Andreas Späth

Green electricity without batteries

2016-02-01 09:21

Andreas Wilson-Späth

If you’ve read this column in the past you’ll know that I’ve been beating the drum for renewable sources of energy, especially wind and solar power, for a long time. Given what we know about these technologies, it just doesn’t make sense to me to invest any further resources or time in polluting and dangerous old alternatives such as coal, natural gas and nuclear power.


What’s more, developments on the renewable energy front keep getting better.


Take the results of a study just published in the journal Research Policy for instance. The authors investigate the application of something called Moore’s Law to solar photovoltaic (PV) module technology (that’s solar electricity panels to you and me).


Moore’s Law suggests that over time, the costs of technologies tend to decrease exponentially and the paper’s predictions suggest “that it is likely that solar PV modules will continue to drop in cost at the roughly 10% rate that they have in the past” and will quickly overtake competitors including nuclear, coal and natural gas.


And then there’s the brand new research that indicates that extensive renewable electricity provision is possible without the need for storing large amounts of energy in batteries.


One of the supposed Achilles’ Heels of renewables which critics like to latch onto has been the observation that the wind doesn’t always blow and the sun doesn’t always shine. Where is green, renewable electricity going to come from at those times?


One answer, of course, has been to point to the potential of a variety of large or distributed energy storage options, an area in which much progress is being made.


According to the new paper penned by scientists from the University of Colorado in Boulder and the American National Oceanic and Atmospheric Administration (NOAA), not only is it possible to slash carbon dioxide emissions from the US electricity sector by up to 80% compared to 1990 levels by 2030 by tapping wind and solar energy sources, but this can be accomplished without raising electricity costs or installing a major power storage system.


The secret lies in the fact that in a large enough geographical area, the wind does blow and sun does shine somewhere all of the time. By replacing the current regionally subdivided alternating current (AC) power grid of the US with a larger, national network of “high-voltage direct current” (HVDC) transmission lines, renewable energy could be distributed from wherever it is being generated to wherever it is needed.


HVDC power lines have the advantage over conventional DC lines in that they can transmit electricity with much less loss over distance, allowing it to be spread efficiently over much greater distances.


According to co-author Alexander MacDonald, “with an ‘interstate for electrons’, renewable energy could be delivered anywhere in the country while emissions plummet. An HVDC grid would create a national electricity market in which all types of generation, including low-carbon sources, compete on a cost basis. The surprise was how dominant wind and solar could be.”


Mark Jacobson of the Department of Civil and Environmental Engineering at Stanford University commented that the study “shows that intermittent renewables plus transmission can eliminate most fossil-fuel electricity while matching power demand at lower cost than a fossil fuel-based grid - even before storage is considered".


A similar approach can be envisaged for other large countries or regions, including Southern Africa which has a variety of areas with excellent potential for harvesting the power of the sun and wind.


It is true that the process of installing an extensive new HVDC grid is no simple matter. It’s expensive and not necessarily without public opposition as the current German experience indicates, but so is building large new coal and nuclear power plants, and the latter will leave us with unconscionable pollution and safety problems that are now entirely avoidable with currently available technology.

- Andreas is a freelance writer with a PhD in geochemistry. Follow him on Twitter: @Andreas_Spath

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Disclaimer: News24 encourages freedom of speech and the expression of diverse views. The views of columnists published on News24 are therefore their own and do not necessarily represent the views of News24.


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