I have three split-system air conditioners in my house. They don't get used much, and it's rare that more than one is on at a time. Nevertheless when I do use them, I feel a certain amount of guilt. No, not out of environmental concerns (and respondents please don't hijack this discussion into an AGW thread). It's because I know that the true economic cost of running my air conditioner is more than I'm paying. Some of the cost is being paid by people who might like to have an air conditioner, but don't.

How does this come about? It's because, being not totally insane, I tend to run the air conditioner only during hot weather. That is, at the same time as other people with air conditioners run theirs. Together we push the demand for electricity up beyond the level it usually reaches. So there has to be generating capacity in the system that is only used in these extreme weather conditions. The rest of the time, that capacity sits idle. The economic cost of this shows in the wholesale price of electricity, which at times rises into the $1000s per megawatt hour. Yet the price I pay stays the same - the power for my air conditioner is only costing me about $200 per megawatt hour, and that includes the cost of delivering it to me.

It doesn't take a mental leap to realise that the rest must be being paid by other electricity consumers - it's factored into the standard charge for electricity.

During hot weather I cause my electricity demand to rise above the level it reaches at the same time on other days. Constructing a system that allows me to do that has a cost, and I really ought to be paying it all myself, rather than imposing a hidden cost on those not fortunate to have his particularly luxury in life. Technology is certainly up to the task - all that's required is the political will.

Sylvia.

Sylvia, the temp 1 meter below the ground is 19-20 degrees year round.(Sydney). Here is a cheap source of cool air that could be run thru an air-con system.

your analysis into the costs is correct but the horse bolted years ago.

in NSW at least a Maximum Demand tariff was levied on all industrial/commercial users and that was used to build the infrastructure needed for the peaks.

the reasom MD was never used on domestic is basically the cost of metering as the MD meter has to continually monitor the MD in every 20 min period.

to give an example of a building I was "rehabilitating" [as the Energy Doctor] back in 1980, ie Sydney Opera House, the bill was $1.5 million per annum of which a million was for the MD and half a million for consumption [from memory only 1 cent per KWh]. Being in SCC area [as it was called] MD was levied on KW rather than KVA [as in Prospect etc] so SOH had no reason to worry about Power Factor Correction.

After my work in redesigning the control system the bill was halved, which is only 3/4 million then but probably $5 million pa now, with rises in tariffs.

hope that explains why you don't need to feel bad pushing up your own MD. In fact the power plants are more efficient with a good head of steam.

Divorce Doctor,

Certainly the cost of metering would have been an issue in the past. But with the program to roll out "Powersmart" meters, I can't help feeling that there was an option to implement demand monitoring as well. Of course, unless those meters contain this feature and it's simply not being used, then the boat has been missed again, given that many (though I don't know how many) of those meters have been installed.

Part of what bothers me in this is not just the ethics of imposing a cost on those who don't use air conditioners, but also the possibility that the system represents a huge market distortion in favour of electric air conditioners, whereas maybe absorption air conditioners, running on natural gas or LPG, could be cheaper in real terms.

One could also be assured that they won't stop running as a direct result of the blackouts they've contributed to. After watching recent events in SA and Victoria, I've been looking at what it would cost to get a backup generator to run at least one of my air conditioners.

just took a look and this meter is not very smart, it just takes place of former single meters for normal/off peak and adds shoulder

and of course you now choose which appliances to get smart with, ie before your water heater was hard wired to a specific meter

so the way it works is supply authority knows when ITS peaks happen so they give you an inducement to not make YOUR peak at same time [like at 4 cents vs 18 cents off peak/peak], so eg you put on washing machine at times other than air con, so back at power station we get what they want ie a flatter curve to keep equipment happier. It seems meter may be capable of demand measurement but besides you and me the average J Doe would not understand how to make use of it even if a MD tariff was available.

in fact MD is unfair in many ways, eg most chillers get serviced in winter and mechanics run it for 30 mins or so therefore the MD is cooked for that month and maybe a 3 grand increase in bill in june over may all because of the service visit

Divorce Doctor,

It comes as no great surprise that the Powersmart meter is a relatively crude device. It's a shame though, because I can't believe it would have been very expensive to make a meter that tracks usage.

I agree that simple maximum demand metering has issues with it. I was thinking of something that retained enough data to allow a household's contribution to the overall infrastructure requirements to be determined. Thus drawing maximum load during a moderate summer night would be considered to be of no consequence, but that same demand during a hot summer afternoon would definitely affect the bill.

Of course, people would complain that they cannot anticipate the cost of running their air conditioner, but this information could be made available on the web, of via a phone announcement service.

It is a pity to see Sylvia's topic languishing a bit, for in a general sense she is highlighting an aspect of an issue that was of sufficient public interest to have precipitated a 'palace revolution' within the NSW government late last year.

The issue? Electricity supply. Widespread public opposition to the sell-off of publicly owned electricity generation and distribution business assets. Prospective dramatic increases in domestic electricity tariffs, accompanied by claimed uncertainties as to continuity of supply into the future if new investment, claimed to be only possible if the grid is 'privatised', is not made. All in all, a pretty significant public interest issue.

Sylvia said:

"During hot weather I cause my electricity demand to rise above the level it reaches at the same time on other days. Constructing a system that allows me to do that has a cost, and I really ought to be paying it all myself, rather than imposing a hidden cost on those not fortunate to have his particularly luxury in life."

Er, no, Sylvia. It has long been accepted that provision has had to be made in any grid electricity supply system that there be a margin of generating capacity in excess of 'normal' or 'predictable' requirements.

It seems that for around 20 years the ongoing investment that would normally prudently have been being made by entities of the like of the then NSW Electricity Commission, in expanded generating capacity and grid capability, have been being avoided. To the consuming paying public, this looks like betrayal of public trust, abdication from responsibility, and ultimately dereliction of public duty on the part of various State governments over those years.

That this betrayal of trust was able to be kept out of sight until recently may have been largely due to a willingness on the part of some in the departmental apparatus related to electricity supply to participate in a National Electricity Market, a marketing arrangement claimed to constitute a possible evasion of provisions of the Constitution with respect to Federal governmental participation in that NEM.

More on 'maximum demand' tariffs, please.

essentially any properly engineered infrastructure went out the window once the "open market" started in 1995 and what we called the "kilowatt cowboys" [bean counters, stock market freaks] got into the market as "consultants" and also hired by the various new suppliers, all trying to do deals with [large] customers, ie deregulation.

at that stage I decided to get OUT of being a [proper] consultant and came to FNQ [where of course there are no buildings big enough to need my expertise].

So I essentially lost all interest in "the big picture" but could fill pages and pages explaining all these matters [and not just in Oz]. But I don't really think anyone would understand things like leading/lagging PF etc

Forrest Gumpp

Even when I'm running my air conditioner, there needs to be a reserve. In the short term, reserve is there to cope with system failures, and random variations in demand. The further demand eats into the reserve, the more vulnerable the system becomes, and NEMMCO will direct load shedding to maintain the reserve and protect the system.

So there still needs to be extra generating capacity in the system specifically to cope with the kind of extreme peak I, and my ilk, cause by running air conditioners.

On the issue of whether there is adequate reserve in the system, NSW is better placed than other states. NEMMCO's medium term outlook graphs

http://www.nemmco.com.au/data/MToutlook.htm

show all NEMMCO states except NSW has having medium term reserve shortfalls. Though I'm not sure why TAS shows one.

If I were living in Victoria or SA, I'd be particularly concerned, with a reasonable expectation of further outages in the coming months, and I'd certainly be thinking of buying a generator. Yamaha produce a 2.4kW model that would power my study nicely, including the air conditioner. As I'm in NSW, I'm in two minds as to whether it's worth the expenditure - it might never get used at anywhere near its power capacity.

That said, the pain of load shedding is spread around - people lose power for an hour, then it's restored, and other people lose it for an hour, and so on.

Of greater concern in some respects are the gross failures of overloaded substation equipment (transformers in particular), where the supply may be disconnected for as long as it takes to replace the equipment.

Sylvia.

Sylvia, thanks for that link to the National Electricity Marketing Management Company medium term forecasts. You observe that NSW is presented as having no forecast Demand Reserve shortfall at any time during the period. Did you notice that the graph appears to have the colours for 'Demand' and 'Demand + Reserve' reversed? Is this a simple 'typo' in the form of reversal of the colours do you think, or is it a more serious error that has resulted in the possible concealing of reserve shortfalls?

Note particularly the event graphically forecast for around the beginning of April 2009 for NSW. I am not sure how to interpret this in relation to the 'DSP' graph which the seemingly mis-coloured 'Demand + Reserve' curve momentarily exceeds.

The reason I comment is that I understand NSW and Tasmania to be the only nett importers of electricity, on an overall basis, amongst the NEMMCO States. Queensland I understand to be the only nett exporter, on the same basis. I derive this from the information in this link: http://www.esaa.com.au/images/stories/Market_reports/2008_07_26nem.pdf I would have thought such nett importer status might have predisposed toward at least some forecast reserve shortfalls.

But I suspect I digress.

Sylvia says:

".....the pain of load shedding is spread around - people lose power for an hour, then it's restored, and other people lose it for an hour, and so on."

How can we be sure load shedding is fairly spread around? Is there a statutorily required published record of all load shedding directed by NEMMCO showing what areas have been affected, and upon what dates and times, and for what duration? Is not the whole claimed point of NEMMCO that it be able to deploy available and/or reserve capacity existing in one State in alleviation of shortfall in another?

I guess my reason for not embracing your 'air conditioner user-pays' for extra capacity to meet this so-called extra demand is a sense that the already highest-paying best customers, retail consumers, look like being treated the worst.

Forrest Gumpp

Yes, I did notice the apparent error in the labelling. I suppose if you squint a bit, you can see a possible reserve shortfall briefly in April, though it would depend on the exact shape of the underlying line. The raw data might indicate otherwise.

As for whether load shedding will be shared around fairly, I suppose one has to trust the distributors to do this, but they have an incentive - reports of several areas without power for one hour each play better in the media than do reports of one area without power for several hours.

The purpose of NEMMCO is to create and operate the electricity market, and manage overall system security (in the power, not terrorism, sense). It doesn't direct power flows between regions. Rather, these are based on price - a region with a supply shortfall will offer a higher price than a region with adequate supply. However, this mechanism is constrained by the capacity of the transmission lines, which isn't really that great in the scheme of things.

Divorce Doctor: essentially any properly engineered infrastructure went out the window once the "open market" started in 1995

That is a depressing picture you paint Divorce Doctor. I hope Enron, the Auckland fiasco, and the North American Blackout of 2003 has brought some sanity back into the situation. Here in Queensland we were about 1 year away from "the brink", but it seems the powers that be noticed just in time and did something. I am not sure linking the whole country into one big grid was the right something though.