Solar power can accelerate to meet half the world’s energy needs in 20 years, say scientists

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By Will Driscoll

Increasing global solar installations at 29 percent per year is a “challenging but feasible” rate that would yield 10 terawatts of solar installed by 2030.  Then, maintaining global production at the 2030 level for eight more years would yield 30 terawatts of solar installed by 2038.  That’s according to an analysis published in Science magazine*; it would be enough solar power to meet half the world’s energy needs for current uses of electricity, plus transportation and heating.**  If wind power provided the other half, we could have 100 percent renewable energy for all energy needs by 2038—twenty years from now.

The solar industry’s dramatic growth (see bar chart) has already yielded cost reductions that are attracting more buyers each year; indeed, low-income China and India have become major markets. And history shows that the solar industry can scale up at a 29 percent rate through 2030.  As related in MIT’s report The Future of Solar Energy, “military aircraft production in the U.S. grew by one-to-two orders of magnitude between 1939 and 1944, highlighting the tremendous level of growth that is possible for commodity-based goods.”  Moreover, the solar industry uses automated manufacturing techniques not available in the 1940s.

A 29 percent annual growth rate also makes intuitive sense.  For every three factories a solar panel manufacturer owned, next year it would need to build and equip another factory—that would be a 33 percent growth rate, or a few points better than 29 percent.

The solar industry needs more than the technical potential to grow at this rate, however.  It also needs a growing backlog of orders for solar panels, to give manufacturers confidence that if they build solar panel factories, the customers will come.  First Solar, for example, pointed to 2017 orders of three times its shipments to justify its plan to double its solar panel manufacturing capacity over the next three years (which represents a compound growth rate of about 29 percent per year).

To persuade the solar industry as a whole to plan for ever-increasing additions to manufacturing capacity through 2030, we need to keep modernizing the electric grid so that more and more solar farms may be interconnected, and the electricity they produce can be transmitted to end users.  Indeed, we need to show the solar industry that we are committed to this grid modernization process over the next 20 years.  After all, military aircraft manufacturers in the 1940s had a ready buyer: the U.S. Government.  Low-cost solar panels will keep finding ready buyers only if those buyers have a way to connect to the grid, and transmit, distribute and sell their solar electricity.  The extent of grid modernization required represents a major infrastructure transition, and so we will need many more people to become educated, trained, and employed in this field.

Since so many electric utilities are dragging their feet on solar, and are not being guided by their state regulatory agencies to take advantage of solar’s plunging costs, we need to keep up the pressure on electric utilities and their regulators in order to achieve solar’s promise.

Here is one possible sequence of overlapping steps:

  • “Unblock” solar:  Eliminate groundless regulations and pricing structures that prevent or penalize solar installations.
  • Institute time-of-day pricing to encourage the use of electricity when the sun is shining, to facilitate the use of all solar power generated.
  • Enact energy efficient building codes so that new buildings use cost-effective energy-conserving construction materials and techniques.
  • Promote distributed storage of electricity, to enable existing transmission lines to deliver power to distribution-level electricity storage when generation is high, and enable the distributed storage to help meet local electricity demand at periods of peak demand.
  • Stop investing in fossil infrastructure.  This includes pipelines, fossil-fired electric generating units, fracking wells, and new gasoline-powered cars, buses, and trucks.  Use the money instead to modernize the electric grid; install solar and wind power; install storage; and buy battery-powered vehicles, as well as electric heat pumps instead of fossil-fired furnaces.
  • Price carbon.  Eliminate fossil fuel subsidies and institute a carbon tax equal to the health and global warming costs of fossil fuels; this would level the playing field between solar and fossil fuels.
  • Build an electric vehicle charging infrastructure, to accommodate long-distance travel by electric vehicles.
  • Build more transmission lines as needed, possibly along existing rights-of-way, to bring solar and wind power from rural to urban areas.
  • Develop cost-effective means to store heat, e.g., in rocks held in insulated underground structures, for use in winter-time heating.

These overlapping steps are broadly consistent with the view of the U.S./German/Japanese solar research consortium GA-SERI, which was largely responsible for the Science magazine analysis.  As GA-SERI stated in a press releaseaccompanying the article:

“GA-SERI’s experts predict 5-10 terawatts of PV capacity could be in place by 2030 if these challenges can be overcome:

  • A continued reduction in the cost of PV while also improving the performance of solar modules
  • A drop in the cost of and time required to expand manufacturing and installation capacity
  • A move to more flexible grids that can handle high levels of PV through increased load shifting, energy storage, or transmission
  • An increase in demand for electricity by using more for transportation and heating or cooling
  • Continued progress in storage for energy generated by solar power.”

The Science Magazine article had 21 co-authors: seven from the U.S National Renewable Energy Laboratory, four from the comparable German agency Fraunhofer ISE, three from Japan’s comparable National Institute of Advanced Industrial Science and Technology, two from solar manufacturers, two from solar certification or research firms, and two from universities.

For those seeking to obtain the article at a university library or by inter-library loan (to avoid the $40 Science Magazine subscription fee), the article is “Terawatt-Scale Photovoltaics: Trajectories and Challenges,” Science 356 (6334), April 14, 2017, pp. 141-143.

** Here’s the calculation:  Solar generated 1.3 percent of the world’s electricity in 2016.  For solar to provide 50 percent of current electricity needs, we would need (50/1.3) = 40 times as much solar power as we had in 2016.  At the mid-point of 2016, the world had about 250 gigawatts of installed solar (see bar chart above).  Forty times that amount is about 10,000 gigawatts, or 10 terawatts.  That would meet half of current needs for electricity.  To electrify 50 percent of transportation (with electric vehicles) and heating (with heat pumps) would each require about the same amount of electricity—for a total need of 30 terawatts of solar, to meet half the world’s total energy needs.

Image: REN 21: Renewables 2017 Global Status Report

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