

"Sustainable Energy - Without the Hot Air" by David JC MacKay - stakent
http://www.withouthotair.com

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electromagnetic
I seriously like the numbers he's giving. He actually outright states what the
theoretical max of certain technologies are, like if wind turbines covered the
whole of the UK we would only extract 200kWh/d per person (which would involve
the levelling of every city to blanket cover the country), and his estimate
for the UK is 195kWh/d per person of usage.

Even his best-case production estimate (which would basically turn the UK into
an importer of everything as 75% of our arable land would be producing
biofuels) he states we would only likely get 180kWh/d/p and that's assuming
the technologies don't conflict (like having 10sqM of PV _and_ 10sqM of solar
heaters on our roofs _per person_ \- so 80sqM of roof usage in a 4 person
house - would be feasible, especially considering the amount of people in high
rises). The actual estimates though, from the Institute of Electrical
Engineers and a half-dozen others, puts the estimate at ~18kWh/d/p of
renewable production, compared to our 180kWh/d/p of consumption. _Big gap_.

Basically our option if we want to cut carbon emissions as much as possible is
to go nuclear. The US has a consumption of 270kWh/d/p and Canada has a
consumption of 350kWh/d/p (due to heating use, in some places basically 8
months out of the year). Both the US and Canada are benefited by being the
3/4th largest country and the 2nd largest country, respectively, which might
make us capable of going green without nuclear, especially Canada.

However the infrastructure costs, employment costs and everything else will be
astronomical. Simply put the US cent/kWh cost for electricity generation
speaks worlds, in the UK it costs roughly 4 cents/kWh for nuclear, 7 cents/kWh
for onshore wind, and 11 cent/kWh for offshore wind. In Europe those costs can
jump to 15-20 cents/kWh for onshore and offshore respectively while nuclear
jumps only to 7 cents/kWh.

The usage of natural uranium in reactors and the reprocessing of fuel (MOX)
can significantly cut down on costs, especially considering that ~$300,000 of
palladium can be recovered from 1 ton of spent fuel during reprocessing. The
MOX can then make a second cycle, bringing up the palladium content per kilo
of fuel purchased. Palladium reprocessed from spent fuel is actually less
radioactive than a granite counter top, and due to its emission type and half-
life (6.5 million years) it eventually decays into silver.

~~~
khafra
Perhaps "like" is too strong a word, but it's rather bracing to get an idea of
how long high-energy civilization can last; barring some miracle like
practical, cheap fusion power appearing in the next decade.

If I were to make a comparison to a work of fiction, it wouldn't be to _Mad
Max_ or _The Day After Tomorrow_ ; but to _The Cold Equations_ , by Tom
Godwin.

~~~
electromagnetic
Nuclear can prolong us for a long time, uranium would basically be a stop gap
to full on conversion to thorium reactors, as it's 3 times more abundant than
uranium, but 550 times more abundant than U-235.

Basically nuclear would only be a stopgap to Fusion. Once fusion becomes
available, you can begin replacing fission with fusion. Existing nuclear power
plants have so much land reserved around them as a buffer zone that entire
fusion plants can be built on them without the requirement of any new land as
the old nuclear plants are decommissioned.

The ITER project currently puts the first commercial fusion plant in 2050,
however that's based on current funding and research. As fusion increasingly
becomes our only alternative I have a feeling the funding will begin going
through the roof. I still wouldn't bet on anything closer than 2035 though.

~~~
mnemonicsloth
1\. ITER (and NIF) may turn out to be irrelevant:
<http://www.technologyreview.com/business/23102/>

2\. It's been a while, but IIRC we're looking at at least 50 more years of
U-235 and maybe two centuries of plutonium and thorium (lowballing). I have a
hard time believing that there won't be even one revolutionary breakthrough in
how we use or generate energy in the next 150-250 years.

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wallflower
I like how he dispenses with the fallacy of saving energy by unplugging DC
adapters or TVs by focusing our attention on the high-energy cost activities
(heating and transportation).

5 minute shower * (5 gal/min) * (440 BTU [to heat water 85 degrees]/gal ) =
11000 BTU or 3.223kWh or ~16 hours of 200-watt HDTV

1 gallon of gasoline = 115000 BTU or 33.7kWh or 10 5-minute hot showers

~~~
electromagnetic
The ironic thing about bodily hygiene is that room temperature water is as
good at killing bacteria as warm or hot water, incidentally its effect is
negligible. Soap works better in warmer water, however as more and more people
use liquid soaps and hand washes its meaningless as the added surfactants
enable it to work just as well at lower temperatures. In fact many liquid
soaps are better at removing grease and dirt at lower temperatures than
standard soap is at better temperatures.

Then there's the whole problem that frequently washing your hands in warm
water without a good liquid soap (which typically contain antibacterial agents
too) can actually _increase_ the bacteria on your hands due to the added
moisture and temperature.

Dropping the temperature of your shower to room temperature will not only save
you significant amounts of energy but will wash you just as well. In fact
plumbing a cold water storage tank into your shower line and keeping it in a
well insulated area of your house, you can spend virtually nothing on heating
your shower water. Even adding a cold water storage tank to your shower line
will likely cut the energy usage of your shower in half even if you take a hot
shower. Most showers either run off a hot water tank (majorly inefficient) or
an on-demand hot water system (either one that replaces the hot water tank, or
a stand alone shower unit connected to your cold water line) and both ways end
up heating ground temperature water: water lines stay at ~55F, room temp is
between 68F-77F and a hot shower is 85F.

So even if you like a hot shower, simply adding a holding tank to the cold
water intake of your shower can reduce the amount of energy you use
phenomenally (potentially a 2/3 reduction). If you're in and out of a shower
in 5 minutes, you likely only need a 25 gal tank, but for an average household
I'd recommend perhaps a 100 gal tank, just in case.

~~~
jules
Also, shower shorter. 5 minutes is way more than enough.

~~~
electromagnetic
Your average guy maybe, but I doubt you'll get too many women or teenage girls
to shower inside of 5 minutes, especially if they have long hair. However a
shower longer than 10 minutes might as well be a bath as your average tub only
needs 60 gals to fill and your average shower pumps out 50 gals in 10 minutes.
So if you take your time showering, you might as well take even longer and
have a good bath instead.

After all a shower is supposed to be a fast alternative to a bath, if you take
forever in a shower you might as well go full hog.

~~~
philwelch
Baths don't seem to make much sense: you're soaking in the very filth you're
trying to clean off of yourself, and after you're done, you're still soapy so
you need to rinse off anyway. It also takes time to draw the bath, time that
you would otherwise be washing yourself.

When I was young though, I would close the drain, shower, and then take a bath
once the bathtub was full.

------
ugh
After 78 pages I now feel somewhat qualified to say something about the book:
It seems to be great. I like its non-preachy style and its very limited and
seemingly well executed approach of supplying the reader nearly exclusively
with baseline numbers. This is what we have – we only have to find out what we
can change and how.

I also like that for once I get a realistic and detailed approximation of my
energy usage. There are quite a few surprises in there.

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RoboTeddy
I read this a couple months ago and loved it. It's a physicist looking at the
hard numbers of energy consumption and (sustainable) production. It's the
opposite of all the wishy-washy environmentalist hand waving that's out there.

Read this if you've ever wondered about how leaving the lights on compares to
turning the heat down a degree compares to...

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sketerpot
This is the book to read if you want to understand sustainable energy issues.
The only part where it's weak is discussing the economics; I would have liked
more material on the costs and how to make sure they're manageable.

And yes, it's refreshing to see a book on this subject written by someone who
can do enough math not to fall for nonsense.

~~~
amirmc
I know this guy and he's pretty approachable. He was always keen to improve
the content of the book so get in touch if you've got comments.

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jonp
Another book of his on a different topic but with same great clarity of
explanation is "Information Theory, Inference, and Learning Algorithms". The
PDF is on his site at
<http://www.inference.phy.cam.ac.uk/mackay/itila/book.html>.

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adw
Incidentally, David Mackay's group came up with the Dasher eye-tracking user
interface and a bunch of cool machine-learning stuff; and for further HN cred,
one of his ex-postdocs is CTO of Songkick.

<http://www.inference.phy.cam.ac.uk/>

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xexers
I'm a bit confused. This author makes the future sound bleak, with impossible
choices. He makes it sound like wind, solar, geothermal, and hydro will never
be enough.

But then, you read a quote like this from another source and the solution
sounds almost easy:

"Less than 1% of the world's deserts, if covered with concentrating solar
power plants, could produce as much electricity as the world now uses."

<http://www.trec-uk.org.uk/images/CSP_map_squares2.jpg>

What am I missing?

~~~
mixmax
One of the major obstacles is that you don't just need power, you need power
on demand. Using current technology it's impossible to store electricity so it
needs to be used right away or it's lost. Wind, solar and many other forms of
green energy aren't dependable enough that you can rely on them as your only
power source. If the wind doesn't blow on a winter night you're going to have
a cold apartment if you're dependent on wind and solar.

There are experiments being done with transferring large amounts of
electricity across countries in Europe based on the assumption that it will
always be windy or sunny _somewhere_ and that if power can be transferred long
enough the uncertainty of supply will be cut drastically.

~~~
streety
You can convert the electrical energy to other forms of energy though and
store it that way. In following the link that nkurz gave the Andasol solar
power station was mentioned which apparently will store excess thermal energy
in liquid salt allowing electricity generation into the night. Pumped storage
hydroelectricity is another, more established, method of storage.

I don't envisage huge vats of molten salt meeting our energy needs throughout
the night but I suspect that energy storage will continue to have a part to
play in meeting our energy needs in the future. It seems to be relatively
expensive but then so is long distance transfer.

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jpcx01
Extremely smart book. Read most way through his draft version a few months
ago. Ordered it in paperback, looking forward to rereading the final copy.

Seems pretty up the middle as he tends to attack all sides who spout off
bullshit numbers. However, there's going to be a lot of political hate for
this book. Oh well, that's the world we live in. Truth and pure data analysis
is very under appreciated in todays hyper partisan political environment.

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kansando
Thank god for physicists.

~~~
stakent
To maintain balance we have politicians and bureaucrats.

~~~
jacoblyles
Balance along what spectrum? Rationality vs. Demagogy?

~~~
stakent
Yes.

Using numbers taken out of context to push own agenda.

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pieter
What a clear way of explaining the problem. Very readable graphs too, I'm
impressed!

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borism
what a lot of you seem to miss is that we need to start cutting on wasted
energy at the same time as we build more solar/wind/nuclear/tidal/etc.

it's not just about replacing hydrocarbons by equal amount of alternatives!

