Low Energy Light Bulbs – Savers or Wasters? A special feature by Dave Mulligan See also  "Low energy light bulbs in the news" & "Low Energy Light Bulbs - Your Contributions"

Where we are now

A great deal is being said about low energy light bulbs. So much so that on 2/1/07 this phrase raised 88,100 Google hits. The first 50 or so were, with two exceptions, enthusiastic promoters and/or sellers of low energy light bulbs. These are also called CFLs - short for Compact Fluorescent Lamp (also for the Canadian Football League - this is the sort of thing you learn on the web!).

They are being pushed hard!

And now, following the highly laudable EU decision on 9/3/07 to reduce greenhouse gas emissions by 20% by 2020, you can be certain that they will be pushed even harder, maybe even to the point of making incandescent bulbs illegal (there are precedents).

But are things really this simple? This article is about asking questions which should be answered BEFORE we all stampede to the LEL shop. However answers seem to be thin on the ground. Why?

Please read on.
 
 

What do they claim? CFLs use only 20 – 25% of the electrical energy of conventional incandescent (filament) bulbs, for the same level of illumination. CFLs last about 6 times as long as conventional bulbs (6000 hours compared to 1000 hours though some claims run to 15000 hours) The only publicised disadvantage is that they cost more than conventional bulbs, but they are claimed to repay the extra cost in electricity savings (sometimes long before the bulb expires). This seems too glib - my life experience has been that very little is as simple as it is made out to be.  So I’ve had a look into it, from a UK perspective as our climate is important in this discussion, and I’d like to share what I’ve found with you. Back to Top
And what do we want? We must be clear about our objective. With the current (justified) concern about global warming, I believe that it is to 1) Reduce carbon dioxide (carbon) emissions to the atmosphere 2) Do this without adversely affecting our environment. And we must be global in our thinking. It's the world that is under threat – not just where we live!  And it is NOT about saving money! That is only a fringe benefit if we can acheive the first two. Let’s now look at the main claims for low energy light-bulbs: Back to Top
Energy Efficiency in Use CFLs are claimed to use only 20% - 25% of the power of conventional bulbs, which appears to be true, but this neglects to say the following:  a) The 75% - 80% of extra power used by conventional bulbs emerges as heat. In northern Europe indoor lighting and heating are used simultaneously for a large part of the year. For any type of temperature controlled (thermostatted) system a reduction in heat supplied by lighting could result in an increased energy usage in heating.  Low energy bulbs are not recommended for use in cold areas (e.g. outdoors) because their efficiency is reduced. As 50% or more of northern European indoor lighting coincides with simultaneous space heating the economic payback of CFLs becomes debatable.  b) The light quality is different, being colder and more severe. This is offset by the use of mercury in the construction of low energy bulbs. This highly toxic heavy metal presents enormous disposal problems, which are dealt with later.  c) The light output is reduced in the cold  d) You only save on carbon emission if your electricity source produces carbon dioxide – coal, gas, oil etc.. Wind, solar, wave, geothermal, hydro-electric and even nuclear need only emit little or no carbon dioxide (see NOTE below). But a huge amount of carbon dioxide may be released by the construction, maintenance, and decommissioning of these facilities. Total carbon dioxide and energy audits are aspects which receive much less attention than they should. The job is not being done properly if they are ignored. So - it may be possible to make a carbon dioxide saving through an electricity saving, but it could be offset by other factors.  NOTE: This may not to be true - see for example White & Kulcinsky (pdf file) who estimate 9 - 20 tonnes of CO2 per gigawatt-hour of wind-farm electricity produced. The current UK electricity generation figure is, I believe, 430 tonnes of CO2 per gigawatt-hour, so wind power appears to result in the release of about 2% to 4% of the CO2 produced by conventional power generation. This is a huge improvement, but, likewise, is definitely not zero. Back to Top   AND ANOTHER THING!   Today (30th March 2007) I heard yet another energy efficiency analyst telling a punter that he would save £9 a year on every low energy bulb. I know what the calculation is, but has anyone ever shown an actual (not theoretical) overall domestic energy saving from low energy light bulbs in the UK, or in any other country with a winter? If you have PLEASE PLEASE SHOW ME (info@nvmdigital.com)- I'd love to see one. Please note that normal scientific and statistical criteria of acceptance must apply - "Harry said he saved £27" isn't remotely good enough. A suitable experiment might be splitting a housing estate into two, with one half on tungsten and one half on LELs, and monitoring their (total) energy consumptions for a year. I bet it hasn't been done. If it has, it doesn't seem to have been reported. Back to Top HOUSING ENERGY RESEARCH - A PRECEDENT In the late 1970s I visited the Building Research Establishment at East Kilbride to discuss foamed (aerated) concrete, which had possible insulation value. BRE had carried out exactly the sort of excercise I described above for cavity wall insulation. They found that, in insulated houses, energy consumption was unchanged, but temperatures and comfort were higher. This is what I think of as a very "human" result, which I find completely credible. I can also understand why publishing a finding like this would not help to promote LELs. Back to Top MY PERSONAL EXPERIENCE In our own house we seem to have shown, over a period in excess of 25 years, a probable energy saving of about 20% - 25% in terms of gas and electricity Kwhs, comparing equivalent quarters. Possible factors include more loft insulation, more double glazing (all of which produced no detectable responses), a more efficient (but not condensing) gas boiler which probably was the main source of saving (less heat into the room and up the chimney - we do now occasionally have to heat our kitchen because the radiator is not big enough and relatively little heat escapes from the boiler), compartmentalising our previously large and open attic space, and our two sons leaving home - which might also have been most of the reason. We seem to be doing slightly better than the national targets in terms of Kwh/sq metre/year, which I think is pretty good considering that we have a three storey semi-detached building which is over 100 years old, which has solid walls, and which is situated in a very exposed position. But it's certainly not wonderful! And statistically I'm not sure that we've made any saving at all!! Recently we have, at some expense, thoroughly insulated our hot water tank and the ceiling above our airing cupboard. Our water now stays hotter for longer, our clothes take two days to dry rather than one, and the loft space, housing our water header tanks and vulnerable pipework, is colder and more at risk from frost. In very cold periods we need to allow some warmer house air into it to prevent freezing. Our energy usage appears to be unaffected. The moral of this story is that nothing is as simple as it seems!! Back to Top
Lifetime CFLs are claimed to last about six times longer than incandescent bulbs. There are test reports to demonstrate that this is possible. However, as far as I can tell, these relate to continuous running.  Life expectancy is said to be reduced by switching on and off (as for their ancestors – fluorescent strip lights). The internet is full of pages asserting the extra lifetime of CFLs, but not providing experimental data. It is as if everyone is telling each other the same thing, but no-one knows where it came from. Likewise I have not so far found any data on the lifetime effect of switching on and off. When I find a research void like this I always suspect that it is because someone does not want to hear the result. If you know of any test data please let me know. Nobody claims that lifetime is improved by switching on and off, so it is fairly safe to assume that it gets worse. But by how much? This leads to a conundrum. If, like me, you are in the habit of switching lights off to save energy you will shorten the lifetime of your low energy bulb. This could mess up the economic saving you expected. But if you don’t switch them off you use more energy. Neither is perfect but which is better? I don’t know how this balances out because there does not appear to be any publicly available data that I can find and use – but you can see that it is not straightforward.  Back to Top
The Mercury Question See also "More about Mercury"
Mercury - What do you do with defunct CFLs??? Low energy light bulbs contain about 5 – 15 mg of Mercury, a highly toxic heavy metal. Mercury is rated as highly toxic by ingestion, inhalation, and by skin absorbtion, and is a cumulative poison like lead. However the metal itself has low chemical reactivity, so, of your options for poisoning yourself with mercury, inhalation of the vapour is probably the worst.  It is unfortunately also the most likely in the home, as mercury vapour can be released if a bulb is smashed when hot. LATEST 5/1/08 Official advice from the Department of the Environment states that if a low-energy bulb is smashed, the room needs to be vacated for at least 15 minutes. A vacuum cleaner should not be used to clear up the debris, and care should be taken not to inhale the dust. Instead, rubber gloves should be used, and the broken bulb put into a sealed plastic bag - which should be taken to the local council for disposal. (BBC News Low-energy bulb disposal warning )  Back to Top	Landfill regulations for Mercury Current UK landfill waste disposal regulations for inert waste forbid more than 0.01 mg/kg mercury in the waste. To meet this criterion the bulb must therefore weigh more than 500 – 1500 kg (0.5 to 1.5 tonnes) - which it clearly doesn’t. You cannot put a low energy bulb in your waste bin. The landfill requirement for hazardous waste (which you also can't put in your domestic waste bin) is no more than 2mg/Kg mercury, equivalent to CFL weights of 2.5 - 7.5 Kg. CFLs cannot be legitimately disposed of by landfill.  BUT according to (European Report p46) the UK appears to be fudging this, by allowing domestic disposal of a few CFLs (the word "few" is also not defined - another fudge) and could mean that up to 20 units (up to 300 mg of mercury) could be disposed of as non-hazardous waste. A rather British conflict of regulations? How can it be safe to dispose of hazardous waste in a domestic landfill? Back to Top
About Mercury Mercury is an element. It is not destroyed by incineration and is made more dangerous if distributed in smoke as it can then be inhaled. It is a cumulative poison in the body. Note that if you break a hot CFL you will have vaporised mercury in the air. My advice is to ventilate the room and to get out fast! Or get out fast first. A used CFL really needs to be sent for specialist treatment to separate the mercury (I've found one - "Some better news"). Alternatively you can try taking it back to your supplier and asking them to do it for you. I would be interested to hear what happens! From 1st July 2007 they should have had to because full compliance with the Waste Electrical and Electronic Equipment Directive came into force.  Locally I have no idea where to dispose of them. Neither has anyone I have asked. Back to Top	Mercury pollution is also indirectly caused by incandescent bulbs There is an argument that CFLs cause less mercury pollution than incandescent bulbs. It goes like this. Coal contains traces of mercury which are released from coal power stations. The extra energy used by an incandescent bulb causes the release of more mercury than is contained in a CFL. Therefore incandescent bulbs are more polluting. For this argument to work your electricity has to come from coal power stations. Gas, nuclear, and all so-called green generators do not release mercury. Remember also that the amount of mercury in coal depends on where you get your coal - it is not fixed. And your CFL has to bring about a substantial total energy saving and well outlive its incandescent relative. Does it? Back to Top

 
 
 

"Embedded energy" AKA "Embodied Energy" This is the energy used in producing an item. This should (but usually doesn't) include every bit of energy/effort involved in extracting, refining, processing, and transporting the materials (plus all services - even financial and accounting use energy) plus all energy usage in manufacturing the item and subsequently transporting, distributing, marketing, advertising, and selling it. Not to mention energy embedded in machinery, buildings etc. for its manufacture, warehousing etc., and the energy costs of employees commuting to work etc., etc., etc. Extreme? No! Because, if it didn't exist, none of these activities would happen. Accepting now that no-one is (or even knows how to be) this rigorous it should be still be possible to provide some basic information on the embodied energy of CFLs and on incandescent light bulbs. After all there is information on building materials and the like, and there are figures for items as complex as wind turbines. But I can't find anything on light bulbs. Again I'm suspicious because CFLs clearly involve lots of bendy bits of glass tubing which must involve significant energy in melting and forming the glass. Incandescent bulbs likewise involve glass (if somewhat less complex) and therefore also are responsible for significant energy use in their manufacture, and possibly (not definitely) need less energy-intensive raw materials. A really simple calculation (one might think) would be to divide the annual energy consumption figure for a LEL factory by its annual LEL production figure, threby producing a figure for embedded energy/bulb. This would of course be less than the actual figure because it doesn't include energy embedded in raw materials, distribution, selling, marketing, etc.. And it would at least be a start! ("But you can't do this!" I hear voices saying, as I have been hearing for most of my life. Of course you can! It is simple division! After you have this first estimate you can refine it - explaining your reasons every step of the way. But at least this is an easy way to start. So why hasn't it been done (or published?)) It's now 5/1/08 - a year since this page was published - and no "embedded energy" data has arrived despite huge numbers of visitors and many communications. Searching the web reveals no information and uncovers large numbers of others who can't find any information either. Do you see why I'm a bit suspicious?   An offer to calculate "Embedded energy" - CAN YOU HELP? I've received an offer from an expert in the field to calculate the embedded energy (also embedded water - a concept of growing concern to many) of a CFL but he needs some inforrmation. Quoting from his e-mail: "I'm able to do a reasonably accurate energy audit of the materials used in CFL's if I can have a precise breakdown of all the materials, (weights etc) for a "typical" CFL bulb. So, starter circuit materials, weights and types of plastics, type of glass etc etc. I have embodied energy data for most materials and there is also information increasingly available on embodied water as well, which is possibly even more important. I can also have a go at estimating the damage to groundwater from the mercury inappropriately landfilled bulbs, (landfill leachate goes through the best liners whether they are clay or geotextiles, which not many people realise)." I haven't yet found this on the web. But it must exist. Otherwise there would be no CFLs.  CAN YOU HELP? Back to Top

Wrapping up! You could argue that low energy light bulbs should not be manufactured as they are a threat to the environment. While I do not particularly agree with this (we seem to have managed OK with fluorescent lights) I note that it is the stated intention of the Nordic countries (Sweden, Norway, Denmark, Finland) to eliminate mercury use. This would eliminate current low energy light bulbs. So far no alternative has been commercially released – though there are thought to be alternatives at the research, and possibly development, stages. See the excellent report "Nordic Ecolabelling of Light Sources" My conclusion from all this is that the sales story for low energy light bulbs is not all it appears to be when you analyse it from a carbon dioxide, energy, environmental, or economic viewpoint. Low energy light bulbs may work out well for you - but they won't for everyone. Think about it carefully before you decide – locally and globally! I suspect that a lot of the push behind low energy light bulbs comes from the need/desire to tick the "reduced CO2 emmissions" box with the most politically acceptable solution. With the recent (9th March 2007) EU agreement to cut greenhouse gas emissions by 20% by 2020,  it is already apparent that CFLs fit this rather neatly -  see for example EU Pushes for Energy-Saving Light Bulbs. They are much more politically acceptable than enforcing things such as: Don't go on holiday - Don't travel - Live next to where you work and walk to it - Don't drive a 4x4 - Don't fly - Ration electricity, gas, petrol, etc. - Charge a realistic price for petrol - at least twice its current price - Only use public transport - Send your children to the nearest school - Walk to your local shops (and take a shopping bag) - etc., etc.... All these could be rather effective at reducing carbon dioxide emissions but are probably equally effective at assuring electoral defeat. So I don't think any of them will happen until the political elite becomes desperate. By which time it could be too late. The excellent recent UN/IPCC draft report on climate change (report - 9.3 Mb pdf) makes it clear that global warming is taking place and VERY FAST. For example ""Some of the changes that we previously projected for around 2020 or 2030 are occurring now, such as the Arctic melt and shifts in the locations of various species."  Worrying stuff! There are numerous other factors not touched on here such as the electronics used to start CFLs, the Yttrium question, other metal contaminants, and the energy usage in creating and "recycling" CFLs. I don't have the data to tell whether they count for much. And what do I do for lighting? I mainly use incandescent lights plus some fluorescent lights (I've just counted them - 7) and I try to switch them off when they are not needed! I also have one CFL in a reading lamp. The light colour and the little delay in starting don't worry me. But I have a difficulty reading by it.   All the above are my current opinions based on my reviews so far of publications and my lifetime experience in industrial research.  If you would like to contribute data for consideration please e-mail me at info@nvmdigital.com and please give your e-mail an appropriate title so that it is not deleted with the masses of junk I receive. Dave Mulligan - January 2007 - January 2008 Addendum - 10/1/07 -  I recommend the article "Stop - Don't ban the bulb!" by W.A.Steer, who seems to be technically very well informed.   Low Energy Light Bulbs - Your Contributions