How do we balance needs of energy, water, and climate?

Nov 15, 2013 by David L. Chandler

In deciding how best to meet the world's growing needs for energy, the answers depend crucially on how the question is framed. Looking for the most cost-effective path provides one set of answers; including the need to curtail greenhouse-gas emissions gives a different picture. Adding the need to address looming shortages of fresh water, it turns out, leads to a very different set of choices.

That's one conclusion of a new study led by Mort Webster, an associate professor of engineering systems at MIT, published in the journal Nature Climate Change. The study, he says, makes clear that it is crucial to examine these needs together before making decisions about investments in new energy infrastructure, where choices made today could continue to affect the and energy landscape for decades to come.

The intersection of these issues is particularly critical because of the strong contribution of the electricity-generation industry to overall greenhouse-gas emissions, and the strong dependence of most present-day generating systems on abundant supplies of water. Furthermore, while power plants are a strong contributor to , one expected result of that climate change is a significant change of rainfall patterns, likely leading to regional droughts and water shortages.

Surprisingly, Webster says, this nexus is a virtually unexplored area of research. "When we started this work," he says, "we assumed that the basic work had been done, and we were going to do something more sophisticated. But then we realized nobody had done the simple, dumb thing"—that is, looking at the fundamental question of whether assessing the three issues in tandem would produce the same set of decisions as looking at them in isolation.

The answer, they found, was a resounding no. "Would you build the same things, the same mix of technologies, to get low carbon emissions and to get low water use?" Webster asks. "No, you wouldn't."

In order to balance dwindling water resources against the growing need for electricity, a quite different set of choices would need to be made, he says—and some of those choices may require extensive research in areas that currently receive little attention, such as the development of power-plant cooling systems that use far less water, or none at all.

Even where the needed technologies do exist, decisions on which to use for electricity production are strongly affected by projections of future costs and regulations on carbon emissions, as well as future limits on water availability. For example, solar power is not currently cost-competitive with other sources of electricity in most locations—but when balanced against the need to reduce emissions and water consumption, it may end up as the best choice, he says.

"You need to use different cooling systems, and potentially more wind and solar energy, when you include water use than if the choice is just driven by alone," Webster says.

His study focused on electricity generation in the year 2050 under three different scenarios: purely cost-based choices; with a requirement for a 75 percent reduction in ; or with a combined requirement for emissions reduction and a 50 percent reduction in water use.

To deal with the large uncertainties in many projections, Webster and his co-authors used a mathematical simulation in which they tried 1,000 different possibilities for each of the three scenarios, varying each of the variables randomly within the projected range of uncertainty. Some conclusions showed up across hundreds of simulations, despite the uncertainties.

Based on cost alone, coal would generate about half of the electricity, whereas under the emissions-limited scenario that would drop to about one-fifth, and under the combined limitations, it would drop to essentially zero. While nuclear power would make up about 40 percent of the mix under the emissions-limited scenario, it plays almost no role at all in either the cost-alone or the emissions-plus-water scenarios.

"We're really targeting not just policymakers, but also the research community," Webster says. Researchers "have thought a lot about how do we develop these low-carbon technologies, but they've given much less thought to how to do so with low amounts of water," he says.

While there has been some study of the potential for air-cooling systems for power plants, so far no such plants have been built, and research on them has been limited, Webster says.

Now that they have completed this initial study, Webster and his team will look at more detailed scenarios about "how to get from here to there." While this study looked at the mix of technologies needed in 2050, in future research they will examine the steps needed along the way to reach that point.

"What should we be doing in the next 10 years?" he asks. "We have to look at the implications all together."

In addition to Webster, the work was carried out by graduate student Pearl Donohoo and recent graduate Bryan Pelmintier, of the MIT Engineering Systems Division. The work was supported by the National Science Foundation, the U.S. Department of Energy, and the Martin Family Foundation.

Explore further: New ideas needed to meet California's 2050 greenhouse gas targets, study reports

More information: Mort Webster, Pearl Donohoo, Bryan Palmintier. "Water–CO2 trade-offs in electricity generation planning." Nature Climate Change (2013) DOI: 10.1038/nclimate2032

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Eikka
1.9 / 5 (16) Nov 15, 2013
Simple answer: recirculate the cooling water to use less of it. Make a big loop of pipe and build farmland on top - grow more food well into the winter.

Although I disagree with the idea that the water is "used up" after it's been through a powerplant. It isn't. It doesn't dissapear anywhere, it isn't polluted - it's just warmer.

Scottingham
3.4 / 5 (5) Nov 15, 2013
I agree with Eikka. Perhaps better use of thermo-electric materials can pull more electricity out of the ejected cooling water.

I also like the idea of nuke plants by the sea desalinating water as well as using it for cooling. It helps to solve the fresh-water crisis. All that thermal energy should be used beyond just the electric turbine spinning.

Of course, now there's the question of what to do with all that extra salt!
Moebius
1.7 / 5 (16) Nov 15, 2013
"How do we balance needs of energy, water, and climate?"

One way NOT to do it is to continually grow a population that was straining the environment when it was half what it is now while we let economists BS us into believing we can support an even higher population. This from a group that is a proponent of economic theory based purely and solely on growth.
QuixoteJ
1.7 / 5 (16) Nov 15, 2013
[the article]including the need to curtail greenhouse-gas emissions
Doesn't Nature emit about 1000 times the greenhouse gases that our civilization does?
julianpenrod
1.3 / 5 (17) Nov 15, 2013
It never was a matter of "balancing needs of energy, water and climate". The issue at hand is not balancing needs, but doing so in a framework that includes vicious, craven corporatist thugs who insist on using things like deceit and bribery to literally fleece the public, even society as a whole. "Maximizing profit", meaning spending as little as possible while charging as much as the market will bear. "Cost effective" meaning engineering the market so they have to bear whatever usurious demands the corporatists make. Monopolization, isolating as much as possible the "means of production" only to themselves. Even fossil fuels and related technologies could be safe using conventional methods conventionally if the proper funds are put into them, and not robbed from the process by crooked corporatists for solid gold faucets on their 200 foot yachts.
julianpenrod
1.1 / 5 (16) Nov 15, 2013
It never was a matter of "balancing needs of energy, water and climate". The issue at hand is not balancing needs, but doing so in a framework that includes vicious, craven corporatist thugs who insist on using things like deceit and bribery to literally fleece the public, even society as a whole. "Maximizing profit", meaning spending as little as possible while charging as much as the market will bear. "Cost effective" meaning engineering the market so they have to bear whatever usurious demands the corporatists make. Monopolization, isolating as much as possible the "means of production" only to themselves. Even fossil fuels and related technologies could be safe using conventional methods conventionally if the proper funds are put into them, and not robbed from the process by crooked corporatists for solid gold faucets on their 200 foot yachts.
rocket77777
2.1 / 5 (16) Nov 15, 2013
Condom is cheapest and best way. Way I see it, religion is organized lies to collect money for few that live in luxury and they want more contributors.
RealScience
4 / 5 (3) Nov 15, 2013
@Quixote - 1000x is way off.

Nature currently emits a bit over 20 times as much carbon dioxide as humans, and also absorbs a bit over 20 times as much. On the balance nature actually is absorbing just a bit more than it emits (partly as a result of our emissions), thereby soaking up about half of what humans emit.

While the extra 5% that humans emit sounds small, especially when half of it gets soaked up, the excess builds up year after year. The atmosphere contains about 4 years of nature's emissions, so humans are increasing the atmospheric CO2 level by about 0.8% per year.

That may not sound like much, but it keeps on accumulating, year after year, and adds up to a 25% increase in 30 years at today's emission rates, and the emission rate is increasing.
ryggesogn2
1.6 / 5 (16) Nov 17, 2013
The demonstrated way not to balance such needs is with state central planning.
The only proven way is with market based economics where the values of energy, water and climate are addressed and accounted for.
Noumenon
2 / 5 (18) Nov 17, 2013
"How do we balance needs of energy, water, and climate?"

One way NOT to do it is to continually grow a population that was straining the environment when it was half what it is now while we let economists BS us into believing we can support an even higher population.


The naiveté mentality that is susceptible to being indoctrinated by far leftest propaganda, is the same naiveté fantasy-land mentality that is incapable of proposing solutions that have even a remote chance in hell of ever occurring.

It's similar to the half-wit expectation that individuals "should" voluntarily reduce their CO2 based energy use by operating counter to their own personal best interests, counter to their intrinsic nature of egoism.

It is why global coal and oil use continues to rise, despite all the AGW chess move 'studies'.
Noumenon
1.8 / 5 (15) Nov 17, 2013
.....

One way NOT to do it is to continually grow a population that was straining the environment when it was half what it is now


Can't you understand that for the same reason that the majority of AGW believers refuse to voluntarily reduce their standard of living, they also will not allow transition from freedom and market based nation to one that invokes social engineering to control every aspect of their lives?

we let economists BS us into believing we can support an even higher population. This from a group that is a proponent of economic theory based purely and solely on growth.


Who should NOT "let" those particular economists put forth their opinions? Who is to be the omnipotent arbiter to decide what economic theory should be the basis for not "letting" a counter analysis of facts?

antialias_physorg
3 / 5 (2) Nov 17, 2013
I also like the idea of nuke plants by the sea

The tsunami-scenario doesn't like that one. If you want nuclear you want it inland (however since you also want it near a river for the required water you are, by definition, siting it along ancient earthquake faults. I.e. in potentially unstable regions. So there's no optimal placement from a safety perspective fro nuclear powerplants in any case)

Doesn't Nature emit about 1000 times the greenhouse gases that our civilization does?

The issue isn't how much nature emits, since nature was in a balance. The emitted and absorbed stuff cancelled out. Humans emit EXTRA greenhouse gasses. We're adding stuff that doesn't get (fully) reabsorbed - so it accumulates.
ryggesogn2
1.3 / 5 (12) Nov 17, 2013
So there's no optimal placement from a safety perspective fro nuclear powerplants in any case

Depends upon reactor design.
so it accumulates.

So?
antialias_physorg
3 / 5 (2) Nov 18, 2013
Depends upon reactor design.
You need water for steam generation and running the turbines. That need does not go away - no matter what reactor design you choose (well, unless you use a thermoelectric conversion...but that means you'd need gigatonnes of nuclear material to replace even one of today's nuclear reactors)

so it accumulates.

So?

So? Really? You have to ask what happens if something accumulates? Let me spell it out: You have to put in resources to mitigate effects (more extreme weather events: floods, hurricanes, harsher winters, droughts,... ).

Since it accumulates it means you'll have to spend ever more of ever less available resources to mitigate the effects (cocaine effect). Until you have less resources available than you'd need to spend. Then it's game over for the human race.

That clear enough for you?
ryggesogn2
1.4 / 5 (10) Nov 18, 2013
You have to ask what happens if something accumulates?

Depends upon what that something is, no?
But what you meant was CO2 accumulation which has yet to demonstrate any harmful effects.
You need water for steam generation and running the turbines.

Which is recycled in the process.
antialias_physorg
3 / 5 (2) Nov 19, 2013
Which is recycled in the process.

Have you ever even seen a powerplant? Go to one sometime. You might learn something.