I often think that the allure of progressivism mostly turns on inability to do basic arithmetic.  My Exhibit A is affordable housing in Manhattan, where we spend in many cases $100,000 per year to subsidize a family to live in a premium location, only to have the family remaining in "poverty" or near-poverty.  How can this possibly make sense?  But here's something that might make even less sense:  the fuzzy math of renewable energy; or, more precisely, the fuzzy math of how much it will cost to try to make a fully-functioning electricity system run primarily on intermittent sources of power like solar and wind.

You probably missed it, back in September 2014, when then-new Mayor Bill de Blasio made the big announcement that New York City would be reducing its "greenhouse gas" emissions 80% by 2050.  (You always have to love those non-binding commitments by politicians for years long after they will have left office and when most of us will be long dead.)  Here is a picture of de Blasio on the day of that announcement, marching arm-in-arm with the likes of Al Gore and Ban Ki-Moon.      

So, how to get from here to an 80% cut in CO2 emissions?  The big idea, if you want to call it that, is to use lots more solar and wind power.  But those things only work part-time, and not on demand; so to turn them into a fully-functioning electricity system you need some combination of back-up power from dispatchable sources, and/or storage.  And if it's only the back-up from dispatchable sources, without the storage, then you're probably going to find the dispatchable sources supplying most of the power most of the time.  If you want well upwards of 50% of your power to come from solar and wind, you are going to need storage.  A lot of storage.

And that brings us to the latest:  Last week New York City announced that it would become the first municipality in the U.S. to have a target for energy storage deployment as part of its commitment to cut CO2 emissions.  From Green Tech Media:

Only two U.S. states, California and Massachusetts, have set targets for energy storage deployments. Now New York City has joined them.  The city government unveiled a storage goal of 100 megawatt-hours by 2020 last week. . . .  

And over at Solar Industry Mag, you can feel the excitement:

According to the mayor, this [100 MWH] target will help reduce reliance on the grid by making variable sources of energy production, such as solar panels, usable for more of the day. Energy storage also helps increase the city’s resiliency by providing backup energy when the grid is offline.  “New York City’s new solar and energy storage goals will bring even more clean energy jobs, cleaner air, and electric system benefits to the Big Apple and will help us get the most out of our solar resources,” commented Donna De Costanzo, director of Northeast energy and sustainable communities at the Natural Resources Defense Council.

One hundred megawatt-hours of storage capacity -- that sounds like a lot!  Or does it?  To put it in a little context, a Tesla comes with a battery pack with about 85 kilowatt-hours of capacity.  So New York City's 100 megawatt-hours would represent the storage capacity of around 1200 Teslas.    Cost?  Tesla says it can now produce the battery packs for around $12,000 each.  (Industry critics think it is really double that or more, but let's give them the lower number for these purposes.)  That means that the 100 MWH of storage capacity will cost around $14.4 million.  That's kind of a rounding error in New York City's budget, currently running over $80 billion annually.  And we have all the way to 2020 to accomplish this.  No problem!

But perhaps we should ask, about how long will the 100 MWH of power last our fair city when the wind stops blowing in the middle of the night?  To make that calculation you need to know our ongoing level of usage of electricity, which as far as I can find runs around 10,000 to 12,000 MW.  A little simple arithmetic, and you calculate that when the sun and wind go blank the 100 MWH will carry the City for about -- 30 seconds!  

So maybe we had better buy, say, a full day's worth of storage capacity, just in case we're dealing with a heavily-overcast calm day in the middle of the winter.  Multiply the $14.4 million by 120 (to get an hour) and another 24 (to get a day) and you get a total cost for the storage capacity of $41.472 billion.  This is no longer a rounding error.  And by the way, nothing says that we can't have two, or even three, consecutive fully-calm heavily-overcast days in the middle of the winter around here.  Are we really going to try to deal with this in any meaningful way with batteries?  For a full three days' storage capacity, we'd need the equivalent of over 10 million Teslas worth of batteries.  Is there even that much lithium available in the world?

Of course, we could always deal with this problem by having a full set of back-up dispatchable power plants at the ready for the calm nights and cloudy days.  At around $3.5 billion per 1000 MW capacity, that will be another $50 billion or so for back-up capacity you may use say, three to five days per year.  No problem!  I could try to criticize de Blasio for not playing straight with the citizenry when he makes big announcements that he is wasting some millions of dollars on totally meaningless amounts of storage capacity, but why bother?  I really don't think he is capable of doing this level of arithmetic.

Meanwhile, pay attention to the news out of South Australia.  That's the large Australian state covering the middle-southern section of the country, with the main city being Adelaide.  On September 25 something called the Grattan Institute put out a Report on the situation of electricity supply in South Australia, and warning of problems to come.  It seems that South Australia has set out to make itself the world leader in generating electricity from renewables, mostly wind.  According to the Grattan Report, wind now supplies about 40% of the electricity in South Australia.  Is that any problem?  The Report discusses two big issues:  (1) the intermittency of the wind power is leading to wild price swings in the wholesale electricity market when the wind suddenly stops blowing and there is a shortage of back-up, and (2) the intermittency also affects the reliability of supply.  From the Report:

On the night of 7 July, the wind was hardly blowing in South Australia and the sun had gone down. Two coal plants had closed earlier that year, and an electricity connection that provides power from Victoria was effectively closed for upgrades. As a result, gas was supplying nearly all the state’s power needs. At 7.30pm, the wholesale price of electricity shot up to $8900 per megawatt hour, a staggering sum when wholesale prices in the eastern states average about $50 per megawatt hour.  Price spikes are a fact of life in the electricity market. Far more troubling was South Australia’s average wholesale price for the month of July - $229 per megawatt hour, more than three and a half times that of the eastern states. . . .   [T]here must be a separate review of the market to ensure that power flows reliably and affordably. . . .  The events of July in one state were a canary in the coalmine, warning of the risks in Australia’s power future. It is time to listen. 

Very prescient on their part!  On September 28 there was a big storm in South Australia, and the entire state was plunged into a blackout.  Was the heavy reliance on wind power and shortage of back-up the cause of the blackout?  That issue is currently subject to big dispute between backers of wind power on the one hand, and skeptics on the other.  An investigation is under way.  The precipitating cause of the blackout seems to be that the storm knocked over 20 or so big transmission towers.  But would that be enough to throw the whole state into blackout absent the problems cause by reliance on wind power?  Here is a round-up from Australian blogger Joanne Nova.  Judge for yourself.