Totten Renewables Chapter in a Climate for Life 08

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An early-morning wave breaks into the sunrise in Ventura,

California. There are many ways to tap the energy available

in the ocean, including harnessing underwater currents, tidal

flows, and wave motion. TODD GLASER

For millennia, renewable energy from the wind, sea, sun, and land

provided all of the Earths energy needs. It was the Industrial Era

that drove humanity to use coal, oil, and natural gas fossil fuels (and

eventually nuclear energy) to support its nearly insatiable appetite for power.

oday we face energy and climate crises that threaten both the survival of the

human species as well as biodiversity across the globe. In response, renewablesare once again being pursued as one of the key solutions to meet our needs

in a sustainable way. Tis chapter focuses on what they actually are and what

they can contribute.

World consumption of fossil fuels has increased exponentially in the past

century, and industrialized countries consume the lions share. In 2005, China

consumed as much coal as the United States, Russia, India, and Australia

combined. However, the United States, with only 5% of the worlds population,

consumes one-fourth of the daily global oil supply, whereas China accounts

for 6% of consumption with one-fifth of global population. Between 2000

and 2025, oil use is officially foreca st to grow by 44% in the United States and

57% in the world. By 2025, the United States will use as much oil as Canada,

Western and Eastern Europe, Japan, Australia, and New Zealand combined.

Te forecasted increase alone in U.S. oil imports will exceed the 2001 total oil

use of China, India, and South Korea (Lovins et al., 2004).

Yet the problems of growth are not limited to the United States. oday, only

12% of the worlds population own cars. Africa and China currently have the

car ownership America enjoyed in 1915. However, Chinas compound annual

car growth was 55% between 2001 and 2005. By 2025, its cars could require

the oil output of a Saudi Arabia or two (which now exports one-fourth of

world oil).

Such harrowing growth rates in fossil fuel usage will dramatically increase

greenhouse gas emissions to a level threatening to derail societys capacity to

stabilize atmospheric concentrations below a safe threshold, triggering multi-century catastrophic consequences (Hansen, 2005; Hansen et al., 2008;

Romm, 2007). Fortunately, a significant fraction of the growth rate in the

global demand for energy and mobility services can be effectively satisfied

through smart energy efficiency improvements, at tens of trillions of dollars

CHAPTER TWO

Michael Totten

Renewable Energy

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lower cost this century compared to conventional supply expansion. Moreover,

as illuminated in Chapter 1: Energy Efficiency, many of the efficiency gains

actually enhance the cost-effectiveness of wind and solar energy options.

Renewable resources take diverse forms and include solar, wind, geothermal,

biological, and hydrological sources. Tey can be used to provide any of the

myriad applications for which humankind requires: thermal heat; solid, liquid,or gaseous chemical fuels; or even electricity.

Many of these sources are highly cost-effective now and will only become

increasingly economical in the coming decades. o facilitate their application

and acceptance, we need to stop providing incentives for outdated and

unsustainable fuel technologies and focus instead on the most ecologically

sustainable renewable sources, notably wind and solar. Te combination, in

particular, of vehicle-to-grid system efficiencies and expansion of wind and

solar energy offers multiple benefits: reduced cost of energy services; dramatic

reductions in greenhouse gases, acid rain, and urban air pollutants; deep

reductions in oil imports; and significantly less wilderness habitat converted

and fresh water diverted to grow fuel crops.

It will also take ambitious research, development, and demonstration

initiatives, coupled with market-based incentives and innovative regulatory

policies, to ensure the timely availability of economically attractive and

affordable renewables on a global scale throughout this century.

Abundant Options

Current global energy consumption is about 15 terawatt-years or 475 exajoules,

the equivalent of oil supertanker shipments arriving at the rate of one every

ten minutes, or the distribution of fuel to service stations by 437 million

delivery trucks per yea r. Projected energy consumption worldwide from 2000

to 2100, assuming no change in human behavior, is approximately 240 times

the current amountabout 3,600 terawatt-years or 113,000 exajoules. Fossil

fuels, also assuming no change in human behavior, would account for three-

fourths of this sum, releasing several trillion tons of greenhouse gases, while

tripling the Earths atmospheric concentration of greenhouse gases (in carbon-

dioxide equivalents) from pre-industrial levels.

Opinion surveys consistently show that more than 80% of citizens prefer

solar and other renewables and energy efficiency to the use of fossil fuels. Tis

is not surprising, given the unimaginably vast amount of renewable energy

flows worldwide. Consider that global human energy consumption in 2007

amounted to just one hour of sunlight landing on Earth. Expert evaluations

conclude that renewables are quite capable over the long term, in combinationwith extensive energy efficiency gains, to economically provide the current

total global energy supply many times over.

Solar. Solar technical potential is conservatively estimated at greater than 50

terawatt-years per year, or more than three times the current annual global

energy use. From 2000 to 2100, solars technical potential of 5,000 terawatt-

years is 277% greater than the remaining post-efficiency supply requirements

(i.e., after harnessing the large pool of cost-effective energy-efficiency

opportunities). Tis solar technical potential was characterized nearly a decade

ago, and faster market developments indicate this potential will increase over

time as continuous scientific advancements and technological breakthroughs

are able to capture an ever-larger fraction of the theoretical potential of

124,000 terawatt-years, or nearly 4 million exajoules per year.

Wind. Wind technical potential is more than 20 terawatt-years per year, or

more than 134% of the current annual global energy use. From 2000 to 2100,

winds technical potential of 2,000 terawatt-years is more than 110% greater

than the remaining (post-efficiency) supply requirements. About 12% of the

energy coming from the sun is converted into wind energy. Winds theoretical

potential is 2,476 terawatt-years, or 78,000 exajoules per year.

Geothermal. Geothermal technical potential is about 160 terawatt-years per

year, or more than ten times the current annual global energy use. Te Earths

interior reaches temperatures greater than 4,000C, and this geothermal energy

flows continuously to the surface. From 2000 to 2100, geothermals technical

potential of 16,000 terawatt-years is 900% greater than the remaining (post-

efficiency) supply requirements. Geothermal s theoretical potential worldwide

A CLIMATE FOR LIFE

Livestock release methane, and research is showing how to

reduce it. At the same time, methane from animal waste can

be recycled into a renewable gas. PETER ESSICK



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is 440,000 terawatt-years, or 14 million exajoules per year. Domestic resources

in the United States are equivalent to a 30,000-year energy supply at the

current rate of consumption.

Biomass. Biomass technical potential is 8.6 terawatt-years per year, or 57% of

current annual global energy use. From 2000 to 2100, biomasss technical

potential of 860 terawatt-years is 48% of the remaining (post-efficiency)

supply requirements. On average, plant net primary production (NPP) is

about 5 million calories per square meter per year. An important caveat about

biomass availability is that global NPP is the amount of energy available to

all subsequent links in critical ecosystem services plus the food, fiber, animal

feed, and biofuel chain. Te Earths surface area is about 500 trillion m 2. Te

net power output stored by plants is thus 19 terawatt-years, or 0.01% (1/100th

of 1%) of the suns power emitted to Earth.

Oceans. Ocean powers technical potential (more than 80% from thermal

energy conversion) is 5 terawatt-years per year, or one-third of current annual

global energy use. From 2000 to 2100, the oceans technical potential of 500

terawatt-years is 27% of the remaining (post-efficiency) supply requirements.

Tere are various potential ocean technologies, such as harnessing the power of

underwater currents, tidal flows, wave motion, and exploiting the temperature

differences between different layers of the ocean

(called Ocean Termal Energy Conversion). More

research remains to be done on the ecological

impacts of the options on marine life, and these

technologies may play a niche role for some island

and coastal communities.

Hydropower. Hydropowers technical potential is

1.6 terawatt-years per year, or a bit over 10% of

current annual global energy use. From 2000 to

2100, hydros technical potential of 160 terawatt-

years is 9% of the remaining (post-efficiency)

supply requirements. Tis potential is further limited by serious ecological,

social, and climatic problems associated with some river sites.

Counting the Costs

Not surprisingly, much of the lively and contentious debate over future

energy supplies tends to reduce itself to one key criterion: cost. Tis is myopic

for two reasons. First, assumptions about long-term technological cost and

performance data inherently contain a fa ir degree of subjective judgment. Te

future is uncertain in too many ways, precluding any technical assessment to

claim complete objectivity or certitude. Moreover, current views on technology

options are heavily conditioned by the long trail of public interventions and

subventions shaping markets and investment patterns. For humanity to avoid

catastrophic climate change, and avert conflicts and wars over oil resources,

there will need to be a dramatic change in the calculus of energy policy-

making and investment decision-making. Tis means it is a wide-open arena

for all energy options, even the current energy giants, since the accumulated

rules and subsidies currently in place are now facing a radical makeover to

align outcomes for climate-positive, real energy-security results (DeCanio,

2003; Smil, 2003).

Second, cost and climate emissions are just two criteria among many for

ensuring a sustainable smart-energy system worldwide this century. Tere



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is a rich literature developed in the wake of innumerable energy crises over

the past forty years stressing important attributes that should be sought in

energy services to achieve a high probability of avoiding adverse impacts and

unintended consequences (Lovins and Lovins, 1982; Lovins et a l., 2004; Smil,

2003). A dozen criteria recur as important attributes of energy supplies:

Is it economically affordable, even for the poorest of the poor

and cash-strapped?

Is it safe through its entire life cycle?

Is it clean through its entire lifespan?

Is its risk low and manageable during financial and price volatility?

Is it resilient and flexible to volatility, surprises, miscalculations,

and human error?

Is it ecologically sustainable, with no adverse impacts on

biodiversity?

Is it environmentally benign in that it maintains air, water, and

soil quality?

Will it fail gracefully, not catastrophically, in response to abruptsurprises or crises?

Will it rebound easily and swiftly from failures, with low recovery

cost and limited lost time?

Does it have endogenous learning capacity, with intrinsic new

productivity opportunities?

Does it have a robust experience curve for reducing negative

externalities and amplifying positive externalities,

including scalable innovation possibilities?

Is it an uninteresting target for malicious disruption,

off the radar of terrorists and military planners?

Among the range of available energy options, only energy services from

efficiency gains rank at the top in every attribute. All other options are

deficient or weak in two or more of these attributes. Te vast expansion of

energy consumption from coal, oil, natural gas, nuclear, hydrodams, and

wood and crops over the past century has revealed a series of grave problems,

some intractable or intrinsic to the energy option, that have been costly to

human well-being and ecological health.

For example, hydroelectric power is promoted as the most cost-effective

renewable energy solution for climate change. Tis is grossly misleading and

highly inaccurate. Actual measurements of hydrodams in different parts of

the world indicate they are responsible for an estimated 8% of total globalgreenhouse gas emissions, and projected expansion in coming decades, mostly

in wilderness areas, could increase this to 15% of total emissions (St. Louis

et al., 2000). Hydrodams have also been the major reason why one-fourth of

freshwater species have been driven to ext inction worldwide (Brutigam, 1999)

Tis is not to say that a ll hydro facilities release greenhouse gas emissions. Not

all hydroelectric plants require dams, and not all dams generate electricity.

And clearly other extenuating circumstances come into play (e.g., the need for

irrigation) (WCD, 2000).

Tis reinforces the point that using multiple criteria to prioritize preferable

energy options this century, coupled with the alignment of public policies

and regulations towards this end, is imperative given the looming threat of

climate catastrophe in need of fast and massive action, while at the same

time avoiding wars and conflicts over the accelerating demand for vulnerable

oil supplies; avoiding and reversing the contamination of air, water, and soil;

avoiding nuclear weapons proliferation; and preventing the destruction of

wildlife and biodiversity loss.

In addition, we must now take into account the increasing occurrence of

climate-triggered mega-droughts, super-hurricanes, deluge-level floods, larger

and longer wildfires, more widespread pest devastation, and the adverse

impacts these will have on energy installations. It is also prudent in a post-

9/11 worldwhere nuclear reactors and large refineries now remain on

constant alert to possible terrorist attacksto design energy systems that are

uninteresting targets (Romm, 2007).

Proper Investment and the Future of Renewables

In spite of renewables overwhelming potential, existing public policiesas well

as the majority of future-looking global energy assessmentsreflect negligible

The cooling towers of a nuclear power plant frame a

traditional windmill in St. L aurent des Eaux in Frances Loire

Valley. Contemporary wind turbines, designed with state-

of-the-art technologies, now deliver electricity at several

times lower cost than nuclear power. THOMAS HOEPKER



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roles for solar, wind, and geothermal energy sources or the ambitious efficiency

gains posited in Chapter 1. On the contrary, they emphasize massive fossil

fuel carbon capture and storage (CCS) operations, aggressive nuclear power

expansion, enormous biomass plantations, and la rge-scale hydro development

(Hamrin, Hummel, and Canapa, 2007). Tis is due less to technical or

economic constraints than to institutional and political inertia.

Over the past half century, governments have provided (and continue to

provide) several trillion dollars per decade in subsidiesnearly two-thirds

have been dedicated to fossil fuels (mostly to coal and oil) and one-fourth

to nuclear power. Only 5% went to all non-hydro renewables (solar thermal,

solar-electric photovoltaics, solar-thermal-electric concentrated solar power

systems, terrestrial wind, offshore wind farms, geothermal heat, geothermal-

electric) and all efficiency (buildings, transportation, appliances, industry,

combined heat and power). For each U.S. t ax dollar supporting wind power or

solar power research and development over the past fifty years, nuclear power

received 100 times more. Even in the U.S. 2008 federal appropriations, wind

power research and development funding was $40 million vs. $400 million

for nuclear. Tis makes no sense given the fact that wind power generates

electricity already competitive to nuclear reactors and has a global technical

potential that could provide twice the level of total global energy needs this

century (in combination with ambitious efficiency gains) (GWEC, 2006).

Moreover, nuclear power continues to receive

unprecedented taxpayer-subsidized insurance

coverage for reactor disasters. A similar taxpayer

burden is now being proposed to underwrite

federally assumed liability of a century-long

leakage risk from carbon capture and storageprojects. Likewise, the fossil fuel industries have

received considerable largesse and investment

stability as a result of long-standing subsidies,

while emerging competitive options like wind

power suffer financial instability because the

Production ax Credit is sunset every few years,

wreaking havoc by disrupting investment flows (Koplow and Dernbach,

2001).

In sharp contrast, however, is the attention that many other nations, as

well as a number of U.S. states, have focused on the future of renewables to

meet the range of environmental, economic, social, and security criteria noted

above. Tere is a growing body of literature describing that future, including

policy targets and shifts in financial incentives based on insights gleaned

from socio-economic and technology scenarios, carbon-constrained scenarios,

and future social visions. Policy targets for future shares of renewable energy

are described for regions, specific countries, states/provinces, and cities. By

2020, many targets and scenarios show a 2035% share of electricity from

renewables, increasing to 5080% by 2050 under the highest scenarios

(Martinot et al., 2007).

wo scenarios with very ambitious efficiency and renewable goals were

released in 2007 by the European Renewable Energy Commission (EREC,

2007) and by the American Solar Energy Society (ASES, 2007), the latter

limited to the United States. Te European Renewable Energy Commission

projects 70% renewables in the electric sector (while constraining nuclear

and large hydro), and the American Solar Energy Society forecasts 50%

renewables in the U.S. electricity sector by 2030 (also ignoring nuclear and

large hydro). Te high penetration rates are directly due to the fact that both



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reports estimate half or more of total energy supply being displaced through

lower-cost energy-efficiency gainsby a factor of four to one in the case of

the EREC projects.

Te ASES report is highly transparent and richly detailed and strongly

demonstrates that energy efficiency and renewable energy technologies

have the potential to provide most, if not all, of the U.S. carbon emissionsreductions that will be needed to help stabilize the atmospheric concentration

of greenhouse gases (Hamrin, Hummel, and Canapa, 2007). However, while

some renewable options accrue multiple benefits and positive externalities

and should be encouraged, other renewable options trigger adverse impacts or

incur negative tradeoffs. Tis is especially the case when a supply option like

biofuels is vastly expanded over space and time.

High oil prices have driven policymakers to set high production targets

and enact lavish subsidies for investors to develop biofuels from agricultural

crops. Mobile liquid biofuelsboth ethanol derived from corn and sugarcane

and biodiesel derived from oil palm, soybean, and rapeseedare not only

more expensive than vehicle efficiency gains by a factor of two to five (Lovins

et al., 2004), but also more expensive than system efficiency gains achievable

by connecting plug-in hybrid electric vehicles to the national electricity grid

system. Genetically modified fuels of the future are likely to lower production

costs, but pose many of the same ecological issues associated with current

biofuels (Jacobson, 2007).

Preeminent Solutions: Electric Vehicles

Research and developments over the past two decades in the production of

electric vehicles and separately in the commercialization of hybrid-electric

vehicles have given rise to the recognition that plugging vehicles into the grid

system would accrue several remarkable benefits far superior to continuing to

run vehicles entirely on mobile liquid fuels. As researchers have pointed out,

Te vehicle fleet has t wenty times the power capacity, less than one-tenth the

utilization, and one-tenth the capital cost per prime mover kilowatt. Conversely,

utility generators have ten to fifty times longer an operating life and lower

operating costs per kilowatt-hour. o tap Vehicle-to-Grid is to synergistically

use these complementary strengths, and to reconcile the complementary needs

of the driver and grid manager (Kempton and omi, 2005).

As discussed in the chapter on efficiency and smart energy services, the

existing U.S. gr id could recharge 80% of Americas 200+ million vehicle fleet

if they were plug-in hybrid electric vehicles, without having to build a new

power plant. Tis would have the positive effect of eliminating 52% of U.S.oil imports (340 billion liters per year) worth some $350 billion savings at the

gas pump, while also reducing total U.S. carbon dioxide emissions by 27%

(PNNL, 2007).

As with the market diffusion rate of any major technological innovation

(accelerated to some degree by favorable public policies and incentives),

declining manufacturing costs and vehicle prices will occur with accumulated

experience of scaled-up production. Researchers note another tremendous

benefit of vehicle-to-grid over time, as production costs drop: providing

battery storage for intermittent wind power and solar electricity generation.

Research calculations suggest that vehicle-to-grid could stabilize large-scale

(one-half of U.S. electricity) wind power with 3% of the fleet dedicated to

regulation for wind, plus 8% to 38% of the fleet providing operating reserves

or storage for wind (Kempton and omi, 2005). For context, currently half

of U.S. electricity is coal-fired.

Te vehicle-to-grid technological revolution is driven by many of the same

digital electronics and advanced materials that enable production and operation

of high-efficiency, lower energy-consuming smart appliances, smart grids,

smart buildings, and smart cars. It offers an economic development strategy

for developed and developing countries alike. With the majority of the worlds

population becoming urban-based, electric and hybrid-electric vehicles can

accommodate the typical urban driving cycles of 16 to 48 kilometers per day.

Longer distances can be provided by the flexible fuel component derived from

local and regional biowastes.

The Role of Biofuels

Local and regional biowastes can be converted to biofuels, providing the

mobile fuels essential for long-range driving beyond electric battery capacity.

An electric Smart Car advertises the New York City Marathon

in Midtown Manhattans Times Square. Using plug-in hybrid

technology, the electricity infrastructure in the United States

could potentially power the daily use of 84% of the nations

cars, pickup trucks, and SUVs. CHUCK PEFLEY



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Such a modest use of biofuels would prevent some of the near-intractable

problems associated with large-scale biofuel consumption.

Unfortunately, one unintended negative consequence of corn-based

ethanol expansion in the United States is that it drives soy production to

Brazil and Argentina (where it is grown mainly for animal feed), which leads

to deforestation and destruction of biodiversity-rich savannah grasslands

and Amazon ecosystems (CARD, 2007; Searchinger et al., 2008; Fargione et

al., 2008). Similarly, oil palm plantations in tropical countries, already one

of the major causes of biodiversity loss, are the preferred low-cost feedstock

for biodiesel. Some of the last remaining intact wilderness habitats for

mega-charismatic species like the orangutan and the Sumatran tiger, and

also rhino and elephant are threatened with conversion to oil palm. Species

extinction will be the outcome of people putting an orangutan in your

tank.

Minimizing biofuel expansion reduces the adverse impacts on ecosystems

and biodiversity loss in tropical countries already being caused by ethanol and

biodiesel plantation growth (Morton et al., 2006; Fearnside, 2002; Killeen,

2007). It also avoids driving up food prices (CARD, 2007).

Harnessing the Sun and the Wind

Solar, wind, and geothermal energy systems are not only the three largest

renewable resources; accumulated scientific

knowledge also gives good indication they will

incur the smallest climate and ecological footprints

when scaled up globally and operated over long

time periods. Solar photovoltaics and wind power

have the added advantage of requiring 95% lesswater per terawatt-year than coal or nuclear power,

biopower or solar-thermal-electric concentrated

solar power (CSP) systems.

In a vehicle-to-grid connected world, with

solar and wind power stored in the mass

distribution of plug-in hybrid electric batteries,

sixty and thirty times less land area, respectively, would be needed than in

the case of biofuels for the same power output (Jacobson, 2007). Roughly

7% of the U.S.s 50 million hectares of urban land area covered with solar

photovoltaic panels at todays 10%-efficient systems could provide 100% of

U.S. electricity. Brownfields could provide most of the land area. Building-

integrated photovoltaic systems (BIPVs) could provide half of the power

(Kazmerski, 2002; Zweibel, 2004). Alternatively, around 2.5% of the North

American Great Plains with dispersed wind farmsor roughly 92 million

out of 363 million hectarescould provide 100% of U.S. electricity. Te

actual footprint of the several hundred thousand multi-megawatt turbines,

hypothetically squeezed into one spot, would be less than the size of one large

Wyoming coal strip mine (Komanoff, 2006; Williams, 2001). Even when

spaced out to optimize wind capture, 90% of the 2.5% could still be farmed,

ranched, or ecologically restored.

Several valuable benefits would accrue to rural communities from such

a strategy. Farmers and ranchers can earn, on average, twice as much from

wind farm royalty payments than they currently obtain from crop and

animal farming. Currently 75% of the Great Plains is farmed or ranched,

but only generates 5% of the regions economic output. Shifting to wind

farming could produce twice a s much economic output on thirty-five times

less land area. Similarly, vast wind resources are available in China and



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India, as well as along coastal regions throughout the world (otten, 2007;

GWEC, 2006; NREL, 2006). China and India will account for 80% of

coal increase by 2030. China annually expands its coal use equivalent to

that of the United Kingdom. It surpassed the United States in 2007 as

the worlds top greenhouse gas emitter. However, Chinas wind technical

potential is estimated at 2 million megawatts, 400% larger than Chinastotal electric generation capacity. In addition, twice as much solar energy

lands on China each year than could be produced from its 800 billion tons

of coal over the next several centuries.

Economies of EfficiencyCombining Heat and Power

Instead of targeting massive investments into central, large-scale, coal, nuclear,

and hydroelectric generating stations, cities around the world should be

looking for energy system efficiencies that could enable phasing in use of local

and regional biological wastes over the long-term. One of the proven options

available globally is decentralized combined heat and power. Whereas central

thermal power plants vent 70% of the energy when generating electricity,

combined heat and power systems capture this waste heat to cogenerate

two, three, or four different energy services (heat, steam, electricity, cooling).

Moreover, in being sited close to the point of use, combined heat and power

systems require significantly less transmission and distribution investment

than centralized power plants, as well as avoiding the 15% transmission and

distribution line losses (WADE, 2004). For example, just the waste heat

discarded from U.S. power plants is equivalent to 1.2 times Japans total

energy use.

Recent assessments indicate that if China moved to 100% high-efficiency

decentralized combined heat and power systems by 2021, retail and capital

cost savings could reach $400 billion. At no extra cost, new emissions of

carbon dioxide would drop 56%, avoiding 400 mil lion tons of such emissions

per year, and nitrogen oxide and sulfur dioxide emissions would decline by

90%. But these results are possible only if the Chinese government adopts

key policies enabling a faster rate of implementation than the current annual

combined heat and power addition of 3,000 megawatts. Some 100,000

megawatts of combined heat and power could be online in several years if a

number of important power sector reforms occur (WADE, 2004).

For nations like China facing water crises, combined heat and power offers

a highly cost-effective system efficiency option for combining the delivery of

energy and potable water. Water consumes considerable energy throughout

the process of extracting, pumping, distributing, heating, and disposing.In California, for example, 20% of the electricity and one-third of natural

gas are consumed by the water sector (NRDC and Pacific Institute, 2004).

Delivering water services efficiently saves money, reduces air pollution, and

cuts greenhouse gases. China faces the additional problem that its water

resources per capita may decline to around 1,700 cubic meters by 2050, which

is the threshold of severe water scarcity. Water shortage a lready has become a

critical constra int for socio-economic development in northern China, where

per capita levels are now below 300 cubic meters. o solve or eliminate water

shortage problems, China is now pursuing all water-efficiency opportunities

(e.g., drip irrigation) that can cut water use by two-thirds on farms (which

consume 80% of al l water).

Alternative Water Supplies

Meanwhile, wastewater and seawater desalination are drawing more and

more attention from researchers and policy-makers as alternative water supply

sources (Zhou and ol, 2003).

Desalination costs currently vary by a factor of seven or more, depending on

the type of feedwater (brackish, waste, or seawater), the available concentrate

disposal options, the proximity to distribution systems, and the availability

and cost of power. Desalinations primary operating cost is for power. One

cubic kilometer (one trillion liters) of wastewater or seawater desalination

requires about 500 megawatts of power. Te reduction in unit energy use by

desalination plants has been among the most dramatic improvements in recent

years due to improvement in energy recovery systems. Estimates considered

valid for China today range from a cost of $0.60 per cubic meter (1,000 liters)

for brackish and wastewater desalination to $1 per cubic meter for seawater

desalination by reverse osmosis (Zhi, otten, and Chou, 2006).

The people of Hveragerdi, in southwest Iceland, use

geothermal energy to heat their greenhouses. Geothermal

heat in Iceland is also used for swimming pools, to bake

bread, and to heat up footpaths, streets, and parking spaces.

ARCTIC-IMAGES/CORBIS



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Extrapolating from technological trends, and given the promise of

ongoing innovations in lower-cost, higher-performance membranes, seawater

desalination costs will continue to fall. Te average cost may decline to

$0.30 per cubic meter in 2025. For comparison, Chinas average (subsidized)

water prices are $0.25 per cubic meter for domestic and industrial use, $0.34

per cubic meter for commercial use, $0.60 per cubic meter in ianjin and

Dalian, and approaching $0.80 per cubic meter at full pricing in cities like

Beijing.

Desalination of wastewater via combined heat and power can capture

double benefits: it reduces contaminated discharges into rivers and, instead,

expands the citys freshwater supplies at lower cost than importing remote water

resources. Te Reverse Osmosis membrane process is universally considered

to be the most promising technology for brackish and seawater desalination

A model of using reverse osmosis membranes powered by combined heat and

power is the Ashkelon plant in Israel, which produces 100 million cubic meters

per year of potable water at a highly cost-effective 50 cents per cubic meter.

Chinas total wastewater discharges annually exceed 60 cubic kilometers (60

trillion liters). As of the late 1990s, less than one-seventh of this wastewater

was treated. Close to 600 million Chinese people have water supplies that are

contaminated by animal and human waste. Harnessing 30,000 megawatts

of co-generation available in cities and industrial facilities potentially could

operate reverse osmosis technologies to purify

these wastewaters, while also providing ancillary

energy services like space and water heating and

cooling.

The Final Hope

As the chapter on efficiency and smart energy

services describes, ensuring the capture of the

immense pool of efficiency opportunities could

deliver more than half of the worlds cumulative

energy services at lower cost and risk than

expanding energy supplies, replacing the need

for 1,800 terawatt-years or 57,000 exajoules of energy supplies. Envision

eliminating the need for 13.8 billion coal railcars this century. However, that

still leaves a demand for another 1,800 terawatt-years or 57,000 exajoules of

energy supply. A lively debate has ensued as to the best options for satisfying

this immense growth.

Smarter delivery of energy services through efficiency gains can effectively

satisfy most of this growth, while saving money and reducing emissions

provide ancillary benefits. Combining these with steady increases in harnessing

energy services powered by wind, solar, geothermal, and biowastes promises

society a long-term, clean, safe, secure, and ecologically sound energy system.

Achieving this ambitious but feasible outcome is fundamental for resolving

climate and energy crises, while bringing all of humanity to health and

well-being and preventing the unnecessary extinction of the planets rich

biodiversity of plants and animals.


Documents

Totten Renewables Chapter in a Climate for Life 08