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Comment by p1necone | Hacker News Reader

> It will be several decades before a combination of renewable overcapacity and energy storage can meet any increase in demand for electricity. In the mean time, anything that causes an increase in demand, such as electric cars, will be met with an equal amount of additional coal or natural gas supply.

There's a lot wrong with this comment, but this bit especially is just made up nonsense.

According to [1] 39.7% of USA energy generation on average is already either renewables or nuclear, and as other commenters have pointed out even if it was 100% coal including transmission losses it would still be more efficient than petrol in an ICE.

And saying that all additional power production built in the US grid will be 100% coal or natural gas for the next two decades is a bizarre claim.

[1] https://www.eia.gov/energyexplained/electricity/electricity-...

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>And saying that all additional power production built in the US grid will be 100% coal or natural gas for the next two decades is a bizarre claim.

The electricity grid has something called a Capacity Factor. Capacity is the ability to produce power measured in Watts. The Capactiy Factor is the fraction of capacity which is actually producing that power at any instant in time. Power demand and supply must be almost exactly in sync at all times to maintain grid stability. This is achieved by turning on and off coal and natural gas power stations, which can be done relatively quickly, to ramp up and ramp down production as demand fluctuates. Capacity must always greatly exceed typical demand so that unusually high demand can be met. Nuclear, wind, solar and hydroelectric power plants always produce whatever power they can independent of demand. This is for a diverse set of safety and environmental reasons. Only fossil fuel plants can "load follow" to meet changes in demand. Like I stated in my original comment, all load following in the US is done with fossil fuels, and that will be the case for many years or several decades to come. Increases in capacity will mostly come from carbon free sources, but until those sources can load follow, either by dumping unused energy in off-peak hours or by storing that energy until it is needed, all load following will be done with fossil fuels. This means additional demand is going to be met entirely with fossil fuels for a long time to come. I hope that helps you understand the concept of marginal demand better.

I'm confused - you posted on a thread about EVs, the problem here is a long term ramp up of demand over the span of years or decades as more and more people swap their ICE vehicles for EVs. This is a problem to be solved by the building out of more power production capacity over the long term. Dealing with short term load spikes with existing infrastructure is a different problem that isn't really relevant in this context.

Power demand from EV charging is pretty predictable too - the bulk of it happens overnight when demand is usually lowest from everything else.

>Dealing with short term load spikes with existing infrastructure is a different problem that isn't really relevant in this context.

EVs sold today are going to be charged on the grid we have today. if that makes their carbon footprint barely better than gas and slightly worse than a hybrid it means our subsidies would be better used to increase carbon free electricity generation and increase hybrid sales. Once EVs have smaller carbon footprints then it will make sense to subsidize them. If you don't care about the short term then yes. The long term solution is full carbon free electricity and EVs

EVs are actually a nearly ideal load for load-scheduling to match net grid draw to times of overcapacity. If anything, they have the potential to vastly improve grid stability, which would otherwise become a concern as an increasing amount of power is supplied by fluctuating renewables.

Adding the charging demand, some of which will inevitably occur at peak-demand, is not going to improve the stability of the grid compared to a gas car that never places any load on the grid at all. EVs will only improve grid stability if owners chose to feed the grid during peak demand.

> Some of which will inevitably occur at peak-demand

Some, but nowhere close to most. If 90% charge their cars at night, or even just at the grocery store after work, that is off peak.

It's not that simple. Feeding power back to the grid certainly helps (and this will likely become ubiquitous; even just tapping into the top 10% of capacity would be a massive benefit). But EVs connected to the grid can even help improve grid stability, even without feeding power back to the grid, through simple frequency-based dynamic demand methods. At peak demand, the grid is most sensitive to marginal loads. EVs that are charging at this time can modulate their power draw, even without returning power to the grid. In effect, if you turn on your kettle, a charging EV can simultaneously lower its draw rate by almost the exact same amount, so that the grid load gets smoothed out. This can be done without any data or networking. It is equivalent to adding additional rotating inertia to the grid, and very helpful for grid stability. It's a technology that is not widely adopted today, but very cheap to implement and likely to spread quickly.

the effect of increasing peak demand is going to outweight that advantage massively

It actually does not.

The fact that EV charging will mostly happen at night means the fraction of EV energy coming from renewables will lag far behind other electricity uses even after some of it is able to be met with renewables. Fossil plants pick up the slack from renewables at night and that effect will increase as solar replaces nuclear.

Why don't you mention "big batteries" ? These make wonderful peakers. Victorian Big Battery (VBB) in Australia is 300MW. Comparable in size with a nuclear reactor.

Thanks to the EV success, lithium batteries costs are falling exponentially. Coincidentally, photovoltaics costs are also falling exponentially.

Conclusion: regarding electricity production, fossil fuels are soon not going to be competitive, PV + batteries would be so much cheaper...

When? With the actual costs curves, in less than a decade.

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