Nonprofit, nonpartisan journalism. Supported by readers.


An interstate for renewable energy could hold costs level, study finds

Researchers argue that the limiting factor for renewables’ contribution to U.S. energy needs is a problem of distributing renewable power from all of the places it could be made to all of the places it could be used.

Photo by Fré Sonneveld

Though it relies on credible data and has a lot of expert number-crunching behind it, you could call it more of an elegant thought experiment than engineering plan.

Still, a paper published this week in Nature Climate Change reaches some striking and encouraging – even compelling – conclusions about finding our way painlessly to an affordable energy future within the next 15 years.

Here’s how researchers at the National Oceanic and Atmospheric Administration and a research institute at the University of Colorado think it could work (my emphasis added):

Our results show that when using future anticipated costs for wind and solar, carbon dioxide emissions from the U.S. electricity sector can be reduced by up to 80% relative to 1990 levels, without an increase in the levelized cost of electricity.

Article continues after advertisement

The reductions are possible with current technologies and without electrical storage. Wind and solar power increase their share of electricity production as the system grows to encompass large-scale weather patterns.

This reduction in carbon emissions is achieved by moving away from a regionally divided electricity sector to a national system enabled by high-voltage direct-current transmission.

As the utilities never tire of telling us, The Whole Problem with wind power (or solar) is that – repeat after me, class – it’s only useful when the wind is blowing (or the sun is shining).

Even then its usefulness is further limited, at least in theory, by demand. Because large-scale storage has proved to be such a vexing problem, it is assumed that any wind or solar power that can’t be consumed immediately must be discarded.

The new paper grew from a different assumption: Across an area as large as the United States, shouldn’t the wind be blowing somewhere (and/or the sun shining) at pretty much any given moment?

A research team led by Alexander MacDonald of NOAA’s Earth Systems Laboratory in Boulder, and Christopher T.M. Clack of the university’s Cooperative Institute for Research in Environmental Science (CIRES), gathered weather data and mapped it to very fine scales of space (13 kilometers) and time (hourly variation).

58% renewables without cost increase

They found that, indeed, wind or sunshine or both are blessing some portion of the country all the time, and in sufficient quantity to provide potentially 58 percent of national demand by 2030 without raising costs, under the likeliest market conditions.

MacDonald and Clack argue that the limiting factor for renewables’ contribution to U.S. energy needs isn’t how much wind and sunshine we have, or whether there’s enough demand for the volts the moment they’re made, or whether the excess can be stowed as compressed air, pumped water, hot sand, etc.

Rather, they say, it’s a problem of distributing renewable power from all of the places it could be made to all of the places it could be used.

Article continues after advertisement

Correcting that problem could instantly change the U.S. power system from its present shape, where utility-scale wind and solar essentially displace conventional power, to its exact opposite, in which boilers fired with coal, natural gas or nuclear fission could be used to buttress and balance a system driven mostly by the sun and wind. Which means a lot of conventional plants could be retired, and many of the rest dialed down dramatically.

And to put the greenhouse gas impact in perspective, an infrastructure change that delivered a 78 percent reduction in CO2 output from the electric power sector by 2030 would exceed by almost two and a half times the 32 percent reduction sought by President Obama’s Clean Power Plan – without raising the cost of electricity.

Or,  to be more precise, without raising the levelized cost of electricity, which is the best way to  look at these things, and the only fair way to compare the costs of electric power from different sources.

And you don’t need to be an economist or energy geek to get it.

Renewables’ cost advantage

Levelized cost is the number you get, typically in cents per kilowatt hour, if you add up all the costs to make electricity at, say, a coal-fired power plant – construction, coal purchases, payroll, maintenance, fines for violating air-quality standards, etc. – and then divide that total by the plant’s lifetime output.

When you consider the low construction and operating costs, and zero fuel costs, for wind and solar  installations, you can see how renewables gain their cost advantage over fossil-fuel plants that have much larger generating capacities  – and also why the falling prices for solar photovoltaic cells in particular are so transformational right now.

For this study, the researchers used the International Energy Agency’s assumption that the levelized cost of electricity to U.S. consumers in 2030 will be about 11.5 cents per kWh (in 2013 dollars), or about the same as it is right now.

To be sure, the upgraded grid would be a major project, likened by the authors to building of the Interstate Highway System, with a new network of high-voltage, direct-current distribution lines at its core.

I couldn’t find a clear figure in the paper for what the DC project would cost; these guys like to break it down into percentages, rates per gigawatt of generating capacity and so on.

Article continues after advertisement

However – and here’s the figure that really matters – they estimate that the improved grid would add a mere 4 percent to the total production and distribution costs.

Apart from avoiding the need to build a storage component that nobody can quite envision yet, the new grid would also provide major gains in efficiency and resilience over the current system of regional grids (think of the blackouts after Hurricane Sandy, or another 9/11 attack).

Water savings, too

And the shift to greater reliance on renewables would pay dividends beyond greenhouse-gas emissions. For example, it would reduce cooling-water consumption in the electric power sector by a startling 65 percent.  

It would take up some land, of course: perhaps seven-hundredths of 1 percent, they calculate, most of it well away from currently developed areas.

The paper has not yet attracted a lot of attention outside the trade and professional press, but Nature did publish a commentary by Mark Jacobson, a professor of civil and environmental engineering at Stanford, who wasn’t involved with the work but found it both novel and important.

In fact, he thought there were additional upsides:

One limitation of the study, which could be addressed with future research, is that it considers the electric power sector before the electrification of other energy sectors (transportation, heating/cooling and industry). Electrification of other sectors has already started, and may occur even more in the future.

Further, it assumes the excess electricity generated by wind and solar is discarded rather than used for some other purpose (for example, hydrogen production or district heating), thereby increasing overall costs slightly.

Which, if other electricity-consuming sectors continue to grow, need not be  the case.

Article continues after advertisement

* * *

I really wish Nature were making these papers available without charge, given their policy significance. If you’re willing to pay for access, however, you can find the MacDonald/Clack paper here, and the Jacobson commentary here. You can also see the authors explain their work in this short video.


MinnPost event: On Monday, Feb. 22, MinnPost’s Earth Journal Circle will present its fourth annual event focusing on substantive discussion of critical issues in the environment. This year’s topic is “Land of 10,000 Lakes: Can We Achieve Water Sustainability?” The speaker is Deborah Swackhamer, former director of the University of Minnesota’s Water Resources Center, who will discuss issues threatening regional water quality and quantity. Earth Journal writer Ron Meador will moderate the Q&A session.