Tim Worstall says:
Jobs are a cost of producing renewables, not a benefit of them, just as with anything else. We want to produce whatever it is we want to produce with the least use of human labour, not the most.
I'm not so sure.
Tim would be right if we had full employment. In such a world, the opportunity cost of having a worker in a low-productivity job is having him in a higher-productivity job. In this sense, low-productivity jobs are a cost. Tim's right, therefore, that - in the long-run, and assuming displaced workers find employment - the sort of technical progress which "destroys jobs" is actually a good thing - as it frees people up to do more useful things*.
However, the more astute of you might have noticed that we don't have full employment. And this changes things. This is because unemployment is costly. The social cost here is not so much the welfare benefits paid to the jobless: these are, in effect, a transfer from taxpayers to Lidl, Matalan and landlords. It is rather that the unemployed are much, much less happy than the employed. This is not simply because they have lower income. "Becoming unemployed is much worse than is implied by the drop in income alone" say (pdf) Di Tella and colleagues. One reason for this is that the jobless suffer from feeling that they are violating social norms about the value of work.
From this perspective, jobs are a benefit; they help - perhaps only partially - to restore people's self-respect and well-being. This might even be true of work that's of questionable conventional "value"**. In Bridge on the River Kwai, Lt. Colonel Nicholson gets his men to build a great bridge - even though it would help the Japanese war effort - because it's a way to improve their pride and morale. I suspect that story generalizes; even digging holes and filling them in again might help increase happiness by improving the unemployed's social contacts and friendships. (It is, of course, a long leap from saying this to saying that work programmes must be compulsory.)
That said, this is is not an argument for creating low-value jobs. Within a voluntary job guarantee scheme, there's an opportunity cost to paying people to dig holes and fill them in again; it's that they could be doing something more useful***.
In this sense, Tim's right that we should pay attention to the quality of jobs that are being created. But to say that "jobs are a cost" is - at our current juncture - far too simple.
* One might quibble here about the quality of jobs. But I suspect the idea that call-centre work is worse than mining or old-style farming owes more to romantic nostalgia than to facts.
** I hate the word "value".
*** The fiscal cost of a job guarantee scheme is another question; if multipliers are below one, it is a cost, but if it's above one, it's not. But this is not the point Tim's making, which is probably just as well.