proven, reliable technology. We can put it on the freeways for long-distance driving. For the commute car, there is no reason for faster charging, however. Why go through the extra expense? If you have 250-300 miles of range, and you can fill your car over night... we'll let's just say we're talking about the fringe that couldn't handle that on an every-day basis. For the long trips, something else will be needed, yes.

Look at flashlight battery chargers. How many are being sold that take all night to charge? very few.

Because it is quite cheap to make fast chargers for that capacity. Why wait when there's no penalty? You can have a fast car charger in your garage if you want one. You would just need to pay for it. And I don't know many who would bother, as it offers almost no benefit.

 

[Darell]

Well the problem with electrical car is still the range and charge time. Sure it's okay for some people's daily commute, but what about longer trips, you'd have to have two cars for that (and I bet most people can't afford that). Even with 100 km range it's not even half way there for weekend ski trips, or even daily commute for a lot of people who live around here. Then there's the time when I take my vehicle to offroad incursion, won't find a place to plug into in the middle of a forest.

Yup, there are all kinds of reasons why EVs won't work. In fact, I started a whole page on it!

http://evnut.com/docs/evs-wont_wok.doc

see:
#11
#12
#13

The point is that NOBODY is saying that an EV today is the perfect car for everybody! If it works for somebody to commute in, great! It should be available. It isn't. What people may be saying is that we soon won't have all that much choice, and in fact WILL be needing to make some changes in how we travel. How soon we start to make those changes will determine how painful the switch is.

Then there's the problem of power, some people like vehicles with decent power, not floor the pedal and read a book before it reaches highway speed.

Haven't we been through this before? I mean all of it?

You think EVs are slow? You've got to be kidding me. Please study up a bit before propagating this kind of nonesense! I never realized that an EV's power was a problem. Not when I've driven a an EV that'll do 0-60 in under three seconds. Or 0-100-0 in eleven seconds. Yes. Eleven seconds on street tires.

See item #7 on link above.

 

[moldyoldy]

Good thread! The best response to all of this is that, paraphrasing something I recall - the source of which fails me (senior moment!): We do not have a technological problem, we have a societal problem. The technology is there for a greater conversion to electricity, electric vehicles are only one aspect. However the capital outlay for a new electric vehicle is rather prohibitive when peformed out of a normal life cycle of a car. It would take better than 10 years to make a change if we all changed as our cars reached their end of life.

As for A/C cutout switches, here in Minnesota Excel Energy prices the electricity in the summer such that it is prohibitively expensive not to allow Excel to install a cutout switch on the house AC. And Excel Energy uses that cutout switch liberally! In my single family dwelling, I minimized the central AC to only a 24K BTU unit, so I am not terribly bothered. In my view, the purpose of the AC is to dehumidify, not to cool the house to 70 deg F or less, although the AC can do that given many hours. In my house (smallish one-story at 1040sqft) even on hot days I rarely see temps above 80 deg F. My electric usage w/o AC is about 150KWH per month in the Spring/Summer/Fall. In Winter the watt-meter creeps up to 200KWH and maybe a bit more per month.

As for electricity usage w/in a house: I converted my house to fluorescents and a low-current-draw refrigerator when it did not make financial sense to convert, although the total expense was w/in my willingness to finance. I have been quite happy with the result. The next technological change is coming up, but the price is still prohibitive - LED bulbs for 120VAC. Fluorescent bulbs use about 1/4 the electricity of incandescent bulbs. LED bulbs for mains usage (120VAC) consume about 1/4 of the electricity of fluorescent bulbs. Unfortunately the price is still about $60-70 per bulb. ((www.cyberguys.com))

In Austria there is virtually no governmental subsidy on solar power and not that many solar panels are visible. Switzerland heavily subsidizes solar power panels and solar panels seem to be everywhere. Which country is correct? In my mind, Switzerland is. This is not an economic discussion any more, although the capital outlay on a large scale is daunting.

Back to battery usage:

In Switzerland, there is a mountain-side stone-walled "hut" absolutely beautifully refurbished into an enviable home with a single large solar panel and two big 27F-size lead-acid batteries and a converter. The total installed cost was about 4000 Franken or about 3500 USD. He has used it for several years with no complaints. The only time he and his wife ran out of battery power is when they and friends played cards all night long - the batteries ran down about daybreak....

I have two solar battery chargers for AA cells that I rarely use since the solar cells are quite inefficient and do not charge fast enough to be useful. Besides, the crank-powered flashlights are coming along nicely.

Battery design is changing rather quickly now. For that matter, energy storage is changing quickly. Toyota stated last year that in 10 years, all of it's vehicle offerings would be hybrid. Metro Transit in Minneapolis has green hybrid-drive buses in routine use.

The point of these comments is that technology is changing fast, fast enough to render many previous experiences obsolete. As the architect who designed my neighbors sunken passive solar-gain house told the owner and me (paraphrased): You have the best passive solar design available right now. In two years there will be something better.

 

[Darell]

Good thread! The best response to all of this is that, paraphrasing something I recall - the source of which fails me (senior moment!): We do not have a technological problem, we have a societal problem.

Bingo.