I had promised in my last post to discuss power generation concepts that are important to  cost analysis. I added a few pages to the site, so here goes:

• Nameplate Capacity or Rated Output  for a generating plant defines how much power it generates in ideal conditions. It is not always a clean concept to apply to all generators, and can sometimes be skewed by the manufacturer for marketing purposes. Here is an in-depth discussion of nameplate capacity.

• Availability Factor is, for a given duration, the percentage of the time when the generator is available to feed its rated output to the grid (even if it does not do so). Intuitively, it is a useful concept to compare technologies – but it is difficult to measure externally, since you cannot know if the generator is not generating due to downtime or to management decisions. It is not often tracked. Here is a more thorough discussion of availability factor.

• Capacity Factor is the most important concept of the three in cost analysis. For a given duration, it is the ratio of the actual generated power divided by the output the generator would have had if it had delivered its nameplate capacity all along. It is a powerful yet treacherous concept. here is my in-depth analysis of the capacity factor, along with a bunch of pretty illustrative plots…

Enjoy, and let me know what you think!

It suddenly strikes me how the very existence of energy storage itself is driven by costs.

If costs were no issue, it would always make sense to add generation capacity to the grid. There would never be a need for energy storage. We could always add peak capacity. Or pair more gas-powered plants to variable renewable energy sources.

OK – I need to correct myself: cost, and the need to avoid carbon generation.  But this could be made the same if we assign a cost to carbon generation, which is the only way to allow rational decision-making in the energy domain. Why? Because cost ultimately captures the accumulation of human labor in one way or another – i.e. the true costs to society as a whole.

It is clear, then, that the analysis of energy storage must focus in great part on cost. This is why I get so frustrated when I see another “miracle technology” showing up in a magazine that will solve the world’s energy problems: what works in the lab means nothing unless it can be made commercially viable. And it’s all an issue of cost. Which is why I focus a lot on cost in this blog.

Over the next few days I will discuss some of the basic cost factors in energy storage, and document them in the site pages for EnergyMag.net.

The output of wind and solar power generation sources is highly variable. Because they traditionally need to be paired with fossil fuel plants to ensure matching supply with demand across the grid, their apparent cost is significantly lower than their real grid cost – but only if they represent more than a negligible percentage of the total generation on their power grid.

These hidden costs are why it makes sense to add energy storage to solar and wind in a power grid.

Confused? Here is how you can figure it out!