Dan,
In your request to Dr. Byrne, you apologized for my "skeptical attitude." I
don't think there is any need to apologize for my skepticism. If
alternative energy production techniques are worth their salt, the
proponents will be able to show this convincingly.
Dr. Byrne's replies ran quite long and I had to compose my comments off line
to free up the phone line. My comments on DR. Byrne's replies are also
lengthy.
My comments on Dr. Byrne's replies:
REPLY: By conventional measures of cost, PV panels cost about $5 per peak
Watt of electricity supplied. Throughout most of the US, this would be
equivalent to $0.20 per kWh, compared to dirty coal plants which can produce
electricity at $0.05 per kWh ... and warm the planet. As long as the latter
is not a cost that we address (and currently we don't), dirty coal plants
are more "economical."
MY COMMENTS:
Dr. Byrne makes a valid point in that more than just the economics of energy
conversion need to be considered. Certainly, the production of CO2 by
burning coal must be taken into account. There is sufficient evidence that
the combustion of fossil fuels has led to an increase in the [CO2] in the
atmosphere and there appears to be a link between increased [CO2] and global
warming. It is not at all sure, of course, that global warming is
necessarily a "bad thing." There have been periods in the past when global
temperatures were higher than they currently are. But let's assume that
burning fossil fuels leads to unwanted global warming.
What Dr. Byrne does not mention is the energy requirements of the production
of the photovoltaic (PV) panels and the environmental costs of producing the
panels. Producing PV panels involves toxic chemicals such as hydrofluoric
acid, arsenic, cadmium and selenium. The environmental costs of the
production and disposal of these materials must be considered, as must the
safety of the workers involved in the PV industry. Hydrofluoric acid (HF)
is so dangerous, by the way that, if you get a drop on your finger, your
finger nail must be removed because the HF will migrate underneath the nail
to the bone and react with the bone.
I do find it curious that Dr. Byrne feels it necessary to qualify 'coal
plants' with 'dirty' throughout his replies. It is also worth noting that
he compares solar energy with coal-generated energy, one of the dirtier
forms of energy conversion: in addition to producing vast quantities of CO2,
it also releases trace elements in the coal, specifically heavy metals such
as mercury, cadmium lead, and uranium. If these elements are not released
to the atmosphere, they end up as components in fly ash or in the scrubbers
and must be disposed of (some fly ash is now mixed with cements to form
concrete to form an 'interim disposal method')
REPLY: I think that your colleague is getting at the fact that solar light
is diffuse and needs a larger area to collect its energy than dirty coal,
for example. But the real estate question has a couple of problems. If you
consider the geology of fossil energy, then real estate must become a
three-dimensional question. In which case, PV -- a 2-dimensional energy
collector -- will require a lot less real estate than dirty coal. And if you
consider that dirty coal degrades the "real estate," while PV does not (at
least while it collects energy), you're probably more interested in PV than
dirty coal from a "real estate cost" standpoint. But the bigger problem is
that sensible use of PV (see below) would use as its "real estate" rooftops
and wall surfaces, i.e., areas that already are in use. Thus, it should
have little in the way of real estate requirements.
MY COMMENTS:
I'm not sure I understand the 2-D vs. 3-D argument other than that it
explains why solar panels need more surface area, whereas coal essentially
represent the integrated the solar energy over the lifetime of the plants
that eventually became coal. In fact, Dr. Byrne does not do solar energy a
favour in the 2-D vs. 3-D comparison because one can argue that, precisely
because fossil fuels are 3-D deposits, less of the earth's surface area
needs to be disturbed to collect it.
I have already commented on the use of the qualifier 'dirty,' and on the
degradation of the 'real estate' and need not do so again. The 'sensible
use' of limiting PV to rooftops and wall surfaces is, to me, another
drawback in that only some wall surfaces (mainly southern exposures) can be
used. If the walls are vertical (optimum use of building materials), the
incident angle of the solar rays is not optimized, nor can the solar panels
swivel to 'follow the sun.' Using the walls of buildings also limits the
density of the dwellings per unit real estate. Each building will throw a
shadow that will preclude the location of another solar-heated building.
This is not to say that PV panels have no use in cities, on walls or on
roofs, but it does place limitations on the amount of solar energy that can
be captured.
REPLY: Yes, like car windshields and home and office windows, you have to
wash panels once or twice a year. I don't know how many workers fall off
panels per year; I also don't know how many workers are injured while
washing windshields and windows -- but PV maintenance is unlikely to add
considerably to the statistic, since sensible use of the technology would
mean co-maintenance of windows/windshields and panels.
MY COMMENTS:
Dr. Byrne may be a bit optimistic here. I certainly have to wash my
windshield more than "once or twice" a year! In fact, every time I drive my
car in the rain, I 'wash' the windshield using the windshield wipers. My
wife would not be pleased if we only washed the windows "once of twice" a
year. ;-) There is another difference: windows in our house are cleaned for
esthetic reasons, not to optimize the throughput of solar energy. I would
think that solar panels would have to be cleaned more often and that the
cleaning frequency may well be a function of the angle the solar panels make
with the horizontal.
I did not intend to suggest that a lot of people are killed or injured
washing windows or roofs, but falling is a major occupational hazard in many
industries. People tend to fall from scaffolds, roofs, etc. and one must
factor this hazard in the equation.
REPLY: Panels are now rated to last 25 years. Field experience suggests that
this is about right.
MY COMMENT: I have seen similar numbers and, with improved techniques, this
number may well increase.
REPLY: Actually, there is already a vibrant recycling market. Because PV
panels contain valuable processed silicon, companies sell the old panels to
others who extract the silicon from them. One company in Delaware,
AstroPower, actually makes panels from recycled cells.
MY COMMENT: I hope they also recycle the elements that make the silicon act
as a semiconductor or photovoltaic cell.
The following reply is too long to put my comments at the end of Dr. Byrne's
reply. I will break his reply in sections and insert my comments where
appropriate.
REPLY: Your colleague asks excellent questions here. Indeed, these are the
core issues. Let me begin with urban energy demand. By shifting the bulk of
the costs of energy use to the natural environment and to future generations
of humans and other species, the industrial era brought about its ally --
the cheap energy era. In this era, we demand a lot of energy. Indeed, the
carbon released from energy combustion is now over 7 billion tons per year
... and rising. Please note that currently only 40% of the world's
population -- the urban part -- have access to "reliable" commercial (i.e.,
you have to pay for it) energy services. As that number grows, we'll be
releasing 2-3 times as much carbon as now.
MY COMMENTS: This extrapolation is only valid if energy conversion is
limited to burning coal and other fossil fuels. Hydro and nuclear power
(also solar energy conversion processes) do NOT generate CO2 (although they
have their own impact on the environment).
I would not necessarily link 'reliable' with 'you have to pay for it.' Lots
of people now pay for unreliable commercial energy services and my guess is
that, with the increased trend towards competition and cost cutting, the
reliability will decrease.
REPLY: How much is 7 billion tons? More than the tonnage of all steels and
other major metals produced worldwide per year. It also is enough to change
the chemistry of the atmosphere. I don't know about you, but when I was
growing up I couldn't imagine that human beings could change the sky. So, we
have an enormous demand for energy in urban areas, measured not only by its
quantitative amount, but by its environmentally disruptive power.
PV cannot supply that enormous energy demand. Nor should it.
MY COMMENTS: This is an important point: solar energy conversion by PV
panels will only be able to provide a limited supply of electrical energy.
Having said this, it then becomes important that provisions be made for
utilities to maintain sufficient generation capacity to satisfy peak
demands. In other words, when PV panels are NOT functioning and the wind
does NOT blow, its exactly a that time that the electrical grid have the
capacity to satisfy the demand. It won't do to say that, when it rains and
it is dead calm, the hospitals and police stations have to decrease their
demand for energy.
In his replies, Dr. Byrne concedes that solar radiation is only going to be
a 'niche player' and will only replace a small fraction of more conventional
energy sources. This is in sharp contrast to proponents of alternative
energy sources who claim that solar and wind energy will be the 'energy of
the future.' Let me cite one example: a few years ago, then Ontario Hydro
(now Ontario Power Generation) made a decision to, temporarily, 'lay up'
about half of its nuclear power generation stations. I'm no going into the
reasons for this decision. Anti-nuclear critics were elated until they
realized that this 'lay up' would not result in a concomitant reduction in
energy demand, but that fossil fuels would be used to meet the demand that
had previously been supplied by uranium. Only when it became clear that the
air quality in Toronto was not exactly improving, did we hear statements
that Ontario was in this pickle because 'not enough money had been thrown at
'alternative energy sources such as solar and wind.'
REPLY:
If PV is to make a difference -- ecologically, socially, technologically --
it should offer an alternative to the enormous energy demand of the cheap
energy/industrial era. What is that alternative? To begin, PV should be used
to cut energy demand in urban societies by collecting solar energy at the
peak of energy demand -- hot summer days ... the same time when solar energy
is at its greatest availability.
MY COMMENT:
But this reply immediately limits the usefulness of PV panels. Dr. Byrne
makes the assumption that the relationship "collecting solar energy at the
peak of energy demand -- hot summer days" is correct. This may well be the
case in southern climates where air conditioning places a large demand on
energy. In other areas (the area I live, southern Manitoba), maximum demand
occurs in winter, when the integrated solar energy per day is at a minimum.
REPLY:
In this role, PV reduces energy demand and the scale of energy systems.
Instead of using conventional energy only during these peak periods, we
would use PV to run the meter backward by supplying converted solar energy
back into the grid. Note that our cheap energy era has resulted in energy
demand during peak months that is almost twice as high as the average. The
result is that we build our power plants to meet these peaks ... and 30-40%
of the capacity of these plants (MW) sits idle, unused, for 80% of the year.
MY COMMENTS:
The recurrent argument by alternative energy proponents is that their energy
conversion can be used to "run the meter backward." But where is "the grid"
going to put this excess energy? It has to be stored somewhere! The most
likely places to "store" this energy would be pumped storage (pushing water
uphill), convert it to "chemical energy" using batteries or electrolysis of
water, or by changes the phase of chemical compounds with high heats of
fusion. None of these processes is 100% efficient.
Dr. Byrne is correct in that much of the installed capacity of power plants
sits unused. Supplying energy to the grid in periods, other than peak
periods, won't do much to reducing the need for installed capacity.
REPLY: With PV deployed on rooftops of urban buildings (what is called the
solar shingle), we can cut our extravagant energy demand. Also, since these
very large plants lose about 20% of their energy in transmission and
distribution, rooftop PV allows us to reduce the transmission and
distribution capacity of our energy systems.
MY COMMENT: But the 20% reduction in transmission and distribution also
goes both ways: PV panels providing excess energy to the grid is also
subject to transmission losses. BTW, the transmission losses are a function
of distance over which the energy has to be shipped. It can be reduced by
transmitting the energy as a DC. This is used by Manitoba Hydro in
transmitting energy from its hydro stations in northern Manitoba to the
south.
REPLY: And we can then move away from large-scale plants that are
hopelessly beyond democratic control.
MY COMMENT: This is, as I see it, the crux of the matter: "hopelessly
beyond democratic control." If there is one philosophical thread running
through the proponents of alternative energy sources, it is the distrust of
'big business.'
REPLY: Currently, our cheap energy system requires experts to run it for us
and they get very confused, even so! That's why we experience loss of power
periodically; and why, probably for the computer you are using, you have
purchased an uninterruptible power supply (a fancy way of saying batteries
for energy when the lights and computers go out). When you use rooftop PV
(which comes with battery storage to smooth out its supply) to cut peak
demand and provide emergency power services, its economics are quite good.
Indeed, we have published a stream of papers over the last 5 years showing
that the savings in energy bills and the cancelled need to buy emergency
power equipment equals the cost of PV at today's prices. That is, PV's
economic benefits, measured in the (inaccurate) unit of cheap energy prices,
pay for its current costs (capital and maintenance).
MY COMMENT: There are a lot of reasons for the interruption of power and,
yes, some are a direct consequence of centralized power generation stations.
Clearly, if we each had a reasonably secure source of electrical energy
(solar panels, windmills, small hydro station) and sufficient storage
capacity (UPS, batteries), we would probably not have to worry about
lightning storms. The trick is to make sure that the supply of energy
exceeds the demands. Again, I can cite my situation as an example. I live
in an area where the maximum summer temperature can go as high as the high
30s (Celsius) and the minimum winter temperature can drop to -40 (C or F,
take your pick ;-) ) Our house is heated electrically and all appliances
are electric (we have no access to natural gas). We use, on average, 35
MWh/a (now that the kids have left home, the use is closer to 30 MWH/a). I
doubt very much if I could replace this using PV panels: 35 MWh/a
corresponds to a continued use of 4 KW and, if I had ways to store the
energy when I don't need it, I could get by with 4 KW installed capacity. I
seem to recall that the solar radiation in Canada is ~100 W/m2, so I would
need 40 m2 to satisfy my electrical demand, assuming 100% efficiency. If
the efficiency of the PV panels and the conversion associated with storing
the energy 'for a rainy day' is, say, 50%, I would need 80 m2. For non-SI
aficionados, this is about 90 square yards. (Note: my calculations may be
incorrect and/or based on incorrect assumptions)
REPLY: This e-mail is getting VERY LONG, so I won't take you through how
essentially the same function can be served by PV in urban transport. For
rural needs, the role of PV is different. Please note that most people in
the world do not have reliable access to electricity. Living in rural areas,
families have no light at night except that provided by candles or kerosene
lamps; no refrigeration for medicines; water pumps that require great human
and animal exertion to work. We have worked for 7 years on the high plain of
Inner Mongolia in China to learn about the needs of rural people. It's been
an amazing lesson. Unlike urbanites, rural people do not live life by the
motto of more is better. Balancing demand with nature's supply is a
fundamental idea applied in every aspect of life. Working with rural
communities in one of the most beautiful parts of our planet, we have tried
to design very small wind-PV systems that can provide about 30 kWh per
month. This would mean lighting at night for community education -- people
are busy during the day with farm and animal chores; refrigerated medicines
so that animals live -- and women and children eat (when meat is scarce,
children and women are often the last to eat in the countryside); improved
water pumping for better yielding fields, healthier animals and healthier
people. For comparison, urbanites use about 2,000 kWh for non-transport
energy. Demand is amply served in the rural areas by very modest wind and PV
systems. Indeed, you need only a 400 W wind turbine and 50 W of PV (not much
real estate -- a few square feet!) to change lives and livelihoods in Inner
Mongolia. And cost? If you compare the cost of running a small diesel
generator to serve rural needs - and include the expenses of transporting
the fuel and travelling back and forth to rural towns to get parts and to
have maintenance work done on these small generators -- the wind-PV system
we learned how to design from rural families costs about one-half that of a
diesel generator per kWh.
MY COMMENT: I would be interested in how PV panels can be used for urban
transport but this is best done off-line. I agree with Dr. Byrne that
alternative energy production has its place and the developing world
certainly would be a place to apply them, if only because their demands have
not reached that of the level of the industrialized world. However, my
query was a comparison of energy conversion methods, not case studies where
alternative energy productions are appropriate.
REPLY: The wonderful thing about renewable energy is that it is available
EVERYWHERE. While solar energy may not be abundant in Yellowknife, wind
(harvested by very small wind machines -- you can buy the 400 W machines
from factories in China -- they have over 60,000 sold across western China;
no US or Canadian company makes such small wind machines) is abundant; and
the region has geothermal, small hydro (not the big stuff that destroy
rivers and communities), and a host of other options. Of course, I presume
that we are not trying to build a New York City in Yellowknife -- hopefully,
we can leave some real estate for other species.
MY COMMENT: Again, Dr. Byrne's reply suggests that solar power will remain a
niche player. Windmills in China and Mongolia are all fine and well, but is
this any improvement over what was used in North America in the earlier
periods of this century? There used to be a time when windmills were
prevalent across the Canadian prairies and the US Midwest. I've read
stories about the annual greasing of the machinery that involved, among
other, climbing up a rickety ladder. Not every farmer relished that chore!
Solomon was right, "there is nothing new under the sun" (pun intended).
REPLY: Quite true. We should also factor in the costs of a warmer planet, a
less biodiverse planet, and a less democratic and less equitable planet if
we leave things as they are.
MY COMMENT: I'm not sure if "self reliance through alternative energies"
would give us a more equitable planet. Seems to me that, au contraire, this
would lead to an :"every man (and woman) for him(her)self," with only the
rich being able to afford the windmills, solar panels, battery storage, etc.
Incidentally, we looked into auxiliary power last fall, what with Y2K and
all that. A short term solution, a generator, would have set us back ~1000
C$ and would have allowed us to keep the house from freezing. Auxiliary
propane heaters were in the same ball park. Neither would have provided
enough electricity or heat. We took our chances and Y2K was a non-event and
the winter was relatively mild.
I know that my bias is clearly showing but I maintain that, in the long run,
nuclear power is the only viable option to provide the energy we have come
to rely on. Then again, if I didn't believe this to be so, I would get out
of the nuclear energy business, even though my last 15 - 20 years have been
devoted to helping to solve the disposal of nuclear fuel wastes.
Chuck Vandergraaf
Pinawa, MB
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