Solar energy can solve global warming. That’s what Paul Krugman claims in his April 18 column in the New York Times, “Salvation Gets Cheap.”
Krugman extolled “the incredible recent decline in the cost of renewable energy, solar power in particular.” He used to dismiss the claim that renewable energy would be a major source of global energy “as hippie-dippy wishful thinking.” But now, he says, thanks to the falling price of renewable energy, the process of decarbonization can be accelerated and “drastic cuts in greenhouse gas emissions are now within fairly easy reach.”
getting cheaper. And solar capacity is growing rapidly. But Krugman is still wrong. Solar won’t result in “drastic cuts” in greenhouse-gas emissions for two simple reasons: scale and cost.
Before going further, let me be clear: I’m bullish on solar. I’ve invested in solar. A decade ago, I paid to have 3,200 watts of solar panels installed on my roof. Why? Simple: I got a big subsidy. Austin Energy paid two-thirds of the cost of my $23,000 system, and those panels now provide about 30 percent of the electricity my family and I consume.
I will also gladly stipulate that Krugman is right about the plummeting cost of solar. In 1980, the average global cost of a solar photovoltaic module (which converts sunlight into electricity) was about $23 per watt. Today, it’s less than $1 per watt. Those falling costs are helping accelerate solar deployment. Between 2007 and 2012, according to BP, global solar capacity grew ten-fold and now stands at about 100,000 megawatts.
But that torrid growth doesn’t spell the end of hydrocarbons. Even if we forget the incurable intermittency of solar energy — which requires grid operators to have stand-by conventional generation capacity (from natural gas, coal, or nuclear) available for periods when the sun isn’t shining — the reason why cheaper solar panels won’t lead to major cuts in global carbon dioxide emissions is that solar’s contribution remains infinitesimally small.
Between 2007 and 2012, the same period during which solar capacity grew tenfold, global coal consumption rose by the equivalent of more than 10 million barrels of oil per day. Meanwhile, in 2012, the contribution of global solar production was equivalent to roughly 400,000 barrels of oil a day.
Put another way, over the past half decade or so, just the growth in coal use is equal to about 25 times the contribution now being made by all of the world’s solar projects. And the coal-fired power plants that have been built over the past few years are likely to run for decades.
Why is coal use soaring around the world? Because demand for electricity is soaring. Since 1985, global electricity production has been growing by an average of about 450 terawatt-hours per year. The International Energy Agency expects global electricity use to continue growing by about that same amount every year through 2035.