Tuesday, December 9, 2008

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.

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”.

Saturday, August 16, 2008

Pop Culture now involved in Energy is Good!

Many people have seen the Paris Hilton advertisement regarding "her" energy plan that is a compromise between the mainstream competing plans by the presidential candidates McCain and Obama. She was responding to the John McCain advertisement that compares Obama to celebrities such as Hilton and Britney Spears.

In reality, both candidates have fairly comprehensive energy plans because it doesn't make any sense not to. Drilling offshore is already done in the western Gulf of Mexico and everyone knows we need to bring on alternatives and some conservation through concepts such the as CAFE standards that are already going to increase.

So we can thank John McCain for luring in the popular culture of the US into the political and energy discussion. Now more people are involved. Great job Senator! He reached out of the aisle this time.

Thursday, July 24, 2008

Ethics: Allocation factors for renewable energy systems

I recently wrote for Worldchanging about how allocation factors can possibly be representative of our ethics. Allocation factors are the fraction of the energy input into a renewable system, usually for analyzing biofuels, that is associated (or allocated) to each of the products.

For example, the main product from corn ethanol is the ethanol, and coproducts are distillers grains for cattle feed. Because these allocation factors can be based upon the energy, mass, or economic content of the coproducts, different analyses of the same process results in different outcomes in terms of the sustainability or renewability of the process. One of the major issues is that what is economically most attractive is often not the most energetically efficient. A possible policy goal could be to guide these two concepts together.

Click allocations factors and ethics to go to Worldchanging website for the article, or read text below:


Moving toward a sustainable, or renewable energy-based economy, stresses the views of how people value their time and exertion. Our system of economics puts value on products and services that allow people to spend less time and/or exertion while performing a task. This value system is exactly why fossil fuels have been the driving factor for increases in accumulation of material goods and leisure time over the course of the industrial revolution.

Historically, fossil fuels have had such high energy density (and energy return on that invested to mine them) that we haven't worried too much about how to allocate the energy invested. When a barrel of oil is refined or a cubic foot of natural gas is burned, it has been obvious that we can produce more products and spend more time in leisure or progressive work. It is because of the concerns of fossil resource scarcity together with environmental effects (air pollution, greenhouse gases and climate change, etc.) that alternatives to fossil resources are sought.

By contrast, when it comes to renewable energy products, particularly biofuels, we've applied intense scrutiny to figuring out the energy return on total energy (or fossil energy) invested because the returns are not as easily determined as being sufficiently greater than one. Part of this scrutiny is because of the inherently lower energy density of carbohydrates (i.e. biomass) versus hydrocarbons (i.e. fossil fuels). Another part of the scrutiny derives from the knowledge that fossil fuels currently permeate the vast majority of the manufacturing and agricultural practices of the industrialized world, and understanding the optimal manner in which to deal with their reduced presence, and possible absence, is not obvious.

Allocation factors are an example of the struggle of society to understand the value of output of renewable energy systems and processes. The allocation factor is a term used to describe how much of the total energy input to a renewable energy system should be “allocated” to, or associated with, both the primary product output (e.g. ethanol, biodiesel, biocrude, etc.) as well as any process coproducts. These allocation factors are also used to assign greenhouse gas quantities to compare competing energy systems. Renewable energy systems that output electricity, such as photovoltaic solar panels and wind turbines, are fairly straightforward in giving an allocation factor of one. That is to say, all of the energy and material inputs that go into manufacturing, operation, and maintenance of the system are used to produce the only output: energy in the form of electricity. There is no product other than the electricity.

Assigning an allocation factor for biofuel production is more difficult. Biofuels originate from some form of biomass (e.g. corn, soybeans, cellulose, etc.) that can be used for multiple purposes (e.g. food and fuel) and the extracting them creates output products besides the fuel itself, termed coproducts. For example, in the typical processing of biodiesel from soybeans, the major outputs are the primary product of biodiesel plus the coproducts of soy meal and glycerin [1]. Fossil fuels have similar product/coproduct distinctions (e.g. natural gas for fertilizers and petroleum for plastics), but because we know there is no long term sustainable use of them, there has been no need to scrutinize how we derive their various products.

So a question arises: for every unit of energy input from field to fuel, how much of that input should be responsible for each product? To answer this question, there are multiple proposed allocation concepts. The different allocation methods for coproducts are three non-energy methods and three energy-based methods [2] that are designated by whether the energy consumption of the processes is allocated according to:

Non-Energy Methods
• the 100% principle such that all energy consumed is allocated to the primary product (e.g. biofuel).
• the mass fraction of each of the products,
• the economic market value of each of the products,

Energy-based Methods
• the energy content (calorific value) of each of the products,
• the energy displaced by each of the products with respect to an existing or customary way of producing the product, or

100% Principle
Allocating 100% of energy inputs to renewable energy systems is the most simplistic and uninformative. There are no decisions to be made, and it removes the capacity for society to learn how to use all available resources and technologies while reusing and recycling as much as possible. On the other hand, its simplicity easily allows policymakers and consumers to understand the impacts and benefits of renewable systems. Essentially, the 100% principle is the extreme case that assumes no useful coproducts are possible, or that coproducts are free in terms of monetary or energy input.

Mass Fraction
Allocating by mass fraction is very straightforward and easy to understand. Techniques that minimize coproducts should be viewed as positive since otherwise, they would not be coproducts but instead the primary product. We can likely assume the primary product is the most market viable, at least at the time the renewable energy project is begun.

Market Value
Using market value to allocate coproducts is the method most akin to the free market principles. Brazil’s past and continued focus upon sugar cane as a cash crop theoretically enables their companies to decide how much sugar versus ethanol to produce from the same crop. If one price is up, they can focus on that product versus the other. Currently, the ethanol price is up as a group of Brazilian companies has arranged the first “practical application of verified sustainable ethanol” trade with Sweden [3]. Thus, a market value of coproducts potentially allows a producer to tune his process according to the rather short time scales of commodity fluctuations. The main drawback of this method is that market prices change, and what could be a good energy balance one day could be a poor one a week later [1].

Energy Content (calorific value) of Products
Focusing upon the energy content of the products seems like a fundamental method because the purpose of renewable energy systems is to produce a product with high energy content. The primary product should in fact contain more energy than the coproducts, otherwise the system may have to be reanalyzed in terms of thermodynamic efficiency. This suboptimal energy content ratio could possibly occur if there is pressure to tailor a biofuel to existing infrastructure (which would be a pressure from the market). The difficulty with this method is that it does not indicate the effort required to achieve the energy intensive fuel or product. For instance, lasers contain high power concentrated in a tight beam, but much power is required to get the energy in that form.

Process Energy Input
Allocation due to the energy input into the renewable system seems like a logical choice because we are, after all, trying to figure out how to allocate the energy consumed in the renewable energy process. However, this allocation method can be somewhat confusing when the primary product and one or more coproducts results from the same subprocess. For example, if there is an unavoidable coproduct that results from the feedstock processing steps, how much input energy went into that unavoidable byproduct? What if the coproduct has no use, meaning it is actually a waste? Nonetheless, this method can often be more straightforward as in the case with wet-milling corn ethanol since during pre-treatment the starch (used for ethanol) is separated from the grain (used for coproducts), and thus subsequent energy used for processing the grain can easily allocated to the coproducts.

Energy Displaced (energy for replacement coproduct)
Allocation due to the energy displaced is an inherently comparative methodology. It requires diligent astute knowledge of the field of the product in order to know the energy input into replacement products. Also, an equivalent replacement product must exist. Here, the energy required for producing the primary product is reduced by the amount of energy required for the replacement product. For instance, Shapouri assumes that animal feed products (e.g. DDG) produced from corn ethanol processing can directly replace soybean meal. A difficulty arises if soy meal, itself a possible coproduct from biodiesel production, might use corn-based animal feeds as a replacement product as well. They can’t both replace each other. So there can be multiple choices of replacement products that can provide a range of answers for the primary product.

Can these allocation factors reveal something about culture, society, and how we value our energy and time? Is there a correct or more ethical method?

Pradhan et al. suggest that the correct method depends upon the question being asked. If renewability is the question, they say the mass fraction should be used, but if economic sustainability is to be determined, then the market value allocation approach should be used [1]. For philosophers who like to find the ultimate truth, this solution is rather non-satisfactory, and it avoids the question of whether the market should recognize that energy return on energy invested (EROI) is the major driver for economic growth or if economic growth potential is the driver for the choice of energy resources. The tail can’t wag the dog, but hopefully with enough flow of accurate information the EROI and economic return will continuously feedback to each other and arrive at the same solution.

[1] Pradhan, A.; Shrestha, D. S.; Van Gerpen, J.; and Duffield, J. 2008. The Energy Balance of Soybean Oil Biodiesel Production: A Review of Past Studies. Transactions of the American Society of Agricultural and Biological Engineers. 51 (1): 185-194.

[2] Larson, E. A review of life-cycle analysis studies on liquid biofuel systems for the transport sector. Energy for Sustainable Development. June 2006, Vol. X, No. 2: 109-126

[3] Guardian, UK. June 25, 2008. Brazil signs deal to export sustainable ethanol. http://www.guardian.co.uk/business/feedarticle/7609299.

Tuesday, May 27, 2008

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:


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.


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 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.


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.


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.

Wednesday, April 16, 2008

Leaving fossil fuels in the ground vs. using them all up now

I wrote a think piece for Worldchanging playing off one of the basic arguments against climate mitigation (we'll be richer in the future and more capable of dealing with any effects) with the idea of leaving fossil fuels in the ground (will we also be more capable of using fossil fuels in the future, and should we strive to leave some?).

One thing that did not get into the article in time (but came the day after I submitted it!) was the fact that the Saudi King himself made reference toward specifically leaving some of their new found reserves for future generations! How is that for some new thinking!

Visit the site to read the commentary (http://www.worldchanging.com/archives/007962.html), or see below.

NOTE: As one of the early bloggers notes, nuclear energy has a wide range of possibilities (over carbon-based fossil fuels), and those were too much to go into for one article, aside from the fact that I am definitely not an expert on nuclear materials, for fission or fusion (always 50 years away!).


Success is Winding Up with Oil in the Ground

Will we always be more capable in the future?

One basic economic argument against substantial climate change mitigation investments often centers on the concept that, because of monetary discount rates and historically-proven continuous economic and technological growth, society will be both ‘richer’ and more capable of dealing with possible negative effects in the future. Proponents of this argument often use it to reason that mitigation is simply too economically costly to pursue.

Can the same argument hold for production of fossil fuels? That is to say, if we are going to be richer and more capable in the future, won’t we have a better use for all energy sources, including fossil fuels? And will part of our ability to deal with societal issues, such as those caused by climate change, be predicated upon having available energy? If the answer to these questions is “yes”, then we should keep our fossil fuels in the ground.

The reason that the idea of preserving fossil fuels and ecosystems for future generations is not widely held is that the pattern since the industrial revolution of the 1800s shows us that energy consumption is highly correlated to economic growth, and thus the ability to become ‘richer’ (Figure 1). But recently Ecuadorian officials have proposed that the international community pay approximately half of the assumed value an oil deposit that lies beneath the Yasuni Amazon ecological reserve in order not to extract the oil [1]. Is this a beginning to question the present value of fossil fuels?

In the United States before the industrial revolution, the labor of 95 out of 100 people were required to feed the population of 5 million. Today, the less than 3 out of 100 are required to feed the US population of over 300 million - with food to spare for export. How is this possible? Fossil fuels provide high energy density storage sources that literally take the place of labor, and since their large scale use, we have used them to accumulate knowledge in how to further reduce physical labor. The huge reduction in farming labor over the last 200 years has resulted in “extra” hours for people to get paid to do things like drive around taking photos of celebrities for gossip magazines.

Because fossil fuels are limited and have provided us with the luxury of excess time, a major goal of society should be to break the causation between increasing fossil fuel consumption and increasing human development. I say human development and not economic growth, because the social aspect of economics is only a part of human development [2]. Extracting more fossil resources by consuming more fossil energy only buys more time to learn how to design and implement sustainable energy systems.

The laws of diminishing returns for fossil fuels cannot be avoided on the time scale of human civilization. Human civilization operated on a 100% sustainable energy a few hundred years ago, and after fossil fuels become completely uneconomical in hundreds of years more, we’ll again operate on a 100% sustainable energy system. The question is: what is that next 100% sustainable system going to look like?

Will it not be a success if human society finds an acceptable sustainable arrangement where we have excess fossil fuel reserves still lying in the ground? That is to say, we could define success as solving the energy and development problem before running out of economical fossil energy resources. Why consume the last of fossil energy reserves? Since reserves are partially defined by the economics of extraction, they are also partially a measure of our culture in how we value things, including energy resources, food, and social goods. If we want future human civilization to live in a manner better than the time before fossil fuels, that demands using our fossil fuels today such that we learn not to need them in the future.

Today we can’t make a photovoltaic solar panel without fossil-powered electricity manufacturing plant. We couldn’t build a hydroelectric dam without fossil-powered vehicles and cement plants. We can’t make and install a wind turbine without fossil-powered steel factories and transport systems. We need to track the progress, or lack thereof, of the ability of renewable energy systems to make themselves.

We didn’t need Nobel Prize Chemist Richard Smalley to tell us that the sun is the only source of energy for a sustainable human society. What we do need is everyone focused on the issue of both cultural and technological adjustments to make the most of solar direct (sunlight) and indirect (wind, waves, crops) energy.

Carey King, PhD, works at the University of Texas at Austin's Bureau of Economic Geology. This is his first contribution to Worldchanging.


[1] Pearson, Natalie O. Ecuador Plans to Nix Exploitation of 1B Bbl Oil Deposit. Dow Jones Newswires. March 03, 2008. Available at: http://www.rigzone.com/news/article.asp?a_id=57679.
[2] Sen, Amartya. Development as Freedom. First Anchor Books, 1999.

Monday, March 10, 2008

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:

- 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. "

- 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.

Friday, March 7, 2008

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!

Wednesday, February 20, 2008

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.

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.

Friday, February 1, 2008

Offshoring Energy and Emissions - Coming back from Developing to Developed Countries

A recent study in the journal in Environmental Science and Technology discusses the 'embodied carbon' in global trade. The concept of embodied effects in global trade has been noted by scientists and engineers by estimating such aspects as the energy embodied in a product when it is made in one place and shipped to another.

Somewhat by definition, making a product in China (say a Barbie doll) and shipping it to the United States takes more energy than making it in the United States and keeping it here. Just think of the energy used to create the infrastructure (tankers) and fuel the cargo ships (low grade petroleum used in ships). You don't need these if you don't travel the globe, but both systems require intra-continental infrastructure.

As peak oil and gas come on, businesses will be forced (albeit in some views 'rightly so') to better account for the energy used to make a particular product or provide a particular service. Products from China don't cost less in the U.S. because it actually costs less to make from an engineering sense; it just costs less based upon how much you value a person's time and labor. Essentially the time of farmer converted to factory worker in China has less value than the average Joe/Jane in the U.S. The 100s of millions of workers in China available to work cheap is the main reason why products have gotten cheaper in the U.S.

Essentially, the CO2 being shipped from abroad to the U.S. (and generally from developing to developed countries) is a proxy measure for energy. As suggested in the synopsis (linked above), the solution is likely to factor the cost into the consumer of the product and not necessarily its producer.

And we should quit shipping electronic 'waste' to China, as someday we'll likely wish we kept it to make use of it via recycling, but that's another story ...

Monday, January 28, 2008

Shell CEO Talks of peak "easily accessible supplies of oil and gas" by 2015

As posted on other blogs (The Oil Drum and The Energy Blog) Jeroen van der Veer, the Chief Executive of Royal Dutch Shell, has suggested that the "easy oil" will not keep up with demand by 2015, and that a "blueprint" future energy scenario is preferable to a haphazard strategy. Now one of the world's largest companies says peak oil is within 7 years. Anyone want to work on battery and capacitor technology!?!

Use the title link to go to the Shell website for the statement, or just read below:

Two Energy Futures

* By Jeroen van der Veer

By 2100, the world’s energy system will be radically different from today’s. Renewable energy like solar, wind, hydroelectricity, and biofuels will make up a large share of the energy mix, and nuclear energy, too, will have a place. Humans will have found ways of dealing with air pollution and greenhouse gas emissions. New technologies will have reduced the amount of energy needed to power buildings and vehicles.

Indeed, the distant future looks bright, but much depends on how we get there. There are two possible routes. Let’s call the first scenario Scramble. Like an off-road rally through a mountainous desert, it promises excitement and fierce competition. However, the unintended consequence of “more haste” will often be “less speed,” and many will crash along the way.

The alternative scenario can be called Blueprints, which resembles a cautious ride, with some false starts, on a road that is still under construction. Whether we arrive safely at our destination depends on the discipline of the drivers and the ingenuity of all those involved in the construction effort. Technological innovation provides the excitement.

Regardless of which route we choose, the world’s current predicament limits our room to maneuver. We are experiencing a step-change in the growth rate of energy demand due to rising population and economic development. After 2015, easily accessible supplies of oil and gas probably will no longer keep up with demand.

As a result, we will have no choice but to add other sources of energy – renewables, yes, but also more nuclear power and unconventional fossil fuels such as oil sands. Using more energy inevitably means emitting more CO2 at a time when climate change has become a critical global issue.

In the Scramble scenario, nations rush to secure energy resources for themselves, fearing that energy security is a zero-sum game, with clear winners and losers. The use of local coal and homegrown biofuels increases fast. Taking the path of least resistance, policymakers pay little attention to curbing energy consumption – until supplies run short. Likewise, despite much rhetoric, greenhouse gas emissions are not seriously addressed until major shocks trigger political reactions. Since these responses are overdue, they are severe and lead to energy price spikes and volatility.

The Blueprints scenario is less painful, even if the start is more disorderly. Numerous coalitions emerge to take on the challenges of economic development, energy security, and environmental pollution through cross-border cooperation. Much innovation occurs at the local level, as major cities develop links with industry to reduce local emissions. National governments introduce efficiency standards, taxes, and other policy instruments to improve the environmental performance of buildings, vehicles, and transport fuels.

Moreover, as calls for harmonization increase, policies converge across the globe. Cap-and-trade mechanisms that put a price on industrial CO2 emissions gain international acceptance. Rising CO2 prices in turn accelerate innovation, spawning breakthroughs. A growing number of cars are powered by electricity and hydrogen, while industrial facilities are fitted with technology to capture CO2 and store it underground.

Against the backdrop of these two equally plausible scenarios, we will know only in a few years whether December’s Bali declaration on climate change was just rhetoric or the start of a global effort to counter it. Much will depend on how attitudes evolve in China, the European Union, India, and the United States.

Shell traditionally uses its scenarios to prepare for the future without expressing a preference for one over another. But, faced with the need to manage climate risk for our investors and our descendants, we believe the Blueprints outcomes provide the best balance between economy, energy, and environment. For a second opinion, we appealed to climate change calculations made at the Massachusetts Institute of Technology. These calculations indicate that a Blueprints world with CO2 capture and storage results in the least amount of climate change, provided emissions of other major manmade greenhouse gases are similarly reduced.

But the Blueprints scenario will be realized only if policymakers agree on a global approach to emissions trading and actively promote energy efficiency and new technology in four sectors: heat and power generation, industry, transport, and buildings.

This will require hard work, and time is short. For example, Blueprints assumes CO2 is captured at 90% of all coal- and gas-fired power plants in developed countries by 2050, plus at least 50% of those in non-OECD countries. Today, none capture CO2. Because CO2 capture and storage adds costs and yields no revenues, government support is needed to make it happen quickly on a scale large enough to affect global emissions. At the least, companies should earn carbon credits for the CO2 they capture and store.

Blueprints will not be easy. But it offers the world the best chance of reaching a sustainable energy future unscathed, so we should explore this route with the same ingenuity and persistence that put humans on the moon and created the digital age.

The world faces a long voyage before it reaches a low-carbon energy system. Companies can suggest possible routes to get there, but governments are in the driver’s seat. And governments will determine whether we should prepare for bitter competition or a true team effort.

Jeroen van der Veer, Chief Executive of Royal Dutch Shell plc, is Energy Community leader of the World Economic Forum energy industry partnership in 2007-2008 and chaired this year’s Energy Summit in Davos. He also chairs the Energy and Climate Change working group of the European Round Table of Industrialists.