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battery vs dam height difference power storage
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| peter E 2005-07-24, 9:06 pm |
| hi all,
can someone please comment of the costs/benefits of using two small
dams at differing heights to provide storage vs battery storage in
rural areas.
I would assert that when the system is sufficiently large then building
two dams becomes cheaper than building very large lead acid battery
storage systems. How much work is involved in building 2 dams each of
say 200 tonnes of water. A typical farm dam may already be in existance
and have a few thousand tonnes of water.
True energy would be lost in pumping uphill and downhill.
Ideally some micro controller would be required in order to link water
downflow rate to that of net electricity demand. Are there and existing
technology that can be bought off the shelf. I have seen the system
demonstrated at an alternative energy center in Wollongong, Australia.-
What is the cost of storage, battery for a typical household system?
N. Peter Evans
| |
| Anthony Matonak 2005-07-24, 9:06 pm |
| peter E wrote:
....
> can someone please comment of the costs/benefits of using two small
> dams at differing heights to provide storage vs battery storage in
> rural areas.
....
Batteries store a lot more energy per pound (or volume) than a typical
pumped storage dam and can be placed anywhere. Dams and hundreds of
thousands of tons of water aren't quite as easy to come by and aren't
anywhere near as portable or small. Batteries are also, if I recall
correctly, more efficient. Since most homepower situations only require,
at most, a few hundred kWh of storage, batteries seem the best option.
Anthony
| |
| peter E 2005-07-24, 9:06 pm |
| yes I know where you are coming from,
my question is more in relation to developing countires where labour is
cheap.
Building a couple of small dams say roughly 15m diameter, about 1m deep
and lining them with plastic and/or concrete is quite doable for a
village population. Spending say $15000 on batteries would be very
almost impossible. Rough figures of 2 billion people living on less
than $2 a day?
If say electricity is generated by wind or PV, this can be used
directly. The excess can then be used to pump water uphill. Yes I know
there is loss of energy in pumping uphill and recovering downhill. I
guess I am more interested in energy per dollar than pure energy
efficiency.
As an academic exercise, say budget is $3000. Could a few low tech wind
turbines be built, a couple of dams built and lined, a generator and
pump fitted or made from car alternators. Add a micro controller to
link downflow water rates to net energy needs. Is this doable in a
country with lots of people and space but few few hard dollars? What
would a PV - lead acid system cost? $20000?
I have read of 6' wind turbines built for $100, True he had a lot of
'junk' to canabalise from in the first place. Wind power in
intermittant. Are lots of low tech wind turbines and 2 dams more cost
effective in rural communities in the third world than PV cells and
batteries? I do not know the answer, just putting the question.
N. Peter Evans
| |
| Arnold Walker 2005-07-24, 9:06 pm |
|
"Anthony Matonak" <anthonym40@nothing.like.comcast.net> wrote in message
news:C5udnZt-SPEcv37fRVn-jA@comcast.com...
> peter E wrote:
> ...
> ...
>
> Batteries store a lot more energy per pound (or volume) than a typical
> pumped storage dam and can be placed anywhere. Dams and hundreds of
> thousands of tons of water aren't quite as easy to come by and aren't
> anywhere near as portable or small. Batteries are also, if I recall
> correctly, more efficient. Since most homepower situations only require,
> at most, a few hundred kWh of storage, batteries seem the best option.
>
> Anthony
It might be added that some areas are alredy using storage ponds.You peak
during prime rate periods and pump during low rate periods,
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| |
| Robert Morien 2005-07-24, 9:06 pm |
| In article <1122187831.909656.312270@g14g2000cwa.googlegroups.com>,
"peter E" <nicholas.evans@students.vu.edu.au> wrote:
> yes I know where you are coming from,
>
> my question is more in relation to developing countires where labour is
> cheap.
>
> Building a couple of small dams say roughly 15m diameter, about 1m deep
> and lining them with plastic and/or concrete is quite doable for a
> village population. Spending say $15000 on batteries would be very
> almost impossible. Rough figures of 2 billion people living on less
> than $2 a day?
>
> If say electricity is generated by wind or PV, this can be used
> directly. The excess can then be used to pump water uphill. Yes I know
> there is loss of energy in pumping uphill and recovering downhill. I
> guess I am more interested in energy per dollar than pure energy
> efficiency.
>
> As an academic exercise, say budget is $3000. Could a few low tech wind
> turbines be built, a couple of dams built and lined, a generator and
> pump fitted or made from car alternators. Add a micro controller to
> link downflow water rates to net energy needs. Is this doable in a
> country with lots of people and space but few few hard dollars? What
> would a PV - lead acid system cost? $20000?
>
> I have read of 6' wind turbines built for $100, True he had a lot of
> 'junk' to canabalise from in the first place. Wind power in
> intermittant. Are lots of low tech wind turbines and 2 dams more cost
> effective in rural communities in the third world than PV cells and
> batteries? I do not know the answer, just putting the question.
>
> N. Peter Evans
Maybe a small generator, generate hydrogen with your surplus
electricity, use to power generator or directly.
| |
|
|
"Arnold Walker" <arnoldwalker@consolidated.net> wrote in message
news:1122188301_485@spool6-east.superfeed.net...
>
> "Anthony Matonak" <anthonym40@nothing.like.comcast.net> wrote in message
> news:C5udnZt-SPEcv37fRVn-jA@comcast.com...
A set of Lthium Ion batteries at the moment is very expensive. Yet these
can store a lot of energy and may be more cost effective, over large works
using two dams - assuming only one house is being considered.
[color=darkred]
> It might be added that some areas are alredy using storage ponds.You peak
> during prime rate periods and pump during low rate periods,
More energy is used to pump the water to the top dam than what is generated.
In grid systems they make sense as over night wasted energy is used to pump
water to the top dam. At peak time these hydro power stations can be turned
in with a moments notice to cope for the high peak demands.
| |
| peter E 2005-07-24, 9:06 pm |
| hi all,
have been doing more reading and thinking about systems suitable for
people in developing countries, say on $2 a day or less (2 billion
people)
The water uphill part could be done using cheap Savonius turbines made
out of discarded fuel drums. They could be linked to small water pumps.
The electricity would come only on the downhill part using a pure DC
generator. All lights/fridges/radios powered by DC current. The
occasional TV could be powered by a crappy $50 inverted.
Advantages, no expensive batteries, no inverters, no computer
controller, cheap to build, only one generator required. Disadvantage
is less efficient and requires wind to blow. If wind does not blow for
a few days then top dam may empty leaving no power at all. Seems a good
balance of cheap power and cheap storage.
Building a couple of small dams is possible, only needs some labour, no
hard dollars.
Total cost $400? not high tech, not efficient, but better than nothing.
OK am finished my rant now,,,, will leave you all in peace.
N. Peter Evans
| |
| JoeSixPack 2005-07-24, 9:06 pm |
|
"Anthony Matonak" <anthonym40@nothing.like.comcast.net> wrote in message
news:C5udnZt-SPEcv37fRVn-jA@comcast.com...
> peter E wrote:
> ...
> ...
>
> Batteries store a lot more energy per pound (or volume) than a typical
> pumped storage dam and can be placed anywhere. Dams and hundreds of
> thousands of tons of water aren't quite as easy to come by and aren't
> anywhere near as portable or small. Batteries are also, if I recall
> correctly, more efficient. Since most homepower situations only require,
> at most, a few hundred kWh of storage, batteries seem the best option.
>
In the years before rural electrification in British Columbia (up to the
1970s) there were a lot of water powered generators in use. With a fairly
constant supply of running water, these penstocks could produce suffient
electrical power for a typical residence or small farm. For regulated AC
output, nothing more sophisticated than a constant-speed governer
controlling water flow was needed. No batteries, no electronics, and very
little maintenance was required.
| |
| sylva@despammed.com 2005-07-24, 9:06 pm |
| On 24 Jul 2005 06:33:11 -0700, "peter E"
<nicholas.evans@students.vu.edu.au> wrote:
>The water uphill part could be done using cheap Savonius turbines made
>out of discarded fuel drums. They could be linked to small water pumps.
>The electricity would come only on the downhill part using a pure DC
>generator. All lights/fridges/radios powered by DC current. The
>occasional TV could be powered by a crappy $50 inverted.
I suspect water may not be a cheap commodity in a lot of the
developing world but I note your point that battery storage is not
readily available to some, cost and life over many charge-discharge
cycles is also high.
We discussed this for a small pacific island community a while back
and while a small Pelton wheel is likely the most efficient means of
getting power out of the falling water a low tech means of pumping it
may fit better with a distributed system of small multibladed wind
pumps such as have been used on farms for many years. With rudimentary
seals these pumps could be efficient and the high torque of the
multibladed wind turbines would mean the ability of taking advantage
of low wind speeds, though capture efficiency would not be as good as
high speed turbines in a 7m/sec average wind, this being the figure
used to decide whether wind is a useful resource in UK.
AJH
| |
| Bill Kaszeta / Photovoltaic Resources 2005-07-25, 1:21 am |
| On 23 Jul 2005 19:14:34 -0700, "peter E" <nicholas.evans@students.vu.edu.au> wrote:
>hi all,
>
>can someone please comment of the costs/benefits of using two small
>dams at differing heights to provide storage vs battery storage in
>rural areas.
>
>I would assert that when the system is sufficiently large then building
>two dams becomes cheaper than building very large lead acid battery
>storage systems. How much work is involved in building 2 dams each of
>say 200 tonnes of water. A typical farm dam may already be in existance
>and have a few thousand tonnes of water.
>
>True energy would be lost in pumping uphill and downhill.
>
>Ideally some micro controller would be required in order to link water
>downflow rate to that of net electricity demand. Are there and existing
>technology that can be bought off the shelf. I have seen the system
>demonstrated at an alternative energy center in Wollongong, Australia.-
>
>What is the cost of storage, battery for a typical household system?
>
>N. Peter Evans
>
You need to consider costs and efficiencies.
You do not state a location, so answers are rough.
I have to do this in $US.
Diesel generated energy is about $0.30-0.40 per kWh.
In a high sunshine area PV dc energy (without the costs of
inverters, regulators, batteries, etc) is about $0.15-0.20 kWh,
higher if there is less sun. These are life-cycle costs.
The lowest cost batteries are lead-acid, have an energy efficiency
of 75-80%, and a life-cycle cost of about $0.05 kWh. This means
that the cost of a stored kWh is $0.05 + 125% of the energy cost or
$0.24-0.55 depending on the cost of the energy before storage.
A really good water pump could be 50% efficient, but I do not know
about the efficiency of small and low technology hydro system.
Even if the hydro was 50% efficient, the round-trip efficiency
would be 25%. Even if the hydro plus dams were free, this means
that the cost of a stored kWh is 400% of the energy cost or
$0.60-1.60 depending on the cost of the energy before storage.
(neglecting the life-cycle cost of the equipment used to pump
the water and generate energy from the pumped water.)
Hard to make a case for pumped storage, even if the equipment
was free.
Bill Kaszeta
Photovoltaic Resources Int'l
Tempe Arizona USA
bill@pvri-removethis.biz
| |
| peter E 2005-07-25, 5:21 am |
| do not disput your logic or maths
what i am getting at is what can be done with x dollars. Say we have
$1000, a fair amount but not a chance at a PV system and lead acid
batteries, controllers and inverters, about $19000 short.
As in my other thread of this bloke in NZ that got an old Mercedes
truck alternator for $300. (the thread iscalled basic alternator
questions, up about 5 listings). What other costs do you have?
Uphill could be done my sanovius windmills using discarded 44 gal fuel
drums. Cost for say 4 units say $200. Each unit made of 2 drums cut in
half. Some rope pumps at $100, have seen these quoted at $100 to make.
Earthworks for dams free except for labour. What else a pump to collect
energy going down, make a banki or pelton out of scrap metal and wood,
say another $100
that is $700 so far, add another $300 for wiring, pipes and
incidentals.
It may well go ove budget and cost 50 percent more. How many people
live on less than $1 a day, 1 billion or so? thus labour is cheap.
Yes from an efficiency point of view the system as described is very
poor. But big savonius rotors can be made from junk, thus efficiency is
not an issue, more about value for money.
I totally agree with you if we are talking about developed countires
where $5000 or $10000 is within reach. I guess what I am trying to do
it put myself into the mind of some of the 2 (or 3) billion people that
live on less than $2 a day and would not mind some electricity.
Is what I described feasable in a dirt poor country for $1000? Tamil
net shows a dirt poor labourer that built a small dam out of earth
about 4 feet high, chucked in an 8 inch srcap pipe that he found. The
water just poured straight onto a wheel of some sort with flat blades.
Was amazingly inefficient with water going everywhere, and badly
designed baldes and no nozzle whatsoever, but the point was that it
worked and was cheap.
I agree with you that from an efficiency point of view makes no sense.
But for those with a bit of space to build a couple of dams and a bit
of wind, what option would be better for say $1000. I have an open mind
and am open to better ideas.
Peter Evans
| |
| Anthony Matonak 2005-07-25, 1:21 pm |
| peter E wrote:
> what i am getting at is what can be done with x dollars. Say we have
> $1000, a fair amount but not a chance at a PV system and lead acid
> batteries, controllers and inverters, about $19000 short.
....
Your basic theory is that this design of yours (savonius pumps
and earthwork dams feeding a water turbine generator) is cheaper
regardless of how poor it's efficiency. Have you tried some
numbers? Do you know how much water you would need at an 8 foot
head to generate the kind of power you're looking for?
My suggestion is that a home made horizontal axis generator that
feeds into a lead acid battery with an inexpensive charge controller
might be cheaper than your design and it wouldn't require placing
a large lake next to the house.
Anthony
| |
| peter E 2005-07-25, 8:21 pm |
| Alright I will have a go at some numbers
from rainbow power company $2500 will buy two 900Ah @ 6V batteries =
approx 2.1 kw hours (agree with maths? think a watt is the energy of
1amp x1 volt for one second, correct me if I am wrong)
Two 8m radius dams at 1m deep and 10m height difference have 200 tonnes
a piece = 200 000 kilos. Now PE=mgh = 20 million joules = 20 000kJ. Now
I hour = 3600 seconds, thus 20000 kJ = 5.5kW hours
Now say I get 40% recovery on downflow = 2.2 kW hours of storage
This is first time I have done this sort of maths and may well be
wrong.
So it seems that two dams of 8m radius at 10m diff in height = same
storage as $2500 of batteries. What additional costs are needed for
batteries, controllers etc? How long do they last? dams can be repaired
Say there is a village of 20 people, spending $10000 on wind turbines,
several electric motors and lead acid storage way beyond means for most
people in developing countries. This can be demonstrated by the x
billion people with no electricity, where x = 2 or 3.
Just assume efficiency of pumping up and generating down in 20%. Thus
you need 5 times the windpower. So instead of having 2 savonius you
have 10 @ $30 = $300. Of course what you would do is build bigger
savonius in first place, there are some seen in the link. Spending an
extra $100 or a few more turbines is doable, spending $5000 or more on
a high tech system is often not doable
Maybe there can be a combination of some savonius turbines pumping and
some generating power directly. Perhaps using smaller, modified to DC,
scrap car alternators - $30 in parts to modify, for the direct
generation. This is probably a better idea, use the storage as a
backup for when wind does not blow, downside is that more than one
generator is required.
here is a link of a site where they make savonius turbines very cheaply
indeed $30 a piece or so
http://carbon.cudenver.edu/engineer...aces/index.html
here is a link of rope pumps for $100
http://home01.wxs.nl/~holts000/rp_hand.htm
I am not saying this system if for you, or for anyone else in the
western world. But there are billions of people out there where $1000
or $2000 is a lot of money. Building 2 dams of 8m radius is not
difficult, not is building some rope pumps, nor are building a few
savonius turbines. Spending $10000 on a good 'western style' system is
very difficult though.
I guess I am not happy as I see a sort of negativity here. It seems I
get comments like "effeciency of system is low, if I was to do it I
would just go direct generation and use battery storage"...etc etc. My
point is that this is a real world and the challenge for poor people is
build with what is within their means. From what I have written water
storage seems a cheaper option in many situations. There will no doubt
be situations where it is not suitable.
Maybe I am moody... it would be nice to hear something like.."in the
developing world low cost power is the best way to go, a system that
used low cost generation and storage would seem most suitable, whatever
the details of that system may be"
am still a bit moody. You are right to criticise the lack of
efficiency, but would be nice to hear something like "i realise that
cost restraints are a big issue in poorer countries"
Peter Evans
| |
| Anthony Matonak 2005-07-26, 12:21 am |
| peter E wrote:
> Alright I will have a go at some numbers
>
> from rainbow power company $2500 will buy two 900Ah @ 6V batteries =
> approx 2.1 kw hours (agree with maths? think a watt is the energy of
> 1amp x1 volt for one second, correct me if I am wrong)
1 watt = 1 amp x 1 volt. No time is involved.
900Ah x 12V = 10,800 volt-amp-hours which is roughly 10.8 kWh.
It's often suggested that one should limit the depth of discharge on
lead acid batteries in order to prolong their service life. Discharge
of 80% seems to be the max recommended so these batteries would have
an available capacity around 8.6 kWh.
> Two 8m radius dams at 1m deep and 10m height difference have 200 tonnes
> a piece = 200 000 kilos. Now PE=mgh = 20 million joules = 20 000kJ. Now
> I hour = 3600 seconds, thus 20000 kJ = 5.5kW hours
>
> Now say I get 40% recovery on downflow = 2.2 kW hours of storage
You're suggesting two large "pools" 16m (52.5 feet) in diameter
and separated by a 10m (32.8 foot) height. Volume of a pool 8m radius
and 1m deep is some 3.14159 x 8 x 8 x 1 = 201 m^3 and water weighs
some 1000 kg/m^3 for a total weight of 201,000 kg for each pool.
Multiply by 10 meters for 2,010,000 kg-m and then by .0027236 to get
watt-hours for 5475 wh or 5.475 kwh.
Math looks good enough to me for a rough estimate. I don't know how
efficient small water turbines are so I can't comment on that part.
> This is first time I have done this sort of maths and may well be
> wrong.
> So it seems that two dams of 8m radius at 10m diff in height = same
> storage as $2500 of batteries. What additional costs are needed for
> batteries, controllers etc? How long do they last? dams can be repaired
Actually, it's the same storage as (2.5 kwh/12V) 208 amp-hours or two
6V golf cart batteries rated at 220 amp-hours and weighing some
62 pounds each at a price of $60/each or $120 total. Let's say shipping
is very expensive and double the price to $240 total.
> I am not saying this system if for you, or for anyone else in the
> western world. But there are billions of people out there where $1000
> or $2000 is a lot of money. Building 2 dams of 8m radius is not
> difficult, not is building some rope pumps, nor are building a few
> savonius turbines. Spending $10000 on a good 'western style' system is
> very difficult though.
I think you'll be hard pressed to build a three story high (32 feet)
swimming pool with low technology, let alone do it for under $240.
Let's not forget that you also need to add the price of a water
turbine/generator.
It's also much easier to store two golf cart batteries than two 52 foot
diameter pools on your property.
> Maybe I am moody... it would be nice to hear something like.."in the
> developing world low cost power is the best way to go, a system that
> used low cost generation and storage would seem most suitable, whatever
> the details of that system may be"
I agree, low cost generation and storage sounds like the best answer.
The low cost method seems to be lead-acid batteries and not pumped
hydro storage.
Wind turbines are probably the least cost generation after water
turbines, if you have wind, and this fellow has plans available for
free download off his site (or you can buy the book).
http://www.scoraigwind.com/
Anthony
| |
|
|
Anthony Matonak wrote:
>
> peter E wrote:
>
> 1 watt = 1 amp x 1 volt. No time is involved.
> 900Ah x 12V = 10,800 volt-amp-hours which is roughly 10.8 kWh.
>
> It's often suggested that one should limit the depth of discharge on
> lead acid batteries in order to prolong their service life. Discharge
> of 80% seems to be the max recommended so these batteries would have
> an available capacity around 8.6 kWh.
>
>
> You're suggesting two large "pools" 16m (52.5 feet) in diameter
> and separated by a 10m (32.8 foot) height. Volume of a pool 8m radius
> and 1m deep is some 3.14159 x 8 x 8 x 1 = 201 m^3 and water weighs
> some 1000 kg/m^3 for a total weight of 201,000 kg for each pool.
> Multiply by 10 meters for 2,010,000 kg-m and then by .0027236 to get
> watt-hours for 5475 wh or 5.475 kwh.
>
> Math looks good enough to me for a rough estimate. I don't know how
> efficient small water turbines are so I can't comment on that part.
>
>
> Actually, it's the same storage as (2.5 kwh/12V) 208 amp-hours or two
> 6V golf cart batteries rated at 220 amp-hours and weighing some
> 62 pounds each at a price of $60/each or $120 total. Let's say shipping
> is very expensive and double the price to $240 total.
>
>
> I think you'll be hard pressed to build a three story high (32 feet)
> swimming pool with low technology, let alone do it for under $240.
> Let's not forget that you also need to add the price of a water
>
> It's also much easier to store two golf cart batteries than two 52 foot
> diameter pools on your property.
>
>
> I agree, low cost generation and storage sounds like the best answer.
> The low cost method seems to be lead-acid batteries and not pumped
> hydro storage.
>
> Wind turbines are probably the least cost generation after water
> turbines, if you have wind, and this fellow has plans available for
> free download off his site (or you can buy the book).
> http://www.scoraigwind.com/
>
> Anthony
Bamboo is available in most parts of the world...
Bamboo wind turbine....and tower....
http://www.bamboocraft.net/gallery/...=1254&limit=all
hope helps....have fun.....steve (sno)
--
Seen it all, done it all, can't remember most of it
This tag line is generated by:
SLTG (Silly Little Tag Generator)
| |
| peter E 2005-07-26, 1:21 am |
| well if your costs for batteries are correct seems best to go with
batteries.
The costs I got were from rainbow power company in Australia, they
specialise in alternative energy technogies, PV, micro hydro and wind.
I cannot explain the differece in battery price of ten fold. Why do
yours cost $250 including shipping, and the specialsit shop sell for
$2500 without shipping? Is there a difference in the quality,
durability?
Why would people buy from rainbow power company when you say same can
be bought for 10 times less. Logic suggests there must be a reason.
Guess I can email them. If your prices are correct then I would go your
way.
Peter Evans
| |
| peter E 2005-07-26, 1:21 am |
| have worked out where I went wrong
I wrote
from rainbow power company $2500 will buy two 900Ah @ 6V batteries =
approx 2.1 kw hours
BUT 900 x 6 x 2 = 1080 Wh = approx 11kW hours not 2.1 !!!
take into account that these are Deep cycle batteries and australian
dollars not US and that accounts for most of the discrepency.
So what does all this prove, batteries do not seem as bad as I first
thought. If villages want to use dams they will need bigger dams, maybe
deeper, 1.5m not 1m,, and further apart.
As for labour to build dam... well assuming there is a bit of space
around then larger dams are a possibility,,, use also for fish farming?
but at $1 a day for labour how much does it cost to build a 6ft high
earth and rubble dam wall say 15m long?
-
Well whatever way is best at least the figures are all out there to
make of them what people want.
N. Peter Evans
| |
| sylva@despammed.com 2005-07-30, 9:21 am |
| On Mon, 25 Jul 2005 19:44:26 -0700, Anthony Matonak
<anthonym40@nothing.like.comcast.net> wrote:
>
>It's often suggested that one should limit the depth of discharge on
>lead acid batteries in order to prolong their service life. Discharge
>of 80% seems to be the max recommended so these batteries would have
>an available capacity around 8.6 kWh.
There must be an optimum dod, 80% seems high to me, but the trade off
is cycles of charge-discharge over variable years of use. I have seen
figures on usenet with storage costs of from 0.05USD to 0.13USD per
kWhr. Presumably these costs take into account capital cost of
installed storage capacity, amortised over battery life, at given dod
and storage-retrieval efficiency.
If 50% dod means the battery lasts better then the installed capacity
becomes 13.6kWhr
>
>
>You're suggesting two large "pools" 16m (52.5 feet) in diameter
>and separated by a 10m (32.8 foot) height. Volume of a pool 8m radius
>and 1m deep is some 3.14159 x 8 x 8 x 1 = 201 m^3 and water weighs
>some 1000 kg/m^3 for a total weight of 201,000 kg for each pool.
>Multiply by 10 meters for 2,010,000 kg-m and then by .0027236 to get
>watt-hours for 5475 wh or 5.475 kwh.
>
>Math looks good enough to me for a rough estimate. I don't know how
>efficient small water turbines are so I can't comment on that part.
One thing is pretty well known and that is it is generally more
efficient to convert the potential energy to electricity if the head
is high. Pelton wheels with a 300 metre head are probably still
capable of conversion efficiency of 90% at the 100kW level. As with
other generation I bet this falls a lot at the 2kW level, not to
mention small alternators are less efficient than similar large ones.
Given a 300m drop then with a 90% conversion through a Pelton wheel
you only need 9.5tonnes of water to store the 7.65kWhr required.
What's the dollar price of a traction battery of 13.6kWhrs capacity
and what is the life in cycles to 50% dod and years?
How does this compare with a 9m^3 container top and bottom of a 300m
fall?
>I agree, low cost generation and storage sounds like the best answer.
>The low cost method seems to be lead-acid batteries and not pumped
>hydro storage.
I think you are right at the domestic level but maybe not at the
village level in a hilly area, especially in conjunction with some non
stored micro hydro or wind.
The battery option looks good on the domestic scale and I see no
reason they couldn't be combined. What would worry me is if the trend
is away from grid power to domestically stored power what the effect
would be on the resources needed for the extra batteries?
AJH
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