The Energy Issue

The Energy Issue is a Columbia University GSAPP initiative to make energy a cultural issue, launched in partnership with Oldcastle Building Envelope®.

The Solar Paradox: How We Underestimate Renewables

The Solar Paradox: How We Underestimate Renewables

If we could harness just one tenth of one percent of the solar energy that reaches the earth, we would have six times as much energy as we consume in all forms today, with almost no greenhouse gas emissions. As promising as that scenario sounds, we still have a long way to go: solar still only makes up about 0.37% of global energy production, and while solar energy has been abundant, the systems used to capture it have been expensive and inefficient.

But evidence shows that could change very soon. Not only are the efficiency of solar cells continually improving, but also solar cell manufacturers are quickly learning how to reduce the costs of fabrication. Geoffrey Carr points out in The Economist that in less than three decades the price of solar PV cells has dropped from an exorbitant $76.67/watt to only 0.74$/watt in 2013. In fact, comparisons are being made between this behavior, dubbed Swanson’s Law after the founder of solar panel manufacturer SunPower Corporation, and Moore’s Law.

Those familiar with Moore’s Law knows it dictates that the number of components that can be placed on a computer chip doubles every 18 months, producing an exponential increase in computing power over time. In other words, the amount of computing power you can buy for a dollar has roughly doubled every 18 months. Similarly, Swanson’s Law predicts an exponential decrease in solar PV production costs. Effectively, costs will halve every three years. For the past 30 years, they have.



What does that mean for the future of solar? If Swanson’s Law continues as expected for the next eight to ten years, solar will be as cheap as coal for electricity, with essentially zero carbon emissions to boot. If it continues for 20 years, then solar will be half the price of coal for electricity.

Despite this astounding rate of change, many policymakers are skeptical of solar power, remaining under the impression that it will require huge subsidies. Now that fracking has resulted in a flood of cheap natural gas in the U.S. market, the need to look to alternative energy sources seems even less pressing. Simply put, we seem to be severely underestimating solar power.

To understand why, we might look at the adoption of solar not as a technical problem, but as a communications issue.  Indeed, the intergovernmental International Energy Agency, regarded as the last word on energy data and predictions, has forecasted that between now and 2035, solar will veer from its historical behavior and exhibit a negative growth rate, falling back to its 2011 level. The IEA’s projections using cost assumptions that are 100% higher than even current market prices, making solar appear prohibitively expensive even as its costs actually plummet. In effect, solar according to the IEA would provide only a dispiriting 4.5% of the world’s electricity by 2035.


However, as Brad Plumer notes in The Washington Post, the IEA has had a particularly poor track record in projecting the growth of solar and wind power. A case in point: in 2000, the IEA predicted that non-hydro sources of renewable energy would produce 3% of global energy by the year 2020. In fact, we reached that point over a decade earlier in 2008.

If solar can shake its unfavorable reputation among policy makers, the dream scenario might not seem so far off. Moore’s Law captured the popular imagination at the start of the computing revolution, which has yet to subside. What if Swanson’s Law were to do the same for solar?