Installing a solar system will protect your home from rising electricity costs and produce a positive annual return on investment.
Solar electricity is one of the cleanest forms of energy available today. By purchasing and using solar power you are combating global warming and are helping keep New Zealand clean and green for this generation and the next.
Cheers, Shane
www.powersmart.co.nz
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Originally submitted by shane@powersmart on 23 Feb 2008
Yes, but at what cost?
"Installing a solar system will protect your home from rising electricity costs and produce a positive annual return on investment"
I'm interested to hear a justifcation for the "positive annual return on investment" statement.
From figures on the website, the smallest residiential unit is as follows:
1,260 watts, 1789KWh annual generation, 10sqm roof space, carbon offset 1110 kg per annum.
This is enough for some lights, but switch on any heating appliance, or even the jug for a cup of tea, and you'll be taking power from the grid. And during nightime, in winter, when the main heating applicances are active, plus cooking, it's not generating any power at all.
The annual generation is equivalent to the power taken by 2 100W lightbulbs.
And what's the expected lifetime of these products? Solar powered water heating should be ok for up to 20 years, I wonder what it is for these systems?
Human beings exhale about 350kg of carbon dioxide each year during the course of normal breathing, so the CO2 saving is equivalent to the exhalations of about 3 people; this doesn't seem very great to me.
positive annual return
Skeptic, thank you for your comments.
The "positive annual return" is a very simple concept. You invest in the purchase of a system and in return you get an increase in the appraisable value of your home and a reduction in your annual electricity bills. Both of the returns are positive and measurable. If you would like to read more about this we have a full technical article that is well supported on our website:
http://www.powersmart.co.nz/assets/Solar%20System%20Payback.pdf
Home owners can install a system of any size that suits their budget, roof space, and/or electricity demands. The average NZ home uses the equivalent 8000 kWh annually. A home built today with energy efficiency in mind can use as little as 2500 kWh annually. Our 1.26 kW system will generate ~1789 kWh annually or ~1/5 of the average NZ home. It is really up to the home owner how much they would like to invest in their own electricity generation. We have much larger systems for home owners that would like to offset their entire demand or generate a surplus.
Yes, the stats you pulled from our website for our smallest system are correct. In fact, for one of our recent customers, a system of this size is currently offsetting more then 50% of their electricity expense. Their home is built in Wellington and designed to be heated by passive solar year round. They also have solar hot water and energy efficient appliances throughout the entire house.
Expected lifetime of the products: our systems are designed for a 25-year maintenance free life and carry a 25 year power warranty.
Carbon offsets are calculated using the marginal rate of 0.62 kg/kWh. As for how much a person exhales in a year - I have no idea.
Carbon offsets are important to some, and not important to others. We are currently working very hard to turn this into cash rebates for our customers and will have more information available on this soon.
Cheers, Shane
www.powersmart.co.nz