Subject: Re: Electric Cars

From: [email-masked] (Dick Schoenling)
Date: 25 May 1995 14:29:36 GMT

In article <[email-masked]>, Peter Graham Thomas <[email-masked]> writes:
|> Some thoughts:-
|> 
|> It Electric vehicles start to make a serious impact on our transportation
|> policy; then the fuel used will have to be made available at the home.

   Why? Is the gasoline pump you currently use available at your home?

|> 
|> In the UK the average house consumes 2 - 2.5 KW per hour, Peak demands
|> could reach 10 kw but that is unusual. 
|> 
|> Now consider an electric vehicle with a 40-50 kW engine, and, say,
|> it is used for 2 hours a day. If we assume an 80-90% charging efficiency
|> the average houshold will have to provide 100-KWh into the car over the
|> recharging period.
|> 
|> Given that electricity distribution systems have been designed around
|> the 2-3 kw houshold demand there will not be enough hours in the day
|> (given a 12 hour charging period, which is optimistic) to charge up
|> the car.
|> 
|> The answer would seem to be to enable each house to have greater average
|> demands. But if electric vehicles are to become the norm, then a wholescale
|> reinforcement of the electricity distribution system is on the cards.
|> 
|> An answer could be 'local generation' from renewables - or from micro
|> CHP around the stirling cycle.
|> 
|> Ideas please..
|> 

Changing the structure/capacity of the existing distribution network
would be prohibitively expensive as well as time consuming. It 
would be much easier to upgrade specific sites, e.g., recharge-parking
lots where you work, "battery stations" similar to today's gas stations
where you would change out the battery pack, assuming it is light
and manageable enough. Alternative power generation at home is also
a possibility. Numerous methods would be neccesary to accomodate
individual environments/requirements, etc. . All in all it will 
require the general public to re-think their position on energy,
both creation and use. All of which will take a long time.

Regards,

Dick Schoenling
Internet: [email-masked]
Raleigh, North Carolina USA

---

From: [email-masked] (DaveHatunen)
Date: Thu, 25 May 1995 17:31:01 GMT

In article <[email-masked]>,
Andrew J. Paier  <[email-masked]> wrote:

[...]

>Okay, as long as we are dreaming of many people using EV cars, why not have a 
>battery policy at the "refill" stations like the old returnable bottles.  You 
>put a deposit on the battery, drain the energy, and return the empty for a full 
>one.  This way they could be recharged over time.  Of course, many of the 
>current battery designs might be difficult or impossible to easily replace, but 
>like I said, as long as we are dreaming...

There are serious problems with this approach, form the standpoint of
practicality. The batteries are big and heavy, and not that easy to
remove and replace. Specialized equipment would be used, but this would
require a large capitalization.

Imagine six or seven vehicles all sitting in a recharge station, with
large 800 lb batteries being moved around. Not only do the batteries
have to be removed and replaced from your vehicle, ditto for whatever
kind of recharging apparatus is required. Right now most gas stations
can run with one guy sitting in a bulletproof booth. A battery exchange
station would have to have several more employees, raising labor costs
considerably. 

Then ask yourself how many batteries the station would have to have on
hand, sitting in rechargers. At least a couple of hundred out on I-5.
Assuming each battery needs sufficient recharge for a two-hour freeway
run, and that about 20 HP is required out on the highway, a 40 HP-hour
recharge is required. This is about about 30 Kwh recharge. On a 24 hour
recharge cycle, each battery charger will draw a minimum of 5 amps at
240 volts. So each 100 batteries would require 500 amps at 240 volts. A
station processing 300 batteries a day would need a 1500 amp service
entrance, probably 2000 amp taking inefficency into account. 

And just where would you put 300 batteries weighing 800 lb each, in
such a way that you could retreive and replace them easily? Such a
battery is maybe, what, 3 ft x 4 ft x 1.5 ft? That's 18 cf, so 300 of
them would require 5400 cf. And maybe half again as much, or 8100 cf,
if you add in the racks and dead space and hydrogen venting around
them. So if the racks were 10 ft high, a floor space of 810 sf would be
needed. But the rack would have to be accessible from two sides so you
could get the batteries, so it would be 10 ft across and 81 feet long.

Whew.

But if a recharge were to cost only about as much as a tank of gas for
an econocar, say $10, then the place would be grossing about $3000 a
day. The 30 Kwh per car, at $0.10/Kwh here in California, would cost $3
per car, or $900/day. That leaves $2100. Six attendants on a 24 hour
schedule (includes a manager with sufficient skill to attend all that
electrical equipment) at an average of $7/hr pay, or $11/hr including
the usual labor overhead, would need $1584/day. That leaves $516/day to
pay the capitalization and rent, and make a profit.

But the installed equipment and plant will probably come to at least
$500,000, and the 300 batteries will add another $500,000 in capital
costs. Call it a cool million (I think that's low, myself). At 6%
that's $60K per year, or about $167/day in interest alone. And we
haven't added in the land cost. Or the other overheads.

And, of course, the station is going to need to replace exhausted
batteries on a periodic basis. How often? How? What happens tothe old
ones?

So what it comes down to is that such a station is going to have to
charge you $10 or more for electricity that would cost you maybe $3.50
at home (California rates). And even then will have a hard time turning
a profit.

But obviously my figures are only semi-educated guesses. Play with them
at will.

-- 

    ********** DAVE HATUNEN ([email-masked]) **********
    *     Daly City California: almost San Francisco      *
    *   but with parking and lower car insurance rates    *
    *******************************************************

---

From: Peter Graham Thomas <[email-masked]>
Date: 26 May 1995 22:35:24 +0100

In article <[email-masked]>
           [email-masked] "Emil Naepflein" writes:

> In article <[email-masked]>,
> Peter Graham Thomas  <[email-masked]> wrote:
> >I think I started this off, but Stan is homing into the problem. It's all
> >right to think of keeping up with a low penetration of EV's, individual
> >filling stations could find the space for their own 500 kVA transformer
> >to cope! - however it is true that the electricity distribution system
> >is designed for an certain energy density (in terms of kW average demand
> >per Customer). The diversity for electricity supplies is very high. You or I
> >could be taking 10-15 kW whilst your neighbour could be 'out'. On average
> >in the UK this comes down to 2-3kW per dwelling. 
> 
> I would assume that the electricity distribution system is designed
> for the maximum use. Or what do you think happens when everybody
> turns AC on in summer or resistance heating in winter? The network
> has to deliver or you would get brown-outs or black-outs. A properly
> designed network does even have additional reserves above the
> absolut maximum seen so far. In germany a normal house connection
> is 3 phase each with 240 V and a maximum of 16 A. This means I can
> use as much as 12 kW power. I have a yearly use of about 3000 kWh. 
> This converts to about 340 W. I am sure the distribution network
> and the power stations can not cope with demand when everybody
> is using their 12 kW. But I am sure there is enough capacity
> available to charge EVs during low demand periods, especially at night.

PGT again:-
Generaly electricity distribution systems are not designed for maximum use. 
They are designed around the R.M.S. value of customer load. As I said the
diversity is v high (12 to 0.34 kW!), and wilst your service cable is 
fully rated, the main power cable that runs down the street is sized 
on the 'diversity' of load on individual services so connected, plus a factor
dependant opon the type of heating used on the properties in the street 
(electric heating has an obvious effect on the cable size/length). 
There is also the matter of voltage drop - over the length of the main 
cable which will limit the useful length of the main. Anyway this 
is getting of the point.

Sure there are reserves in the system, and the idea of controling the time
when individual high loads are switched on (time-switch, radio control etc
are used, however this is only a panacea, not a cure.

> 
> >
> >Electricity Co's have most of their cash tied up in the distribution 
> >network, and a serious upgrade of this would cost billions. It would also,
> >in my opinion be stupid. Indeed I'm sure you are aware that a lot of 
> >electricity companies (mine included) are already looking at 'Demand
> >Side Management', that is actualy encorageing Customers to reduce demand
> >rather than investing in infrastructure upgrades and new Power Stations.
> >
> 
> When the charging of EVs is handled intelligently by the utilities
> you can have a lot of EVs before a upgrade of the distribution
> network is necessary. Demand side management is the important thing here.
> In germany it is already possible to use two tarifs. One for
> normal demand periods and one for low demand periods. The low tarif
> is normally half that of the normal tarif. The meter has two counters
> and the switch between them is done by a clock or in newer versions
> remote controlled by the utility. If you have a electric water boiler
> or electric space heating with storage capability, they are turned
> on automaticaly when the switch occurs and charged. This low tarif
> charging is not done with the full power. Instead it is only enough
> power used to charge it during the normal 8 hour low tarif period.
> In this way the load is levelled.
> Why couldn't the same scheme used for EV's? To level the load even
> more the utilities can control all the charging stations individually.
> You just enter the time you want the EV fully charged, and the
> the utility schedules the charging. This all can be controlled by
> sending messages on the phone network (or better ISDN) without
> any additional infrastructure. The tarifs can be used to give
> the people which use long charging periods, which are better for
> scheduling, an incentive. People which want the EV charged in
> a shorter period have to pay a premium.

See above. Yes time switching can, and will, be used - however it is
not the solution when EV's start to make a real indent in the transport
market.
> 
> >So there is a real issue here. If we are going to seriously into EV's
> >then the idea of clean, distributed (embedded) generation - connected
> >into the low or medium voltage networks has to be considered.
> >If mached to local loads such generation systems would also reduce 
> >energy losses in the distribution systems - by avoiding dragging 
> >the amps through the wires from the bid power stations (about 7% is 'lost').
> >
> >So think of ways of generating clean energy at maximum efficiency as close
> >as possible to where it is used - be it the Service Station or your
> >household.
> >
> 
> Here PV on roofs and small cogeneration units instead of regular
> furnaces can be used. PV is still to expensive, but it is a
> clean way to generate electricity.
> Small cogeneration units may be the best way in the near future.
> But they should be controlled by the utility to allow limited Supply Side
> Management. This way cogeneration units in your neighbourhood can
> be turned on when you have scheduled your EV for charging. The
> cogeneration units should have heat storage for several kWh to
> allow a better match of actual heat and electricity demand.
> 
> Cogeneration units are available in sizes from 3 kW. They have
> a much better total efficiency because the waste heat is used.
> The only problem is, that the utilities normally don't pay
> a fair price for the electricity.
> 
Spot on Emil. And they won't until it hurts - and it won't hurt until
they can't meet the demand without reinforcing the distribution network
at great cost - then cogen will come into it's own.

Regards

-----------------------------------------------------------------------------
Pete Thomas           |  "First you forget their names, and then their faces
Yr Wyddgrug           |   Next you forget to pull your zipper up
Welsh Wales           |   Then you forget to pull your zipper down"....
-----------------------------------------------------------------------------

---

From: [email-masked] (Emil Naepflein)
Date: 26 May 1995 07:46:29 +0200

Emil Naepflein

---

From: Peter Graham Thomas <[email-masked]>
Date: 26 May 1995 20:16:55 +0100

In article <[email-masked]> [email-masked] "Dick Schoenling" writes:

> |> Some thoughts (now edited):-
> |> 
No, but then I can put all the diesel in my car I need for 1-2 weeks
average motoring in 5 min at a Station. So there is no direct comparison
here.
> both creation and use. All of which will take a long time.

Ok. Where I work there are some 300 car parking spaces - allways full.
So, on say 5kW charge were looking at a demand of 300 x 5 x .3(diversity)
=450kW. And this has to be done at low voltages (30-50V)? Methinks that,
there are some serious problems in terms of cable size to distribute
the power, even if it stays as 3ph AC. Might have to go to small 'pit'
transformers for every 50kW or so & distribute at 13.8-kV. Guess it
is possible - but this it the point of this thread - to flush out
the practicalities of EV transport...

Regards

---

From: Peter Graham Thomas <[email-masked]>
Date: 27 May 1995 08:43:37 +0100

In article <[email-masked]>
           [email-masked]  writes:
> 
> YES.  So.California Edison says they can support 200,000 electric
> cars before they would have a need to upgrade any of their plant.
> 
> I would think that any large metropolitan community would have
> the same type of infrastucture issues and their ability to handle
> a large number of EVs charging before running into upgrade concerns.
> 
> And really now, how long do you think it take to get 200,000 EVs in 
> 
> So.California, let alone the rest of the country ?  The ZEV mandate
> expects something like 20,000 EVs being sold in all of California
> in the first few years.
> 
> Tony Cygan
> 

Tony. I guess California Edison are a vertically integrated Co. In that
they Generate Distribute & Sell electricity. I would guess it's the
Generation arm who are behind this statement. I would be interested
to see if my guess is right. Who in CE made the statement, and how
could this Group find out the reasoning behind it? If it's right then
either CE have been very far sighted, or you are paying over the odds
for a Rolls Royce distribution system.

A second question. How many vehicles in total operate in California
Edison's supply area? Bet its more than 200,000.

Regards  
 
-----------------------------------------------------------------------------
Pete (doubting) Thomas|  "First you forget their names, and then their faces
Yr Wyddgrug           |   Next you forget to pull your zipper up
Wales UK              |   Then you forget to pull your zipper down"....
-----------------------------------------------------------------------------

---

From: [email-masked] (DaveHatunen)
Date: Mon, 29 May 1995 02:11:52 GMT

In article <[email-masked]>,
Peter Graham Thomas  <[email-masked]> wrote:

[...]

>Edison's supply area? Bet its more than 200,000.

It's probably close to 10,000,000, maybe more. That 200K is a drpo in
the bucket, hobbyist stuff, and I'm not a bit surprised SoCalEdison
could handle it.

But replacement of a significant percentage of those ten million is
another story altogether.

--

---

From: [email-masked] (DaveHatunen)
Date: Mon, 29 May 1995 02:11:52 GMT

[...]

--