Water — Is There Enough for Biofuels?

Fri, 09/10/2010 - 6:42am
JIM LANE, Editor & Publisher, Biofuels Digest


By JIM LANE, Editor & Publisher, Biofuels Digest

Researchers publishing last year in AMBIO: A Journal of the Human Environment proposed that energy production systems be measured not only in terms of energy return on energy investment (EROEI), but energy return on water invested (EROWI).

The researchers noted in Burning Water: “Water withdrawals are ubiquitous in most energy production technologies … several assessments suggest that up to two-thirds of the global population could experience water scarcity by 2050 … human demand for water will greatly outstrip any climate-induced quantity gains in freshwater availability … and [freshwater availability] will be driven by the agricultural demand for water, which is currently responsible for 90 percent of global freshwater consumption”

The researchers found that fossil-based fuels have “one to two orders of magnitude” less water intensity than “the most water-efficient biomass technologies,” and suggest that water security may well be a limiting factor in the production of biofuels.

In a note at, a trio of authors contend: “There simply is not enough freshwater on the face of the earth to make the production of biofuels a viable and significant alternative to the mining and usage of fossil fuels.”

Is Water Really a Limiting Factor?

It has been suggested by experts in the field, I think, among the earliest by American Biofuels Council founder Sean O’Hanlon, that the ultimate limiting factor in biofuels production will be the availability of water.

It is also a fair expectation that biofuels’ critics will begin to focus on water, and water availability, as an argument against the development of bioenergy facilities. There will be three lines of argument, familiar to those who followed the development of the food vs. fuel debacle: first, that there simply isn’t enough water; second, that water (if available and abundant) should be prioritized for human consumption and for food production; third, that intense water usage on a scale necessary for biofuels production represents an unsustainable intrusive impact on the environment.

The developers of biofuels have routinely pointed to the comparative improvements in water intensity in biofuels production, and for sure, the use of water in bioprocessing has come down drastically to a few gallons of water per gallon of fuel, comparative or better than the production of fossil fuels, and in many cases, far better than the profligate use of water by many well-established industries.

How Much Water Is There? What Do We Use It For?

But the debate does not revolve around the usage of water for bioprocessing. It is about the use for agriculture. It takes 3,000 gallons of water to grow a bushel of corn at a 200-bushel-per-acre yield, researchers say. That’s about 1,000 gallons of water for a gallon of fuel. That’s what drives people crazy.

Let’s put this in context, using corn as a (simplified) proxy. If we were to replace the U.S. fuel supply entirely with irrigation- and corn-based fuels, we would require 300 trillion gallons of water — that’s about twice what the U.S. draws down as a whole each year.

Overall, the U.S. draws roughly 350 billion gallons of freshwater per day, or about 1,100 gallons per person per day, and another 60 billion gallons of saline water per day.

What drives the corn lobby crazy is that a lot of that water simply falls from the sky: Irrigation is almost unheard of in the heart of Iowa corn country. Let’s put this into another context. According to a recent History Channel documentary, Hurricane Katrina carried 425 trillion gallons of water. Let’s put this into another context: the Renewable Fuel Standard for corn ethanol requires about 150 billion gallons of water, less than the U.S. as a whole uses in a half-day. That’s assuming all the land is irrigated, which it isn’t. And that’s a small water investment for the gain in energy security, say many.

Where does all this water go — these 350 billion gallons per day? Irrigation indeed takes a huge chunk — 128 billion gallons per day, or 37 percent of all water use, with 60 million acres receiving irrigated water as of 2005.

But the big use is not for agriculture or personal use. It is for electric power generation — that’s 41 percent of the total, or 143 billon gallons per day, and a total of 201 billion gallons per day including the use of saline water. It’s used for cooling.

Irrigated or Non-Irrigated Water

When we look at water usage for agriculture, we must carefully separate out crop production that uses rainfall, and production that uses stable aquifers, and production that depends on unstable aquifers.

Saline, Brackish or Fresh?

The use of saline or brackish water is a critical factor. While water usage must be monitored for any use — water is, in the end, water – there is far less chatter about saline water shortages, or the use of brackish, than fresh water.

What uses brackish water or saline? Algae, for one. Joule Unlimited’s Solar Converter system, for another.

Comparable Alternatives

The availability of alternatives is a critical factor in evaluating the use of water. As we have said many times in the Digest: Let there be no doubt about it, there is no civilization without energy systems. For many parts of the world, there isn’t even any food. What do we mean by that? We mean that rice isn’t eaten raw, it is boiled to make it edible. Cassava, the staple crop of Africa, forms cyanide in the human digestive tract unless it is boiled intensively prior to consumption. That power for cooking, for lights, for transport, for communications, for industry, has to come from somewhere.

Fuel cannot be looked at in a vacuum, but in comparison to reasonable alternatives. For example, as we have seen above, abandoning biofueled cars for plug-in electrics does not necessarily reduce water intensity. In our current mode, it increases it, by increasing the load on our water-intensive power generation system.

Four Principles for Sustainable Water Use

1.) Restrictions and guidelines on biofuels, based on availability of water, must be based on local availability. It is ridiculous to forbid the establishment of biofuels production in areas, for example, with sufficient rainfall to support bioenergy. But it is sensible to look carefully at the viability of a biofuels system dependent on freshwater irrigation, within the context of overall water availability, alternative sources, stable aquifers and community development goals.

2.) Where water is not abundant, fuel production systems should be weighted according to water availability factors: Some value should be added to projects that do not create an intermediate biomass or are highly efficient in doing so. The next priority should be those systems that use saline water. The next priority: brackish water. The next priority: the use of biomass with low comparative water needs. The next priority: the use of non-irrigated land.

3.) For water to become an effective criterion, water regulation and law must itself change to provide the stability from which effective resource planning can flow.

Though it is not well-known, U.S. law (and state law) regarding the regulation of water is a patchwork of riparian and pueblo water rights, places where water is most precious, such as in the parched U.S. Southwest, there is a tangled web of law erected by states, the federal government and local communities — not to mention the carry-through of rights from the Treaty of Guadeloupe Hidalgo that settled the Mexican-American War.

There are international issues, too: “Under a 1944 treaty, Mexico is supposed to send about 350,000 acre-feet water annually into the Rio Grande … But since 1992, Mexico has fallen more than 1.5 million acre-feet of water in arrears.”

4.) Where communities consume more energy than they (locally) produce, they are depending on other regions to deplete their water resources to generate power, fuel or other forms of energy for transmission. This is NIMBY at its worst — water depletion is OK, as long as it is happening in your backyard — leave my lawn and sprinklers alone. If water is to be ultimately regulated to ensure sustainability, communities must look to cap-and-trade systems or other mechanisms that create costs for unsustainable practices. Right now, the limiting factor in water is the cost of pumping it and the ability of regimes to resist the temptation to over-mine their resources.

The SIMBY Factor — a Solution in my Backyard

If water usage is to be considered at all — except in the ways it is already considered, i.e. can I afford it and can I get enough ­— a community-level system is essential. The worst solution in the world is simply to ban a good solution because it is not perfect, and entice energy suppliers to go to the developing world to procure energy on despoiling terms.

It is an interlinked world we live in — ravaging the South for cheap, extra-legal sources of energy for the North is a driver of global instability of which the environmental lobby had better take notice. It is pointless to address climate change in Europe and America without addressing the legitimate aspirations of Asians, Africans and Latin Americans for a better life.

SIMBY — or a solution in my backyard — is no solution at all. Even the Garden of Eden was wiped away by the flood.

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