Distributed solar generation

12th March 2015
Going Solar PV install in East Melbourne

Nigel Morris reports in Solar Business Services (11/3/15):

"One of the most common myths we hear is that high solar penetration rates are devastating for the [reticulated electricity] network. High penetration solar can cause changes in voltage and frequency and well, apparently, will just about wreck the whole world if you believe what some people say. Now whilst it’s true that in isolated instances and situations solar adds a new dimension of variability to the energy network here’s the simple fact – the grid is already a highly dynamic and variable beast. ... A new study released today by the Australian Renewable Energy Agency looked at this very issue. Conducted by the highly esteemed CAT Project’s, the study used the Alice Springs grid network as a test case and in short asked two fundamental questions. The first was 'What solar network penetration rates can be accepted without adversely and materially affecting network performance?' and the second was 'What affect does geographic dispersion of solar have on the first question?'. ...

"The first, important, mythbusting fact is this – network demand (ie load) is actually already highly variable. Network demand is not the stable, consistent, smooth profile some suggest but rather is made up of countless, constantly varying individual changes. This is pretty logical when you think about it because although their are load patterns, humans are a diverse lot who do things at different times for sometimes bizarre reasons and constantly changing random factors affect the resulting load pattern. ... So, the study measured, analyzed and found in highly granular detail that load varies. So how does solar affect this? ... The findings come as no surprise to people who understand solar and who have been arguing its merits for eon’s. In some other countries where solar capacity is far larger, the measurement and aggregation of distributed wind and solar generation, load and weather data have been available for years. What these data points have shown is that natural geographic diversity has a smoothing effect; the sun may or may not shine in specific allocations, but when viewed as a whole there is a natural, organic tendency to balance each other out." ...

"The results did show that (logically) if you plonk a huge 10MW wad of solar in one spot in Alice Springs the impact is worse; and it adds more variation to network conditions. This is not ideal although it can be mitigated through power control equipment and network design. However, if you instead distribute that 10MW wad of solar over a wider geographic area in 1MW wads, the impacts are substantially mitigated – to the point where it is barely discernable over the natural organic variation in load that the network already see’s. In fact the results of the study found that it was 'no worse than what the power system already accommodates'.

Read the full article here

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