I am right on the cusp of going into the dreaded "DAC" [Domestic Alto Consumo] electric rate for excessive usage over the previous 12 months. To put that into perspective, if in the next week I use three kWh more than I used last year over the same time period, my bi-monthly July-August electric bill will increase from $27 to $105 USD. I take daily meter readings and analyze the data in a spreadsheet, so I know to the nearest kWh exactly where I stand.

It looks like I will squeak by this time, but barely, so I am looking for ways to save; even one kWh per week on average would do it. I am actually running the house pretty economically now as far as usage. If I exclude my refrigerator and the computers (with accessories like router, cable modem, VOIP phone) I am using one kilowatt hour per day for the entire house. That doesn't leave a lot of room for improvement. This isn't guesswork: remember I take and record daily meter readings.

I have 23 light fixtures in my house with halogen bulbs similar to the one pictured below, except that most, if not all of them are 50 watt, not 20 watt. What would I do to change over to LED lights? Can I get LED bulbs to fit the existing fixtures, or do I have to tear up my ceilings and cabinets and install new fixtures? How expensive is this?

tanstaafl.

That looks like a MR16 lamp with GU5.3 socket/base, but Rob would probable know off hand.

If that is correct, then Toshiba make something suitable http://www.toshiba.com/lighting/products/led-lamps/mr16-gu53.jsp although not quiet bright enough, they seem to max out at 35w equivalence.

And don't forget that it might now pay to upgrade to a more energy-efficient computer, as discussed previously.

That's a weird bulb, usually line voltage MR16 will have GU10 bases... you might have to swap out the sockets to use a line voltage led.

This would appear to be the manufacturer's page for that bulb, if that helps.

Would LED strips be better than a bunch of flood lights?

http://www.oznium.com/flexible-home-leds

I would hate to live that close to the line that a light bulb would make or break the situation.

How about a large change like a gas refrigerator or solar panels?

You did not mention water heater so I would guess that is not electric. If so a timer or a more efficient unit could help.

Gas lamps

These are 12V, which is what I would expect in the UK with that GU5,3 connector. Exactly as Larry says, you would want to factor in changing the lampholders over to GU10.

What I would sell here is the Lampholder at 1.25, and a Megaman Modo 4.5W GU10 (42W Equivalent, non-dimmable, available in 3000K and 4000K) at 8.00, that's all inc Tax. This is all in 230V though, but I would imagine you would be able to find something similar in 110V in Mexico, at the same price you're looking at roughly 190 Pesos.

This is not really an answer to your question, but I'm wondering: why don't you consider photovoltaic solar panels? Those would easily cover your electricity needs in the area you live in and give you a lot more breathing room. Heck, even if you don't want them to cover your entire electrical power needs, even one or two panels would be able to create a lot more breathing room for you and keep you far away from that dreaded limit. Of course installing PV panels would cost more than simply replacing your lamps with LED models, but in a few years I'm sure you'll start saving a lot of money with a couple of those, especially in the sunny climate you're living in.

If you already have solar panels, then I guess I have missed that from the other posts and I'll shut up then.

I like that, different.

I reckon you need at least 11w LED to come close to a 50w halogen, 14w would be more convincing. Our new house has these:

http://www.orluna.com/products/mini_recessed.aspx

and these:

http://www.nationallighting.co.uk/LED_Lighting/LED_Fittings/LED_Downlights/LUCIDA/pid/988

The 2nd ones are probably as close to a 50w halogen as I've seen from an LED but definitely not GU10. I know that Phillips, Toshiba and others do higher powered GU10s but the Phillips (which I've seen) has a little fan in it (v annoying).

An alternative might be CFL GU10s, I haven't seen any in operation but might be worth a look:

http://www.tlc-direct.co.uk/Products/GUC...CFc0mtAodfi4A9Q

That is a tough call, Mark, not made easier by knowing you are right.

The LED light idea is a dead end for me, I think. In order to make my goal of <3,000 kWh for the previous year, I have (with her permission) run an extension cord from my downstairs neighbor up to my level, and am running the computer system and associated peripherals plus my refrigerator off of her electric meter. The entire remainder of the household is using slightly less than one kWh per day, and lighting is only a small portion of that. LEDs aren't going to save me much, certainly not on a cost/benefit basis.

So... I am either back to looking at solar panels again, or looking at a more efficient computer. My computer with its peripherals (modem, router, two telephone base stations) uses 220 Watts. The peripherals use 30 of that, the monitor another 36, which brings the tower down to 154 Watts. That tower contains a dual-core 3gHz processor, 4 GB RAM, four hard drives totaling a bit over four terabytes, plus a sound card that replaced the on-board sound when it died, and a pretty good (256 MB) graphics card. The hard drives stay, that's non-negotiable except the system drive might be replaced with an SSD. A replacement computer would have to meet or exceed these specs performance wise.

How much power could I save? Four drives plus 4 GB RAM and a 3 gHz dual core processor (or equivalent) are gonna eat a fair number of electrons. Even if it used only half the present power, that would save me just 77 watts. Of course, 77 watts, 15 hours a day comes to about 35 kWh per month... That's a tough call on a cost/benefit basis, because it comes to less than $2.50 per month, assuming I stay out of DAC through some other means.

At this point the solar panels are looking better. I haven't priced new computers in a long time, but I have studied the local solar panel situation extensively and made up a very intense spreadsheet (I can hear Bitt chuckling clear down here in Mexico ) to analyze cost/benefit, and a 2-panel setup would cost me $1820 (USD) including tax and installation, would keep me out of DAC and save me $609 per year. It would amortize in three years, after which it would continue paying back at $600-$700 per year as the cost for electricity went up.

Ooops. I just talked to the solar people. They require a minimum of six panels in order to make enough voltage to tie into the grid. That doesn't look so good, with a $5500 up-front cost and an eight-year amortization. Ironically six panels doesn't save me significantly more money per year than two panels, because even two panels keeps me at the lowest rate per kWh.

Sigh... Back to square one.

tanstaafl.

Do they pay you if you put excess capacity back into the grid? Could help pay off the panels quicker with the minimum of six.

Have you talked to more than one company? I doubt this is the case for all panels. In any case, I would think the this is entirely a case of using the right transformer. (solar panels produce DC current and this needs to be transformed to AC current)

Is that 154W at idle or peak usage ?

Don't know about how close to "peak" it is... but a fairly intense spreadsheet recalc doesn't change the wattage significantly.

OK, Quake III Arena bumped it up another 50 (!) watts.

So, no, 154 isn't peak.

tanstaafl.

A new computer (carefully chosen) should be able to cut that wattage down by AT LEAST half, probably to 1/3 your current average. On top of that, replacing the hard drives with a pair of modern 3TB drives would give you more storage, speed, and probably cut the energy usage by another 10-15W.

Cheers

I think the solar idea sounds perfect, even at $5500. You would then be able to basically use as much electricity as you want without the worry of prices going up, and you can stop making spreadsheets and use the time to enjoy all your electricity in some new way of your choosing.

Hot Country + Solar = no brainer

Actually, if you like spreadsheets, you'll love Solar. I have a small remote solar system setup, and with the help of Bitt I am able to monitor stats and make graphs from about 120 miles away. Some of the Solar regulators chuck out a huge amount of data if you ask them to.

Cheers

Cris

Seconded. It might a a big investment, but with the climate Doug lives in, it'll pay off for sure.

+2

Yes and no.

They won't pay cash for electricity I put back into the grid, they will give me a credit on future electric bills but I have already factored that into the amortization schedule. What frustrates me is this: The Mexican government subsidizes very heavily the first 100 or so kWh to help out the really poor citizens. Even TWO solar panels would put me into that subsidized rate structure, and adding four more panels, while cutting my annual electric cost by more than half, would still save me just $138 ($USD) per year compared to having just two panels.

Billing with Current usage with A/C 2 hours per day for two months::: $855 annual cost. (on the DAC rate)
Billing with Add two solar panels with A/C 2 hours/day for 2 months:: $230 annual cost. 3.2 year amortization
Billing with Add four more solar panels the same A/C for two months: $ 92 annual cost. 8.6 year amortization

Four additional panels cost $3659 extra, and will save me $138/year. It would take more than 26 years to make up the difference between 2 panels and 6 panels and I would be 93 years old by then. As was said, two panels would be a no-brainer. Six panels... I'll have to think about that one. Another way to think of it is that I would spend $3659 to save $11 per month on my electric bill.

I have the solar people coming over to see me next week, and we'll talk about alternatives. Most commercial solar panels produce 18 volts per panel, although specialized panels can be of other voltages, at considerable expense. I think I'll be restricted to the six panel minimum. We'll have to see.

tanstaafl.

Would it be cheaper to just get a quiet gas generator and run the A/C on a generator?

Looks like you could get a quiet Honda or Yamaha 2kw inverter generator for under $900.

Bicycle hooked to an alternator. Get some exercise and electric.

If you could only harness humming bird power.

Only found the hand crank one on ebay, but there is a pedal version too:

http://www.ebay.co.uk/itm/CLANSMAN-MILIT...3#ht_500wt_1081

The instant you buy the panels they will not be worthless. I would think they would raise your real-estate value or could be sold used. Perhaps weigh in your resale value and compare the cost payback of the panels to the interest rate your money makes in the bank/401k/

I was able to get a solar panel that they use to keep Volkswagen batteries charged on the lot or the boat over to the USA used for around $20 off eBay. Your prices seem pretty high to me.

I probably should take a look at my usage. But the minute I fire up the TIG welder I shoot it all to hell.

Nice, military too

I was going to say – hire a local to run in a big wheel . However that might be a bit insensitive and dehumanizing. But probably still cost effective while boosting the jobs and the economy. I guess practicality isn’t always the correct way to do things, oh well.

Well, there's good news and bad news. The good news is I will never have to worry about DAC again. The bad news is I don't get to buy a bunch of neat new solar panel toys. The solar guy pointed out the error of my ways.

For two years I have labored under a misconception of what triggers the DAC rate. I was sure that once I averaged Exceso rate for a year, that would put me in DAC. But as Maureen Jellison said in Lucifer's Hammer, "That turns out not to be the case."

0-150 bi-monthly = Basico rate
151-250 bi-monthly = Intermedio rate
251-500 bi-monthly = Exceso rate (actually, it's 251-9999, but the 500 matters because...

To achieve DAC I have to average more than 500 kWh each two-months for a year, not the 251 I had previously thought. So I have 3,000 kWh per meter per year to play with, not 1,500.

Today I received my latest electric bill(s). My computer cost me $161 pesos for two months; the remainder of the house cost me the same. That works out to a total electric bill of of about $12.50 (USD) per month, $25 for the bi-monthly bill. The DAC rate for the same electricity would have been just under $100. It really pays to stay out of DAC.

So all this time I have been sweating bullets not to exceed half of the allowable usage to stay out of DAC. Live and learn, I guess.

tanstaafl.

It's a shame that in a country like yours that solar isn't encouraged.

The government are clearly trying to help people by creating such a low rate for lower income families, and I can't really understand why they wouldn't encourage people to be eco-friendly at the same time.

They could create a whole industry that actually pays it's way in a country like Mexico.

I think if I were you I'd still have gone for solar, I like the idea of doing my bit, and even paying a bit into the system.

Cheers

Cris

How's that low carbon firework business coming on then

At the moment we are really really low carbon !!!



Cheers

Cris

Solar panels are insanely expensive and stupidly inefficient. They also break and from what I've read, can be a PITA to recycle. Maybe in 10-20 years time.

My situation here is unusual compared to the typical Gringo scenario, because my actual consumption is so low. (I used 160 kWh last month, with two powerful computers, a 22 cubic foot refrigerator/freezer, and air conditioning. Anybody [except for John Bjorgen! ] wanna compare?) My usage is more like that of a typical Mexican family than it is like a typical Gringo household here that will use three, five times (or more) than what I use, going well into the DAC rate. And believe me, that DAC rate will "...encourage people to be eco-friendly..."

There are lots of homes here with solar panels on the roof, not because the owners are trying to benefit the ecology, but because they are trying to benefit their own economies. Taking a hypothetical example, someone with a swimming pool, a large house and extensive use of A/C, a big set of 24 solar panels would drop their annual electric bill from $3261 down to $157 dollars. That would pay for the solar installation in seven years. A no brainer, right? Everyone should do it.

Well, yes and no. It would benefit that hypothetical rich Gringo, but he is using more electricity every month than his Mexican neighbor two streets down the hill uses in nearly a year. That Mexican is already getting his electricity for $157 a year. Even a much more modest solar installation that would cut his electric bill down to $75 a year (the minimum fee to stay connected) would cost him nearly a year's gross salary.

So, yes, the Government does encourage eco-friendliness, disguised as fiscal advantage. If you don't conserve, you pay for it. And FWIW, while it is the Government that "encourages" the eco-friendliness, it is not the Government that pays for it. It is the people on the DAC rate who pay a cost per kWh that is considerably higher than the cost of production who subsidize the low-income, low-usage clients.

Ironically, if every DAC client went solar, there would be less electricity consumed nationwide--a Good Thing. But... due to economy of scale that would likely increase the unit cost of production and without the DAC money to subsidize the low-usage clients, their cost for electricity would rise substantially (more than double). This, I think, would be a Bad Thing.

Go figure.

tanstaafl.

Isn't that what they were saying 10-20 years ago?

And honestly, not much has changed. Lots of new "breakthroughs" to read about every now and then, but good luck finding those commercialized.

That's because the physics of solar radiation haven't changed. The often-quoted power density figure of solar energy (1367 W/m^2) that gets everyone so excited is for the *entire* electromagnetic spectrum, while devices to convert this radiation to electricity work over a relatively small spectrum, thus capturing only a small fraction of the area under the power vs. frequency curve. Oh, and don't forget you only get COS(latitude) of that radiation to begin with -- half up here in Minneapolis. Running a toaster in Minneapolis on solar cells takes quite a large area, even on a sunny day. It's not ever going to replace coal.

Says the skeptic who's still powered by coal. Meanwhile some of us have no electric bill .

EDIT: Yeah it doesn't work everywhere, but the sad thing is that millions of people live where it would work fabulously and don't bother to take advantage of it simply because of the higher up-front cost.

Efficiency wouldn't be as significant an issue if the price were substantially lower. Which brings us back to some of those many breakthroughs, some of which only slightly increase efficiency, but promise dramatically lower costs. Still waiting for it.

For now it's Nuclear, Hydro and Natural Gas around here.

My personal feeling on Solar that it will never pay a massive part in grid electricity, but my recent experiments with site specific use have certainly proved cost effective and reasonably efficient for low voltage use, even in the UK.

To me it seems a little bit daft that in such hot countries that more people are not encouraged to fit solar on their roof as part of their energy consumption, what ever the efficiency of the panels is. Once installed the panels could be swapped in 10-20 years time and they have run their life.

The UK has had an interesting solar scheme backed by government for the past few years. My neighbour has had "free" solar panels installed, and even in our dodgy climate has seen his electricity bill fall quite a bit.

Cheers

Cris

Around here "free" solar panels are everywhere. In fact you get paid to have them installed and keep them installed. The catch is that you don't own them until after about 20 years. Basically the companies providing them are renting your roof. They provide power back to the utility and cut you a cheque every month for some dollar amount - I don't know how it's calculated. And I'm not sure how these companies make money with this.

The drawback is that your roof's warranty is pretty much out the window and that you're going to have a very hard time replacing the shingles under the panels when needed. New construction around here have been installing roofs that won't last longer than 10 years or so.

I note the use of passive voice ("...people are not encouraged...") and that is the root of the problem.

Just who is it that is supposed to encourage these people?

The electric company? They're in the business of selling electricity, not buying it.

The solar panel manufacturers? Why would they want to sell their products at a loss?

The government? Here in Mexico, the government IS the power company.

Where I live, solar seems like a marvelous idea, until it's time to pay for it. Solar is expensive, particularly in relative terms. There is no way that the majority of people here can put two year's gross income on their roof when many of them can barely put tortillas y frijoles on the table every day.

From the point of view of benefiting the ecology and reducing consumption, CFE (the Mexican power company) does indeed encourage low usage through their punitive rates for high consumption - something I am in favor of. (The punitive rates, that is, not the high consumption )

tanstaafl.

And when that runs out, most states can start burning asphalt. I'm sure there's a lobby group somewhere that can make it happen.

Ultimately, government (or their captive power company) can do a whole lot to change incentives around through surcharges, punitive rates, incentives, and whatnot. In the U.S., there are various tax breaks if you install solar. A buddy of mine in Napa has rates comparable to what you've described in Mexico, where if your electrical usage goes over a threshold, your price goes up. With his new solar system, when he's selling power back to the grid, that number offsets his usage from the grid and keeps him out of the punitive rates.

I'm intrigued by the companies who "rent your roof" and give you some money back. That's attractive for a lot of reasons, not least that you don't have to put any money up front. You don't see much of this happening in Houston, even though we get lots of sunlight. I figure our problem is that the "deregulated" Texas electrical market, where you buy power from any one of hundreds of companies who buy power wholesale and virtually sell it back to you for a profit. There's a separate company who "delivers" the power, but you're not directly their customer. In this universe, it's quite complicated to sort out how you might sell power back. To whom? For what price? Do I have to buy power at the retail price and sell it at the wholesale spot-market price? Can I sell my power to somebody different from whom I buy it?

Dan, Ontario is also de-regulated in the same way. Most people stick with their local municipal provider.

They can't sell it without getting it from somewhere. That doesn't mean that installing a distributed power generation system is cost effective for them, but if it's cost effective for anyone, it would be for them, due to the fact that a large program would reduce the cost of hardware through economies of scale.

That's not very long. Round here roofs tend to be made of slate, the same stuff that Wales is largely made of. Wales has been left outdoors in some truly appalling weather conditions for a lot more than 10 years and hasn't failed yet.

Sounds like you could save a lot of money on shingles by giving them a protective covering of solar panels.

Peter

Exactly. The government could simply change the construction code to require a small number of grid-tied panels on all new construction. This would especially make sense in places like Arizona and Nevada where they get 300+ sunny days a year and electrical usage due to A/C usage spikes at roughly the same time that peak power output is attained through the panels. Win-win-win.

Hawaii already requires solar water heaters on all new construction. São Paulo has required it since 2008. If the government is really serious about decreasing dependence on foreign oil, that's one way to cut a lot of usage, especially in the southwest.

Too funny. Thanks Peter.

I'm going to guess that had Wales still had ample tree cover 100 years ago that most of it's housing with have ended up with wooden shingles too. People use what is cheap in their local area to roof their houses. Or at least the used to, before modern transport arrived.

Which also leads to oddities in some places, like Dorset, where you have houses roofed with substantial bits of stone that threatens to fall through the inadequate wooden sub structure at any moment

It's totally a job for government, a change in the building codes would do it (as suggested above), then the costs would slowly come down, and in time actually become cost effective.

I think seat belts are a great example of this, it's a no briner, they are a great idea, but people didn't just automatically adopt them. It took legislation and each car coming with them fitted from new. Over time we don't even think of it.

I don't think it makes sense everywhere, the UK for example is not a great place for Solar, but in counties like Mexico the government would actually do themselves a favour, they wouldn't need so many power stations ???

Cheers

Cris

You forgot the wink smiley on that line.

Fixed.

Getting back to the original post, there's a company called Cree which manufactures LED modules for precisely this application. They announced these modules over a year ago and now, they appear to be "available" as ALT Asteria V6 bulbs, in several different color temperatures and light spread angles. There's one German vendor who has it for EUR 45 or thereabouts. I can't find an American reseller, making me wonder just how much these things are actually on the market, ready for sale.

This week's "efficiency record" for solar cells:

http://www.engadget.com/2012/08/20/ibm-a...ar-power-cells/

11.1 % using "common" materials instead of silicon (which is the common and more efficient variety of photovoltaic cell).