Water and Transportation Fuels

View my white paper on Sigma Xi regarding the water consumption required for various types of alternative fuels. See: http://www.sigmaxi.org//programs/issues/King.pdf. (also see below for full text of article if link).

In this white paper I refer to an article I wrote in Environmental Science and Technology on this same subject of the Water Intensity of Transportation. In this paper I calculate the "gallons of water per mile" that are embodied via consumption (meaning mostly evaporated) and withdrawal (taken from a water source and returned to the source) during farming, mining, processing, and refining of feedstocks into fuels.

Feedstocks studied are petroleum, coal, natural gas, sun, wind, biomass (corn and soy).
Fuels studied are ethanol, gasoline, diesel, biodiesel, electricity, hydrogen, and natural gas.


FULL SIGMA XI ARTICLE:
On the Water Consumption for Transportation Fuels
Carey W. King, Ph.D.
University of Texas at Austin
Center for International Energy and Environmental Policy

Driving light duty vehicles (LDV) on most alternative fuels and energy sources will
consume more water per mile driven than by driving on gasoline and diesel1. The
exceptions are using compressed natural gas with natural gas powered pumps, electricity
derived from non-thermal renewable electricity (e.g. solar PV and wind), and hydrogen
derived from either electrolysis of water using non-thermal renewable electricity or steam
methane reforming. To effectively plan for the environmental consequences of moving
from high energy density petroleum to lower quality fossil fuels and biomass, we must
not unduly distribute fuels with low energy return on investment. Water consumption is
just one environmental attribute for focus, but an important one from a quantity and
quality perspective.

In 2003 the average fuel efficiency of the U.S. LDV fleet was 20.5 mpg of gasoline.
These gasoline vehicles consume, via embodied water in mining and refining, 0.1-0.2
gallons of water per mile (gal H2O/mile). Using tar sands, coal, and oil shale converted to
liquids consumes 0.3-0.5 gal H2O/mile. If using electricity from the average U.S.
generation mix, driving a car using an electric motor from a battery consumes 0.2-0.3 gal
H2O/mile. If the grid electricity is used for electrolysis of water to create hydrogen, using
that hydrogen in a fuel cell vehicle results in consumption of 0.4-0.5 gal H2O/mile. Using
non-thermal renewable electricity for electric and fuel cell vehicles consumes less than
0.05 gal H2O/mile, and obtaining the hydrogen from steam methane reforming of natural
gas consumes just under 0.1 gal H2O/mile.

The other major category of potential LDV fuels is biofuels. If the biomass feedstock is
irrigated, using so-called “blue water” from aquifers and reservoirs, the water
consumption for corn-based ethanol (E85) and soy-based biodiesel is orders of magnitude
higher than other fuels with U.S. averages of 28 and 8 gal H2O/mile, respectively. Note
that only 10% of soy and 15-20% of corn bushels are irrigated in the U.S. However, some
highly irritating regions of the U.S. could embody over 100 gal H2O/mile by growing
irrigated corn converted to E85. Cellulosic-based irrigated grasses could result in 1-9 gal
H2O/mile of consumption. Without irrigation, fueling today’s fleet of LDVs using E85
ethanol and soy biodiesel would consume 0.1-0.4 gal H2O/mile, comparable to
unconventional fossil conversions.

For almost any product or application, but certainly for agriculture, the embodied water is
essentially transferred to drier regions. For instance, in providing food aid to developing
nations, the U.S. essentially becomes a net exporter of water – that is water embodied in
the exported food. If a given region does not have the climate, or irrigation water source,
1 King, C. W. and Webber M. E. Water Intensity of Transportation. Env. Sci. & Tech. Online
9/24/08 at: http://pubs.acs.org/cgi-bin/abstract.cgi/esthag/asap/abs/es800367m.html.
for growing a certain crop, importing that crop may be a good option. However, should
the irrigation water be drawn from a fossil aquifer, the same crop grown under a different
circumstance will not be sustainable in the long term and should be considered a fossil
fuel itself simply based upon its supply chain, or life cycle. The irrigation of biomass
represents the growing of that biomass in areas with insufficient rainfall. This
relationship itself does not necessarily imply a lack of sustainability. For instance,
diverting nearby river water into a reservoir can create a stable supply source that can
withstand the normal climactic variations in rainfall.

The embodied water concept for agriculture can also be applied to biofuels but with
additional focus upon thermodynamics and energy return on investment (EROI). Many
regions may import some sugar cane-based ethanol from Brazil, yet don’t have the
climate to grow the sugar cane. Because of the relatively high EROI of cane ethanol over
corn ethanol, international shipping can make sense. Thus, the history, or supply chain, of
the biofuel is important, not just its final properties. The supply chain of fossil fuels will
also become more important over time as lesser quality resources are extracted. There
was no need to pay attention to EROI from the early coal beds and oil wells because they
so clearly allowed increased lifestyle and leisure relative to the world before the
industrial revolution.

In the concept of moving to non-petroleum fuel sources, the Renewables Fuels Standard
(RFS) of the Energy Independence and Security Act (EISA) of 2007 has been both good
and bad from a policy perspective:

Bad in the sense that the RFS initially pushes a feedstock-fuel combination, corn
ethanol, that has detrimental environmental consequence in terms of nutrient runoff
and low EROI. But, the consequences of runoff can be minimized by not overfertilizing,
more widespread use of better tilling practices, and buffer strips next to
major rivers.

Good in the sense that the RFS has pushed forward the scrutiny of how we use energy
resources, biomass included, and focused much attention on how we can create better
biomass to fuel conversions. It has also raised worldwide awareness on the ethics of
how agricultural land should be used: food, fuel, or both?

Today, the struggle for new fuel supplies is clouded because it is not obvious what
options best provide for increased or even continued levels of lifestyle and leisure. What
is more obvious is that there are geographic regions that can sustainably grow certain
kinds of biomass that other regions simply cannot. Unconventional fossil resources such
as tar sands and oil shale have lower EROI and higher water consumption needs than
conventional petroleum. The need for more water in industrial fuel systems is an
indicator of moving to lower energy efficient sources.

Lawmakers creating future policy regarding agriculture and energy need to be cognizant
that the tie between energy and water will only increase into the future. Generally, energy
sources with lower energy density tend to require more water for mining, farming,
refining, and processing. Certainly an increase in vehicle fuel efficiency decreases the
“gallons of water per mile” traveled, but in then end, fresh water sustainability is
measured on only one “per” basis: “gallons of water per Earth”.

Water and Energy Nexus: Nature Geoscience May edition

I have recently written a commentary for Nature Geoscience in which I and my co-authors discuss the tie between energy and water usage. For those who have a subscription to Nature, you can link to the article here. Alternatively, you can sign up for free and read the article OR just read my pasted text below:

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TEXT OF ARTICLE
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Water and solar energy enable trees and plants to grow today, just as hundreds of millions of years ago. Creation of the deposits of biomass that became fossil fuels depended on these two resources. The technological advances that have changed human life profoundly over the past decades and centuries have altered, but not resolved, this close coupling between water and energy. Current technologies for power generation, with some exceptions such as wind turbines and photovoltaic solar cells, rely heavily on the availability of large amounts of water. Primarily this water is needed for cooling thermoelectric plants and supplying fluid pressure and flow for hydroelectric power generation. But in a changing climate, it is not clear whether sufficient volumes of water will continue to be available where needed. And if, in an attempt to combat climate change, petrol is replaced by biofuels at a significant scale, more water will be needed for irrigation. Furthermore, clean fresh water is a basic necessity for human health and development. Large quantities of water can be provided — as long as sufficient energy supplies are available to reach deep aquifers, treat dirty water or desalinate the oceans. But a scarcity of energy implies a scarcity of water, just as constraints on water availability threaten the supply of energy, at least with the current infrastructure. Because of this interconnection (Fig. 1), water and energy cannot be treated in a disaggregated fashion, as is common today with both

markets and policy makers.

THE NEED FOR WATER IN POWER GENERATION

Large power plants present a strain on water resources. In the US in 2007, thermoelectric power generation, primarily comprising coal, natural gas and nuclear fuels, generated 91% (3,500 million MW h) of total electricity. These thermoelectric power plants require cooling by water, air or a combination of the two (Table 1), amounting to 40% of US freshwater withdrawals. Open-loop (or once-through) cooling withdraws large volumes of surface water, fresh and saline, for one-time use and returns nearly all the water to the source with little of the overall water being consumed by evaporation. While open-loop cooling is energy efficient and low in infrastructure and operational costs, the discharged water is warmer than ambient water, causing thermal pollution, which can kill fish and harm aquatic ecosystems. Thus, environmental agencies regulate discharge temperatures, taking into account a water body’s heat dissipation capacity. Closed-loop cooling requires less water withdrawal because the water is recirculated through use of cooling towers or evaporation ponds. However, because the cooling is essentially achieved through evaporation, closed-loop cooling results in higher water consumption (Table 1). The alternative, air-cooling, does not require water, but instead cools by using fans to blow air over a radiator similar to that in automobiles. The power efficiency of this is lower, up-front capital costs are higher and real-estate requirements are larger, making it a less attractive option economically.

Water is obviously central to power generation in hydroelectric dams. In the US in 2006, hydroelectric power plants generated approximately 7% (268 million MW h) of total electricity. Fifty-eight percent of US hydroelectricity is generated in California, Oregon and Washington alone, making the power supply vulnerable to regional changes in water availability. Though hydroelectric power is attractive for many reasons, it is least reliable during droughts when the need for water may take precedence over hydroelectricity.

THE NEED FOR ENERGY IN WATER PRODUCTION

The relationship goes the other way too, in that energy is necessary for producing and delivering fresh and potable water, just as water is necessary for generating energy. For example, energy is needed to convey, heat and treat fresh water and waste water. Heating water in homes and businesses for cooking, cleaning and other municipal and commercial uses consumes 3.6 quads, or 3.6%, of total US energy consumption. Thus, the need for hot water represents an important enduse for energy. Combined heat and power systems are efficient because they use otherwise wasted heat to do useful tasks.

Supply and conveyance of water is one of the most energy-intensive water processes, estimated to consume over 3% of total US electricity1,6. However, the energy use for supply and conveyance of water varies widely depending on the local infrastructure. Many gravity-fed systems require little energy, whereas long-haul systems, such as that in California, require vast energy investments to move water across the state and over mountain ranges. The average surface water treatment plant consumes over 370 kW h Ml–1. Tapping into groundwater sources also requires energy for pumping, which is dependent on aquifer depth: at a depth of 120 m, 530 kW h Ml–1 is required1,6.

Recent news articles illustrate these competition between water resources and power generation: the debate of whether to use water from a reservoir to serve municipal needs for drinking water versus generating hydroelectric power arose with Uruguay’s Salto Grande dam and the US Colorado River lakes; a natural gas power plant and private landowners argued over groundwater rights in Texas; and hydroelectric dams were taken offline in response to drought in Georgia, among others2–5.

As freshwater supplies become strained, many have turned to water sources once considered unusable, including brackish ground water and sea water. Although use of these water sources mitigates constraints on drinking-water supplies, treatment of brackish ground water and sea water requires as much as 10–12 times the energy use of standard drinking-water treatment. However, usually, untreated saline water can be used to cool the thermoelectric power plant that may be required for desalination.

Partly because of the high energy requirements, proposed desalination water treatment plants in Carlsbad, California, and Chennai, Tamil Nadu India have been opposed7,8.

Wastewater treatment also requires large amounts of energy, which will increase as discharge regulations in the US become stricter, requiring increasingly energy-intensive treatment technologies.

Estimates range from 250 kW h Ml–1 for trickling filter treatment, which uses a biologically active substrate for aerobic treatment, to 350 kW h Ml–1 for diff used aeration as part of activated sludge processing, and 400–500 kW h Ml–1 for advanced wastewater treatment that uses filtration and the option of nitrification6. Sludge treatment and processing alone can consume energy in the range of 30–80% of the total energy used in a wastewater plant; other physical and chemical treatment processes use much of the remaining percentage.

A THIRST FOR TRANSPORTATION FUELS

Two of the earliest fuels were wood and dung. They are still the major primary energy fuels for many regions of the world, providing 8.5% of the primary energy globally10. Trees require water for growth, as do the animals that supply dung. But modern liquid fuels such as gasoline, ethanol and diesel also require water for their extraction, farming, processing and refining. This ‘embodied water’ is not directly used in a vehicle, but rather indirectly required to make the fuel.

Water use for transportation can be considered in a similar fashion as for power generation in the form of withdrawal — that is, the amount of water that is necessary, but may eventually be returned to the system — and consumption, for example, through evaporation. However, in the context of transportation, consumption can additionally be associated with irrigated farming and as a feedstock. Generally, while driving light duty vehicles using current petroleum-based gasoline (assuming an average fuel economy of 20.5 miles per gallon (mpg) = 8.7 km l–1) and diesel (28.2 mpg = 12.0 km l–1), embodied water is withdrawn and consumed from nature at rates of up to 1.5 l km–1 and 0.3 l km–1, respectively.

Using liquids converted from other fossil fuels (coal, oil shale and tar sands) means that the rates of water consumption and withdrawal are 2–4 times and 1–2 times higher, respectively, and they are much more concentrated in regions where the fossil fuel resources exist.

Propelling vehicles using hydrogen and electricity also has substantial water impacts when drawing from the average US electric grid (owing to water used for power plant cooling as discussed earlier). Under these assumptions, driving ‘electric’ miles using a fuel-cell vehicle with hydrogen via electrolysis and a plug-in hybrid electric vehicle (PHEV) or electric vehicle (EV) consumes water at 0.9 and 0.5 l km–1 while withdrawing 27 and 17 l km–1, respectively11,12. Using wind and photovoltaic solar power to supply required electricity for transportation makes water intensity negligible. However, even if every US light duty vehicle mile were driven via US electric power with current technologies, US water demand would only increase by 0.9% (3.4 billion litres per day). Most of the fuels under consideration to replace petroleum are more water intensive, with biofuels residing at the top of the list. Only for fuel crops that are not irrigated is the water intensity comparable to petroleum fuels. But many fuel crops are irrigated, and accounting for irrigation can cause water consumption rates to be 2–3 orders of magnitude higher than without irrigation. Although only 15–20% of US corn and 5–10% of US soybean bushels are irrigated to any degree, there was still a substantial water contribution to biofuel crop farming at nearly 5,700 gigalitres (3.5% of US water consumption) in 2005 for the production of ethanol alone. Given that agricultural irrigation is the most water-consumptive sector of the US economy, high water usage is not surprising. But by switching to biofuels, this water consumption is likely to grow.

Additionally, competing water demands oft en make the siting of ethanol plants difficult because they require large amounts of water. Ethanol processing plants consume water for cooling processes, including the exothermic fermentation reaction, requiring 1–3 million litres per day to produce 250,000–750,000 litres per day of ethanol13,14.

LOOKING TO THE FUTURE

We see trends towards more water- intensive liquid fuels, more energy-intensive water sources and a growing population that will require more of both. These challenges will be exacerbated by climate change, which may cause geographic and temporal changes in the amount, annual distribution and form of precipitation (for example, as rain or snow). Because cities and their infrastructure are built on the basis of past precipitation patterns, such climatic changes may require substantial adjustments. In regions where water becomes scarcer, people must weigh the pros and cons between moving the people to the water and moving the water to the people (the latter of which requires continuous additional energy).

Regional climate projections will be needed to inform planning and policy. When siting new power plants, governments and power generators need to consider water availability over the plants’ lifetimes, normally on the order of several decades. Policy for energy and water resources should be integrated to consider less-water-intensive options in agriculture, such as forestry, and in electricity generation, such as wind, photovoltaic solar and air-cooling technologies. In the fuel sector, water consumption and withdrawal need to be included in environmental impact analyses such as those dictated by the Energy Independence and Security Act of 2007, which requires life-cycle analysis for understanding the greenhouse-gas impacts of renewable fuels. Like diversified long-term financial investment strategies, future water and energy infrastructure should also be diverse and multiscaled in order to create resilience in an uncertain climate and energy future. For example, Ghana has had highly fluctuating reliability of electricity supply owing to heavy dependence upon hydropower or other single energy sources, without extensive electric grids to help transport electricity in tough times.

Distributed energy systems provide smaller-scale systems and add resilience to electric grids dominated by large centralized power plants, but they are usually considered more expensive owing to conventional financial and appraisal systems that account for capital but not operating expenses. For new power plants at greenfield sites in the US, open-loop cooling has been outlawed for all practical purposes by the environmental constraints on water intake velocity. The trend since the 1980s has been towards closed-loop cooling. However, closed-loop cooling makes the use of sea water more difficult, because evaporating water with high proportions of dissolved solids can create foul-up problems. Nevertheless using sea water, waste water and other low quality water for cooling should be encouraged where possible.

We also need policy that allows the operating costs and energy consumption of buildings and homes to be integrated into the construction, sales and finance phases of development. More energy efficient buildings within larger cities require less bulk city services. We must ask ourselves why we require no energy return on investment for crown moulding yet claim photovoltaics do not pay back fast enough. Fortunately sustainable concepts such as LEED (Leadership in Energy and Environmental Design) and projects such as the China EcoBlock18 guide and demonstrate integrated water and energy infrastructure via whole system design.

Water and energy cannot be separated. With an unlimited supply of available energy, we would be able to supply as much clean water as the world needs. In the real world of resource constraints, we need to simultaneously conserve water and energy. Thankfully, water conservation and energy conservation are synonymous with each other, so we have the opportunity for swift progress.

PHEV/EVs and water - Finally a good article

It seems that the first paper (regarding water for electric vs. gasoline miles) on our work on the "water intensity of transportation" has gotten quite a bit of attention in the media. I've reported on this already, but included here is finally a good and responsible article that properly demonstrates the scope of the issue.

For an example of an article that does a good job, see the following:

ScienceNOW published this article - online today (3/10/08)

Bottom line (I repeat), electric and plug-in hybrid electric vehicles will use more water because people will charge their cars from the general electric grid. This grid is dominated by thermoelectric power plants (coal, natural gas, and nuclear), and these plants consume and withdraw water as part of cooling. To lessen the water impact, we can focus on (1) generating electricity in thermoelectric plants using technology that consumes and withdraws less water and (2) using electricity from sources that don't consume and withdraw water (wind, PV solar).


For examples of articles that do a poor job, see any of the following:

Popular Mechanics

- The quote below is very misleading and incorrect. The water intensity, or gallons/mile, for withdrawal is 17 times greater. This is not a 17-fold increase in water demand, even if all light duty vehicles (cars, trucks, SUVs) ran on full electric power, because water is withdrawn for many other purposes AND if all miles (2.7 trillion) in 2005 were driven on electricity, that would amount to about 900 billion kWh, when the entire nation generated 3,883 billion kWh without any measurable amount of PHEV/EVs. Thus, all light duty vehicle travel by electric miles would be only 23% more electricity (and associated consumption and withdrawal), NOT 17 times more. See misleading quote from article:

"Though most of this water is returned to the source (albeit at a higher temperature), a 17-fold increase in demand would pose a real problem for water-stressed regions, making power plants more vulnerable to shut down during times of drought. "

New Scientist

Chemistry World

- The following quote is completely incorrect. The nation's water consumption (which includes that for irrigation, municipal use, mining, and thermoelectric generation) will NOT triple if we switch to PHEV/EVs. See above comment on the Popular Mechanics article, same argument goes for not tripling nation's water consumption with all electric light duty vehicle travel. See misleading quote from article:

"Michael Webber and Carey King, from the University of Texas at Austin, suggest that powering America's cars with electricity, rather than gasoline (petrol), could triple the nation's water consumption."


Have a good day.

Another article about my PHEV/EV and water usage - unneccesarily alarmist

Another article, this time in New Scientist, has been written about my paper on "water of the plugged-in automotive economy". See a recent post on water used while driving on electric miles for my basic take on how to interpret the analysis.

Phil McKenna, the journalist and writer of the article, chose the title " 'Thirsty' electric cars threaten water resources". This is an unfortunately alarmist title. The article prompted some to blog on the New Scientist page that I was against plug-in hybrid electric vehicles (PHEV) or electric vehicles (EV). This is certainly not true. Some suggested I must be paid or work for some petroleum or natural gas company. This is also certainly not true.

I gave Phil information to present the scope and scale of electric driving upon the electricity grid and water resources, but he didn't mention this.

For example:
1 million PHEV40s (PHEVs that have a 40 mile range) would drive about 7.3 billion miles per year. This is about 0.3% of miles driven by light duty vehicles.

The resulting water consumption is 1.7 billion gallons, or ONLY 0.13% of water consumption already associated with power generation.

The resulting water withdrawal is 76 billion gallons, or ONLY 0.11% of water withdrawal already associated with power generation.


I, and my coauthor, chose to independently look at link between energy and water. This work is a first foray into this area, and we have also analyzed other fuels (biofuels, hydrogen, coal to liquids, etc.) that is in the review process for publishing.


So ... NO ALARM. We have time to plan for 10s of millions of PHEVs, let's get them on the road!

Hold back the flow ... of false claims on water for transportation

This past week my colleague Michael Webber presented some preliminary results (currently under review for publication at Environmental Science and Technology) at the 2008 annual meeting of the American Association for the Advancement of Science. A journalist from the Toronto Star reported about the results of our work. And Gordon Quaiattini, the president of the Canadian Renewable Fuels Association (CRFA), put in his 2 Canadian cents worth of comment to the Star editor.

First, our work on this is under review so I won't comment too much on the methodology until it is accepted and published, but I can clarify some aspects of the table in the Toronto Star article as well as the comment by Mr. Quaiattini.

As far as Mr. Quaiattini is concerned, let me assure him that neither me nor Michael are against biofuels. What we are for is understanding the impacts of all fuels. That is why we presented information that compares a variety of fuels, and future work can focus on additional biofuels and alternative fuels.

Mr. Quaiattini claims that 85% of U.S. corn is non-irrigated. This is fairly consistent value as in 1998 we show approximately 1.9 billion bushels irrigated (see http://www.nass.usda.gov/census/census97/fris/fris.htm Table 22) out of about 9.8 billion bushels of US corn grain (see http://www.nass.usda.gov/ and select 'US corn grain' stats for 1998 in the pull down menu) - this gives 15.6% irrigated. He also states the numbers of 3 gallons of water to process the corn into a gallon of ethanol, and this is at the lower end of the range of values we used.

The data presented in the aside in the Star article lists ethanol water 'use' (note in this case consumption and withdrawal are roughly equivalent) as 40-130 gallons per mile driven on E85. This is close, but not quite accurate as noted. We calculate 12-136 gallons per mile driven on E85 derived from irrigated corn in the U.S. The range exists because not all regions that grow corn need the same amount of irrigation. Obviously some regions get more rain than others. We have made no claim (yet!) on the total water consumed and withdrawn for travel in light duty vehicles in the US.

NOTE: when considering ethanol derived from non-irrigated corn, the values for consumption and withdrawal are less than 0.5 gallons/mile. This shows you that the vast majority of the water of concern is for irrigation.

IMPORTANT:
Does this mean we should not use biofuels? ABSOLUTELY NOT!!!

What it does mean is that we need to understand the limits of our water resources while considering the tradeoffs that that the "biofuels vs. fossil fuels" debate entails. Fossil fuels are essentially really old biomass as nature has done a lot of work for us in growing the plants and storing them in the ground (over 100s of millions of years) for us to now use. Biofuels are essentially really young fossil fuels.

When planning for growing crops either for food or fuel, we need to use both the land and water resources responsibly. I applaud the efforts of the Canadian Renewable Fuels Association and other similar organizations that are helping promote alternatives to fossil fuels for transportation or stationary applications. I believe we can avoid a water conundrum, and our work is providing information to help society do just that.

Water for Transportation - publication on "electric miles"

A paper of mine has been published online today in the journal Environmental Science and Technology. The paper describes how much water is used, that means consumed and withdrawn (which are two different concepts) for driving a vehicle on electricity as "fuel". This pertains to electric vehicles (EV) or plug-in hybrid electric vehicles (PHEV) while they travel on battery power alone.

First, two basic definitions:

water withdrawal is that water which is taken from a source, run through a process, and returned to the source or some other source.

water consumption is water that is withdrawn but not returned to the source due to evaporation (for example - in cooling processes for steam power plants) or evapotranspiration (evaporation from through plants).

Due to water consumed and withdrawn for cooling steam electric power plants (coal, nuclear, geothermal, solar concentrated power, and most natural gas), we can associate that water usage with the electricity generated from the plant. Assuming that an EV or PHEV is charged with electricity from the generic U.S. grid, each mile driven by a average light duty vehicle (a car, pickup truck, or SUV) will consume 0.2-0.3 gallons of water and withdraw 8 gallons of water. This is approximately 2-3X more water consumption and 12X more water withdrawal than when driving a light duty vehicle on petroleum gasoline.

Does this mean we should not pursue EV and PHEV technology? ABSOLUTELY NOT.

There are many benefits to the integration of EV/PHEV vehicles which include the ability to use a diversity of fuels sources - anything that can end up generating electricity (burning stuff to produce steam, nuclear power, wind power, photovoltaic solar, etc.). The ability to use a variety of transportation fuels by way of the electric grid is very powerful and important.

While the water consumption and withdrawal is higher than using petroleum gasoline, we can easily plan and accommodate for the increase in water usage per mile. The use of EV/PHEVs will occur gradually, and water resources will not be the limiting factor for their adoption. Full speed ahead for electric cars.