Tuesday, 27 January 2009

Lightbulb Dilemma

This morning going into work, there was a segment on our local ABC about the energy saving light globes.

Yes, they save energy (between 60 to 80%, depending on the brand), but they also contain mercury and they have deleterious effects on some people's health, eg, those people with radiation sensitivity and some people with epilepsy.

Like many people we "greened" our lighting several years ago, but now we are having second thoughts.

So, I thought I'd do some calculations so we could compare the energy savings with the other environmental factors.

Assume an average household has about 20 lightbulbs (including outside lights, lamps and room lighting) - count them up and be surprised!

If these are all energy savers, which have about 5mg of mercury each, at any one time, there is about 100mg or 0.1g of mercury plugged into the light sockets. There are currently about 130,000 households in Canberra, so if everyone is using energy saving bulbs, there is 13,000g or 13kg of mercury plugged into our light sockets in Canberra alone, not counting the amount used by business and government.

Across Australia, if everyone used energy saving bulbs in their households, we'd have in excess of 800,000g or 800kg of mercury. And that's not counting businesses, schools, government, hospitals, etc, etc. That's a lot of mercury to dispose of safely!

Now to the energy side of the equation. Assume each household uses 4 lights for 4 hours each day, amounting to 16 lightbulb-hours. If these are (on average) about 70W bulbs, each house would use 1.12 KWh each day for lighting or 408.8 kWh each year. If the energy saving bulbs save, on average, 70%, the energy saving per household each year would be 286.2 kWh.

In Canberra, this would save about 37.2 GWh each year. Across Australia, it would be more like 2346 GWh. That's a lot of energy!

It takes about 1 tonne of coal to make 2500 kWh of electricity. So, each household using energy saving bulbs would save about 114 kg coal. Across Canberra, this would be about 14,882 tonnes of coal. Across Australia, it would be 938,700 tonnes of coal. Not to mention the water and other resources required.

So, at the end of the day, in order to light Australia's households, we have over 800kg mercury vs nearly 940,000 tonnes of coal.

I'm really not sure how to balance this equation. It's a lot of mercury to dispose of safely and it's a lot of coal to dig out of the ground.

Because of the potential health risks, we've decided to use the old incandescent lightbulbs as long as possible. But we minimise our lighting and strive to have only one light on at a time at night, maximum two. I'm not absolutely sure we are doing the right thing. But then I'm not absolutely sure that the new energy saving light bulbs are the right way to go either. So, it comes down to a personal decision.

Would love to hear your thoughts on this one.

love and light


nfmgirl said...

I bought one or two bulbs, with the intention of slowly switching over. Then I saw a story about how it would cost about $1000 to clean up your home if you accidentally broke one of those bulbs. Needless to say, I have yet to make the switch, and resent that we are being forced to change to CFL bulbs, knowing how toxic they are. So we help the environment by being energy efficient while we plan on putting toxic mercury into the environment? Doesn't make sense to me.

Here's an article about the cost of cleaning of mercury from a broken bulb. http://www.naturalnews.com/021916.html

Cheryl said...

Hi naturewitch....you have really got me thinking on this one. We changed over around two years ago. I am not sure I have done the right thing now. This is an issue I will have to think long and hard about.....

Julie said...

We changed all our bulbs a couple of years ago now, so needless to say we've been rather concerned of late - not so much about the mercury as the stories of the UV rays causing skin cancer! "They" are now recommending that you don't don't sit closer than 1 metre to a CFL - well, we've got all CFLs in our reading lamps and the lights in our ceiling fans would be closer than 1m away from our heads in our lounge room... Terrific! Not. I really don't know what to do about it now, but it's definitely worrying...

River said...

My unit has a mix of incandescent, fluoro, and one of the energy saving ones. the place is poorly positioned regards natural light so if I'm in the kitchen, that light (fluoro) goes on, when I leave the room, it gets turned off. Ditto other rooms. The only light that is on almost continuosly is the energy saver over the dining table, this is where the computer is, where I read my books and newspapers, where I watch the tv which is at the other end of the room. (It's a combined living/dining). Because it's on the western side the sun coming in the window is unbearable, so the blind is pulled down, hence the need for lighting. But I trained myself years ago to turn lights off when leaving a room, so I think I'm doing my bit to save energy.

naturewitch said...

Hi nfmgirl
Yes, being forced to use something "they" know is harmful can make you start believing in conspiracies! I too resent being forced to do something which may harm my family. Thanks for the link - will check it out. xx

Hi Cheryl
I'm in sort of the same space that you are. We changed over, but are now changing back, now that we know the implications of CFLs. In Australia, they are stopping selling incandescents, but you can still get some if you know where to look, so we are stocking up. xx

Hi Julie
I didn't know about the skin cancer thing - that's just another reason not to use them, in my books. Thanks for the information. xx

Hi River
Yes, we too are conscious about what lights are on and turn them off when leaving the room. I figure it balances out not using energy savers. xx

goingferal(ish) said...

Damn, can nothing be simple? I knew nothing about what's in these buggers. It seems I ahve to research absolutely every single thing that I bring into my house. That is ridiculous and impractical. Being a good greenie, I have these in every single light bar the ones we want to dim. Damn damn damn.

Darren said...

You're leaving something out of your calculations. How much mercury is present in the coal being burned for electricity?

Mercury emissions from coal-fired power plants are around 0.012 mg/kWh. Since incandescents use more power, they result in a lot more mercury emissions over the lifetime of a comparable CFL bulb. Plus, the mercury from power generation goes straight into our air and water. Only about 14% of the mercury in a CFL will actually be released when it goes to landfill - the rest is bonded to the inside of the bulb.

Also, older-style thermometers contain mercury - about 500 mg. That's more than 100 CFLs worth, and we don't seem to get too concerned about having them around.

Newer style CFLs are coming out with 1.4 - 2.5 mg of mercury, so the situation is getting better. And CFLs are only a transitional solution anyway - we'll have LEDs eventually which will last much longer and use even less power.

My local council has a recycling program for CFLs (as well as incandescents), which ensures they are disposed of properly. Hopefully more will start doing the same.

River said...

LED's are coming? Bring them on! I have an LED torch and it's superbright. With LED light globes, finally I'll be able to actually SEE.

naturewitch said...

Hi Feral
Yes, I got to thinking that every new technology needs thorough researching before we use it. A bit difficult, as you say. xx

Hi Darren
I didn't know that burning coal emitted mercury. That is an another interesting bit of info to throw into the equation.
I knew about the older style thermometers, but don't have one of those.
Unfortunately, there isn't a recycling program here, so disposal is a bit scary really.
On balance, which do you think is better? xx

Hi River
LED would be good. Maybe we should start researching those now. xx