The Case for Grid-Connected Energy Storage in parts
THE CASE FOR GRID-CONNECTED
This past week, I attended the Midwest Energy Forum at the University of Chicago. The Forum focused
on the future of the U.S. electricity grid and the technologies that are likely to transform it over the next 30
years. Experts in many of these technologies, including energy storage, wind, solar, nuclear, gas, and
high voltage DC transmission systems, made presentations.
Of all the technologies discussed, however, I came away with the impression (which I suspect was shared
by many) that energy storage was the poor stepchild of the renewables industry. Although the
representatives of the wind, solar and other renewables industries were polite and nominally supportive of
storage, they were consistent in their message that storage has a long way to go and that it was certainly
nowhere near as important as the renewable energy technologies they were advocating.
In fairness, the storage experts did not do much to rebut this perception. While several experts gave
good presentations about what storage could do on the grid, none explained with anything near the
coherence of the wind, solar and transmission proponents why what storage could do was important and
why the public or the government should care about it.
It is, of course, critically important that the energy storage industry make its case for support to the
government and to the public in a way that is honest, rational and persuasive. Our colleagues in the wind
and solar industries have done a great job of doing that. At least in terms of public relations and dialogue,
I would agree with them that storage has a long way to go.
So let me give it a try: Storage is important for the same reason that wind and solar energy are important
but only more so--and only assuming that the true value of wind and solar energy technology is properly
While it is true that wind and solar are relatively clean forms of energy, cleanliness in itself is not their
principal value to the grid. Some experts argue that because of the cycling of thermal energy plants that
generally must take place in order to balance the variable nature of wind and solar power, the overall
environmental benefits of wind and solar are overstated. Whether or not that is true, it is certainly true
that the relative environmental benefits of wind and solar energy depend on the nature of the fuels they
replace. Where that fuel is relatively clean natural gas (which appears will be the case in the United
States for the foreseeable future), it is difficult to argue that the low relative environmental benefits of wind
and solar over natural gas justify the billions of dollars of subsidies that the wind and solar industries have
But wind and solar energy are, in fact, of great value to the electricity grid. Their value, however, derives
not just from the fact that they are relatively clean but from the fact that they each represent a useful new
power resource that permits us to operate the grid more flexibly. Society can use this new flexibility to
change the way that electricity is generated and used across the system so as to pursue whatever goals
society wants to achieve.
A good example of this is what is happening in Germany. Following the Fukushima accident, Germany
decided to abandon nuclear power completely within 11 years. This is no minor ambition, given that in
2010 about 22.4% of all electricity in Germany came from nuclear power. One may agree or disagree
with Germany’s plans to transition away from nuclear power. But what is beyond question is that
Germany could never hope to effect such a transition, let alone to have a rational discussion about doing
so, but for the resources and flexibility that wind and solar power (and perhaps storage) now provide.
The fact that wind and solar energy have become useful resources for grid operators—whether to move
away from nuclear energy, or move towards cleaner fuels, or to emphasize distributed generation, or to
achieve whatever other goals society might want to achieve with its electric power system-- is solely a
consequence of the investments that have been made in wind and solar technologies over the past ten
years. Ten years ago, both wind and solar energy were not far beyond the stuff of tie die t-shirts and
Hollywood playthings. No knowledgeable person would have supposed that wind or solar energy could
be a major source of generation on the electricity grid. Costs were too high, reliability was suspect, and
capacities and efficiencies were far too low to be of any practical use on the grid.