| RAINBOW POWER COMPANY LTD
E-mail Newsletter #74
29 July 2004
Please note that the advertisement above comes from
our server, Topica,
and we do not necessarily endorse this product or
service.
CONTENTS:
1. GERMANY PV MARKET
2. MONTHLY SPECIAL
3. INVERTER SELECTION
1. GERMANY PV MARKET:
Quite a few people contacted me after the last newsletter
about the big
Renewable Energy push in that country. For those
of you wanting more
info, I didn’t have any one source. However
if you put Germany – Solar,
etc in Google, you’ll get lots of references.
A couple of readers leapt to the defence of the UK
following my comment
that like their Coalition of the Willing partners,
Oz and USA, they were
doing little to advance the course of Renewable Energy.
I had made that
comment after seeing the UK at the bottom of some
list – however I can’t
put my hands on it.
Anyhow, to clarify the situation, Peter from the
UK pointed out: “I
heard something similar regarding Germany and PV
- jobs in sector have
increased from about 1500 in the mid 90's to 10,000
currently. However
to judge countries’ greenness by their willingness
to subsidise PV seems
bogus. What about wind and solar thermal? Further,
they are wrong about
the UK. The UK is an Annex 1 country regarding Kyoto
(unlike US &
others), has had an escalating REO (renewable energy
obligation) of 3%
pa since 2002, has a carbon tax, has 100% capital
allowances on energy
efficiency products (paid in year 1!), was the first
country in the
world to have an active Carbon Trading system in
place (2002) (open to
all - note Denmark's system was and is still only
for generators) and
has a Kyoto agreement to have emission levels reduced
to 20% below 1990
levels by 2010.”
And Simon from the UK pointed out: “The UK
and Germany are the only two
countries to meet their Kyoto pledges in 1990.
The UK and Germany are taking on extra CO2 targets
to keep the EU
emissions down to Kyoto levels, while allowing Spain
and Eire to expand.
The only difference is that Germany has a continental
climate, which
means their AE requirements are best met by solar,
while Britain has a
maritime climate (cloudy and windy) and our AE requirements
are best met
by wind.
Britain has legislation mandating the big electricity
distributors to
offer grid-tie contracts to any and all AE generators
- even the
household ones. That has been in place since the
Thatcher years.
Britain also has a scheme to put PV panels on the
roofs of schools and
other Government buildings (wind is not so clever
in urban environments,
for safety reasons) and this scheme was expanded
last month.”
http://www.britainusa.com/sections/articles_show.asp?SarticleType=1&Article_ID=5291&i=104
http://www.environment-agency.gov.uk/yourenv/639312/641102/644077/644095/?lang=_e
http://www.dti.gov.uk/energy/renewables/publications/pdfs/windfs5.pdf
2. MONTHLY SPECIAL: In August, we are featuring
our 12 Volt LED light
in a dichroic fitting. Buy them this month and get
10% off. They use
only 90mA and give a very directed light onto a desk.
I would point out
that it does have a rather ‘cold’, bluish
light. If you really like
warm coloured lights, we suggest you stick with our
hybrid fluoros.
3. INVERTER SELECTION: This month’s longer
article is about choosing
an inverter.
Selecting an inverter to meet your needs is a major
decision. Inverters
are quite costly and we tend to become very dependent
on our power
sources. In some cases, your entire house, including
your lights and
fridge may be powered from it. Before we go into
the choice of an
inverter, I’d suggest that we almost always
recommend using a DC fridge
(and not an AC one) through your inverter. We often
suggest that some
or all of your lights be run straight off the battery
bank.
Lately there has been quite a proliferation of economical
imported
inverters coming into the country. We get asked for
a price and often a
customer says they can get ‘something bigger
for half the price’. Like
a lot of things in life ‘you get what you pay
for’ and ‘if it is too
good to be true, it probably isn’t’.
In selecting an inverter to meet your needs, a solar
designer will look
at the type of loads you have – their wattage,
power factor, continuous
and surge power requirements. S/he will also assess
whether or not a
cheaper modified square wave inverter would do the
job. Once this
determination is made, a specific model inverter
needs to be chosen.
What are some of the things one should consider?
WATTAGE: This is usually the first and often only
thing that an
uninformed person may look at. Biggest is not necessarily
best! In
Australia, inverters are usually given a continuous,
intermittent (30
minute), and surge rating. Be wary of inverter specifications
that
don’t give you such ratings. We’ve seen
some imported units with the
surge rating in huge print and the continuous rating
in the fine print.
Large inverters will be less efficient on very small
loads than smaller
inverters. Lightweight inverters with no transformer
generally do not
have much surge ability.
OUTPUT WAVE SHAPE: A true sine wave is best. Cheaper
inverters don’t
mention it, or are termed modified square or sine
wave. Many appliances
including fans, washing machines, stereos, digital
clocks and timers,
will not work satisfactorily on this type of inverter.
Many items will
run slower, or hotter or noisier on square wave type
inverters.
FREQUENCY AND DISTORTION: Good inverters typically
hold their frequency
to within .01% and have less than 4% harmonic distortion.
AUTOSTART: Does the inverter have a standby/autostart
mode? This
typically reduces the DC load to about 0.05 Amps
when then is no load
on. I’ve seen cheaper inverters drawing 2 Amps
continuously with no
loads on! Is the demand start sensitivity adjustable
in case you want
it to start up with say one fluoro light?
MINIMUM INPUT CURRENT: How much power does the inverter
use if it is on
‘run’ mode to run or detect a very small load? A good inverter might
only use 0.6 Amps.
INPUT VOLTAGE: A battery on a solar system may typically
vary from as
low as perhaps 10 volts up to 15.5 volts when the
solar is ‘equalizing’.
Our good inverters will generally operate between
10 to 16 volts.
OUTPUT VOLTAGE: Will it maintain its AC voltage
to 3-5%?
EFFICIENCY: How efficient is the inverter? Does
the specification just
give you one ‘peak efficiency’ or does
it show you a graph with small
50-100 Watt loads up to its rated power?
SAFETY: Does the inverter meet all relevant safety
standards? In
Australia these would include AS 3100 and AS 3108
and ‘C Tick’ with
respect to low radio frequency interference. Can
your electrician
install it through a ‘safety switch’ (‘MEN’ compatible).
DISPLAYS: Does the inverter identify common faults
such as low and high
battery, overload, over temperature, etc?
WARRANTY: How long is the warranty? Our good inverters
come with a
5-year warranty. Where do you have to return it to
for warranty? For
example, Australia is a big country. Are there service
agents in most
states?
CONCLUSION: The choice of an appropriate inverter
is an important and
complex choice. Consider carefully the recommendations
of an
experienced solar designer and think twice about
buying the cheapest
products you can find!
By the way, our FAQ section on the website has a
large selection of
articles about running various appliances off inverters.
That’s all for this month folks! Send us your
questions and articles for
the next newsletter. However, there is no need to
send our newsletter
back to us when you reply!
If you would like a price or product information,
please tell us which
country you are from if it is not evident from your
e-mail address. This
allows us to assess if local GST (tax) is applicable
or whether 240 Volt
50HZ products will work in your country, etc.
Also please note that the advertisement below comes
from our server,
Topica, and we do not necessarily endorse this product
or service.
Dave Lambert and the RPC crew
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