Solar photovoltaic (PV) mass-market polycrystalline panels are typically about 15% efficiency. Pretty terrible, right?  Maybe, maybe not.  

Cars - both gasoline and electric vehicles, despite what the electric car hype machine claims - are only slightly more efficient at 15-25%, as is eating, and biology had all of existence to perfect that process. Ethanol and other biofuels, which were the darling of anti-science environmentalists in the Anything-But-Oil camp before electric cars because they are the ultimate solar-powered device, are a dismal <2% efficiency.

Yet maybe an efficiency fetish is just as misguided as the Anything-But-Oil one. Regardless, efficiency is what people talk about and that may be a mistake - there are lots of other reasons why solar power in current form is unworkable but efficiency may be just as misguided when critics bash it as when zealots promote it.

Efficiency can be improved, and has been in for NASA applications (to around 40%) but those manufacturing costs are insane. It doesn't keep the interns working at the Department of Energy who are squandering $35 billion on corporate welfare from insisting the Miracle of Capitalism will bring those costs down, ironically requiring massive taxpayer funding first to do so, but in the non-government world where we don't get to play with Monopoly money, actual science and economics are in force. So let's stick to data and the data says solar is not great, and maybe it never will be, but it isn't awful.

Writing at Do The Math, Tom Murphy, associate professor of physics at the University of California, San Diego, tackles the evolution of PV technology and why the efficiency concerns are not all they are cracked up to be.

He is right. Even current silicon is reasonably efficient compared to mature technologies so why Energy Secretary (and Nobel-winning physicist) Steven Chu was determined to fund copper indium gallium diselenide (CIGS) companies (not basic research, actual companies, to the tune of a million dollars per job in government funding) remains a mystery of how astute scientists can lose their minds when they enter politics, just like anyone else can.

But solar won't get better any time soon, especially if we are rewarding old technology we know is not great with unlimited government money. "There are really good reasons why the efficiencies will not climb to arbitrarily high values. Basic physics stands in the way, and I am left impressed with what we’ve got," he writes.   But I have a whole book coming out in September that has a section dealing with the physics obstacles so read his piece in the interim.  He does a terrific analysis of how we got to where we are.

Of course, cultural obstacles also remain if solar power is only almost as good as the low end of cars; just like you can't get a job writing at the New York Times by telling an editor you are as good as their worst employee, existing technology cannot replace an incumbent by being on the low end of what existing technology has. Cars replaced horses - even without a Department of Energy to pork barrel Ford Motor Company - because they were clearly better than horses even while the cost was far higher.

Solar power, regardless of efficiency, has a much different problem - all the land it will take:

Land area, shown as black dots, needed to produce 18 terawatts. Source: WikiMedia.

It's only a dot, right?  Well, America has far more open space than Africa and many claim that is still not enough - and that dot, as Murphy notes, is more actual space than every paved road in America. Like when ethanol was implemented rather than gushed about, environmentalists will turn on solar rather quickly when they stop buying into environmental corporation marketing claims and see what this actually means for the environment.  You think roads need repaired a lot?  Wait until you get the maintenance bill for solar panels.

Don’t Be a PV Efficiency Snob - Tom Murphy, Do The Math
H/T Dan Drake, who sent me the link on GooglePlus