Friday, May 11, 2012

Intermittent Wind Cannot Replace Baseload Power

Affordable, utility-scale batteries are a number of decades away. One cannot rationally discuss the topic of national or international grid dependency on intermittent power sources without admitting that basic fact.

We should first look at some basics.

Let's look first at two graphs depicting power grid load curves:
This graph looks at
  • baseload power -- predictable 24/7 power loads
  • intermediate load -- predictable loads of intermediate duration
  • peak loads -- less predictable shorter duration loads.
for both summer and winter conditions. It is clear that baseload and intermediate load, being predictable, would require predictable supplies of power, generated by reliable power sources.

Energy sources that are intermittent are -- by definition -- not predictable, and generally unsuitable to supply baseload and intermediate load power. In the same way, intermittents are even less suitable to supply peak power, since in that case both the load and the supply are unpredictable to grid managers.
This graph looks at grid load curves in summer and winter, but assumes a large electrical vehicle fleet, which is re-charging itself during non-peak hours, when power charges are lower. When such a large-scale re-charging takes place, the grid load curves are essentially altered to make most demand into baseload.

Such a grid load curve -- where most of the load over 24/7 is baseload -- matches both nuclear power plants and coal power plants almost perfectly.

Here is a very basic introduction to the problem of trying to use intermittent power supply for critical power loads which must be supplied on a reliable basis:
Here is the analogy: Suppose there is a car on the market that is very environmentally friendly. Its mileage is phenomenal! I call it a “super-green” car.

This super-green car has the same horsepower as a conventional car. It will handle steep hills as well as a conventional car. It has the same 0 to 60 mph performance. The only difference is that when you try to start it in the morning, it will only start 25 percent of the time, and you can never predict on which day it will start. It runs, randomly, 25 percent of the time.

Would you replace your conventional car with a super-green car to get you to work every day? To keep the analogy simple, let us assume that if the car starts on a particular day, it will also take you home at the end of the workday. If it doesn’t start on a particular day, however, it won’t start that day no matter how often you turn the starter key.

To most people, the answer is obvious. Most of us would not hold on to a job very long if we randomly showed up at work only 25 percent of the time. So the answer is no, the super-green car cannot replace the conventional car. Horsepower is the equivalent of capacity in this analogy. An intermittent electrical power source with a capacity (or power capability when it is working) to generate 1000MW cannot replace a conventional power plant with a capacity of 1000MW. Even though the capacities are the same, the power plants are not equivalent. Yet capacity comparisons are made all the time, as if this somehow makes the power plants equivalent. They are not equivalent.

Capacity factor

Others would say that since the capacity factor is 25 percent (the car works 25 percent of the time), you would just need four cars to reliably get you to work every day. This is also not true, however. There is a chance that none of the cars will work on a particular day. As a matter of fact, this probability can be computed, if the probability of each car not working is independent of the other cars not working. It is 0.75 x 0.75 x 0.75 x 0.75 or (0.75)^4, which is equal to 32 percent. So if you owned four super-green cars, the probability of none of them working on a particular day is 32 percent. So, with four super-green cars, you get to work 68 percent of the time, which is better than 25 percent of the time, but it is still a long way from 100 percent of the time.

Another problem with using capacity factor as an equalizing parameter is that there are times when more than one car will start. The extra cars, however, are of no value to you as far as getting to work is concerned. The extra working cars do not average out with the demand to get to work on time each day. They are working at the wrong time.

Note that in the case of a wind farm, the probability of each turbine not working is not independent. If the wind doesn’t blow in a particular area, it will affect all wind turbines. The probabilities are not randomly independent. Therefore, wind farms must be in separate weather patterns, in order to significantly reduce the unavailable time.


A better equalizing parameter is generation. When the super-green car works, it generates highly economical miles. That parameter has its problems as well, however. The generation of economical miles can be increased simply by taking the long route to work. Those extra economical miles are of no value as far as getting to work is concerned. In the same way, generated electricity has no value unless there is a demand for it at the time that it is generated. This is because electricity has zero shelf-life. It must be consumed when it is generated.

So, when generation cost comparisons are made between intermittent and baseload power sources, this presumes that the resulting electricity value is the same. This is actually not the case, because electricity generated when the demand for it is not certain does not have the same value as electricity that is generated when there is demand for it.

There is no perfect equalization parameter when making comparisons between intermittent and baseload generated electricity. Capacity is by far the worst, next comes capacity factor, and the best is generation, but it is not perfect.


So, the conclusion is that intermittently generated electricity cannot replace baseload generation. Just like there is a chance that none of the super-green cars are working on a particular day, there is also a chance that no electricity is generated by an intermittent source. Hence, all the conventional power sources are still needed. _Energy Collective
Go to the link above and skim through the article, then read the comments. It is obvious that many of the readers of the website live in a land of green dreams and wishful thinking. Affordable and reliable utility scale storage batteries are decades away. And yet these green dreamers want to push big wind and big solar onto the grid today! And at a much higher proportion of total grid capacity than power grids can adjust to. In other words, for all their good intentions, these green commenters are promoting policies that would crash the power grid!

It is true, of course, that large scale electrical fleets capable of converting grid load curves to an overall 24/7 baseload graph, are also decades away. Because the same technological limitations on utility-scale batteries also apply to EV batteries.

Even if utility scale batteries were available, would it make sense to replace nuclear, coal, and gas power plants with big wind and big solar? Of course not. If you look at the total costs of methods of power generation over their lifetime, adjusting for the cost of infrastructure buildup and conversion, and adjusting for the costs of backup power, maintenance, and replacement -- it becomes clear that big wind and big solar are not even close to ready for prime time.

Green dreamers will be the death of us all -- which is exactly what many of the purveyors of these green dreams are hoping. The people behind the green dreams know better, but they do it anyway. Powerful individuals in the big money green-industrial-political complex -- better known as lefty-Luddite dieoff.orgiast greens -- would like nothing better than to see 90% or more of the global human population simply disappear. At least they believe they would like to see it.

Energy starvation of the advanced world -- through forced conversion to unreliable intermittents, through forced carbon taxes and trading, through carbon hysteric rules and regulations etc. -- will have cascading effects on the emerging and developing worlds, leading to significant hardship and possibly large-scale death. At least that is the hope and the plan, by the lefty-Luddites at the top of the food chain. The green dreamers who leave vacuous comments on Energy Collective websites are the expendable cannon fodder.

As for those who understand the potentially disastrous effects of green faux environmental policies being forced onto the industry, commerce, and power supplies of the advanced world: Hope for the best, but prepare for the worst.

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