Intermittency — Marketing Term or Misunderstanding?

When I arrived back in California in 2007, a study was underway to determine whether renewable electricity could feasibly contribute 33% of California’s electricity supply portfolio by 2020.  The study had been commissioned in the wake of California’s first renewable portfolio law, which called for 20% of the state’s electricity to be “renewable” by 2010.  At the time, according to a definition of “renewable” that excluded the state’s fleet of large hydro-electric power plants, renewable electricity accounted for less than 10% of California’s annual electricity usage.  The law was enacted in 2002.

The “Intermittency Analysis Project”, under the leadership of Dora Yen-Nakafugi at the California Energy Commission, had taken a lot of effort and time, due to the complexity of project scoping and modeling necessary for a credible result.  Meantime, there had been adjustments in the portfolio standard, in part to lower the bar as to timing, in part to raise it as to percentage.  An executive order by California’s governor had added an aspirational standard of 33% by 2020, which eventually became the legal and regulatory standard for to the state’s investor owned utilities.  So, part of the project’s challenge also had to do with a moving legislative and regulatory target.

The study concluded that the 33% standard could be met without major changes in the state’s bulk electricity delivery infrastructure, aka the “transmission grid”.[1]

So, state agencies having jurisdiction over grid operation began to consider how their work and responsibilities would be affected if the standard were implemented.  In the humorous but all too true “Six Phases of a Project”, the third phase is listed as either “panic” or “total confusion”.  Something like this ensued.  At the beginning, data was crunched and published emphasizing randomness in the variability of wind power production at a specific site in California.  The point seemed to be that some increased level of electricity generation “intermittency” might be feasible, but it would have profound and scary implications for grid operators.

The point of this blog topic is not to analyze intermittency scariness.  There are several important and technically sound responses that focus on managing the issue rather than fretting over it.  A body of detailed and independent analysis addressing the concern has blossomed and has pointed to important mitigating factors.

One technical point that continues to be overlooked in all of this is that electricity grids have always been designed and operated to accommodate an inevitably high degree of variability in both localized and regional demand.  In other words, the state’s grid already handles significant “intermittency” in one fundamental dimension quite satisfactorily.  The proper strategy going forward is to deal with overall supply and demand “variability”.  For example, it will be quite feasible to expand the use of demand response measures, time of use pricing and smart grid information.  These measures can significantly increase predictability and reduce variability in aggregate demand, thus opening a wider window for variability on the supply side.

What I overlooked for a long time was the use of “intermittency” as a political marketing term to discourage policies supportive of renewable energy deployment.  The intended message to the public was, “You don’t want your power to be intermittent, do you?” to hark back to an earlier blog, Words Do Matter.  At a minimum, people and organizations favorably disposed toward renewable energy should avoid the terms “intermittent renewables” and “intermittency”.  They imply a problem for which there is no solution.  This is far from the truth.

Yes, it is true that solar and wind resources are variable.   Typical levels of variability, and even the occasional “perfect storm” of coincident and compounding supply and demand ramps, are quite manageable in thoughtfully designed market structures using modern information resources.  The proper immediate course is to make full use of new solar and wind forecasting tools that enable grid operators to plan for the inevitable and daily variations.  (Our compliments to Jim Blatchford at CAISO for leadership in this direction.)

In the US and California, long term electricity supply planning is increasingly neglected under a questionable assumption that market outcomes are unpredictable, and current market structures can continue to serve us well in the long term.  This is a mistake.  Cost effective strategies will be available to accommodate ever increasing renewable electricity percentages.  But these strategies won’t be deployed in 20th century business as usual market structures.  They should be the focus of increased attention to long term electricity system planning.  Each strategy needs its own discussion.  Future blogs will take them on one by one.

For now, let renewable energy advocates agree to stop validating the marketing messages of renewable energy opponents.

– Gerry Braun

© 2012 The IRES Network