Monday, February 04, 2008
7 best ways to stop load shedding
We are in the middle of an energy crisis and each of us need to make some dramatic changes to ensure that we have electricity, and that the economy can continue to run.The first thing we each need to realise is that in the short term Eskom and the government can't help us. In fact, the only short term solution is to punish everyone by load shedding or electricity rationing.
The next thing to realise is that we can help ourselves and everyone else. Here is what to do (keep reading and find out how...)
- Turn off the air conditioners
- Turn off your geyser
- Turn off your pool pump
- Turn off anything that consumes standby energy (TV's, DVD players, cell phone chargers, etc.)
- Switch to CFL and LED lights (and use fewer lights)
- Run appliances as late at night, or early in the morning as possible
- Use your computers in energy saving modes
Eskom's problem explained
We first need to understand the problem to know how to address it properly. There is a lot of confusing information out there, from silly politician's statements, through to confusing technical information.
There are two types of energy shortages, supply shortages and capacity shortages. Think of it like a dam and pipes. A supply shortage means there is not enough water in the dams, while a capacity shortage means the pipes are not big enough to get everyone enough water.
Eskom has a capacity shortage. That means there is not enough power generating capacity to deal with the peak demands.
Each type of problem requires a different approach to solve it. The supply shortage means we have to use less (just like when there are water restrictions). A capacity shortage means we have to either demand less, or spread the demand out better so that everyone gets what they need. This can easily be done.
Spreading the load
Eskom needs to reduce the demand by about 3000MW (megawatts) [1]. So in other words, we need to spread out the load more evenly so that during the busy times there is enough for everyone.
- Turn off the air conditioners
- Turn off your geyser
- Turn off your pool pump
- Turn off anything that consumes standby energy
- Switch to CFL and LED lights (and use fewer lights)
- Run appliances as late at night, or early in the morning as possible
- Use your computers in energy saving modes
This is not a suggestion that people like, but let's look at how this could work.
Eskom estimates that HVAC (heating, ventilation, air conditioning) contributes 5400MW (about 15%) to peak demand. If we guess that half of that can be turned off without any dire consequences, we already have 2700MW of the required 3000MW. This would be quite an extreme approach. Eskom estimates that 10% could be saved by just applying some simple principles.
Start with good insulation! If you have good insulation you will need to cool much less in the summer, and heat less in the winter. Make sure your ceiling insulation is in good condition and find out what else is practical to do (weather stripping, better windows, etc.)
Use the fan to circulate cool air from outside early in the morning. Only turn the air conditioning on in the mid–morning. Set the temperature as high as possible, and make sure that it is no more than 10º lower than the outside temperature.
Conservative power saving: 600MW
Turning off your geyser for a large part of the day can help significantly with reducing the peak demand. This does require a bit of planning and organisation, especially if you have a large family.
I can turn off my geyser in the morning, and still have enough hot water to bath in the evening. Then just before I go to bed, I turn it back on to heat up for the morning. This may vary, depending on your geyser and its insulation. One thing worth investing in is a geyser blanket (if Eksom hasn't already come to install one for you).
Remember that each time you use hot water while the geyser is off cold water is running into it and cooling the hot water. You want to try to use hot water all at the same time, i.e. get everyone in your family to shower/bath at the same time, then you should have enough hot water for everyone.
Turn your geyser off before you leave in the morning, and turn it back on just before you go to bed. Play around and find out what works for you.
Businesses need to look at how the geyser is used, and try to keep it off before 10h00 in the morning and after 18h00 in the evening.
If one million households with a 2kW geyser element do this...
Estimated power savings: 2000MW
Pool pumps can consume anything from 500–1500W. You will have to experiment with your pool and see what works, but try to run your pool pump at night (after 20h00) rather than during the day when there is a high demand for electricity. You can also look into other lower power pool maintenance options, like the Floatron.
Estimate power savings: 120MW [1]
TV's, radio's, DVD players, video machines, microwaves, computers, cell phone chargers and (some) ovens are just a few of the things that consume power even while we are not using them. If any of these items are turned on at the plug they can consume anything from 0.5W to 30W (have a look at the results of this guy's power audit).
The easiest way to do this is to use a multiplug (power strip) with switches.
It is really hard to estimate this, but a lot of small savings will add up for everyone. I suspect the savings could be a lot bigger than we think.
In the 2001 census there were 7.8 million households using electricity as their main source of lighting [2]. If each of those house were to change a single 60W incandescent bulb for an 11W CFL the savings would be significant (learn more about the benefits of CFLs). Also consider changing your halogen downlights to LEDs.
Unfortunately household lighting does not play a big role during the day. Commercial and industrial users are the ones that need to examine their lighting and reduce their consumption. An easy way to reduce lighting consumption is to retrofit electronic ballasts to your fluorescent lights which consume up to 38% less energy than magnetic ballasts. Commercial installations also stand to win a huge electricity (and money) saving by changing to LED lighting.
Obviously the simplest thing you can do is make sure that lights are turned off when you are not using them. Security lights can also also be changed to motion sensing to avoid them running all night.
Estimated savings: minimum 400MW
Washing machines, dishwashers and tumble dryers require a fair amount of power to operate (particularly tumble dryers). By simply operating these out of peak demand you can help to alleviate the load on the network. It might not always be practical, but running them before 07h00 or after 20h00 can help to make a difference.
Estimated savings: 250MW [1]
We often use our computers in energy inefficient ways – allowing a screen saver to run, or leaving a computer on when you are away from it for a while. Some simple changes to your computers settings can help to reduce the load it puts on the network.
In XP set your power management to "Minimal power" (to ensure the CPU uses as little as possible), and in Vista choose a power saving power plan. Try to optimise the settings for your own situation. Turn off screen savers, and set your computer screen to turn off instead. Set your computer to sleep if not used for more than 20 minutes. Allow it to hibernate if not used for an hour (desktop computers can do this too!)
Again, this is difficult to estimate, but if every business took a small amount of time to do this the total savings could be significant.
With those conservative savings we can "load shed" over 3000MW. I think it is worth doing so that we can keep out homes and the economy powered.
PS. Post your energy saving tips here in the comments, or add to the list we have going on The Forum SA!
References:
[1] National Response to South Africa's Electricity Shortage
[2] Census 2001: Census in brief
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I'm Duncan Drennan and this blog is about spreading ideas regarding engineering, our environment and creating a better world. You can also follow me on Google Reader.
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Hey Duncan.
ReplyDeleteGreat Post. I think there's a small problem with running pool pumps at night - the noise factor. Most pool pumps are situated close to the pool. An open water area acts like an acoustic amplifier - and this is worse at night when things are quiet.
My dad did this and received multiple complaints from the neighbours.
I can suggest people shift from chlorine based pools to salt-based pools. It requires far less maintenance and the motor only has to run about 2 hours a day.
Hmmmm....quieter pool pumps? Or possibly noise reducing housing?
ReplyDeleteThank you, Love the positive side.
ReplyDeleteSwitch off your aircon (please), and dress according to SA climate. (SA people dress lovely anyway).
Hey Duncan - does switching off the geyser really help? I've heard conflicting reports. Apparently heating a geyser from cold uses more energy. Okay, so now that I've typed that sentence I'm thinking, perhaps it does use more energy, but using that energy at night when demand is low decreases the daytime/peak demand.
ReplyDeleteHi Duncan - congratulations on a great post. I invite you and your readers to take a look at http://www.energycrisis.co.za .
ReplyDeletePeter
Paul, the energy saving is not really that big (energy = power x time, hence measured and sold in kilowatt hours - kWh).
ReplyDeleteLike you said, it is about moving the demand to another time, which is the current issue we have.
You probably will save a small amount of energy by doing it, but nothing too significant. Think of it this way: the greater the difference in temperatures the faster the geyser will cool down. So if the geyser cools a little, then it starts to cool a little slower.
If you keep the temp high (like a thermostat does) then it has to use a little more energy (because it cools faster) to keep it close to the set temp. Turning it off for a while means it will be on (consuming energy) for a little bit less in a day.
Probably easier to explain with a picture.
Most importantly though, you got the point with the load shifting.
Hi Duncan,
ReplyDeleteGreat blog!
Given the comment about temperature differences being a factor, how about dialing down the geyser thermostat as an option.
What would an optimal temperature setting for a geyser be?
Dave, it is a tricky one. It depends on how you use hot water (bath, shower, dishes, etc.), when you use hot water, and how well your geyser insulation.
ReplyDeleteWhen we moved into our house the geyser was set at 55º, but that was a little low, so I tuned it up a bit.
With your thermostat a bit lower you will conserve a small amount of energy and also cause your geyser to be on a little less.
Insulation of your geyser and pipes will be the biggest win in my opinion.
Hmmm, you run a electrical inspection company....I wonder if the clients would mind if you tuned all the geysers you inspect down by 5º? ;)
Dave, in this document they recommend 55ºC....your mileage may vary.
ReplyDeleteThis comment has been removed by a blog administrator.
ReplyDeleteYehuda, thanks for popping by and leaving a comment. Unfortunately you seem to have missed the gist of the post, namely that in South Africa we are experiencing load shedding, and this is about trying to shift that load and gain a more stable supply through the whole day.
ReplyDeleteRather than just copying and dumping another article of yours here, why not engage in the conversation, and link to articles when necessary?
Thanks.
I have put my 2 geysers on swimming pool timers and my electricity bill was reduced with R460 the last 8 months average compared to the previous 8 months average.
ReplyDeleteMy geysers are only switched on 1,5 hours in the middle of the night and again 1,5 hours in the middle of the day. We are 5 people in the house and have warm water all the time.
My usage also went down 44,4 % over that period (from average 2250 units/month to average 1250 units/month).
I have ignoramuses that belittled that. They even said it is impossible, my accounting is wrong etc. Even the technical director said in the newspapers that it does not work.
However, my accounts proves my point.
I have done my MBL at the School of Business Leadership, UNISA.
Hey Duncan,
ReplyDeleteGreat tips, here's another more radical approach to energy saving:
http://earthlandscapes.blogspot.com/2008/01/green-roofs.html
Just for those that haven't thought about it: Beware when deciding to turn down the temperature on your geyser's thermostat. Having less-warm water in your geyser will make you use more of it (usually you use more water from the cold pipe to even out the final temperature). This then requires more cold water to be heated again in the geyser. I'm sure there is some optimal point, though, because you also don't need to heat the "fresh" water as much as with a hotter setting. But, I haven't done the calculations yet.
ReplyDeleteGreat Post,
ReplyDeleteI want to only comment on Computers though. Switch to Notebook computers as they average around 55 to 65 watts versus 300 to 450 watts for a PC plus another 50 watts or so for a CRT monitor. Plus, when you are load shedding you can still use the Notebook (bearing in mind the cheapest notebooks normally only run for 1h30 versus 3 hours for the better ones). Assuming 2,5 million PC's in use at any time the savings would be at a minimum 250w x 2 500 000 = 625Mw. Rough estimate off the top of my head but the savings might be real enough.
Luckily there are people out there who are trying to help. I stumbled onto a site the other day called www.SheddingAid.co.za. They have a useful service that allows you to search for Generator Powered petrol stations and atms in a suburb. All I can say is big up, keep up the good work and thank you for trying to make a difference.
ReplyDeleteHi Duncan to switch off the Air conditioning sounds like a good idea, that's if the South African summer never happened. So here is my thoughts, and correct me if I'm wrong but for heating purposes, air conditioning is one of the most cost effective solutions available today with saving of up to 70% compared to conventional heating methods, do people who use air conditioning then not actually save on electricity in winter compared to say people using underfloor heating or oil heaters.
ReplyDeleteSo the extra electricity we use during summer we more than make up for by saving electricity in winter.
It's great to see a focus on conservation, this message is getting a little lost among all the talk of recycling and green power generation. It's better not to use the power in the first place, than to waste it but just try to generate it in a greener way. One point about CFL's, because of their lower "power factor" they are not quite as energy efficient as they appear. Most have a power factor of about .6, which means the utility has to deliver about 40% more power than the bulb uses. That means the transmission costs are higher and there is more load on the utility. As well, the mercury content of CFLs has to be a serious concern. That is why LED lighting is a wiser choice in the long run. Although the upfront costs are considerably higher, on a bulb-replacement basis the cost of quality LED light is comparable to halogens, incandescents and CFLs because of the very long LED lifespan, and the huge energy savings and high power factor make them almost a "no brainer" if you're using your lights many hours per day.
ReplyDeleteWith the stringent energy conservation approach that is being used most modern devices have power factor correction built in. I can't say for certain, but I am quite sure that many CFLs have power factor correction. LED lights required internal power converters to obtain the correct output for the actual LED, so they would suffer from power factor issues as well. Again, a well designed LED light would compensate for the power factor.
ReplyDeleteWith regards to the energy loss, it is only the energy loss from transmission that will increase, and that extra loss will be far lower than 40% of the total energy. The reactive power is not consumed, just passed backwards and forwards causing higher transmission losses which are a small factor compared to the actual power consumption.
CFLs do have mercury, but are a huge improvement over incandescents in this regard as coal power stations emit mercury. LEDs definitely improve on the mercury levels though.
Hi Duncan,
ReplyDeletewhile I do appreciate your efforts in conserving more energy, as I live in a country which has a hot climate throughout the year, I really can't live without aircon.
Worst still, when I parked my car in an open carpark during the day, even with the car aircon switched on, it is still so warm.
Hi Soh,
ReplyDeleteThe electricity supply issue was a particular problem in South Africa that had to do with peak demand outstripping the supply. At that time whatever could be done to reduce the peak demand had to be done to ensure a continuous supply.
While I agree that turning off the pool pump saves us electricity, it really affects the pool's pH balance and easily dirtying the water. However you were right to look into other pool cleaning alternatives but it isn't comparable to standard pool pumps.
ReplyDeleteelectricity supply is big problem in the whole world ,the methods shown in blogs are really useful but along with these we should try our self to reduce the power consumption because saving in electricity will save our nation from power crisis
ReplyDeleteHey Duncan,
ReplyDeleteGreat Blog, as we all know that electricity supply is becoming a very big problem around the whole world, if everyone would make a small change to there general day to day routine by just switing off lights, turning off air cons and keeping the heating on low rather than full, it would not only save energy but also be good for the environment.
modern lighting
Brian
I like the idea of LED lighting and keen on implementing them in my home. thanks for the info.
ReplyDeleteI don't know if I could go a whole year or even one full day for that matter w/o using my A/C or heater. I do think we could start managing how we use though. For example, if you're going out of town for a few days, just shut the sucker completely off!
ReplyDeleteGreat post, all South Africans need to work together by saving electrcity by impleting the mentioned tips to stop the blackouts untill Eskom builds new power stations.
ReplyDelete