Energy in a Nutshell
By Alice Friedemann
Last revision:
Introduction
Oil is the most convenient
form of energy ever discovered, second only to nuclear fuels in its energy
density. As a liquid, it’s easily
stored, transported, and used. It’s wonderfully
combustible, but with a high enough flashpoint that it doesn’t explode
easily. Its complex hydrocarbon chains
are the basis of the petrochemical industry, which uses oil and natural gas as
a component in over half a million products, and each item is made with fossil
fuel energy.
Basically, if you wanted to
invent an ideal energy source, you’d create oil.
The infrastructure
supporting oil use is huge, and not easily replaced. Trillions of dollars have been spent to build
refineries, oil vessels, drilling rigs, the military air and naval fleets we
use to ensure the oil keeps flowing, and the distribution system (i.e.
pipelines, oil-delivery trucks, gas stations, etc). Not to mention the billions of cars, trucks,
airplanes, and other combustion engine machines that use oil.
The energy to create all these
combustion engine-driven machines -- from the mining of metallic ores to
fabrication -- is monumental in scale as well.
You can’t suddenly build a new fleet of solar, wind, coal, or nuclear
driven tractors, trucks, and cars and billions of batteries, especially at a
time when energy is growing more scarce and expensive.
It took us about 50 years
for the world to switch from wood to coal, and another 50 years to switch from
coal to oil. We have a very, very short
time to try to switch to something else -- less than three decades -- and
whatever we try to switch to won’t be as good as oil or we’d already be using
it.
Since there is such a very
short time left to make a transition, the energy source any
The problems with energy
resources are listed below. While it may
not seem fair that the bright side is left out, that’s all most people ever see
– after all, there’s fame and fortunes to be made from positive press releases,
and negative results aren’t news.
Non-technical
Challenges
There’s been a lot of debate
about the technical hurdles to overcome – is there enough uranium, do biofuels
have a positive net energy, etc., but there’s been very little discussion of
the other hurdles.
Population
Declining energy is only the
tip of the iceberg. Population growth is
at the heart of the converging issues that the Club of Rome models show
bringing ecological collapse between 2020 and 2030. The convergence of global warming, depletion
of fresh water, forests, soils, and fisheries; desertification, loss of
biodiversity, and contamination of our air, water, and soil with toxins will
overwhelm the ability of governments to cope.
There is no energy solution
that can support the world’s current population, let alone a population that’s
increasing.
Energy is the tipping
point. We have already far overshot the
carrying capacity of the planet, but cheap and plentiful energy has allowed us
to work around many of these issues, for example, by pumping large amounts of
clean water from 500 feet.
If it turns out that an alternative
energy resources can exist without any fossil fuel inputs, and has a high
enough energy content to do significant work, then that energy resource could
sustain a certain population, but it will be a much lower number than the
current fossil fuel-based civilization.
Garrett Hardin, in “The
Ostrich Factor”, details how a state-level society could keep its population in
check without the usual war, starvation, and disease. The higher the population of a region when
the “Limits to Growth” are reached, the harder the fall, the more environmental
damage done, and the greater the likelihood that democracy will not survive.
The environmental and
scientific community has been shamefully silent on the issue of
population. It’s way past time to speak
out.
Economic
Even if a crisis strikes and
democracy goes out the window while our government focuses on energy
The people with real money
aren’t going to invest in alternative energy.
They wouldn’t be wealthy if they threw their money away on non-viable
projects. Even if they’ve inherited
their wealth and believe in perpetual motion, they have advisors who keep them
out of trouble. They have viewpoints
similar to Peter Huber’s: “For the next several decades at least, alternative
energy sources aren't serious choices; they are pork barrels, delusions,
demonstration plants and daydreams. (Huber)
Global trade and
just-in-time delivery have too many interdependencies which will be easily interrupted
by wars, oil shocks, hurricanes, and other disruptions to build new power
plants of any kind quickly. Time is
critical. As Hirsch points out, you’d
want to start preparing for Peak Oil at least thirty years ahead of time.
(Huber) Huber, Peter.
Political
Politically, it will be hard
to devote money and energy to new projects when people are freezing and hungry. The existing energy is likely to be diverted
to agriculture and essential services, the way blood flows to your body’s core
if you plunge into icy water.
All of these projects must
be done in a time of increasing hardship, which means increasing crime, and the
risk that key engineers will be hijacked or kidnapped, requiring local
governments to divert increasing amounts of energy to maintaining order.
If wars are being fought
over the remaining oil fields, and large naval fleets patrol the seas to
prevent piracy and the continued flow of oil, the military will use an increasingly
large percentage of the available oil. (Bucknell)
Social
There’s a great deal of
local opposition to building the following types of power facilities: LNG (Liquid
Natural Gas), windmills, dams (hydropower), coal, and nuclear power.
If a
Psychological
Back in 1981, Commander
Howard Bucknell III wrote that the public’s understanding of the energy
situation was far removed from reality, because when given uncertain and
contradictory information, the public believes what they want to believe.
Howard Bucknell III. 1981. Energy and the National Defense.
http://www.energyskeptic.com/EnergyNationalDefense_Bucknell.htm
The public and politicians
have always blamed energy shortages on oil company conspiracies or outside
enemies, which lessens the urgency to adapt.
Ninety percent of the public
is scientifically illiterate, and when you combine that with the psychobabble
of the Self-Help and Positive Thinking movements, the public is more likely to
think of Peak Oil proponents as pessimists.
Scientists and engineers are
paid to solve problems, so they tend to see energy problems as challenges that
can be solved.
Finally, the worst-case
implications are so depressing that very few people are willing to contemplate
them.
EROEI – Energy Returned on Energy Invested
Before we throw what
remaining resources we have at “solutions”, it would really be a good idea to
spend the energy on something that might work.
For decades scientists have longed to study EROEI, but haven’t been
unable to obtain funding, the EROEI of various energy sources.
Ultimately, all that matters
is energy. When it comes to evaluating
alternative energy sources such as ethanol, if it takes more fossil fuel energy
to create ethanol than the energy contained in the ethanol, then ethanol is an
energy sink, and it’s not worth pursuing.
Tad Patzek at LBNL and
U.C.Berkeley, has not been able to get funding for a project which would
determine a consistent thermodynamic description of all major energy capture
schemes, both biological and fossil, so that we could compare apples to
apples. This would be a simpler way than
EROEI to see what energy sources might replace fossil fuels, because EROEI gets
endlessly bogged down in which inputs of energy to include or exclude –
boundary issues.
Patzek wrote me that one of
the reasons he suspects he can’t get funding for this is that “no one wants to
know that they may be working on a senseless project, such as industrial
hydrogen from algae.”
Charles Hall, at SUNY, who’s
written some of the most important papers on EROI for decades now, has gotten a
total of $800 in grant money to study EROI.
He believes it’s too political an issue.
Hall guesses you’d need an
EROEI of at least 5 to continue western civilization.
Keep this number in mind
when EROEI figures are mentioned below. Most
of our infrastructure was built when oil had an EROEI of 40 to 100 (i.e. one
barrels’ worth of energy netted you 40 to 100 more barrels of oil).
The issues and problems of energy “Solutions”
I’ve pulled the issues with
energy alternatives from books, scientific journals, and internet discussion
forums such as energyresources and the oildrum. I find people are bored silly by anything with
a lot of numbers and equations, so this is a very easy to understand and
non-technical discussion of the issues.
In fact, it’s too simple – discussion of complex energy issues does not
lend itself well to the
sound-bites, so you’ll need
to follow up with your own research by reading the references to get the full
picture.
Since oil is so fabulous,
why not just drill for more? Economists
don’t believe that there is a finite amount of anything, all you have to do is
drill a hole, pour money intp it, and Voila! – black crude flows out. When a resource is scarce, the Market goes
out and finds more. And people thought
Cargo Cults were crazy…
Even if the oil industry had
five hundred quadrillion dollars, there simply aren’t enough knowledgeable
people to hire – they were all fired during the oil bust of the eighties, and
now over half the current engineers and drilling rig employees are nearing
retirement. And there aren’t enough
drilling rigs. The average age of the
existing rigs is older than when they’d usually be retired – they’re rusting
and need to be replaced. And the overall
infrastructure may be in bad shape, as the recent news of BP having to shut
down its
1) Coal doesn’t contain as much energy as oil. It’s fifty to two hundred percent heavier
than oil per unit of energy generated, which makes it far more energy-intensive
to transport.
2) According to David Goodstein, professor of Physics at
Caltech and author of Out of Gas: the End of the Age of Oil: “We use
about twice as much energy from oil as we do from coal, so if you wanted to
mine enough coal to replace the missing oil, you’d have to mine it at a much
higher rate, not only to replace the oil, but also because the conversion
process to oil is extremely inefficient. You’d have to mine it at levels at
least five times beyond those we mine now—a coal-mining industry on an
absolutely unimaginable scale.”
3) Turning even more heavily to coal will accelerate
global warming and sudden climate change.
4) Coal is lumpy -- you can’t pour it into your gas
tank.
5) Liquefying coal takes half the energy contained in
the coal.
6) Coal liquefaction requires huge plants that are as
expensive to build as oil refineries (no new refineries have been built in the
7) We barely have the rail infrastructure to get coal to
electrical generation plants. Currently
40% of train cars carry coal. Even if
the train network were increased, there is a limit to how many trains can
physically be brought to a coal mine.
8) When coal is burned in coal-fired power plants, coal
emits more radiation than nuclear power plants.
The acids released are ruining farmland and forests. Coal also emits arsenic, sulfur, and mercury,
which is why you can only eat fish a few days a month across the lower 48
states.
9) There is a notion that we have hundreds of years of
coal to burn, but if we turn mainly to coal provide liquid fuel (it already
accounts for half of our electricity generation), then we have about fifty
years of coal left, and even less than that if our use of it and our population
continues to grow exponentially.
10) We’ve already
mined the best and most accessible coal.
The deeper we dig, the greater the minimum energy requirements. Since
the best quality and most accessible coal were mined first, more and more
energy is required to mine and refine increasingly poor quality resources.
11) Mining coal is
tremendously destructive to the environment.
12) Liquefied coal
(CTL) is a water guzzler, requiring 3 barrels of water for every barrel of
coal.
13) We don’t know
how to sequester carbon dioxide with the certainty that it won’t escape back
into the environment. The space to
sequester carbon dioxide is limited, and if the plan is to inject it into
geologically stable oil wells, the cost of running pipelines from the power
plant might be prohibitively expensive both energy and dollar-wise.
14) CTL might make
people foolish enough to think we can continue on the way we have been, and not
make changes in our lives.
1) Tar/oil sands are truly problematic. The process of conversion uses a great deal
of natural gas to infuse the tar/oil sands with hydrogen, and we’re running out
of natural gas at an even faster rate than oil.
Production of oil from tar sands requires between 400 and 1,000 cubic
feet of natural gas per barrel of oil produced, which releases five times as
much carbon dioxide as conventional oil production.
2) These sands also take a tremendous amount of energy
to process, requiring expensive mining, crushing, high temperatures,
centrifuging, and a lot of water to strip the oil from the tar sands to which
the oil is clinging. Consider this
description of Brendan Koerner’s about how oil sands are mined:
“
3) In
4) No matter how the extraction is done, the process is
slow, and will never replace the amount of oil we’re presently using.
5) It’s not clear whether the EROEI will continue to be
positive as the mining pit gets deeper.
It takes more energy for a 400 ton truck to get back to the factory from
300 feet down than when it’s initially scraping the surface.
6) Using nuclear power to refine tar sands won’t work,
because it wouldn’t be long before the oil sands being mined were too far from
the nuclear power plant to transport it there economically.
Oil
shale is any sedimentary rock that contains solid bituminous materials that are
released as petroleum-like liquids when the rock is heated.
1)
Restoring the land after mining the shale will be very energy
expensive. When oil shale is retorted,
the inorganic portion of the shale expands considerably. The spent shale
remaining after retorting has no commercial value, but it must be disposed of
in an environmentally acceptable manner. Ideally, the spent shale is placed
back in the mine, refilling the mined-out cavity and helping to prepare the
area for land reclamation. Because of the popcorn effect, the volume of spent
shale is greater than the volume of the mine from which it was taken. Thus even
if the mine were completely refilled, there would still exist some amount of
spent shale for which alternative disposal methods must be sought
2)
Shale oil needs to be mined, pulverized, and heated to get the oil
out. It's done with machines that burn
oil to dig, drill, blast, crush, load, haul, dump, heat, hydrogenate, refine,
and transport the ore and final product.
3)
The hydrogenation step requires a tremendous amount of water to provide
hydrogen to refine the shale. Separating the hydrogen from the water uses a
large amount of energy. An estimated one
to four barrels of water are required for each barrel of oil. Where this water
would come from is a mystery, the
4) Randy Udall and Steve
Andrews: "Compared to the coal that launched the Industrial Revolution or
the oil that sustains Western Civilization, oil shale is a pathetic
pretender…When it comes to energy, quality is everything. Quality can be
measured in various ways—cost, convenience, and cleanliness all matter-—but
energy density trumps them all…Pound for pound, oil shale contains one-tenth
the energy of crude oil, one-sixth that of coal, and one-fourth that of
recycled phone books...Dung cakes have four times more energy than oil
shale…Searching for appropriate low-calorie analogies, we turn to food...Oil
shale is said to be “rich” when it contains 30 gallons of petroleum per ton. An
equal weight of granola contains three times more energy. The “vast,”
“immense,” and “unrivaled” deposits of shale buried in
5) Steve Mut, CEO of Shell's Unconventional Resources
unit, spoke at the Denver ASPO 2005 conference about Shell’s project to use
shale oil. He pointed out that people
have been trying to do this for over 100 years, so there was no guarantee
they'd succeed. Shell has been working
on a small-scale project for over two decades.
If they decide to scale it up to a level of producing significant
amounts of shale oil, it would require eight to ten gigawatts of power a day,
as much as a large city uses.
1) Currently it’s used for about 25% of our energy,
mainly for electricity, heating, and cooking.
2) But we don’t have enough natural gas left to
substitute for oil – natural gas production peaked about 1970 and has a much
steeper depletion rate than oil.
3) We could import natural gas in liquefied form (LNG),
but that requires billions of dollars of large processing plants and special
ocean-going tankers. All of the
proposed new LNG facilities have been prevented by communities worried about
the explosive potential of the LNG facilities and ships.
4) Natural gas can’t be used by most vehicles, though
there are Fed Ex and other vehicle fleets running on natural gas
currently. It can take up to 8 hours to
fill a tank up with gas – it needs to be forced in and pressurized to be dense
enough to power a vehicle.
These are a crystalline form
of methane gas and pure water that exists where pressures are sufficiently
high, or temperatures sufficiently low.
1) They’re at depth in oceans, so they’re hard to get
to. If you get them and bring them to
the surface, they expand 164 times, which makes it hard to store and transport
them. You’ll need to use energy to
compress them into a high enough density to do work
2) Bringing them to the surface will release carbon
dioxide, increasing global warming.
3) Drilling in the geologically unstable areas where
methane hydrates are found could trigger landslides, which could damage
underwater pipelines and cables.
4) We don’t know how to get them in significant quantities
yet, and the problems of doing so may be insurmountable
5) They are not concentrated in reservoirs like
oil. They’re dispersed in thick layers
at considerable depths. That would make
them very ecologically destructive to mine, since you’d have to cover such a
large area of the ocean floor to get them, sifting through millions of cubic
yards of silt to get a few chunks of hydrate.
6) One of the hypotheses for extinctions in the past,
such as the Permian, which killed 95% of life on the planet, is that a massive
release of methane hydrates occurred.
Even if we don’t mine them for energy, it’s possible that global warming
will release them again as the permafrost melts in polar regions.
7) Since methane hydrates form at low temperatures, you
could try to mine them by raising the temperature. You don’t need to raise the temperature much,
and it’s easy enough to do this by drilling for geothermal heat. The problem is, it’s very hard to distribute
the heat into the gas hydrate layer.
You could also play with pressure and antifreeze to mine hydrates, but
there are problems with these methods as well (Deffeyes. 2005. Beyond Oil, pp
74-76).
Nuclear Power
“To produce enough nuclear power to equal the
power we currently get from fossil fuels, you would have to build 10,000 of the
largest possible nuclear power plants. That’s a huge, probably nonviable
initiative, and at that burn rate, our known reserves of uranium would last
only for 10 or 20 years.” (Goodstein).
The range of estimated
uranium reserves left ranges widely, varying from 30 to 500 years. But as the concentration of uranium in ore
declines (since the best ore is used first), while at the same time the energy
to mine, transport, and concentrate the ore is declining, the higher estimates
appear to be unlikely.
Nuclear power has been
unpopular for such a long time, that there aren’t enough nuclear engineers,
plant operators and designers, or manufacturing companies to scale up quickly
(Torres 2006).
Nuclear plants require huge
grid systems, since they’re far from energy consumers. The Financial Times estimates that ten
thousand billion needs to be invested world-wide in electric power over the
next 30 years. “More than half of the investment needed in the utility sector
will have to be used to build and improve transmission networks”. (Hoyos 2003).
Nuclear plants must be built
near water for cooling. Scientists
believe one of the likely outcomes of global warming is a rising sea level. About half of existing power plants are
vulnerable to this and will need to be decommissioned ($$$ to do: find exact
number). If we wait too long, floods
damaging the electric grid could lead to a catastrophe by swamping both the
electric grid and nuclear power plant backup systems, and eventually flood the
nuclear power plant itself.
Are there enough sites to
build 10,000 new nuclear plants? If sea levels are rising, does that lessen the
possible building sites even more?
One of the most critical
needs for power is a way to store it.
Large storage batteries of any kind – for storage or for transportation
-- have not been invented despite decades of research.
A great deal of the electric
power generated would need to be used to replace the billions of combustion
engine machines and vehicles rather than providing heat, cooling, cooking power
and light to homes and offices. It takes
decades to move from one source of power to another. It’s hard to see how this could be
accomplished without great hardship and social chaos, which would slow the
conversion process down. Desperation is
likely to lead to stealing of key components of the new infrastructure to sell
for scrap metal, as is already happening in
Breeder reactors
Greenpeace has a critique of
nuclear power called Nuclear
Reactor Hazards (2005) which makes the following points:
1) As nuclear power plants age, components become embrittled,
corroded, and eroded. This can happen at
a microscopic level which is only detected when a pipe bursts. As a plant ages, the odds of severe incidents
increase. Although some components can
be replaced, failures in the reactor pressure vessel would lead to a
catastrophic release of radioactive material.
The risk of a nuclear accident grows significantly each year after 20
years. The average age of power plants
now, world-wide, is 21 years.
2) In a power blackout, if the emergency backup
generators don’t kick in, there is the risk of a meltdown. This happened recently in
3) 3rd generation nuclear plants are pigs
wearing lipstick – they’re just gussied up 2nd generation -- no
safer than existing plants.
4) Many failures are due to human error, and that will
always be the case, no matter how well future plants are designed.
5) Nuclear power plants are attractive targets for
terrorists now and future resource wars.
There are dozens of ways to attack nuclear and reprocessing plants. They are targets not only for the huge number
of deaths they would cause, but as a source of plutonium to make nuclear
bombs. It only takes a few kilograms to
make a weapon, and just a few micrograms to cause cancer.
If Greenpeace is right about
risks increasing after 20 years, then there’s bound to be a meltdown incident within
ten years, which would make it almost impossible to raise capital.
It’s already hard to raise
capital, because the owners want to be completely exempt from the costs of
nuclear meltdowns and other accidents.
That’s why no new plants have been built in the
The Energy Returned on
Energy Invested may be too low for investors as well. When you consider the energy required to
build a nuclear power plant, which needs tremendous amount of cement, steel
pipes, and other infrastructure, it could take a long time for the returned
energy to pay back the energy invested. The construction of 1970’s U.S. nuclear
power plants required 40 metric tons of steel and 190 cubic meters of concrete
per average megawatt of electricity generating capacity (Peterson 2003).
Never underestimate
NIMBYism, which is already preventing nuclear power plants from being built. The
political opposition to building thousands of nuclear plants will be impossible
to overcome.
The costs of treating
nuclear waste have skyrocketed. An
immensely expensive treatment plant to cleanup the
References
Dininny,
Gately, G.
Goodstein, D.
(Greenpeace)
H. Hirsch, et al. 2005. Nuclear Reactor Hazards: Ongoing Dangers of Operating
Nuclear Technology in the 21st Century http://www.greenpeace.org/raw/content/international/press/reports/nuclearreactorhazards.pdf
Hoyos, C.
(NAS) “It is clear, therefore, that by the
transition to a complete breeder-reactor program before the initial supply of
uranium 235 is exhausted, very much larger supplies of energy can be made
available than now exist. Failure to make
this transition would constitute one of the major disasters in human
history."
Peterson, P. 2003. Will the
Torres, M. “Uranium Depletion and Nuclear Power: Are We
at Peak Uranium?” http://www.theoildrum.com/node/2379#more
Wolfson,
R. 1993. Nuclear Choices: A Citizen's
Guide to Nuclear Technology. MIT Press
1)
Ultimately dams silt up, usually within 25 to 200 years, so hydropower is
not a renewable source of power.
2)
We’ve already dammed up the best rivers. There are now more than 45,000
dams around the world, affecting more than half -- 172 out of 292 -- of the
globe's large river systems.
3)
Damming prevents salmon and other fish migration.
4)
We've built dams in more than half of the large river systems and have
decreased the amount of sediment flowing to the world's coasts by nearly 20
percent. This is causing long-term harm
to the world's river ecosystems and raising risks that many coastal areas --
sometimes hundreds of miles from the dams -- will be flooded soon because they
are deprived of sediments that help offset soil erosion. The harmful effects of
ebbing soil deposits will be accelerated by the rising sea levels caused by
global warming, say the researchers.
More than 37% of the world's population, or over 2.1 billion people,
live within 93 miles of a coast.
5)
Dams are reducing biodiversity
The most important reason
renewable energy sources will never be able to replace fossil fuels: the energy
to build windmills, solar panels, and so on, takes more energy than what is
delivered.
Take windmills for
instance. When all of the oil is gone,
windmills must make more windmills solely on windmill power. Windmill power must be stored to concentrate
the power enough to do useful work. So
right off the bat, windmills must not only be able to generate enough power to
build mining equipment and factories to mine iron ore to make more windmills
out of steel with, the windmill is also making batteries from start to
finish. Plus all of the components of
the electrical grid to deliver the windmill power to customers. All of the components need to be delivered,
the people who make the components need to use windmill energy to get to work,
and the windmills have of course, made all of the tractors, trains, trucks, and
other components of agriculture so the windmill workers don’t go hungry. Now finally, if there’s any extra energy
after all this energy expended to make more windmills, finally other people
outside of the windmill industry can have some power.
Whatever problems fossil
fuels might have, they contain orders of magnitude more energy than renewable
sources such as wind, solar, hydrogen, and biomass. Replacing them with renewable energy sources
has several major challenges:
1) The main problem facing us is the need for a liquid
transportation fuel that can be used in existing vehicles. Solar, nuclear,
wind, geothermal, wave, and tidal power don’t address this need.
2) Natural gas based nitrogen fertilizers have allowed up
to five times as much food to be grown as could grown otherwise, and that plus
mechanization from planting to harvesting, and oil-based distribution and
processing has allowed an extra four to six billion people to exist on the
planet than could otherwise be supported.
There are no renewable energy sources that can fertilize plants, except
for guano, and there are very finite amounts of that. Bat guano used to be so important to farmers
that the U.S. Congress passed the Guano Islands Act in 1856. This allowed
3) Most renewable energy (except oils from plants) can’t
replace the half million products made from the complex hydro-carbon chains
contained in fossil fuels, such as plastic, medicine, paint, pesticide, etc.
4) Renewables such as wind and solar are very diffuse
and need large collection areas to capture their energy in real time.
The energy-literate scoff at perpetual motion, free energy, and cold fusion, but what about the hydrogen economy? Before we invest trillions of dollars, let’s take a hydrogen car out for a spin. You will discover that hydrogen is the least likely of all the alternative energies to solve our transportation problems. Hydrogen uses more energy than you get out of it. The only winners in the hydrogen scam are large auto companies receiving billions of dollars via the FreedomCAR Initiative to build hydrogen vehicles. And most importantly, the real problem that needs to be solved is how to build hydrogen trucks, so we can plant, harvest, and deliver food and other goods.
Hydrogen isn’t an energy source – it’s an energy carrier, like a battery. You have to make it and put energy into it, both of which take energy. Hydrogen has been used commercially for decades, so at least we don't have to figure out how to do this, or what the cheapest, most efficient method is.
Ninety-six percent of hydrogen is made from fossil fuels,
mainly to refine oil and hydrogenate vegetable oil--the kind that gives you
heart attacks (1). In the
Only four percent of hydrogen is made from water. This is done with electricity, in a process called electrolysis. Hydrogen is only made from water when the hydrogen must be extremely pure. Most electricity is generated from fossil fuel driven plants that are, on average, 30% efficient. Where does the other seventy percent of the energy go? Most is lost as heat, and some as it travels through the power grid.
Electrolysis is 70% efficient. To calculate the overall efficiency of making hydrogen from water, the standard equation is to multiply the efficiency of each step. In this case you would multiply the 30% efficient power plant times the 70% efficient electrolysis to get an overall efficiency of 20%. This means you have used four units of energy to create one unit of hydrogen energy (3).
Obtaining hydrogen from fossil fuels as a feedstock or an energy source is a bit perverse, since the whole point is to avoid using fossil fuels. The goal is to use renewable energy to make hydrogen from water via electrolysis.
Current wind turbines can generate electricity at 30-40% efficiency, producing hydrogen at an overall 25% efficiency (.35 wind electricity * .70 electrolysis of water), or 3 units of wind energy to get 1 unit of hydrogen energy. When the wind is blowing, that is.
The best solar cells available on a large scale have an efficiency of ten percent when the sun is shining, or nine units of energy to get 1 hydrogen unit of energy (.10 * .70). But that’s not bad compared to biological hydrogen. If you use algae that make hydrogen as a byproduct, the efficiency is about .1%, or more than 99 units of energy to get one hydrogen unit of energy (4).
No matter how you look at it, producing hydrogen from water is an energy sink. If you don't understand this concept, please mail me ten dollars and I'll send you back a dollar.
Hydrogen can be made from biomass, but then these problems arise (5):