How about using mini wind turbines?

I briefly look at the economies of PV panels.

But how about wind turbines?

Look at the links below:
http://store.sundancesolar.com/airxwitu.html
This one is US$625 for 400W (at 12.5m/s)
(P.S. I've seen the real product in front of me. My boss ordered one from USA to look at feasibility.)

http://cgi.ebay.com.au/EnviroWin ... 64865QQcmdZViewItem
This one "may be" A$400 for 200W (RRP$589).

If I use the same methodology:
For the first one, US$625 = HK$4875

Assume electricity rate = $1.1/kWh for simplicity.

kWh required to payback the wind turbine = 4875 / 1.1 = 4432 kWh

Time required to generate = 4432 kWh / 0.4 kW = 11080 hours

Now I need to check the "wind flower" of HK. But just assume we can have 16 hours a day of wind for the wind turbine.

Then no. of days = 11080 / 16 = 692 days = 1.9 years

This seems quite attractive!

For case 2,
For the first one, A$400 = HK$2600 (for A$1=HK$6.5)

Assume electricity rate = $1.1/kWh for simplicity.

kWh required to payback the wind turbine = 2600 / 1.1 = 2364 kWh

Time required to generate = 2364 kWh / 0.2 kW = 11818 hours

Assume we can have 16 hours a day of wind for the wind turbine as before.

Then no. of days = 11818 / 16 = 739 days = 2.0 years

This also seems quite attractive!

But practically, do you have the space to install the wind turbine?

And also, some costs were not taken into account, like battery, regulator, installation, freight charge, etc.

But it worths a look.

But I better declare that I have no interest in the wind turbine manufacturing industry.

Maybe I should have some interest or investment in this!

Is solar panel cost effective?

I hold the view that photovoltaic panels are not cost effective at this moment (solar energy to electric energy conversion efficiency is only up to 20%; to power a TV, you need over 1 sqm of panels and one 175W panel costs A$1925, see: http://www.solazone.com.au/PVpanels.htm ).

Now go to that link and look at some real numbers!

175W panel cost A$1925.

Now, look at the tariff rates here:
http://www.energy.com.au/energy/ ... _July_07_EA_Res.pdf

Now, if I assume the most expensive rates of : 27.61 cents/kWh

The solar panel needs to generate : $1925 / 0.2761 kWh of electricity to pay for itself. This is 6972 kWh.

For this panel to gnerate 6972 kWh of electricty, it takes 6972 / 0.175 = 39840 hours of full capacity generation.

If I have an average of 9 hours of sunshine each day, it takes 4426 days or 12.1 years of continuous full sunshine everyday.

So unless you are really keen to "show" your committment to ESD, solar panels (photovoltaic panels) are not cost effective if you already have connection to the power grid.

P.S. The story would be somehow different with remote areas where generators or power lines are required to supply electricty. By that time, the comparison will be the installation and running costs of generators and power lines. PV panels will be attractive for those applications.

Is CFL's more environmental friendly than light bulbs?

To be Editted:

Accepted fact:
Running energy and running cost of CFL is lower than incandescent lamps (normal light bulbs)

For:
The efficacy of CFL is higher than incandescent lamps.

Look at the link below:
http://en.wikipedia.org/wiki/Luminous_efficacy

Efficacies of some common light sources:
For a 40W incandescent bulbs: 12.6 lm/W (base)
For a 100W incandescent bulbs: 17.5 lm/W (39% more)
For 5-24W CFL: 45-60 lm/W (257% - 376% more)
For fluoro tubes (光管) 32W (T8): 60 lm/W (376% more)
For fluoro tubes (光管) 28W (T5): 104 lm/W (725% more)
For white LED : 26-70 lm/W (106% - 456% more)
For white LED (prototype): up to 150 lm/W (up to 1090% more)

Note: Efficacy (not efficiency)is a term in lighting science to measure the power (Watts, W) required to produce the luminous flux (or simply speak the amount of light, units in lumens). In mathematical formula,

lighting efficacy = Luminous flux (i.e. amount of light, unit in lumens) / Power input (Watts, W)

So in simply words, to produce the same amount of light, CFL takes less energy than light bulbs.

Doubt (not yet against):

Look at this link: http://www.nvmdigital.com/photos/lelset.html

I have been to a technical seminar and I knew it before looking at this blog.

This may not be so relevant to HK. But the fact is in climate that requires heating, the use of CFL means that the demand in heating increases. More heating energy is required. This is because the “waste heat” produced by incandescent lamps is actually quite useful in colder climates.

So unless the impact of the “total energy” used for a household is calculated (mostly likely by energy simulation), CFL may not necessarily save your energy.

But generally speaking, on the operating energy side even for temperate climates, CFL should save energy when compared to incandescent lamps.

Yes, this is the concept I like to introduce.

Well, a more technical term would be "life cycle costs".

When considering energy use, the following should all be taken account into:

Phase 1: Manufacturing of materials and components, or embodied energy.
Phase 2: the energy used in the actual manufacturing of the product
Phase 3: the energy used to transport the product from production plants to the point of sale
Phase 4: energy is consumed at the operational phase (operation energy)
Phase 5: energy is consumed in the demolition/recycling process of products as well as in the recycling of their parts

So, it is not just the operational energy.

Apart from the embodied energy / life cycle energy issue (which I may still have some elaboration), the other big issue for CFL is the mercury.

You can see from this link that a LED light supplier is running a “scare campaign” for CFL to promote LED lights. (http://www.newstarget.com/z021907.html)

The damage of mercury is real.

But is it that bad and terrifying?

Well, handling of used CFL’s and normal fluoro tubes really need some extra care. We can’t let the mercury vapour escape to the atmosphere or contaminate the soil.

Some sources suggest that it would take 16,667 cubic meters of soil to “safely” contain all the mercury in a single CFL. That is about 3.3m high of soil over a whole football pitch for one single CFL!!!

So handle CFL with extreme care and not to break it. In case a CFL is broken, open all the windows and stay away from the room or house altogether.

This is from US EPA: http://www.epa.gov/mercury/spills/index.htm#flourescent

QUOTE:

What to Do if a Fluorescent Light Bulb Breaks

Fluorescent light bulbs contain a very small amount of mercury sealed within the glass tubing. EPA recommends the following clean-up and disposal guidelines:

1. Open a window and leave the room for 15 minutes or more.

2. Carefully scoop up the fragments and powder with stiff paper or cardboard and place them in a sealed plastic bag.
‧ Use disposable rubber gloves, if available (i.e., do not use bare hands). Wipe the area clean with damp paper towels or disposable wet wipes and place them in the plastic bag.
‧ Do not use a vacuum or broom to clean up the broken bulb on hard surfaces.

3. Place all cleanup materials in a second sealed plastic bag.
‧ Place the first bag in a second sealed plastic bag and put it in the outdoor trash container or in another outdoor protected area for the next normal trash disposal.

Note: Some states prohibit such trash disposal and require that broken and unbroken lamps be taken to a local recycling center.
‧ Wash your hands after disposing of the bag.

4. If a fluorescent bulb breaks on a rug or carpet:
‧ First, remove all materials you can without using a vacuum cleaner, following the steps above. Sticky tape (such as duct tape) can be used to pick up small pieces and powder.
‧ If vacuuming is needed after all visible materials are removed, vacuum the area where the bulb was broken, remove the vacuum bag (or empty and wipe the canister) and put the bag or vacuum debris in two sealed plastic bags in the outdoor trash or protected outdoor location for normal disposal.

And thanks to super316, HK has CFL and fluoro tube recycling facilities. (See #1: http://www6.discuss.com.hk/viewt ... amp;extra=page%3D2 )

So the question comes back, does the use of CFL’s worth the risk?

One argument about the risk of CFL against incandescent bulb is that coal-fired power station will release mercury stored in the coal.

So when you compare the energy saved by using CFL and the mercury used in manufacturing CFL and compared that to the mercury released by burning coal, it is still “a little bit” more environmentally-friendly using CFL. See figure:

http://upload.wikimedia.org/wikipedia/commons/thumb/1/11/Mercury_emissions_by_light_source_%28en%29.svg/300px-Mercury_emissions_by_light_source_%28en%29.svg.png

But then the against-CFL arguments comes back and say this is valid only if the power used is from coal-fired power station. It is not applicable to renewable resources.

Well, this is valid.

But considering that the majority of electricity comes from coal-fired power station (and nearly 0% renewable electricity for HK), the savings from mercury released from coal is still valid.

Well, think, dig (i.e. research) and dig!

Don't take things for their face values!!