In his article, “Is Renewable Energy Compatible With a Reliable Electric Grid?,” Mr. Bredenberg refers to a recent study by electric-power research firm Synapse Energy Economics Inc., prepared for the Civil Society Institute(CSI). The CSI study found that, “the U.S. electricity grid could integrate and balance many times the current level of renewables with no additional reliability issues.” The study is an attempt to dispel concerns regarding the variability of renewables, “especially wind and solar…solar panels only generate power when the sun is shining, and wind turbines only spin when the wind is blowing.”

Mr. Bredenberg then quotes me from my report, “Hidden Costs of Wind Electricity.” First, there are several technical problems with the Synapse study and some apparent confusion by Mr. Bredenberg about my report.

The “Hidden Cost of Electricity” is an analysis of the cost of wind generated electricity, taking into account various hidden costs and costs imposed on folks other than the wind generator themselves, due to the nature of wind generation. In essence my report doesn’t address the question of whether more wind or other renewables is conceivably and physically possible, but rather what is the total cost, including hidden and offloaded, of wind. It is conceptually possible to increase wind generation while maintaining grid reliability, as the Synapse Report shows. That would be very costly, however, requiring huge investments in energy storage, in massive amounts of ‘flexible’ generation, and the abandonment of well functioning existing power plants (not yet fully amortized), as noted by Synapse. In short, the study calls for the complete replacement of a working system.

Making it more difficult and complex to maintain power, frequency, and voltage will strain both the generation equipment and personnel, and that will increase the probability of a cascading failure. It does not, as they claim, lead to more reliable service.

In all regions analyzed by Synapse, imports are required to maintain load (i.e. matching demand and supply). In other words, load was not satisfied by the renewables scenario, but depended on imports from other regions and on increased “flexible generation.” In a select few cases, wind generation is curtailed even when available, but the report does not make clear whether that is timely and available to other regions for use. Curtailment means the wind is wasted. In other words, reliability requires resources beyond the renewables. The Synapse conclusion is at odds with the Synapse analysis.

The terms “backup” and “balancing” have different meanings. Backup generally refers to the requirement to provide power when the sun is not shining or the wind is not blowing. That is a multiple-hours, or diurnal or longer phenomenon. Balancing refers to the instantaneous (less than 1/60 second) requirement to maintain harmony on the grid for power, voltage and frequency. It can be threatened when the wind suddenly increases or decreases, like when it gusts. Wind creates threats to the grid’s stability as much, if not more, when it’s is generating ‘full out’ than when it’s off due to lack of wind. It is that phenomenon to which I refer in the piece quoted by Mr. Bredenberg - operating flexible generation units in stop and go mode degrades their efficiency compared to ‘cruising.’ That has both capital recovery and fuel cost implications which are not considered in the Synapse report.

The terms ‘predictability’ and ‘stable’ are also confused when discussing wind forecasting done by regional grid operators. Having been involved with improvements to wind forecasting for twenty years, this is particularly disturbing. Wind forecasting HAS improved greatly over that time, but being able to predict the wind for tomorrow as likely being ‘gusty’ is far different than being able to manage wind’s ‘instability.’ Remember, wind’s output is a cube function of the wind speed, so a gust at 20 mph produces eight times the electricity as does a 10 mph baseline wind. If that’s happening every five minutes, for example, the grid operator will have a very serious challenge regardless of whether he anticipated it ahead of time or not. Knowing the wind will be gusty tomorrow does not mean anything can be done about it when it occurs.

Finally, the Synapse report acknowledges the need for increased Demand Side Management, which is just one way of saying electricity is turned off when supply is short of demand. That can be voluntary through programs customers sign up for with incentives (they’re paid to not use electricity) or through involuntary central dispatch decisions. Either way, load is not met if it is traditionally defined as meeting customer demand. Turning off customers’ lights is hardly maintaining reliable service.

The Synapse report addresses different issues than does Hidden Cost Of Wind Energy, and glosses over some significant cost items: huge additional transmission lines that are seldom used, untested and costly large amounts of energy storage, and the capital recovery and efficiency impacts of the ‘flexible generation’ required to maintain the grid. The report’s suggestion that the ‘all renewables’ scenario would result in cost savings of $83 billion compared to business as usual is unsupported.