response 1 of 37:

Nov 26 02:31 UTC 2002

I expect my new house to use as much as 8000 btu/hr of heat during the very
coldest days, which comes out to the amount generated by producing 1.1KW
electricity, which is probably a lot more than the house would use but could
be used for hot water.  Sounds promising.  From your short summary I do not
understand what fuel is used or what it costs per KWH - can you give more
specific details?

response 3 of 37:

Nov 27 18:06 UTC 2002

The calculated heat requirement for the house at 0 degrees F outside is about
2.2KW, or about 6000 BTU if I recall correctly.  We can heat on time of day
rate for about 2.3 cents/KWh.  My electric bill at two addresses (without heat
or hot water) totals as much as $20/month at 8.x cents/kwh, or about 8 KWh/day
(to run a large freezer, two refrigerators, electric stove, several computers
since I work at home).  The 6000 BTU is the maximum figure for heat and might
average half that over the winter.  3000x24 = 122,000 BTU/day for space
heating and I think you calculated 6 gal of 120 degree water (more than I am
likely to use in a day - I shower at about 95 degrees) = 3400 BTU, call it
125,000 BTU/day heat.  At 50% efficiency the same amount of electricity, 3400
BTU/h per watt, divide 125,000 by 3400 = 36 KWh/day, over three times the
electricity I could use in order to generate heat on a cold day, but
reasonable for not so cold days.  I calculated at one point that in January
the heat bill would be about $40/month at 5-6 cents/KWh = about 25 KWh/day
of heat, which is still 3 times the electricity I would be using.

This means having to sell back electricity to the grid even during cold
weather when running the system enough to produce all the heat and hot water.

In November or March it might balance out, but during April-October I would
still have to buy electricity from the grid (or invest in some expensive solar
equipment).  

Am I off by any powers of ten somewhere?  

The power company does not particularly want more electricity in the winter,
which is when such systems would generate excess, and most people use more
heat at night when it is colder out, which is just when there is least demand
for electricity.  People with air conditioners use more electricity during
hot weather when nobody will be cogenerating electicity along with heat.
You would really have to combine solar generation with this sort of system
to balance the loads out.

I think that Detroit Edison (or whatever it is called now) is paying such low
prices for electricity that you sell to the grid that you would get less for
your electricity than it cost to generate it.  I could heat cheaper just by
buying off-peak electricity at 2.3 cents/kwh.  But perhaps in 5 years the
economics of this will have improved.  It might help to throw in an electric
bike except those are not practical during heating season.  My heating season
coincides with icy sidewalks.

response 5 of 37:

Nov 28 03:07 UTC 2002

Re #3:

>This means having to sell back electricity to the grid even during cold
>weather when running the system enough to produce all the heat and hot water.

Only if you insist on generating more electricity than you need.  If you
need 8 KWH/day (333 watts average) of electricity (which is converted to
heat) plus another 6000 BTU/hr, the fuel cell would produce 1136 BTU/hr
waste heat from the electric requirement leaving 4864 BTU/hr.  If you
revved up the fuel cell by another 264 watts (total electric output 597
watts, extra waste heat 901 BTU/hr) and fed that to a heat pump with an EER
of 15 (264 watts in, 3960 BTU/hr out) you'd have another 4860 BTU/hr of
heat.  Your energy input would be 4072 BTU/hr for this output; not bad, eh?

Using a heat pump as a dump load gives you a lot of flexibility in the
heating season.  Heat pumps can heat DHW too.

>In November or March it might balance out, but during April-October I would
>still have to buy electricity from the grid (or invest in some expensive solar
>equipment).  

Or generate juice and throw the heat away, just like the plants which
make your juice now.  It's not a panacea, it's just a way to take a huge
whack out of annual energy needs without a bit of lifestyle change.

>People with air conditioners use more electricity during
>hot weather when nobody will be cogenerating electicity along with heat.

I did say it wasn't a panacea.  However, this problem would not be
exacerbated by such a system; the use of highly efficient ground-coupled
heat pumps for air conditioning might even reduce it somewhat.

>I think that Detroit Edison (or whatever it is called now) is paying such low
>prices for electricity that you sell to the grid that you would get less for
>your electricity than it cost to generate it.

Answer:  net metering.  I'm sure the electric company would be happy if
you produced a slight excess during peak hours and consumed a bit in the
off-peak; it would make their lives a lot easier and reduce their costs.
Or you could generate a substantial excess during the day and sell it
for 5 cents a KWH, and the electric company turns around and wheels it
over the lines to all the people charging their electric cars at the
office where they sell it for 10 cents a KWH.  Everybody's happy (except
the oil producers).

response 7 of 37:

Nov 28 18:17 UTC 2002

Heat pumps are not efficient at below-freezing temperatures so an air-to-air
heat pump would not make sense in this scenario, since it would only be
practical during the times of year when you don't need more heat than you
would get by generating enough electricity for your non-heating needs.
Ground-water heat pumps are rather expensive and tend to require that you have
a pond or a deep well, and they are also high maintenance, as we know from
talking to a couple of people who have them.

During hot weather I would not want to generate heat near the house in order
to produce electricity.  I suppose someone could rig up a system in which the
waste heat ran an air conditioning system.  In the summer solar power would
make a lot more sense than cogeneration.  

I don't see this as being really practical except during the spring and fall
when heating needs matched electrical needs more closely.

Does this fuel cell produce AC current (in the $1500 model)?

It might help to use hot-water heating so that excess heat at any moment could
be stored for later use.  And incorporate solar water heating in this somehow
as well.  

I think Detroit Edison is paying people about 3 cents/KWh.  I will try to find
out.  

response 9 of 37:

Nov 30 04:23 UTC 2002

Re #7:

>Ground-water heat pumps are rather expensive and tend to require that
>you have a pond or a deep well, and they are also high maintenance, as
>we know from talking to a couple of people who have them.

There are designs for ground-side loops which merely run a length of
tubing under the yard, or vertically down a small-diameter hole.  It
is not necessary to pump water or even have a water supply for heat.

>During hot weather I would not want to generate heat near the house
>in order to produce electricity.

People using air conditioners are doing just that, so I doubt they would
have the same objections.  However, the economics are different if you
cannot take advantage of the waste heat.  (At worst, you are back to the
current model of buying juice generated somewhere else.)

>I suppose someone could rig up a system in which the waste heat ran an
>air conditioning system.  In the summer solar power would make a lot
>more sense than cogeneration.  

If you do not have a use for the waste heat, there is no "co-" in the
generation.  I expect that the capital cost of a heat-driven A/C system
would make it unpopular, despite how much I find it attractive from the
standpoint of cleanliness and elegance.

Something that was mentioned is that the fuel cell operates at about
800 C (~1470 F).  This temperature is high enough to operate a gas
turbine, and turn perhaps 20% of the waste heat into electricity in
large units.  If the fuel cell grabs 60% off the top and the gas
turbine converts 20% of the remainder, that's 68%.  Then you can run
a steam cycle off the gas-turbine exhaust...  It should be possible
to get 75% net efficiency out of very large installations.

>I don't see this as being really practical except during the spring
>and fall when heating needs matched electrical needs more closely.

Did you fail to grasp the point of the heat pump?  You could get as
much heat as desired by generating electricity to pump heat; the
limit on usefulness is not set by cold weather, but by warm weather.
If you need less heat, you generate less juice and turn off the heat
pump.  When you don't need as much heat as is generated as the byproduct
of your electric demand, you've got issues.

>Does this fuel cell produce AC current...

Electrochemical cells produce DC.  (Duh!)  DC can be inverted to AC.
Cheap inverters seem to be running ten cents a watt or less these days.
As the price of mass-market electronics continues to drop, I expect that
we'll see 5 KW sine-wave inverters for $300 or less if demand creates a
market for volume production.

>... (in the $1500 model)?

This is not yet a product and does not have a price tag attached.
The only thing that's currently known is the raw-materials cost,
given as $37/KW by the article.  Multipliers between that and price
of the theoretical product can be estimated, but no more.

>It might help to use hot-water heating so that excess heat at any
>moment could be stored for later use.  And incorporate solar water
>heating in this somehow as well.  

One of many opportunities for efficiency and price arbitrage, if the
markets develop far enough for homeowners to be players.

>I think Detroit Edison is paying people about 3 cents/KWh.  I will
>try to find out.  

Let's see.  If my fuel cost is $.017/KWH and I can turn that into
electricity at 50% efficiency, I could sell the electricity for
$.03/KWH and enjoy heat at an incremental cost of $.004/KWH.  So
long as I need heat anyway, it sounds like a great deal.

Re #8:

>What is the 'top incremental cost of power'?

The price of the highest-cost power that's actually required to meet
demand, I suppose.  That's how much the incremental kilowatt costs.
As demand falls, the utility stops using (or buying from) the highest-cost
generators first and the incremental cost of power drops.

The contract rider makes a lot of sense for Detroit Edison, because the
more sources they have for power the less they'll have to use the
highest-cost suppliers, and the less their power costs the more money
they can make at the same rates.  Also, the closer the power producers
are to the consumers, the less the load on their lines and the longer
they can go without expanding.  The only thing that would concern me
is the metering and interconnection requirements, which might be
prohibitively expensive for really small (less than 10 KW) producers.
Environmentally it may well be a win regardless - I'd have to learn
more to be sure.

I have some recent energy figures that I'll try to incorporate into
an analysis of fuel-cell possibilities sometime tomorrow.

response 11 of 37:

Dec 1 02:36 UTC 2002

I dug up a DOE figure claiming US residential usage of 4.940
quadrillion BTU of natural gas in 2001 (preliminary numbers).
If my figure of 245 gallons savings per 83 million BTU of gas
is accurate, use of the fuel cell/heat pump/electric car
scheme could save 14.6 billion gallons of gasoline per year.
This is without increasing natural gas consumption.

Cogeneration possibilities for commercial and industrial properties
would probably increase this figure by a substantial factor.

response 13 of 37:

Dec 2 01:47 UTC 2002

Sindi, I don't think you quite realize that most people are living
in houses which can have their heating plant and water heater replaced
(and are designed for that), but can't be insulated to R-30 for love
nor anything but huge sums of money.  Nor are most people willing to
live with the discomforts that you are.

Most people expect their houses to be no colder than 65 in the winter
and no hotter than 78 in the summer, and they will not give up personal
vehicles absent an utter collapse of the economy.  I prefer to work with
people's desires, not against them.  Fortunately the gains which can be
achieved even within these constraints are enormous.

response 15 of 37:

Dec 2 18:18 UTC 2002

Trains would not become much more useful until they build more stations
and there are better local transportation options at their termini. If
cars became much more expensive to operate, and whole transportation
infrastructure would have to be (re)created.

response 17 of 37:

Dec 3 00:09 UTC 2002

A lot of train stations that already exist are not currently in use (such as
Dexter and Chelsea).  

response 19 of 37:

Dec 3 03:02 UTC 2002

I suspect it would be a lot cheaper to rebuild the old train routes and
stations than to keep building new highways.  There is already a Toledo to
Ann Arbor train route with no passenger service since 1950.   Public
transportation within cities to take people to train stations is also possible
and is the norm in most of the world.  (Chicago seems to be building its new
train stations on the theory that everyone travelling by train will arrive
there in a car.  We had to walk along a 4-lane highway in the mud to get to
the station a mile away because there were no sidewalks leading to any of the
businesses, all of which were behind huge parking lots).  In Boston the subway
system goes to the Amtrak stations and the airport.  It is not difficult to
arrange bus routes to include train stations.

response 21 of 37:

Dec 3 03:33 UTC 2002

My grandparents insulated the first floor of their house to modern
standards.  It was time consuming and very expensive -- it basically
involved gutting the whole first floor and building new, thicker
interior walls, since the studs weren't thick enough to hold more
insulation.  Definately not an easy process.

response 23 of 37:

Dec 3 23:40 UTC 2002

I note that Sindi admits that increasing the depth of the the
insulation of a house involves re-covering the outside at the
very least (an option not available with brick structures, to
give just one example).  This is expensive and involved,
whereas replacement of the heating plant can be done in a day
or two.

And Sindi, if you must drift on topics such as rail transport,
please make your own item for it.