OzEA -- Topics / Discussions

These discussions are currently [Sept 2010] developing into working documents.
They will slowly become more sophisticated and targeted as the OzEA project develops.

OzEA_TI0004

Tom Stacy
Subject: demand reflecting wind as negative demand
Date: 2010-12-23 (at 12:08:09)

I have a question about the data sets at: http://www.oz-energy-analysis.org/data_viewer/dv1a.php

I am looking at the period September 6th through 13th in particular. It appears the correlation between wind subsidence and demand are too strong to be random. Therefore I must ask: Is the curve labeled "demand" calculated on aggregated demand, or in all generation other than wind generation? If the latter, then wind is counted as "negative demand" and I can deduce actual load by subtracting wind supply from demand. The data suggests this may be the case. I need to know definitely for some presentations I am making which utilize the data. Please e-mail the response to tfstacy@gmail.com. Thank you.

Tom Stacy, Ohio, USA

OzEA_TI0005

francis
Subject: Re #4 the apparent negative relationship between wind power and demand
Date: 2010-12-26 (at 16:24:38)

Yes, seen this before, but do not have a definitive explanation. The data is as found and described on the respective data pages.

When I first laid out the data for the data viewer traces I made a mistake in the processing, and the result shows this negative relationship clearly. In fact, it's a mistake that is worth making. So, the way I have the data laid out in the OzEA format is like a table with each row being the data values for one day; in concatenating the this data into a vector for the year I first around concatenated the columns instead of the rows (for all traces) and in this view most data points are followed by what was happening 24 hours later, with the first 1/24 of the overall being the first hour of the days, and so forth. Looking at the data I this way, the relationship you observe is seen very clearly.

Our best guess is that there is significant off-grid wind power powering one thing or another, and when there is little wind these loads come onto the grid, and thus into the official numbers for demand. But there may be other plausible explanations. We do not know for sure why this relationship is seen. Anyone?

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