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Renewable energy and storage

Energy storage is often hailed as the "holy grail" of the electric grid, but listening in on a California Energy Commission (CEC) workshop on the matter yesterday leads to several observations. This workshop was part of a CEC effort to gather input on the implications and potential implementations of energy storage in the state, for its Public Interest Energy Research (PIER) report on the topic, a somewhat parallel effort to one being explored by a proceeding opened by the California Public Utilities Commission on the topic.

Storage technologies and the business cases for them lie at the center of a tangled web composed of legislative directives, regulatory policies, specific grid applications, cost/benefit analyses, cost-effective alternatives, even basic philosophical views of the market—to name just a few strands in that web. 

Today I'll merely try to set the stage for further coverage of this multi-faceted issue. "Multi-faceted" is such an understated qualifier that I might suggest that this "holy grail" could prove to be as elusive as its biblical namesake.

That few will be satisfied with my exegesis underscores my point. Nevertheless, into the breach!

California has legislated for itself a hefty renewable energy portfolio (33 percent by 2020) and, subsequently, an energy storage portfolio directive (AB 2514) that beginning this year requires the state's utilities to develop five-year plans for energy storage and to begin procurement in 2014. The idea is to find a way to take increasing amounts of inexpensive, off-peak, variable wind and solar energy and store it to relieve expensive, on-peak demand. That presumably would preclude the need for more fossil fuel-fired base load and peak generating units, saving capital and lowering greenhouse gas emissions.

It appears that quite a variety of energy storage technologies can perform short-, medium and long-term storage, fulfilling various grid requirements from frequency regulation to renewable energy integration. Challenges arise over how to tailor a specific technology to a specific application in a cost-effective manner, while known, cost-effective alternatives remain in the toolkit.

Beyond the technical hurdles, many object that this approach ignores more cost-effective solutions, that costs and benefits cannot be properly allocated and that further tinkering with regulated markets only further delays the arrival of free market forces that would properly value everything about the grid and its commodity. Then there's the cost to ratepayers of pursuing renewable energy and the storage that could serve it. Not to mention a raft of unintended consequences.

I acknowledge that this is a somewhat brutally crafted summary, but let it serve to introduce aspects of yesterday's hearing that further illuminate the storage challenge.

The players who presented or participated in panels yesterday included utilities, vendors, federal and state policymakers, researchers, industry associations, industry research groups, attorneys, independent system operators (ISOs), system integrators and engineering firms, with a dash of citizen comments.

We're talking about the U.S. Department of Energy, the California Public Utilities Commission, the California Energy Commission, the California Independent System Operator, the University of California, the Electric Power Research Institute and the California Energy Storage Alliance, among others.

Those others included the state's largest utilities, such as Southern California Edison, Pacific Gas and Electric, San Diego Gas and Electric, Sacramento Municipal Utility District and Los Angeles Department of Water and Power. Most if not all of these utilities already have energy storage projects underway, at least in the demonstration phase.

But these lists and threads articulated above should give a sense of the disparity of interests, motives and viewpoints coming to bear on the storage issue.

Here are just a few of the questions that panelists sought to illuminate, if not answer:

  • How can storage help the state achieve its RPS?
  • How will storage help the state meet its self-imposed greenhouse gas emissions targets?
  • What can be done to better define energy storage's role?
  • What are cost estimates for energy storage?
  • How can its benefits be quantified?
  • How do utilities see the issue?


One citizen who commented on the record for this hearing had other questions:

  • Why is California's current fleet of pumped-hydro plants, in excess of 3,000 megawatts, inadequate?
  • How will subsidies for storage affect the availability of low-cost, off-peak energy for electric vehicles?
  • What policy and wholesale market changes, other than subsidies, narrow the cost-value gap for storage?


And one citizen commenter merely called for more coal-fired base load generation and descried the cost that storage and renewable energy would impose on ratepayers.

And this is just the set-up, sans details of the hearing itself. Like an addled spider and its web, the threads are many, not particularly straightforward and the playing field is full of competing interests.

We'll do our best to unravel it, thread by thread, issue by issue, in coming months.

Phil Carson
Intelligent Utility Daily






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