A 0kWh day yesterday!

[DamonHD]

With the rest of my family away and almost no discretionary usage other than my laptop and a few cups of tea, I achieved a (nearly) 0kWh day, ie the import meter was reading the same kWh units at the end of the 24h period as at the start.

In reality I used about 0.8kWh more than was PV-generated, but as the tenths started on "1" I just scraped by with a few 10s of Wh to spare without flipping the next unit by the time the PV was generating and winding the meter back this morning.

Now folks, that ~1kWh/day is the target that I understand the Indian government has set to get in electricity to every (rural) home.

So my minimum is still an aspiration for much of a nation on 1 billion people.

Makes you think?

Rgds

Damon

[AbyssUnderground]

Things can only get better Damon :-)

My 36w of thin film is doing its job again now the sun is coming back to life. I can finally run my lights every night all night until I go to bed. Thats 0.45A for around 6 hours per night (3Ah ish).

[TomW]

Yeah, it truly does make you think.

Most of us "civilized" folks are energy pigs. Nay, energy addicts. And just like a junkie and his heroin need, we will sell our children's future, steal and kill for it. And we need more and more.

Great that you decided to be part of the solution rather than just another part of the problem. Now, on to the rest of the parts of the problem.

Thanks for sharing.

TomW

[DamonHD]

Well, with me out of the house for the last ~36 hours it went negative, ie the house exported about 0.8kWh overall to the Grid in that time.  And this with slightly-below-yearly-average PV generation.

The major loads in the absence of moving bodies are the fridge/freezer and my Internet server and SDSL modem.

So, we're just about a net generator on 'base load' which is good.  Everything beyond that is discretionary use.

Rgds

Damon

[DamonHD]

Yesterday the system generated only 0.16kWh, ie less than 10% of what might be expected for a typical March day!  Worst day so far, under very gloomy dark cloud.

Today, however, we came within a few % of maxing the system out, peaking at 1.03kW against a nominal maximum of 1kW and an actual limit of 1.1kW.

Without watching the graphs myself I wouldn't have believed the intermittency of roof PV!  It really is a learning experience, and it gives a feel of how difficult it will be for a grid operator to balance the system with ever-larger portions of unstored use-it-or-loose-it RE.

Still, that's the fun bit of engineering, surely?

Rgds

Damon

[TomW]

Damon;

Have you seen the phenomenon known as "cloud edge effect" yet?

I have seen it spike my amps up to around 1.5X full sun output.

Has to do with the lense effect from cloud edges. Usually shows as a short term spike.

Interesting stuff.

Thanks for sharing.

TomW

[DamonHD]

Yes, I believe that the 1.03kW reading was indeed cloud-edge stuff, else I would have expected 800W--900W at that time with a clear sky from my limited observations so far.

Very interesting to observe.

I used the edge of that cloud to boil myself the water for a cup of tea in my 1kW travel kettle!  Does that count as a silver lining? B^>

Rgds

Damon

[ghurd]

Well balanced system!

At least they didn't sell you an oversized inverter for the PVs.  :-)

G-

[DamonHD]

Oh not oversized at all IMHO, in fact it won't capture quite all that it might in mid-summer, because I said that I wanted to maximise mid-winter performance given the west-facing roof, etc.

No, I think that the panels and inverter have been matched well, and I really like the remote wireless monitor which draws pretty graphs...

http://gallery.hd.org/_c/mechanoids/_more2008/_more03/Sunny-Beam-wireless-generation-monitor-for-Sun
ny-Boy-grid-tie-gridtie-inverter-for-small-solar-PV-microgeneration-system-2-DHD.jpg.html

Rgds

Damon

[DamonHD]

Today with snow and sun I collected this lumpy data set which shows how fickle the power output is.

Rgds

Damon

[DamonHD]

Sorry, typo in the link.  Should be http://www.earth.org.uk/WW-PV-roof/data-PV1/W20080324.csv

Rgds

Damon

[DamonHD]

Another record day from the PV system: 4.38kWh so far and still (just) going.  Sun is going down pretty much due West, and though only maybe 20--30* above the horizon I'm still getting ~200W.

Rgds

Damon