As official Manhattan Contrarian April Fool Germany -- not to mention U.S. states like New York and California -- careen toward 100% renewable energy utopia, few stop to ask the question of how this is supposed to work from an engineering perspective.  Is it as simple as just building a bunch more wind turbines and solar panels and assuming that everything will be just fine?  A youngish Stanford professor, Mark Jacobson, puts out a couple of papers saying that he's made a computer model, and all it will take to make a 100% renewable system (solar, wind, water) will be maybe a little new-fangled storage (not yet invented), plus a few extra transmission lines (no costs provided).  Suddenly this guy has a celebrity following ranging from Mark Ruffalo to Leonardo DiCaprio to Governor Jerry Brown of California.  But before we go down the road of covering the landscape with these devices, will anyone address what it will take to make this work as a reliable 24/7 electricity system, and how much that project will cost?

From time to time some serious group of people will put out a real study pointing to a few of the engineering problems of these fantasies, yet somehow these types of studies never draw the same level of attention as guys like Jacobson.  So I do my small part to publicize them.  In this post back in June 2017 I summarized a study then out from a group of authors led by Christopher Clack that dissected numerous flaws in Jacobson's work.  Clack did a pretty good job eviscerating Jacobson, but his study did not go as far imagining what it might take to create an alternative system that would actually work, let alone attempting to assign any sort of costs to such a thing.  (However, Clack did strike enough of a nerve to draw a defamation lawsuit from Jacobson, since withdrawn.)

We now have a new study out from a group of authors led by independent consultant Matthew Shaner, published in Energy & Environmental Science in February.  The full study is behind a pay wall (it will cost you 42 pounds!), but the link goes to the abstract, and there is also a long article summarizing the results by James Temple in the MIT Technology Review of February 26.  Shaner et al. have analyzed 36 years of global, hourly weather data (1980-2015) in order "to quantify the covariability of solar and wind resources as a function of time and location, over multi-decadal time scales and up to continental length scales."  The title of Temple's summary gives you the first hint as to the results:  "Relying on renewables alone significantly inflates the cost of overhauling energy."  Let's have some details:

[A] study published in Energy & Environmental Science [has] determined that solar and wind energy alone could reliably meet about 80 percent of recent US annual electricity demand, but massive investments in energy storage and transmission would be needed to avoid major blackouts. . . .  Relying on these intermittent sources alone would requiring building many more solar and wind farms to produce excess energy during particularly sunny and windy periods, plus huge storage systems that can bank hours’ or even weeks’ worth of power.     

We then get this small clue as to the cost of starting down this road:

Just getting to 80 percent of demand reliably with only wind and solar would require either a US-wide high-speed transmission system or 12 hours of electricity storage. A storage system of that size across the US would cost more than $2.5 trillion for a battery system.

Two and a half trillion dollars is about two-thirds of a year's worth of the entire federal budget.  Maybe we could swing it if we could just skip Medicare and Social Security and National Defense for a year?  But suppose you want to do away completely with those evil fossil fuels?

To meet all the nation’s annual electricity needs with 99.97 percent reliability, utilities would have to build 12 hours of storage plus at least twice the amount of renewable-energy generation, the study found. Or businesses could deploy slightly more wind and solar coupled with more than a month’s worth of storage. 

If 12 hours of storage goes for about $2.5 trillion, I guess the month's worth will set you back about 60 times that, or $150 trillion.  That's about 8 times the full annual GDP of the U.S. these days.  No problem!  Don't forget, by the way, that electricity is only about 40% of U.S. energy consumption, the remainder consisting of things like transportation (planes, trains and automobiles), industry, and home heating.

Back here in New York State, the official goal is to get 50% of our electricity from renewables by 2030.  Supposedly, with a few heavy-handed incentives, private investors will just build the generating facilities on their own.  A January 26 report from the Empire Center lets us know how that's going:

Renewable energy companies aren’t building the windmills and solar panels Governor Andrew Cuomo hoped for when he pledged in 2015 to have 50 percent of the state’s electricity come from renewables by 2030.

I guess we shouldn't be too surprised about that.  So what's the solution?

The state will build them itself.  Part GG of Cuomo’s proposed Transportation and Economic Development (TED) Article VII budget bill would let the state Power Authority . . .  “finance, plan, design, engineer, acquire, construct, operate or manage” renewable energy projects, defined as “solar power, wind power, hydroelectric, and any other generation resource authorized by any renewable energy standard adopted by the state for the purpose of implementing any state clean energy standard.”

Yes, it's the strategy of just building lots of new solar and wind facilities -- at taxpayer expense of course -- and assuming that they will all turn into a workable 24/7 system.  You would be very safe to bet against this.