The Smart Energy Council makes two basic mistakes

The Energy Minister has claimed the Coalition’s seven proposed nuclear sites will barely make a dint, providing only 3.7% of our grid’s energy needs. However, that 3.7% is 11 GW of nuclear capacity as a proportion of the “300GW” of generation in the 2050 grid, calculated by the Smart Energy Council, a renewable industry body.

The Smart Energy Council makes two basic mistakes.

The first was including energy storage in the comparison with nuclear. Of course, storage doesn’t generate anything — it just stores energy — so should be ignored when considering how much electricity we need to meet our needs every year.

The second mistake was using gigawatts (GW) instead of gigawatt-hours (GWh). These cause a great deal of confusion in the energy debate, but they can be understood by using water as an analogy for energy.

Gigawatts tell you the size of a pipe carrying water from a source, but not how much it carries each day, month, or year. If the source depends on the weather like the gutters in a roof do, then the pipe might be empty most days when it’s dry, but fill with water when it rains.

The Smart Energy Council assumed we need a total ‘pipe size’ of 300 GW in 2050. When we take out the storage from this number, it turns out the total ‘pipe size’ is more like 240 GW, which is still quite a lot. They assume the Coalition’s plan would only give us a nuclear ‘pipe size’ of 11 GW.

But we only need 240 GW of generation precisely because renewables only use their ‘pipes’ about 22% of the time. 11 GW sounds small in comparison but nuclear uses its ‘pipes’ 90% of the time.

Instead, gigawatt-hours is how you should measure energy needs, in the same way that the right way to measure ‘water needs’ is gigalitres. If you want to know how much water comes off your roof each year, you wouldn’t measure the width of your downpipes.

So how many gigawatt-hours do we need? Because it nearly always produces electricity, 11 GW of nuclear would provide a substantial 20% of our grid’s 450,000 GWh of energy needs in 2050 — five times what the Smart Energy Council claimed.

In the energy debate, whenever you read GW, look for an ‘h’ at the end. Otherwise, you might be sold a pipeline with 80% of its capacity closed off.

Photo by eric anada