"Sustainable Energy - Without the Hot Air" by David JC MacKay
withouthotair.com
withouthotair.com
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.
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.
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.
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.
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
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.
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.
When I was young though, I would close the drain, shower, and then take a bath once the bathtub was full.
Also, you don't need to be heating your water to 150 degrees (65 + 85). In fact, that's dangerously hot. Even if you did have your water heater set that high, you'd be diluting the stream substantially with cold water to get it back down to a comfortable temperature.
Between these two, it would appear that he's easily off by a factor of 5 or so.
However, this is what the book encourages. To learn how to make your own calculations and understand the numbers bandied about in the media about energy and energy systems.
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.
Read this if you've ever wondered about how leaving the lights on compares to turning the heat down a degree compares to...
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.
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?
1) His general point is that no single energy source will be sufficient. We're going to need a combination of many different sources of power, combined with as much improvement in efficiency as we can muster. He concludes that it is very difficult, but not impossible, and that tradeoffs will be necessary.
2) Covering the electrical needs of the world is an easier task than covering the total energy needs, and even covering the current energy needs will not account for increasing demand by the developing world. Still, this is an approach worth exploring. It's covered in considerable detail in Chapter 25: http://www.inference.phy.cam.ac.uk/withouthotair/c25/page_17...
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.
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.
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.
Using numbers taken out of context to push own agenda.
it's not just about replacing hydrocarbons by equal amount of alternatives!