groar's solar panels thread

[groar]

Originally Posted by knowbodies

Whoa! Is that number correct or is that a typo? At current exchange rates, that is 9 times what I pay per KWh (I pay $0.10 per KWh).

This isn't a typo

I'm buying electricity at the following rates :

• 0.0673€/kWh in off peak hours (10:30 PM to 6:30 AM in my region) and
• 0.1106€/kWh in peak hours.

I'm selling all the electricity I'm producing at the following rates (I signed my contract in Nov. 2008) :

• 0.31193€/kWh for non-integrated installations and
• 0.57187€/kWh for integrated installations.

Our system is integrated as it permits a faster pay back, add a real value to the house and we didn't had 25m² (225 sqft) in the garden without any shade. The pay back is important as this is a very big investment (our biggest one after the house) and we don't want to block our other projects during too long, the credit tax helps too.

The selling rates are changed every year and are based upon 2 price indexes, 1 of which is based upon energy price. The integrated rate was 0.55€/kWh 2 years ago, so it's a 2%/year increase. For all contracts signed before end of 2009, these rates are reactuated every year based upon these 2 price indexes during 20 years.
The rates for contracts signed after 2009 are unknown as the law is for the 2006-2009 period. We don't know what ERDF (who's buying my production) will do in 20 years (continue or not to buy and at which rates), but by then the installation will have been refunded (nearly twice) so free & clean electricity will be great.

These rates are high in France as all European countries will have to have a certain percentage of renewable energy in 2012 and we are late compare to other countries.

Denis.

[groar]

Originally Posted by Daox

Also, I'm liking the weekly updates. Its interesting to see the fairly wild fluctuation in power generation. I wonder if in summer if that will tame down?

Not asked to me but as I have it, here is my raw production (in blue) since connection and the average on the last 7 days (in red) :

The 6 consecutive days at zero were the week far from home, so I couldn't note the production. I only know there has been 15.4 kWh in 6 days with 3.4 kWh the last day.
The day at near zero was the blackout day.

The summer should be more stable when there isn't any cloud. In fact the luminosity can vary a lot depending on the kind of clouds.

Even if today was a bad day (only half the forecast production for a February day), the max instantaneous power has been beaten from 1.768 kW to 1.835 kW : a hole in a cloud

Denis.

[groar]

Thanks to a simple assembly (see http://ecorenovator.org/forum/conser...nsumption.html), bought already made as I don't know how to use an iron... I will be able to monitor my PV production.

Currently I'm just testing it so I'm logging the raw data in a flat file then transcode and graph them through several scripts and the rrdtool database. Even if this assembly may be useful only on French meters, I'll post my scripts when they'll be of better quality, ie usable without having to be reverse engineered.

Here are the hourly productions (Wh) for these two days calculated from raw data :

Hours	2009-02-20	2009-02-21
07-08	0	0
08-09	12	24
09-10	57	183
10-11	283	394
11-12	803	781
12-13	1217	1159
13-14	1393	1424
14-15	1451	1457
15-16	1366	1259
16-17	1083	920
17-18	593	363
18-19	20	14
19-20	0	0

Here are the graphs for the 2 consecutive days monitored :

• The instantaneous intensity (Amperes) :

• The instantaneous appearing power (Volt.Amperes) :

• The production (Wh) :

See comments in this message about the pro/cons of these data right under respective graphs.

The first day was very cold so everything was frozen during the first hours. The difference is important before 11AM. During the second day some clouds were crossing the sky, so the curves are more erratic.

I ordered a second assembly so I'll be able to monitor both production and consumption meters at same time

Denis.

[Daox]

Thats very cool groar. How much do those datalogging devices cost out of curiosity? It looks like a pretty nice setup!

[groar]

Originally Posted by Daox

Thats very cool groar. How much do those datalogging devices cost out of curiosity? It looks like a pretty nice setup!

45€ (57.70$ at 1,2822$/€, taxes and shipping included) each for the USB version, 35€ (44.88$) each for the serial version. As there is less and less computers with serial connections, I bought the USB one. This also permits me to have several assembly, 1 for the production and 1 for the consumption in my case, as I don't have any computer with several serial connections.
In both cases, the system see the assembly as a serial device so it has to be initiated with correct parameters. When I saw data arriving at 1200 baud, it reminded me the first time I used a modem 22 years ago...
Several schemas for such an assembly are published on Internet, but I don't know how to use an iron and this one is of good quality

The specialized data recorder for my inverted costs several hundred Euros but it permits to get data for each input (panel strings) and output of each inverter it monitors. I knew that such simple assembly to get data from the meter exists. If it only permits to get data generated by the meter, it's far cheaper and enough to automatically get production (yearly, monthly, weekly, daily, hourly...).

Denis.

[groar]

I'm far from home this week, but I can access my graphs so I can post this one with instantaneous consumption (HC & HP, respectively Off Peak Hours & Peek Hours) and production (PV), the sum of both (To), the cost of each and the total cost.



When the white line (consumption minus production) is under 0 then I'm producing more than I'm consuming
A negative cost means money is entering the pocket
As you can see, there has been a variable weather today.

I always have to study the best way to configure the rrdtool database (see comments in this message).

Denis.

[groar]

The last 8 days have been very sunny

At one side our panels have beaten all the records.
Sunset and sunrise are separated by 12h15 and this duration will increase until 21st of June. Also the sun isn't very high in the sky at midday, so the max instantaneous has been around 1850W while panels' max is 3000.

Here are the charts :

HP: Peak Hours (06h30-22h30) / HC: Off Peak Hours (22h30-06h30)

Here are the numbers :

Day	Production	HC Cons.	HP Cons.	% of Prod. vs Cons.
Mon	11179	9056	12878	50.97%
Tue	11196	10289	12283	49.60%
Wed	10883	9457	13261	47.90%
Thu	11106	11198	10142	52.04%
Fri	11682	8080	9550	66.26%
Sat	11969	10340	11175	55.63%
Sun	11987	9630	13981	50.77%
Mon	11685	9777	11017	56.19%
Total	91687	77827	94287	53.27%

Note: the Mars' average forecast is 8.5kWh/day.
The best production day is Sunday it was also the coldest day, so the panels' efficiency was higher.

At the other side this week was the hotter, so the consumption was the lowest. As I worked at home all week, and today, I opened all the shutters and let the sun heat the inside which helped a lot The consumption is 20% lower than current Mars' average and 40% lower than February's average.

But weather forecast is cloudy or rainy, and colder for next days

Denis.

[groar]

As shown in 8th post we passed the 1Mwh produced this month despite all months except 2 not far under the forecast for a total production at -17% under the forecast since end of november

Denis.

[Daox]

Do you think it has to do with the heat? The angle should be better in the summer, right?

[groar]

Originally Posted by Daox

Do you think it has to do with the heat? The angle should be better in the summer, right?

By now the sun is already rather high so it will not change a lot during next month. The day duration is already 15 hours long. The longer day, around 21st of June, lasts 16 hours.

Apparently from installations at less than 50km from me, the 2009 winter production is up to 30% less than 2008 winter production. While I have the feeling that my system seams to work correctly then it's OK. Now I knew that been toward west I was going to loose 15% over the year and around 40% over the winter. Statistically during next 10 years there will be sunnier and cloudier years...

The heat do have an effect : several times I have seen 2 consecutive sunny days (so the sun angle difference can be ignored) and the hotter day is less productive by a few %. I didn't note the temperatures so I can't evaluate the effect per °C.

In fact since November the weather is really cloudy. Only during 2 months the production has been near the forecasted production :-( Lately there has been some sunny days with some small white clouds during all day long, but in the end of the afternoon there have been big dark clouds. Because my orientation toward west, this means I'm loosing much more than the same amount of clouds during the morning.
Once the clouds were so dark that in 2 minutes the production went from over 1.5kW to 0 and we had to switch on the light at 6PM while the sun set was at 8PM.

Thanks to EcoModder.com - Googlemap ME I'm realizing how high is my latitude (43.6°) : only 10 North American is higher than me.

Denis.