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Australia is going solar – or at least that’s
what we’re told by Government agencies,
environmentalists and corporate spin
doctors. But if you take a really good look
look
at what’s
on offer,
arereally
you getting
at what’s
on offer,
are you
getting
a good deal?
a good deal?
Solar Power for All:
Does it
Add Up?
By Ross Tester
8 S
8 Silicon
iliconCChip
hip
www.siliconchip.com.au
www.siliconchip.com.au
A ten-panel “plug&power” rooftop system from Pacific Solar. This would be capable of generating 1.5kW and cost between $10,000 and $15,000. Photo courtesy Pacific Solar.
W
ith much fanfare and breastbeating, several initiatives
have been announced to
convince Australians to generate their
own electricity, simply by placing
photo-voltaic (or solar power) panels
on their otherwise-wasted roof space.
Of course, there is nothing particularly new about generating electricity
from the sun. Photo-voltaics have been
known about – and used – for many
decades.
There are two main reasons that
it has taken a recent boost in profile:
(1) “Green” is fashionable. Concern
about the environment has escalated
dramatically in the last decade to the
point where some people are prepared
to pay extra for “green” power.
(2) Perhaps even more importantly,
vast improvements have been made in
the efficiency of photo-voltaic cells in
recent years. And with the amount of
money being poured into R&D, it is
expected this will continue.
Coupled with this is a very significant reduction in cost – as volumes
rise, costs should continue to fall.
“Greenhouse” gases
If you say something often enough
www.siliconchip.com.au
and loud enough, most people start
believing it. Could this be the case with
the so-called “greenhouse effect”?
The theory, albeit very abridged,
goes something like this: we humans
produce too much carbon dioxide. The
two main culprits of CO2 production
are (of course) that evil monster, the
car, along with fossil-fuel (mainly coal)
burning power stations.
Problem is, no-one wants to give
up their car or turn off the air conditioner!
This large amount of CO2 acts like
a one-way valve for sunlight (and
therefore heat) entering our atmosphere and striking the earth. The
earth heats up, which will eventually
cause polar ice caps to melt which
in turn will cause oceans to rise,
flooding low-lying areas. Another
consequence is a major change in
climatic conditions.
Cut the CO2 emissions and we’ll cut
the greenhouse effect. It’s that simple.
The point is, it is still JUST a theory.
Most people are firmly convinced it
is fact, simply because there are so
many people telling them it is fact. We
even have Government departments
and agencies set up to deal with the
“problem”. However, there are many
experts around the world who don’t
believe the greenhouse effect is the
one true gospel. Many refer to it as the
“greenhoax” effect.
In 1995, skeptical scientists signed
the Leipzig Declaration on Global
Climate Change, stating that they
“cannot subscribe to the so-called
‘scientific consensus’ that envisages
climate catastrophes and advocates
hasty actions.”
But their voices are generally not
heard amongst the incredibly sophisticated PR machine of the environmental lobby.
The greenhouse effect is taught in
schools as fact. The alternative point
of view – that climate change is a
natural phenomenon – barely rates
a mention.
Yes, there is some evidence of global
climatic change. That proves the theory, of course – except that there is also
evidence that the Antarctic continent
is colder now than it has been since
records were started! Whoops – better
ignore that one!
And in the overall scheme of things,
we’re still only talking the blink of an
eye in not just human history, but the
March 2002 9
Wind and water:
two of the most
prolific and
abundant forms
of renewable
energy. At right is
Australia’s largest
wind farm near
Albany in Western
Australia. Below is
the turbine hall of
a hydro-electric
power station. No
wonder they call
it “clean” power!
into the decaying material underground. While not truly renewable
energy (it must run out in time!) it
is relatively non-polluting (in fact,
it uses and therefore removes a potentially polluting gas).
Another form of bio-energy burns
the waste material from a production process (eg, the bagasse left
over from sugar-cane crushing) in a
similar manner. In many instances,
this also produces steam and other
energy for use in the plant – socalled “cogeneration.”
Courtesy
Western Power.
history of our planet.
Who is right? Only time will tell.
In the meantime, it does make sense
to try to limit the amount of CO2 and
other pollutants entering out atmosphere from power stations – if only
to make us feel better about the air
we breathe!
And that’s where “clean, green”
renewable-energy electricity comes in.
Green power
Photovoltaic cells are not the only
way to produce non-polluting electricity. There are four main ways to
do it:
(a) Wind-generated power – this has
started to make an impact in Australia recently with several “wind
farms” established in relatively-constantly-windy areas. The advantage
is that the wind is free, if not constant. One disadvantage, apart from
fairly low output per generator, is
reportedly the swishing noise of
the blades for people living within
a few kilometers!
To show just how far wind farms
10 Silicon Chip
have come, in January this year it
was announced that the world’s
largest wind farm, a 520MW, 200
turbine installation, would be built
off the coast of Ireland at a cost of
more than $1 billion. Proponents
claim that wind farms will be able
to produce more than two thirds of
Europe’s electricity by 2020.
Incidentally, the first grid-connected wind farm in Australia was
opened at Crookwell, NSW in 1998.
At 4.8MW it doubled the previous
wind generation capacity in the
country! For more information on
the Crookwell wind farm, see the
January 1999 SILICON CHIP.
The largest wind farm in Australia
is currently the 21.6MW plant at
Albany, WA, with twelve 1800kW
turbines on 65m towers.
(b) Bio-energy – burns the methane gas
created during the natural decomposition of organic material to drive
a turbine. Several bio-mass power
stations have been established on
the sites of old rubbish tips, tapping
(c) Water-generated power – immediately, most people think of
hydro-electric and for the most part
(at least in Australia) they’d be right.
However, the “green power” people
will not allow their power to be
sourced from any new dam or river
diversion so this option is now, for
all intents and purposes, at its peak
(upgrades to existing hydro-electric
facilities are allowed).
Turbo installations range from
backyard, hobby types (perhaps on
a stream flowing through a rural
property) producing perhaps a couple of hundred watts, to giant dams
with huge flows of water, producing
many megawatts.
There is another source of water
power, as yet relatively unknown in
Australia, and that is tidal. In many
places in the world (including the
north-west of Western Australia)
tide heights are measured in tens of
metres and this inflow and outflow
can be used to generate electricity
via a turbine. The disadvantage is
that the flow stops, builds, reaches
a peak, stops, builds in the opposite
direction, reaches a peak and stops
again, twice every day. Due to lack
of flow around high and low tide,
electricity of any significant magnitude can only be generated for
perhaps half to two-thirds of each
six-hour cycle.
An ocean wave converter generator is reported to be currently
under construction (or at least in
planning) off the coast of Portland,
Victoria.
(d) And, of course, solar power,
where in most cases the electrical
energy is created through sunlight
striking a photo-voltaic cell. Until
quite recently, the amount of power
generated this way was either very
www.siliconchip.com.au
small or very expensive – but this
is changing. It is solar power we are
looking at in this feature.
Before we leave this introduction
there are two other forms of solar
power generation which bear mentioning.
The first is where a large “field”
(perhaps several hectares) of
sun-tracking mirrors (called a “heliostat”) focus the sun’s rays on a
steam-producing boiler (usually high
on a tower). This in turn drives a
turbine, generating electricity. Such
systems are in use overseas. The
temperature at the focal point of the
mirrors can be extremely high – many
thousands of degrees!
The second form of solar generation, still somewhat in the “theoretical” stage but likely to appear
this decade, is a huge solar-powered
“chimney”, incredibly tall (a kilometre or more) and 5km wide at the
base. The sun heats air at the base
which rushes up the chimney, driving
turbines on the way. Such a project,
which will have a peak output of
200MW, has recently been announced
for Ned’s Corner in far north-western
Victoria.
But this is not quite the solar installation for a suburban house!
Solar for all
There is no doubt about it – the
“push” for solar power is gaining
momentum (even if the installation
is not quite keeping pace).
It received quite a “kick along” prior
to the 2000 Olympic Games when 629
buildings in the Olympic Village (now
the suburb of Newington) as well as
the 19 lighting towers on Olympic
Boulevarde were fitted with solar
power modules from BP Solar.
You may have seen recent television adverts supporting the “solar for
schools” project – in fact, there are
now more than 25 schools listed as
“generators” of electricity via their
solar panels.
Few, if any, would be significant net
producers of power; they would use
all the power they generate themselves
(thereby reducing their energy bills).
They are somewhat fortunate in that
most, if not all, of their power demand
occurs during daylight hours.
When you have large expanses of
roof space (and often, in the case of
schools, elevated roof space at that,
away from shading of trees and other
buildings) there is room to fit large
numbers of solar panels.
The rule is simple: the more panels,
the more power. On the downside,
naturally, the more panels, the higher
the initial cost.
But even with a large installed solar capacity, can a school – or even a
house – generate enough electricity
to make it an economic proposition?
You be the judge.
One product/company which
caught our attention (after much media fanfare!) is “Plug&Power” from
Pacific Solar. This company, by the
way, is a spin-off from the University
of NSW which provided the intellectual property.
The company’s vision is “to have
developed solar cells seen across the
rooftops of the world”. While this is
a laudable objective, their claim that
“the majority of households have
enough sunshine and roof area to produce their entire energy needs” bears
closer examination.
Its solar panels measure 1.68m
x 0.84m (1.41 square metres). Each
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courtesy Pacific
Solar.
www.siliconchip.com.au
March 2002 11
its payback period beats me!)
Note that none of the grid-connected
systems (as far as we are aware) have
any form of storage – ie, no batteries. This means you cannot get any
power from your system at night, nor
anything significant when it’s raining
(or even heavy cloud). When it does
produce power, you either use it – or
sell it.
Selling your electricity
The owner of this house in Sydney’s inner west “is interested in a sustainable
future”. He chose Plug&Power because of the “low maintenance, design and
modular construction”. Pic courtesy Pacific Solar.
comes complete with its own inverter
and is capable of generating 150W in
direct sunlight mounted at the right
angle on a north/north-east-facing
roof.
Pacific Solar maintain that the average house in Sydney has enough roof
area to allow 21 modules (29 square
metres). These are capable of producing around 3.2kW (maximum).
Their examples, to give them credit,
are based on a probably-more-realistic
15-module, 2.25kW system.
According to accepted figures,
there is 1500kWh/kW of solar energy
available in Sydney per annum. With
a 95% efficient panel mounting (28°
angle, north-east facing) that reduces
the figure to 1425kWh/kW.
Their figures assume an annual
electricity usage of about 6800kWh
in a year. The 15-module system
is capable of producing nearly half
the annual usage (1425 x 2.25 =
3206kWh). But is that realistic? And
what happened to the earlier claim
of “to produce their entire energy
needs?”
I know that in my own case, the
6800kWh is very much understated.
My last four electricity bills shows
it’s closer to 10000kWh. And that’s
for a two-person household (albeit
all-electric, with a pool).
On the face of it, to produce
10000kWh “to provide all my energy
needs” I would need to have not 21
12 Silicon Chip
modules but 46. That’s some 66 square
metres of roof area which have to face
the right direction – north!
Admittedly, about 30% of this energy is for hot water and you wouldn't
use solar electricity to heat water
(you’d simply use a solar heater). But
that would take away some of my roof
space . . .
What cost?
So far, we haven’t looked at costs –
let’s do so now.
To install a solar power system,
you’re up for anywhere between
$5000 and $30,000, depending on
size (of system) and the supplier.
Large systems may go even higher
(we’ve seen quotes for $50,000). Now
before you fall of your chair, it’s not
quite that bad because the Australia
Government has a rebate program
to encourage more people to install
solar power.
There are various rebates depending
on the size of your installation. A small
installation is worth $5.00 per watt of
installed solar capacity while a larger
one is worth $7500 plus (in NSW)
$2.40 per watt over 1500W.
The program, which is available
to all owner-occupiers, runs out in
2004. There are some conditions, one
of which is an agreement to keep the
system running for at least five years.
(Why on earth you would spend all
that money and pull it out way inside
If you install a system which generates more power than you can use,
in many cases you can sell the excess
back to your power company. Some
energy suppliers apparently do not
yet have a firm policy on this but of
those that do, the majority will pay
you (or give you a credit on your bill)
at the same rate as you currently pay
for electricity.
In at least one case, it’s much more
generous than that: the Northern Territory’s Power and Water Authority
sell power to you at 12.9c per kilowatt-hour but will buy power back
from you at 16.9c per kilowatt hour!
Hey, let’s move to Darwin!
In some cases the power companies
will charge you extra to install either a
special bi-directional electricity meter
(normal meters cannot run backwards)
or install an “outgoing” meter which
is read in conjunction with your normal “incoming” meter. The first is
subtracted from the second to achieve
your power usage.
Payback period
Putting in a solar system is not
going to make you rich in power
savings. In fact, it’s probably not
even going to break even. Let’s look
at the sums:
Say the system you put in costs
$20,000. Take off the full Government
rebate and you’re still paying more
than $11,000.
If your current electricity bill is,
say, an average of $200 per quarter,
$11000 is equivalent to 55 quarters –
almost 14 years – before you recover
your investment. Take into account
interest lost or paid and it’s probably
more like 20 years. Even discounting
a tad for the pittance you’ll receive
in energy credits, you’re still well
over 18 years before it starts paying
for itself.
Given that the average Australian
family will move house at least once
(and probably twice or more) in that
www.siliconchip.com.au
Better ways to save “greenhouse” gases
So installing a solar system on your
roof may not be the way to go. But
you still want to do something about
reducing greenhouse gases. What
can you do? There are plenty of things
you can do and they will also give you
a big payback in terms of reduced
energy bills.
Here are some of them:
(1) Buy a new car. No, we are serious.
If your car is more than ten years
old, you should buy a new one, to
help the environment. Can’t afford
a new car? Well, then you certainly
can’t afford “plug&power” or any
other of these schemes either.
(2) Get rid of your lumbering full-size
4WD. We cannot understand how
anybody who is concerned about
greenhouse gases can justify driving these monstrosities. Typically,
they use 80% more fuel than a big
car such as a Commodore, Falcon,
Mitsubishi Magna or Toyota Avalon.
And full size 4WD vehicles use at
least twice the amount of fuel compared to medium-size cars such
as Ford Lasers, Toyota Corollas,
Mitsubishi Lancers etc.
safer than 4WD vehicles. OK, so you
want a 4WD for your bush holidays.
Fine. Buy a small car and hire a 4WD
during your holidays – you will still
save heaps.
(3) Buy a new fridge. If you don’t have
air-conditioning or a swimming pool,
your refrigerator’s electricity use is a
major part of your electricity bill. New
refrigerators are much more efficient
than your old unit, especially if it is
more than ten years old.
By the way, put your old fridge on the
next council cleanup for recycling.
Don’t use it as a beer fridge or give it
away for the same use – you do want
to see electricity saved, don’t you?
(4) Get rid of your freezer. Most households simply don’t need a separate
freezer. You’re better off using fresh
meat anyway. Instead, buy the largest refrigerator which will fit into your
kitchen and use the freezer compartment in that.
(5) Replace your old dish-washer.
New machines use less water and
consume less power. They’re much
quieter, too.
with a gas system. It may not be
cheaper to buy or to run, but it will
produce less greenhouse gases.
(7) Use gas heating or a reverse-cycle air-conditioner for your home
heating in winter. Gas heaters are
far more expensive to buy than
electric radiators but they produce
less greenhouse gas to give the
same (or more) heat. The same
comment goes for a reverse-cycle
air-conditioner. They cool in summer, as well.
(8) Install a solar hot water system.
This list is not comprehensive but if
you really want to spend some money to reduce your greenhouse gas
emissions, these are the intelligent
decisions you can make.
OR you can invest your money in
“green” companies. If you have lazy
$5000 or more laying about, why
not invest it in companies which are
committed to a “green” outlook.
Apart from being much cheaper to
drive (and therefore more greenhouse-friendly), new cars are much
(6) Use gas hot water. When your electric hot water system fails, replace it
There are quite a few such companies listed on the Australian Stock
Exchange or you can invest in an
“ethical” managed fund. That way, you
benefit the environment and hopefully,
make a profit as well.
18 years, you will probably never get
out of the red!
Can’t afford a big system? Here’s
one being marketed at the moment:
Pacific Solar’s "Member’s Pack”. It
comprises a three-module system
along with a Sunlogger (keeps track
of energy generated), a Sundown
program for your PC and a regular
newsletter.
It costs just under $6000 (and that’s
after the government rebate) but the
one thing you can be sure of is that
you won’t ever generate much power
to sell!
They claim this system “on average
will supply enough electricity over a
year to run the lights, television, video,
microwave and toaster of the average
house. . .”
Oh yeah?
Let’s see: the three-module system
at best generates 450 watts. But that
doesn’t happen from dawn to dusk.
Nor does it happen when it’s cloudy
or rainy.
We mentioned the accepted figure
of available solar energy in Sydney
is 1425kWh/kw per annum. With the
450W system, you’re going to produce
641kWh per year (.450 x 1425)
OK, so you have this 641kWh per
year to play with.
Now let’s see. In order – lights in an
average home, say 10 rooms with an
average 75W globe; 750W. Television:
oh, about 250W. Video: a modern one,
say 50W. Microwave: about 1000W.
Toaster (even a measly little one):
800W. All that comes to a smigeon
under 3000W.
Naturally, not everything is going to
be on all the time. The average Aussie
TV set is on for 5 hours a day. 5 hours
x 365 days x 250 watts = 456kWh
per annum. Most people leave their
videos on constantly – 440kWh. The
toaster may only get a workout for 10
minutes a day (if that) – 48kWh and
the microwave perhaps half an hour a
day – 182kWh. Lights, of course, vary
all over the place and are usually only
on for 5-6 hours a night. Let’s then
assume that one third of the lights will
be on at any one time – say 22kWh
(probably a bit conservative because
most light usage will be in the kitchen/
living/lounge room areas).
That’s 456 + 440 + 48 + 182 + 22
. . . 1200kWh (1.2MWh) per annum,
in round figures. Now when I was at
school (it was a couple of years ago
and things might have changed . . .)
1200kWh into 640kWh doesn’t go
(even if I did fail maths!).
So who is kidding whom?
www.siliconchip.com.au
March 2002 13
Solar panel installations do
not have to be roof-mounted.
This one is on a frame in the
back yard and has the added
advantage of being able to
turn to track the sun, keeping
the angle at the optimum for
virtually the whole day.
Incidentally, buying that 1200kWh
from your electricity supplier at 10c
per kWh will cost you the princely
sum of $120. Makes the $6000 installation cost of the solar system looks
pretty sick, doesn’t it?
640kWh would of course cost about
$64 so you’re looking at a payback
period of, oh, about 100 years give
or take.
Of course, all this assumes that
energy costs will stay around where
they are now. While most fuels have
risen dramatically in recent years,
electricity is one which has shown
admirable restraint.
Again, I remember from school in
the (late!) sixties, we used a figure of
5c per kilowatt hour in maths problems. Today my power bill says I pay
9.38c per kilowatt hour – not bad
for forty years of often double-digit
inflation!
But that’s not to say our electricity
costs will not increase in the future:
they probably will. Then there may
be some better cost justification for
domestic solar power.
Costs of the solar panels themselves will almost certainly continue to fall. Not only due to costs of
production but also due to the huge
amount of R&D investment, solar
panels will not only get cheaper in
the future, they will get more efficient
at converting the sun’s energy into
electrical energy.
And Pacific Solar, among others,
are getting pretty excited about thin
film solar panels which are expected
to start appearing about the middle of
this decade. This second generation
PV technology is expected to more
than halve the cost of manufacture.
14 Silicon Chip
While we're talking of the future, let
me throw this one in: all the reading
I’ve done on this subject tells me that
heat is one of the biggest problems
with solar panels. So why not produce
a solar panel which is water cooled
– presto, a solar water heater built
into the photovoltaic panel? Sounds
feasible, don’t you think?
Another random thought (I have
plenty of those): it seems to me that
cladding a roof (with tiles, iron, etc)
then placing the solar panels above
that is a waste of roof cladding. Why
not make a solar panel which IS the
roof cladding?
But I digress . . .
The environment
Most of the “case studies” I have
read involve a significant environmental commitment on the part of the
homeowner installing solar power.
They wanted to “do their bit” for the
environment and were willing to pay
to do it.
Australians today are generally
much more environmentally conscious than their parents or grandparents. In those days there was scant
information about the environment;
there was even less effort to improve
it.
Today, that’s all changed. We recycle
our garbage as much as possible. We
try not to pollute our waterways. We’re
conscious about dirty car exhausts.
And so on. People today get a “warm
and fuzzy” feeling about doing the
environment good.
Even if they are sometimes misinformed or even misguided, that
doesn’t hurt anyone and may leave
the planet a better place for our
children!
If you believe in the greenhouse
effect and want to minimize CO2, fair
enough. Each Plug&Power module installed (or similar product from other
suppliers) prevents almost 250kg of
CO2 from being generated in a coalfired power station each year. Wow!
(Yes, I am being facetious . . .)
A 10-module installation (1.5kW)
will save over 60 tonnes of CO2 over
the system’s 25-year life.
Again, in the overall scheme of
things this isn’t going to achieve much
at all. There are much better ways
to reduce energy use and therefore
“save the environment” (see separate
panel).
Despite the intense efforts of the
Government and industry to promote
solar energy for homes, the Australian Bureau of Statistics has indicated
recently that the use of renewable
energy, especially solar power for
domestic purposes, has actually
declined.
Perhaps consumers are thinking
more with their wallets than their
SC
hearts?
References:
(These are just some of the websites where you’ll find information on solar power
for the home. Google "solar power" and you’ll get thousands more!)
Pacific Solar ("Plug&Power" is their trademark): www.pacificsolar.com.au
BP Solar: www.bp.com/bpsolar
Western Power (WA): www.westernpower.com.au
Citipower (Melbourne): www.citipower.com.au
Energy Australia (Sydney): www.energyaustralia.com.au
An excellent educational site for school projects, general information, etc:
www.env.qld.gov.au/sustainable-energy/publicat/
Links to hundreds of solar power sites: www.pv.unsw.edu.au/solpages.html
The "Greenhoax" effect: www.geocities.com/Yosemite/7915/Greenhoax.html
(or Google "Greenhoax effect")
www.siliconchip.com.au
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