We’ve been pleased to serve with the NEMwatch widget (sponsored by RenewEconomy) for many years.
That may mean that the question you’re asking has already been answered a number of times … so to make it easier for you (and us) we have collated some of them here in a FAQs table:
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Frequently asked question: |
Answer |
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Q0) What’s the difference between MW and MWh? |
Perhaps this isn’t actually a ‘Frequently Asked Question’, but it should be – as we see no end of confusion amongst NEM spectators in this respect. A MWh is a measure of volume, whilst a MW is a measure of rate. On 24th April 2018 we published this lengthy ‘explainer about electricity demand’ that includes the following animated image that helps to explain this visually: What is included in the RenewEconomy widget are instantaneous MW … so they are rates of Supply and Demand (not volumes). |
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Q1a) Where is the ACT? … or… |
About the ACT We understand that the ACT is of interest to a number of people as a particular point of focus (you might live/work there, or you might be involved in the “100% renewable by 2020” project. Commercial Focus -> we don’t show the effect of the commercial contracts struck by the ACT government for the same reason we don’t show the effect of any other commercial contract between wholesale buyer and seller. In other words, the Live Supply & Demand widget is focused physically (i.e. on the location where electricity is physically produced, and consumed), not commercially. The ACT Government’s high profile “100% Renewable” project would be great subject matter for another widget, which would need to be specifically focused on that topic. We’d love to develop this (and already have some ideas for how it would work, and look) for a willing sponsor, at some point in the future. If you are interested, please call (+61 7 3368 4064) and let us know. Physical Focus -> we don’t even show the ACT physically on the Live Supply & Demand widget because the data pertaining to the territory is subsumed into the NSW Region, in terms of how the NEM is structured. Hence you should read demand in the NSW region as the sum of both demand in the NSW State (the lion’s share) plus demand in the ACT. There is not too much generation actually within the ACT boundary. |
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Q1b) Where is the NT? … or… |
About the NT It’s on our list to include visibility of the NT … but we’re not currently aware of any public source of real time information about the fuel supply mix. What will complicate this process further is that there are actually three separate (smallish) grids supporting the main communities in NT: Grid 1 = Darwin + Katherine Grid 2 = Alice Springs Grid 3 = Tennant Creek Note that these grids are not connected with themselves, or anywhere else. |
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Q1c) Where is MT Isa? … or … |
About Mt Isa Maybe, if ‘CopperString’ proceeds and after it is completed, there will be real time visibility of what’s happening in Mt Isa. Until that time, it operates on its own grid not connected to the QLD Region of the NEM. |
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Q1d) Where is WA’s NWIS? etc… |
About the North-West Interconnected System (NWIS) The main grid supporting the bulk of the population in Western Australia is in the south-west of the state. That’s called the South-West Interconnected System (SWIS) and supports the WEM. There is another sizeable grid that is the NWIS – but there is no real time visibility we’re aware of that we could include into the widget. |
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Q2a) What are the three size categories of solar PV? … and what is Villain number 8? |
The AEMO does not have visibility, in real time (or even after the fact) of production from a large amount of solar PV – rather it needs to estimate this (we see this as Villain no8a in this energy transition). Readers can think about the ‘visibility of solar’ in three broad buckets (not two): Bucket #1) Large Solar – there are a growing number of solar farms (most Semi-Scheduled, some Non-Scheduled): i. for which the AEMO has visibility via InitialMW readings in the MMS. Bucket #2) Small Solar – there is also a growing volume of rooftop PV installed across the NEM and the SWIS. The both AEMO and the APVI estimate the output for this, on a slightly lagged basis, using a ‘Sample and Extrapolation’ method. Key thing to understand here is that: … but the registration threshold for SRES is 100kW! Bucket #3) What this means is that there is a growing volume of Medium Solar (larger than 100kW but below 10MW, say) which is completely invisible to the data sets compiled on the grid. Villain no8a indeed! |
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Q2b) What is ‘demand the AEMO doesn’t see’? |
On 24th April 2018 we posted this detailed explainer about how electricity demand is measured in real time (i.e. by actually measuring supply, and assuming this equals demand if frequency is stable). … hence, the flip side of the ‘how much is being produced by solar?’ question above is that the AEMO also does not know, in real time, how much Underlying Demand is actually being met by injections from both: 1) ‘Medium Solar’ … which (as we note above) is not even visible in the estimates! 2) ‘Small Solar’ … which we use the APVI’s and AEMO’s estimates to approximate. Keep in mind that: (a) Some of this ‘Small Solar’ is self consumed at home, whilst some is exported into the wider grid where its goes to meet someone else’s demand; so (b) From the perspective of this widget it does not matter where it is consumed, as it all represents ‘demand the AEMO does not see’. |
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Q3) What happens, when Supply > Demand in a region of the NEM? … or… Q3) What happens, when Supply < Demand in a region of the NEM?
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In the SWIS, we know that supply must equal demand … hence those bars should always be the same length. However in the NEM each region is connected to at least one other – so there are many times when Supply is greater than Demand (or vice versa). When this happens, the difference is being supplied by the neighbouring and interconnected region. |
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Q4) Why can’t I see percentages here? |
Something here. |
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Q5) Another question |
Answer to come… |
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Q6) Another question |
Answer to come…
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Hopefully these FAQs have answered 95% of the questions you might have!
If you have more questions about this widget, please drop us a line using this feedback form, remembering to provide us a phone number we can reach you on if we have questions about your suggestions..