Solar Panels and PHEVs

<div class='quotetop'>QUOTE(Mad Hatter @ Aug 31 2007, 05:43 PM) [snapback]505173[/snapback]</div>

I now wish I had installed a geothermal system at my hobby farm, instead of the natural gas furnace and conventional A/C. Neighbors who have built within the past 2-3 years with heat pumps, have utility bills on average one half of mine. I have an ICF home with 8 inch forms, so the finished exterior walls are 12 inches.

Manitoba has about the cheapest power in Canada, and they have some interesting comparisons for yearly heating/ccoling"

http://www.hydro.mb.ca/earthpower/benefits.shtml

http://www.hydro.mb.ca/your_home/home_heat...comparisons.pdf

One last note: The geothermal system is *very* sensitive to the quality of installation. If you have a scam artist or doofus install the system, you'll have problems and be very disappointed.

For example, with our -40 winters, the ground loop pipes should ideally be installed 10 ft down, even deeper if possible. Some doofus installers put the pipes only 3-4 ft down, which is the frost level, and the systems switched to supplementary electric heat once the bitter cold started.

 

<div class='quotetop'>QUOTE(jayman @ Sep 2 2007, 10:22 AM) [snapback]505900[/snapback]</div>

Speaking of "geothermal systems" . . . Mad Hatter may want to think twice about digging down too deep for his system.

He lives in the Clear Lake Volcanic Field.
http://vulcan.wr.usgs.gov/Volcanoes/Califo...clear_lake.html

And about ten miles from Kelseyville is The Geysers . . . the largest complex of geothermal power plants in the world.

http://www.geysers.com/

And not much further south is the Old Faithful Geyser of California, in Calistoga.

http://www.oldfaithfulgeyser.com/

If he isn't careful, he just may have an old faithful geyser of his own shooting up in his back yard.
Cooling his house would then probably be like trying to cool hell itself. :lol:

 

<div class='quotetop'>QUOTE(Boulder Bum @ Sep 4 2007, 02:54 AM) [snapback]506682[/snapback]</div>

Yeah, that's about right. They're assuming 200 Wh/mile. The Volt is supposed to have a mile range so there you go.

 

<div class='quotetop'>QUOTE(Boulder Bum @ Sep 4 2007, 11:16 PM) [snapback]507164[/snapback]</div>

Utilities have to serve at least 40K customers to be subject to the requirements of Amendment 37. They're obviously not in that category. Move into the mountains west of boulder. Xcel is the service provider there. My biz partner is installing an 8.1 kW system on the house he's building near Nederland.

 

<div class='quotetop'>QUOTE(Boulder Bum @ Sep 5 2007, 10:55 AM) [snapback]507362[/snapback]</div>

Ah, but the voters in that area could have overturned it. That was another part of the Amendment. Yeah, that commute would be beyond horrific.

 

I am still going through the other posts but off the top of my head I would not worry about it. I have a 6.5 kW system which is on the large size (at least around here). Normally around 3 kW. I seem to be generating around 27 kwh per day but I use about 50 kwh for a 2500 sq ft house.

You do not want to get a system larger than what you use because you do not get money back for unused power. Only a credit to be settled at the end of the year. Most say size your system for about 90-95% of your needs.

Swamp coolers are really good depending on the area. We had one in El Paso and at 100 deg the house would be around 65 (my wife likes it freezing - opposite of me). Three key points when using a swamp cooler -
1) you need a low humidity (anything over 50 tends to reduce efficiency),
2) maintenance - wash the filters annually and change out every 2-3 years ,
3) you have to keep the windows open to allow air flow or you will build an overpressure system and no more cool air can be blown into the house.

Most the people I met in El Paso who had issues never had a swap cooler before and treated it like a A/C unit.

 

Regarding your A/C needs, check out Coolerado, made right in Denver.

 

Coming in late to this thread, as I have been away.

Consider a few thoughts about PV (solar electricity).

As one who lives off grid much of the year, and one who has been involved in Re/Pv for more than 20 years I know a bit about it.

First, while full electric and plug in hybrids will be a great advance in transport and should be supported one should consider a couple of issues before jumping into Pv.

First, before any investment in Pv to charge Evs or to reduce the loading on our houses, one should do EVERYTHING, to conserve. The rough numbers are like this. For every dollar spent on conservation, one will save ~$10 in Pv costs. Putting Pv on your house to power you car may make you feel good, but if you continue to live in an efficient dwelling you are really no further ahead. Conservation can be found in all kinds of areas, and while not as "sexy" as solar panels on the house, the net payoff both to your wallet and to the environment. For example, a ground source heat pump, or water heat capturing heat pump give much more net energy savings than a similar cost in Pv. Solar water heat is ~1/4 the cost of Pv for a similar amount of BTUs.

Finally, batteries are not a zero sum game. For example, most batteries require about 125 watt/hours of charge to recover 100 watt/hours of battery capacity. It is like if you burn 10 gallons of gas driving 100 miles, you would have to put in 12.5 gallons just to refill the tank. Additionally, there are some considerable losses in any Pv system, between panel ef, wiring ef, inverter ef etc. In a typical off grid system, the net/net system efficiency is somewhere in the 50% range. That is, for a name plate rating of 1000 watts say, you will be lucky to get ~500 useable watts out of the battery net/net. A well designed grid time might approach 90+%. (add in charging a EV and net system ef drops again to near off grid rates)

A typical grid tie Pv system will cost between $7-10/ watt before tax credits, state and local tax credits, and utility rebates.

Mind you, I am a huge proponent of Pv solar, EV, and most RE technologies, but it has been the experience of many of us in the field, that too many people are ready to jump in with "Ready, Fire, Aim!" thinking that they are going to get this great system that will provide all their energy. The reality is that one should do considerable research on both the PV and the conservation side before committing to it.

In my opinion, it makes little or no sense to put 10Kw of Pv on a McMansion. It makes little to sense to put the same 10 kw on a house that is filled with inefficient lighting that is used inefficiently, in a house that is poorly insulated, that uses hot water inefficiently etc, etc, etc.

For those that are interested I suggest that you visit:Solar Electric Power Discussion Forum by Northern Arizona Wind & Sun - Powered by vBulletin This is a forum that is populated by some very smart, very learned folks who have forgotten more about Pv than most of us will ever know.

Icarus

 

Icarus, thank you for that post. Have solar panel systems come down in cost over the last 10 years? I always read about "new, cheap, and more efficient" solar panels, but do any of these ever come to fruition? How far fetched is the idea of living completely off the sun? Ie, no grid electricity and fully electric cars, charging from the sun, etc?

 

RP,

Your question(s) have no simple answers. First, Pv solar panels have gotten cheaper over the years, but not in the order of magnitude that some would like. Currently Pv prices are as low as they have ever been, but this is due largely to the world wide recession more than efficiencies in manufacture. The reality is that the price has remained relatively constant over the years. When advances until technology advances which would tend to lower the price, it is usually followed by an increase in demand that eats up the lower price, resulting in basic stasis. Current raw panel prices are around $3/watt.

Along the way, ancillary technologies such as inverters, charge controllers etc. have gotten way more efficient, and somewhat less expensive.

As for your question as to the feasibilty of moving off grid. The reality is that is the wrong approach IMHO. Because of the increased costs and decreased system efficiency of battery based off grid system, you dollar only goes about 1/2 as far in buying solar capacity. As mentioned before, battery based off grid systems are lucky to run more than ~50% efficient net/net, while grid tie systems run well into the 90% range.

What is often misunderstood, is the basic value of the grid. Consider this example. In a typical off grid system, you spend your day charging your batteries from the sun, and then drawing your batteries down at night to power your loads. This system runs ~50%, but when the batteries near full charge, the system begins to have capacity but has no where for the power to go, so it dials itself down. (Further decreasing efficiency) Add to that, you need to replace the batteries every 3-10 years depending on how well you take care of them, further adding to the life cycle cost. (Most people destroy a number of battery banks until they learn the "sweet spot" between capacity and the ability of the battery to recover at certain draw down levels.)

So let's look at a gird tie alternative. Given the same dollars, you would have a system that is about twice as big, all things being equal. This system might run more than twice as efficiently as the battery system, with the net result of providing ~4 times the power out of the system. The value of the grid, is that it serves as a huge, free (in the sense that you don't have to pay for it's capacity and replacement) battery bank. You can feed power into the grid as you have excess, as many hours of the day you can, and then you can "draw down" from the grid 24/7 as you need to, with little fear that the "battery will run down". Regardless of whether or not your utility has advantageous solar purchasing agreements, the grid is your friend. In many cases the grid is REALLY your friend. With time of day metering, net metering, utility rebates etc, it can reduce you net cost dramatically.

So now to answer your fundamental question. Is it feasible to live off grid? (Or relatedly, grid tie with ~100% solar). Once again, the answer is at once simple and very complicated. One can live 100% off grid, but one has to realize that it comes at some considerable cost, either in dollars or in lifestyle. The reality is you don't have to go back to the cave, but if you intend to live off grid (or 100%PV) you either have to spend a huge amount of money, or you have to do a huge number of things to reduce your consumption.

The reality is that most people waste huge amounts of power (electrical and other) and that there are tons of efficiencies to be gained if we look for them. Let's use my house as an example.

We live much of the year on an island in Northern Canada, hundreds of KM from the nearest grid. We generate all our power. We use ~ 1kwh of electricity per day. To put that in perspective, that is enough to run one 100 watt light bulb for 10 hours! By making the house and our lifestyle very efficient we live quite comfortably. Having said that we have other non-electric energy costs. Our fridge is propane powered, (a conventional fridge would add ~.5kw/day to the load). Our washing machine is Honda powered, we cook on a propane stove, we have a propane toaster! (No electrical heated appliances!) and we heat with wood. Our out of pocket energy costs for propane and gasoline (for the house) is ~$20/month. Our solar system is ~500 watts and we seldom need to run a generator to charge the batteries. To replace this system today, it might cost ~$4-5000 or so including labour.

Now if we lived in a conventional house, with a conventional life style, in an efficient house one might use ~20 kw/day. A battery based system to produce that much power might be 15kw and cost ~$150,000, and would need to have it's batteries replaced fairly often.

The same house, grid tie, might get away with a 8kw system, costing something between $40-80,000.

So you can see that for every kwh you can save in the loading, you save a ton of money on the system cost. It comes down to efficiencies, lifestyle choices, and choosing the correct energy for the job. For example, Pv solar to heat domestic hot water, cost ~4 times as much as direct solar heating of that water. A 1500 watt toaster running for 12 minutes a day equals about 300 wh/day, nearly 1/3 of our total. Same with a hairdryer or iron, or coffee pot, so we do all these things non-electrically. (There are tons of alternatives if you look for them.)

The bottom line is, as I have too often suggested, before you consider any Pv solar do these things first, or you are throwing money away. First, do every conservation measure that you can find. Second, find some more conservation. Third, do still more conservation! Then and only then, do solar hot water, (Unless in your conservation you have done heat pump waste heat hot water!) Then consider passive and active solar space heat. Finally, after all of that, after doing considerable homework consider Pv solar.

Finally, transportation adds another huge element. The reality is that if you add in transportation to the solar equation, the nut gets even harder to crack. The one reality of and huge advantage of EVs and PEVs is their potential POSITIVE impact on the grid. I know that there is legitimate concern about the impact of a large number of grid tied vehicles drawing from the grid. There is a second, often unnoticed ADVANTAGE of these cars. The reality is that plug in cars can not only buy power from the grid, but they can also SELL power to the grid! In addition, the technology exists to program a car to buy power at off peak times when it is cheap(er), sell it at peak hours when it is expensive, all the time having the computer in the car to manage the power such that there is always enough power in the battery to go a prescribed number of miles.

Aside from the obvious benefits of such a system, the added side benefit is that by having a huge number of cars plugged into the grid 23/7 (remember, most of the time cars are parked!) these cars can serve as a giant battery bank, supplying the grid with it's most expensive/most polluting power: The instant spike of power that is required occasionally. To produce this power now, the grid must keep a significant number of generators spinning, wasting energy just waiting for that spike. In addition, these batteries could then serve as a decentralized battery bank for the grid for solar and wind to feed into, evening out the spikes of now sun or not wind in certain areas.

(For more information on this subject, do a search for Dennis Hayes of the Bullet Foundation for his speaking and writing on the subject)

So, finally, to answer your question,, yes you can do it, but you must be committed, and it does take work,,, and money.

Icarus

 

Thanks for the push to conserve before jumping into PV, icarus. A single 230w solar panel will cost about $1500. installed. It will produce about $.07 of electricty per day, or enough to run a 100 watt lightbulb for seven hours. So it is much wiser to simply turn off the light!

We just sent in the down payment on a 7kw system for our house this week. It will produce about twice what we use (10.5 kwh/day average in last 12 months-- two adults, two teenage daughters, 3000 sf). My hope is to use it to charge a PHEV sometime down the road. In the meantime we'll sell our excess back to the utility company.

Since I'm still enjoying the learning curve. Are any readers here aware of a forum for solar similar to Priuschat?

PA P

 

Try here:Solar Electric Power Discussion Forum by Northern Arizona Wind & Sun - Powered by vBulletin

Icarus

 

My math skills aren't that hot ... but:

If a 230watt panel generated seven cents of electricity per day

And we have 36 panels (36 x 7¢ = $2.52 per day) times 30 days (one month) then our electric bill would be $76.

But in fact, our bill (as of 10 months ago) used to average about $220. So now I'm confused. Our bill is extinguished, and we have over 2,300Kwh surpluss, the last time I checked (we're in Nashville right now so who knows how much higher the surpluss is). Many areas have electric rates on a tier system ... charging only a few cents for the first few Kwh used, then going up, sometimes 3 or 4 times more, if you use a lot.

We too, planed surpluss into our system so we could recharge our transportation. So now, we wait. BTW ... You're being charged over $6.50 per watt. Seems a bit high, considering the huge incintives many states provide now days ... not even counting the 30% fed credit. Perhaps you're quoting pre incintivised amounts?

.

 

A general FYI,

Pv panel costs are now in the $3-4 per watt area. ( I have seen some name brands below $3. Installed, grid tie systems run between $5-10 an ac watt. So a 1000 watt system (1kw) might cost between $5-10k installed soup to nuts. This is before any federal/local/state tax credits, any federal/state/local per wh incentives, before any utility incentives. Depending on WHERE in N. America you are, these incentives can reduce your final cost in many cases to less than 1/2 the gross cost, making Pv solar not only viable, but affordable.

But, given all of that, it makes little sense to build a large Pv system until you have done everything else to conserve the energy that you do use.

Icarus

 

Icarus and hill, thanks for your responses. The solar forum looks good! I could have explained the numbers in my earlier post a bit better.

I think the 7 cents/day production per panel is close to accurate for our current situation of electricity costing 10 cents/kwh. This rate will be increasing 30% beginning of the year.

Hill, I find it amazing that you have off set a monthly $220. electric bill with 36 panels and have produced an excess of 2300kwh (in 10 months?) Is your electric that expensive or is my math wrong.

We are expecting to produce 8,000 kwh annually with our thirty 235 watt panels. 8,000 kwh divided by 365 days divided by 30 panels equals .73 kwh/day/panel. At 10 cents per kwh equals 7 cents/day/panel.

The $1500 price per panel I mentioned was straight retail, just to give the big picture of the overall cost of a system (to the consumer, grant provider, tax credit provider, etc.) and to show how important it is to conserve rather than throw money into a system. At 10.5 kwh/day for our family of four I feel we are doing okay at conserving. I am sure many are doing better.

The cost of our 7kw system breaks down roughly like this-- installed price $47,000 less state and utility company grants of $30,000, less 30% federal tax credit of $14,000, less state tax credit of $500.

PA P

 

Are you suggesting that y our total (net) out of pocket expense for a $47,000 system is $2500? 47-10-14-.5=2.5?

In that case, why isn't every one on your block doing it?

Icarus

 

Are you folks accounting for any difference between buy and sell rates?

The city utility that provides my electricity sells generic electric energy for $0.039 to $0.080/kwh, depending on tier. I live just outside its core service area, so pay a slightly higher rate. And because my house is all-electric, it always hits the top tier.

Residential PV production in this state is purchased by utilities at $0.15 to $0.54/kwh, depending on which incentives apply. No residences actually get the highest rate yet because the qualifying equipment just became available two months ago, and the entire manufacturing volume is locked up by a non-residential client for several more months.

These price differences mean that a residence can completely wipe out its annual electric bill by producing only a fraction of its electric energy.