RUTHFULLY YOURS

A new book, Taming the Sun: Innovations to Harness Solar Energy and Power the Planet, is available from MIT Press.  The book touts the wonders of solar energy and tells us that there is an urgent need to invest trillions in more solar energy.  The book is filled with outright errors.  The author, Varun Sivaram, has a boundless faith in technical progress that he thinks will make solar cheaper and more practical.

Since solar cells and integrated circuits are both manufactured using silicon wafers, the author assumes that something like Moore’s Law must apply to solar cells.  Moore’s law predicts the halving of the price of integrated circuits every 18 months or so.  But integrated circuits become cheaper because they become smaller, taking less real estate on the wafer.  However, solar cells don’t become smaller, because they need to collect sunlight, and the amount of energy they collect is proportional to the area they occupy.  In any case, the cost of the silicon components of solar energy is rapidly becoming negligible.  At least 75% of the cost is for mundane things like concrete, steel, power lines, land, etc.

Solar has the huge problem that it doesn’t work at night.  It doesn’t work during the day if it is cloudy.  Even the sunniest city in the USA, Yuma, Ariz., has 50 cloudy days a year.  If there were a cheap and scalable method of storing electricity, the prospects for solar would be better. But the best method of storing electricity, pumped storage, is expensive and dependent on favorable terrain.  Neglecting many costs, utility-scale solar farms cost about $2,200 per kilowatt of nameplate capacity.  Under favorable conditions, the average power produced is about 25% of nameplate capacity.  If a realistic computation of the unsubsidized cost of electricity is made, solar electricity costs 12 cents per kWh, under good conditions in sunny locations.  Natural gas can deliver electricity for less than 5 cents.

The graph below is from the book and purports to show that the cost of solar power is now cheaper than the U.S. residential electricity price.  I won’t argue with the 10-cent-per-kWh price for residential electricity, although the Energy Information Administration says it is closer to 12 cents.  However, the price of about 5 cents per kWh (yellow line) for solar is confusing and not correct.  The first error is that Sivaram is comparing apples and oranges, comparing the retail price of conventional electricity with the generation cost, or wholesale cost, of solar electricity.  The second error is that the generation cost for solar is around 12 cents, not 5 cents.  So perhaps he is using the subsidized cost of solar, which in some circumstances might be 5 cents.  But subsidized solar costs the same; the money just comes out of different pockets.

The author, now about 28 years old, is a high school valedictorian, a Rhodes Scholar, and a star in the solar energy firmament.  The author’s father, Siva Sivaram, at one time ran Twin Creeks Technologies, a California solar energy startup.  Sivaram (Junior) is also a science fellow at the Council on Foreign Relations, an adjunct professor at Georgetown University, a fellow at the Columbia University Center for Global Energy Policy, a member of several advisory boards, and much more.  His book is weak, with a speculative flavor, but apparently, it is what important people want to hear.  The message is that if you say nice things about solar energy, you may go far in the world.

Sivaram buys into the most extreme global warming propaganda.  By 2050, “climate change is serving up droughts, floods, and heat waves with alarming regularity.”  He claims that in 2016, solar energy was the cheapest source of electricity on the planet – a ridiculous claim.  As I have stated, my own analysis puts the cost of solar electricity around 12 cents per kWh compared to less than 5 cents for natural gas.  That is not the whole story, because there are ancillary costs associated with solar energy.  Solar energy has to be backed up with a fossil fuel plant because it does not work at night or when there are clouds.  There is no capital investment benefit from solar energy because you still need the backup gas plant.  The only real advantage is the saving in fuel when the solar farm is actually delivering energy.  That fuel is worth less than 2 cents per kWh.  So the proper comparison is the 12-cent cost of solar versus the 2 cents of fuel saved for each kWh.  The difference is the subsidy for solar, sometimes explicit and sometimes hidden in electric bills.  Neither is solar an efficient vehicle for cutting carbon emissions.  It costs over $200 per ton of CO2 emission avoided from using solar, computed by applying the 10 cents per kWh of subsidy or waste to the task of avoiding CO2 emissions from natural gas.  There are much cheaper ways of buying carbon offsets.

Sivaram touts the idea of wrapping buildings in some future flexible solar panels.  This neglects the fact that building walls are vertical and not necessarily facing south, resulting in great inefficiency in collecting sunlight.

Sivaram sums up his desires with this:

The final type of innovation that solar needs in order to achieve its potential is systemic innovation, which involves refashioning entire energy systems – including physical infrastructure, economic markets, and public policies – to enable a high penetration of solar energy.

The obvious question is, what is so important about solar energy that we need to refashion the entire energy system?  That money would be better spent on nuclear, where there is a genuine path to lower cost and extremely safe CO2-free energy.  A new nuclear technology would feature smaller reactors built in factories and shipped to the site.  New engineering would create reactors that run for 25 years without refueling.  Fuel breeding within the reactor would lower already low fuel costs.  Thorium fuel could enable new types of reactor with many advantages.  These innovations are based on good theory, and only engineering is needed.  In contrast, making solar practical and competitive requires going down a path that is currently invisible.