E-News Issue #74
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.”
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.
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 'equalising'. 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.
Cheers from Dave and all the RPC crew.
Dave Lambert (Director)
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- Issue #79 - 05/01/2005