Solar Power

[Anonymous Poster]

How many of you use solar power? What are some of the basics on solar power, like what does it cost to get set up? I'm interested in using it for my house to help reduce the cost of air conditioning and heating. Also, my garage is not air conditioned or heated, so I'd like to get it set up for both but don't want to have to buy a bigger AC/Furnace unit nor do I want to pay the extra cost of electricity and propane.

 

[GlueGuy]

I have been seriously looking into this since the CA energy thing has been happening. There are lots and lots of options, but the best way for someone that's already on the grid is to do a "grid-tie" system. The energy the solar system generates causes your meter to slow down, or run backward if you have enough production. Best thing is that it usually is generating most when the load is high.

These systems are available from many vendors, and in CA, you can get a credit of up to $4.50 per watt (or 50% of the cost, whichever is less). I've seen 2KW systems running anywhere from $15K to $18K. With the CA rebate, that puts the pay-back time at just under 10 years if you use all the energy you produce. If you produce more than you use, the payback could be a lot longer (no gain for producing too much energy).

If electric rates rise (and they probably will), the pay back gets a lot shorter, especially if you are an energy hog and use more than 130% of baseline. In fact, based on some scenarios I've run, payback could be as short as 3 years.

If you're interested, I can send you some links to manufacturers and integrators.

The GlueGuy

 

[gws]

If your idea is to put up some photovotic panels and then convert sun to electric to run your AC and electric heater, you can forget that ideas. Its just not cost effective. With the exception of running a fan or two solar power isnt going to help your AC issue. You can use solar heat,but it is pretty poor when it gets real cold and is hard to retrofit onto an exsisting house. Retro fitting a house for anthing but photovotic is not cost effective. If you want to put up panel to power your homes electrical that is possible but unless your state is offering kickbacks for alterative energy or you have no other option solar is not cost effective.

If your building new and design solar into your home its doable but difficult otherwise.

MY mom named me Gary.

 

[patrickg]

Please don't call a penalty (piling on) B U T I too am the bearer of sad tidings. I have been studying solar power as in PV systems as well as various passive solar applications in energy efficient architecture since the eighties. Get your hands on "Home Power" magazine. They publish articles on various solar installations. Their advertisers are the folks who you would get your "stuff" from. When it comes to electricity, I think (I don't wanna fight with other posters) that you will be lucky to get a payback on any major solar electric project in much under 10 yrs (if you build to code). In "Home Power" they give schematics, actual parts used, sources for those parts and lessons learned, etc. Many of the projects are carried out because someone has the money and wants to, N O T because it pays. Wind, if you have enough, or water if you are that lucky are both more feasible alternatives. Unfortunately, not everyone has enough of either to generate a meaningful quantity of electricity.

In the desert I get 12-14 amps at 12 volts from the panels on the roof of my camper. This is sufficient to run an evaporative cooler through the heat of the day(5-6 amps). Luckily if the sun shines enough to make it hot then it shines enough to run the cooler. It keeps my 225 AH at 12volt batteries (two Trojan 6 volt golf cart batteries in series) fully charged till sundown even with satelite TV, stereo, or ham radio going much of the day. 225 AH carries us easily through a long winter's night of TV, cards, chatting with other campers, etc. I also have a regular mechanical refrigerated air type A/C on the camper and I could run it for about an hour before the batteries would be dead (if I bought an inverter big enough for the job. If we go into a humid situation then we have to fire up the propane powered generator to get the power for the A/C.

If you were off grid and a great distance from commercial power, then perhaps solar would be cheaper than a long run of wire and the poles to put it on. Even off grid, diesel is probably cheaper than solar (it just isn't green enough for a lot of us). No one likes to hear it but conservation saves much more than trying to build an alternative source. Are you using compact fluorescents in place of filament bulbs. Wanna invest in some technology? Buy LED lights. Last a loooooong time, lots of light for a watt, contribute little heat (in summer lights cost you twice, once to run them and again to run the A/C to remove the heat).

Anyway, unless you have very low relative humidity you aren't going to use solar electricity to air condition and certainly not to heat.

Patrick

 

[StoneHeartFarm]

Solar power has a way to go before it will power the standard American home. It IS possible, but, you can forget the heavy load appliances (hair dryers, electric heaters, welders, dish washers, etc.). Look at your electric bill, it should tell you how many kiliowatts you have used in the current month. Look at the bills for the last 6 months and average those usage figures. A reasonably priced solar system, of the kind that GlueGuy is talking about probably would'nt produce more that about 200-300 killowatts per month. So, to be totally utility free you would need to cut your usage to less than that. Some people can, and actually take pride in their conservation efforts. Myself, I like to fire up the AC when its hot and my welder when somthing is broke. The problem with non-intertie systems, is you only have so much electricity stored. If you use it up for the welder and AC, then you sit in the dark at night. It would be like the Amish around here. They run their wood shops off windmills with belt drive for the various tools. When the wind blows, they work. If the wind doesn't blow....

What MAY be possible is a limited system that would only supply a water pump and maybe a furnace blower. The cost for solar panels/wind generator, inverter, batteries, etc. is prohibitive, for something that really doesn't save much on the electric bill, and would probably only come in handy in an electrical outage situation.

You might try the following site http://www.thoughtscreate.com/education

SHF

 

[GlueGuy]

People are missunderstanding what is possible here. An grid-tie system can pay for itself because it eliminates two major issues with solar: storage, and demand. It also serves to provide power when the system needs it the most: summer time mid-day.

A simple 1KW system doesn't have to supply all your power, it only has to supplement it. In our area (S.F. Bay area), a 1KW system provides about 2200KwH or electricity per year. This is without a tracker, without batteries. Installed cost is about $5,000-$5,500.

If you are below the lifeline rate, then power cost is $.11 per KwH, or $242/year payback. That puts the payback at 22 years. Too long.

If you are 100% to 130% of the lifeline rate, then the cost per KwH is $.15/KwH, or $330/year. That puts the payback at 16 years. Still too long.

If you are 130% to 160% of the lifeline rate, then the cost per KwH goes to $.20 per KwH or $440 per year. That puts the payback at 12.5 years. Starting to look reasonable, but more than most would want to afford.

Finally, if you are over 160% of the lifeline rate, the cost per KwH goes to $.25/KwH or $550 per year. That puts the payback at exactly 10 years. Now we're starting to get somewhere.

If electricity rates go up (and I have a bridge in my back pocket if they believe that they won't /w3tcompact/icons/smile.gif), then the payback could reasonably be expected to go below 10 years for people that use roughly double the lifeline rate. It may still be more cost effective to figure out more efficient ways to use electricity (energy star appliances and stuff, or compact flourescents for example), but solar helps more than just you. It also reduces the load on the grid, just when the grid is most vulnerable.

If solar gets just a wee bit cheaper, we might want to re-visit this discussion.

The GlueGuy

 

[Anonymous Poster]

GlueGuy, What is this "lifeline rate" you're talking about?

 

[GlueGuy]

The "lifeline rate" is a number of KwH of usage (usually prorated on the month) for the particular area you live in. PG&E (local electric utility) supplies this along with your bill to indicate how much energy you use compared to some "average" that only they know. From the average, they calculate what the "lifeline" rate is (again, they don't supply the formula, but we trust 'em, right /w3tcompact/icons/wink.gif).

At any rate, the CPUC (California Public Utilities Commission) uses the "lifeline rate" as a basis for what they can charge customers. If you use at, or below the lifeline rate, you get the cheapest electricity of all. The CPUC set 130% of lifeline as the point at which they can start "jacking it to ya", and it goes up from there.

FWIW, last year the cost "buy" electricity at the the wholesale level was $30/MwH (mega watt hour), or $.03 per KwH. In March of this year, some electricity "manufacturers" were charging up to $3800/MwH or $3.80 per KwH. If that rate were passed on to the customer, the payback for the previously mentioned 1Kw solar setup would be 240 days!

The GlueGuy

 

[StoneHeartFarm]

GlueGuy,

I guess power bills must be a little different out here in the real world (ie, the non-artificially-inflated-because-the-power companies-figure-we-ain't-got-no-money-and-can't-afford to-pay-for-their-new-condos-and-swimming-pools-part-of-the-country /w3tcompact/icons/laugh.gif). Here, they still give us a discount if we put in electric water heaters and heat.

My bill shows my personal consumption history and that's about it. Up to 400 KwH, power is $.08730 per KwH and is $.08380 after. So, the only real way for us to figure the savings (gain), would be to determine the number of KwH from the solar system and deduct that many KwH from the bill (calculated at the lower rate). That number divided by the cost of the system would provide the pay back period.

I heard somewhere in southern CA (Los Angeles County?) they were thinking about requiring all new construction to have roof top solar. You heard any more about that? Volume is probably the only thing that will bring the cost of solar down to be competitive here. For all the government's million solar rooftops initiative, I don't see much happening around here.

SHF

 

[GlueGuy]

SHF,

I haven't heard about that thing in LA, but it wouldn't surprise me.

We were talking about this at dinner last night at a friends house last night. They live off-grid, and have a 1KW solar system out of necessity. They have their panels wired to provide 48V DC, and then run to a pair of Trace inverters. These are nice, as they let the AC "idle" until there is a real load.

At any rate, someone mentioned that payback time is not the only consideration. One consideration is the "greater good" argument that solar is clean, and reduces the amount af polution for each watt generated. I can't argue with that, except that I still think there needs to be a cost consideration.

The other argument is the cost of a rolling blackout to a business. This could be a biggy. One of the friends is in the chip-making business. When a chip fab gets hit with a rolling blackout, it's a really big deal. They can lose the whole production run, plus, there is a really big clean-up afterward. Apparently losing power at the wrong time can actually break stuff (besides the chips).

So, for some businesses, besides the cost of the power, there is the cost of avoiding a blackout. Seems there could be incentives given to a business that wants continuous power: You produce X amount of power (solar or whatever, as long as it's not a big polluter), and we will guarantee you reliable power. A little give and take maybe...

BTW - Your power is cheap. Out here, even the wholesale cost of power is almost what you pay. /w3tcompact/icons/frown.gif

watch out. I don't think this is only California's problem. In another decade, I bet the rest of the country will catch the cold as well. Just a matter of time...

The GlueGuy