Just how Safe are Fossil Fuels, Wind, Solar and Nuclear Power?

This article I'm going to compare safety for different form of electric generation.  Lets start with the energy deathprints.

Energy’s Deathprint

Energy's deathprint is a rarely talked about measure of the number of deaths per unit of energy produced for different power sources.  Here are the results from two studies on it.

From page 168 Sustainable energy without the hot air

As you can see coal, oil and biomass are particularly bad.  This is because of small particles released while burning thing (i.e. ash or fly ash).   These don't agree with people very much.  Not only do these particles cause deaths, but they also cause other health problems.  Some countries do a better job of filtering them out then others.  With a bit of searching you can find info for a variety of similar studies.   Here is another one.  I thought this review of it was particularly insightful. 

Carbon Footprints

Global Warming is a serious issue.  One study projects that...

Worldwide, upward of 20,000 air-pollution-related deaths per year per degree Celsius may be due to this greenhouse gas.

That's rather extrema considering how long the temperature changes are projected to last.  Here is a graph that shows the carbon footprint for various forms of electric generation. 

From Carbon footprint of electricity generation by Stephanie Baldwin

 The units for the graph are gCO^2eq /kwh.

From page 8 of Carbon footprint of electric generation.  I suggest reading the whole PDF.  It's not very long, and definitely worth it. 

Ranges in each electricity generation technology are due to

1. Differences between individual plants – some older and/or less efficient
    
2. Different technologies – e.g. run-of-river vs. reservoir storage
    
3. Different LCA input (boundary definition) parameters
    
4. Different studies – some studies older, so had older data (2000 was cutoff date)

In regards to the difference for nuclear power.  From page 18 of Carbon footprint of electric generation.

 Issues: 

1. Nuclear also has a very small carbon footprint 
2. Most CO 2 emitted during uranium mining (40% of life cycle CO2) 
3. Global uranium reserves – lower grades may cause footprint to rise in future 
4. 3 studies: AEA ( to 6.8g), Öko ( to 30-60g), Storm van Leeuwin ( 60 to 120g)

I would like to add to this that there are two important issues for understand nuclear power's carbon footprint.  One is the method of fuel enrichment.  Some have a bigger carbon footprint than others.  The other is the type of reactor.  Some reactors are able to use much more of the natural uranium mined then other which reduces their carbon footprint.  I'm really hopping we will start making more breeder reactors so we can use all of it. 

Radioisotopes Released into the Environment

I'll just give a brief description for coal, natural gas and nuclear power that will hopefully give you some idea about the radioisotopes (i.e. the stuff that produces radiation) they release into the environment.   For your information sometimes when people in the news talk about radiation they are talking about radioisotopes and sometimes they are talking about ionizing radiation.  If you’re not familiar with these concepts you may wish to read my post Some Basic Information Useful for Understanding Nuclear Power Safety.

Radioisotopes and fossil fuels 

There are radioisotopes mixed into almost everything.  This includes fossil fuels.  When you burn the fossil fuels these radioisotopes become more concentrated (in the ash) then they are in the natural environment.   This can result in people having more radiation exposure then they would otherwise. 

Radioisotopes Released by Coal

The main radiation release from coal  is in the form of fly ash.  In order to give you some idea about what this entails let me start out with a few quotes.

From the USGS -  Radioactive Elements in Coal and Fly Ash: Abundance, Forms, and Environmental Significance

Introduction
Coal is largely composed of organic matter, but it is the inorganic matter in coal—minerals and trace elements— that have been cited as possible causes of health, environmental, and technological problems associated with the use of coal. Some trace elements in coal are naturally radioactive. These radioactive elements include uranium (U), thorium (Th), and their numerous decay products, including radium (Ra) and radon (Rn). Although these elements are less chemically toxic than other coal constituents such as arsenic, selenium, or mercury, questions have been raised concerning possible risk from radiation. In order to accurately address these questions and to predict the mobility of radioactive elements during the coal fuel-cycle, it is important to determine the concentration, distribution, and form of radioactive elements in coal and fly ash.

Emphasis Added

10-30 ppm uranium in fly ash

10-30 ppm thorium in fly ash

From the EPA - Coal Fly Ash, Bottom Ash and Boiler Slag

In 2012, 59 percent of the coal consumed by electric utilities and independent power producers in the United States resulted in the generation of about 68 million tons of fly ash, bottom ash and boiler slag. An additional 42 million tons of other residuals were generated from flue gas desulfurization and fluidized bed combustion.

Fly ash is carried up with hot flue gases and trapped by stack filters. It is the largest of the coal combustion residuals (about half) by weight.

Stack filtration devices, such as electrostatic precipitators, baghouses and scrubbers are routinely used to reduce the emission of fly ash. They are about 99 percent effective. Only about one percent is released into the air.

Emphasis Added 

Now lets do a little math with these numbers.

68,000,000 tons * 50%  * 1% = 340,000 tons

So, in 2012, 59 percent of the coal consumed by electric utilities resulted in 340,000 tons of fly ash being released into the air.

((340,000 tons * 10ppm) / 1,000,000) * 2,000 lb./tons = 6,800 pounds*

((340,000 tons * 30 ppm) / 1,000,000) * 2,000 lb./ton = 20,400 pounds*

*assuming tons is short tons and ppm is a mass fraction.

Extrapolating for the other 41% we get...

6,800 lb / .59 ≃ 12,000 pounds
20,400 lb / .59 ≃ 35,000 pounds

So in 2012, we had roughly between 12,000 and 35,000 pounds of radioactive uranium and roughly between 12,000 and 35,000 pounds of radioactive Thorium being released into the air by  electric utilities resulted. If it wasn’t for the consumption of coal in production electricity this Thorium and Uranium would have remained under ground where it couldn’t possibly hurt anyone. Instead it was released into the air in the form of small particles which often end up the the lungs of people and animals.

Now lets talk about Radon 

Radon is a colourless odorless gas that is responsible for a large part of people's yearly radiation dose from natural sources.  So let try and figure out how much radon is release from a years worth of coal.

In the Us 858,000,000 Short tons of coal a burnt each year.  There is around 1 to 3 parts per million uranium in Us coal.   So there is between 858 and 2574 tons of uranium in a years worth of coal.  

Assuming that the amount of uranium has stayed basically constant over the years, that none of the decay chain products have left the coal and that the decay products move through the chain at roughly the same speed (all fairly safe assumption to make), then the Radon produced each year by the coal equals the uranium 238 that decays each year.

So between...

  (9,600 Gd/sec   X  3.15569e7 sec. / 6.02214129×10²³) X 222 ≃ .11Grams
   decays a sec         in a year                 1 Mole                   mass Rn-222


  (29,000 Gd/sec  X  3.15569e7 sec. / 6.02214129×10²³ ) X 222 ≃ .23 Grams
     decays a sec       in  a year                  1 Mole                   mass Rn-222


So a years worth of coal in America creates around .11 to .23 grams or 590 to 1,800 TBq of radioactive gas. Of course this says nothing about where it's released, and it also says nothing about the addition Rn-222 that it will continue to released from the coal ash ponds for years to come.

So should we all panic and run for the hills? 

Probably not.

According to the first source.

The radiation hazard from airborne emissions of coal-fired power plants was evaluated in a series of studies conducted from 1975–1985. These studies concluded that the maximum radiation dose to an individual living within 1 km of a modern power plant is equivalent to a minor, perhaps 1 to 5 percent.

 From a more recent study.

McBride and his co-authors estimated that individuals living near coal-fired installations are exposed to a maximum of 1.9 millirems of fly ash radiation yearly. To put these numbers in perspective, the average person encounters 360 millirems of annual "background radiation" from natural and man-made sources, including substances in Earth's crust, cosmic rays, residue from nuclear tests and smoke detectors.

There are a lot of radioisotopes in the coal all the Us burns each year, but not all of it ever reaches the public (Most fly ash is captured and stored),  Radon-222 has a half life of only 3.8 days so it's unlikely to get to far plus it will quickly be diluted in as it spreads out from the plant and also the radio isotopes in coal aren't that concentrated to begin with although burning it makes them  somewhat more so. 

Radioisotopes Released by Natural Gas

I know what you're thinking.  They couldn't possible pump radioactive gas into our homes right?  Well...

It has been known for over 40 years that radon, a radioactive gas, is present in natural gas. Reports by R.H. Johnson 7 and C.V. Gogolak 8 calculate the health effects due to burning natural gas in kitchen stoves and space heaters. In an US Environmental Protection Agency report, Raymond Johnson calculate s the number of lung cancer deaths due to inhalation of radon in homes throughout the U.S. as 95 due to radon concentrations in the pipeline of 37 pCi/L.

Yikes. By the way that quote came from this study that estimates the problem is much worse in New York because of gas from the Marcellus shale.  It estimates that the gas from the Marcellus shale raises the death toll by 1,182 to 30,448 a year.  That is a significant number.  Here is a blog post contesting that study. Unfortunately neither the study or the blog post that contests it have actual measurements from the Marcellus shale well heads.  Something you would think someone would want to take.

While this all sounds scary it should be noted that there is controversy in regards to the effect of low level radiation. 

Radioisotopes Released by Nuclear Power

Here is an awesome graphic that explains it all.

Source http://xkcd.com/radiation/

Conclusion

There isn't one really.  I hope learned something and you enjoyed it.

Is this What They Mean by Clean Energy?

Germany is destroying whole towns in order to power their country.



Wind and solar require other power sources when the wind isn't blowing or the sun isn't shining.

If those other sources are coal then they bear part of the responsibility.

Both Low EROEI and Low Power Density is a Serious Problem - Wind Addition

In my last post I talked about how having both low EROEI and low power density is a serious problem.  I used solar as an example.  In the comment section someone mentioned something about 80% of our power coming from wind, but wind isn't much better. It has a higher EROEI, but it's power density is terrible.  I'll explain below. 

If you haven't read the last article you might want to do so now.

First I'll start with the sources.

Source One - Catch 22 of energy storage.

EROEI for wind with storage is 3.9. 

Source Two - Sustainable Energy — without the hot air

The red stack (i.e. energy consumption) in figure 18.1 adds up to 195 kWh per day per person (page 103).

4,000 m^2 land per person in UK.  

Source Three - Rethinking wind power

Keith’s research has shown that the generating capacity of very large wind power installations (larger than 100 square kilometers) may peak at between 0.5 and 1 watts per square meter.

Now lets think about it a little.

Lets start by talking a bit about EROEI.   The comment that inspired this post gave me a link that says EROEI is meaningless.  I disagree.  EROEI is very important when it gets close to one.  I'll explain but first let start with this definition from Wikipedia for anyone unfamiliar with the term.

In physics, energy economics and ecological energetics, energy returned on energy invested (EROEI or ERoEI); or energy return on investment (EROI), is the ratio of the amount of usable energy acquired from a particular energy resource to the amount of energy expended to obtain that energy resource.

EROEI is important because it creates a multiplier effect for other quantities.  Other quantities include things like space, different material and man power.   The closer EROEI gets to one the closer the need for those other quantities get's to infinity.

For example:

Imagine that you had a some solar panels that had a EROEI of 2. One meter square of them produces let say 5 watts average. For simplicity's sake lets stick with only this one kind of power source for now.

If you wanted to get 5 watts from these panels you would need both the one meter squared, plus another half a meter squared to maintain the one meter squared, plus another quarter meter square to maintain the half meter square and so forth.  This goes on endlessly, and when you sum up the results you get the multiplier.

∑n=0∞12n=1+121+122+...+12n+...=2

Thanks to Mark44 on physics forums for this!

Now lets talk about the multiplier

The multiplier works for all quantities not just area.

For example:

if it take 5 people to maintain some generation that produces 5 watts and the multiplier is 3 then that 5 watts really needs 15 people (5 X 3 =15).

Here is the formula you need to figgure out the multiplier for any given EROEIs.

Where X = EROEI

This doesn't only apply to a one power source systems.  Any power source that with EROEI close to one would require outrageous amounts of different resources in order to contribute significantly to our total energy supply.  

Now for Wind

The multiplier for wind isn't that bad, but the power density is crap.  At between 0.5 and 1 watts per square meter even if you covered the whole of the UK with wind turbines the yield would still kind of suck.

Here's the math

4,000 m^2 is space in uk for each person.

1.34 is the multiplier for wind

So...

4000 / 1.34 ≃ 3,000

Around 3,000 is how much possible space for wind for each person when you minus the space for wind turbines needed to maintain the system.

So between...

           (3,000 * .5 * 24)/1,000   ≃ 36  kWh per day per person

           (3,000 * 1 *  24)/1,000   ≃ 72  kWh per day per person


So maybe you can get close to 80% if you cover the whole of the UK with wind farms (assuming the EROEI doesn't drop because of diminishing returns).  Do you think people can really cover so much of the UK with renewable energy?  What about space they need for other things like energy storage.  It's really hard for me to believe, and even if you could I think it would be pretty horrible.  

The Hidden Costs of Wind and Solar: Part II intermittency (i.e. variability)

Wind and solar are intermittent (i.e. The wind isn't always blowing and the sun isn’t always shining).  This creates costs that need to be accounted for properly.

Lets start by talking about the electric grid sense understand it is important for understanding the issues with intermittency.  With the electric grids the amount of electric power produced always needs to equal the amount used.  Matching production and use with uncontrollable and difficult to predict sources like wind and solar can be tricky. Things like clouds and changes in wind speed can cause problems.  One way of understanding this problem is to think of the electric like a giant bucket.

"The Western Grid is like a giant bucket," said Mark Avery, SRP's grid manager "with a bunch of spouts running in and out, and you have to keep the water level constant." The Denver Post

Picturing the electric grid as a giant bucket. Some people are taking cups of water (electric power) and pouring them into the bucket while others are taking cups of water out of the bucket. If the bucket become empty it’s bad because people can’t get their water, and it’s also bad if the bucket gets too much water and starts overflowing. The water in the bucket isn't very deep (just enough for someone to get a cup full) so the rate of the water going into the bucket has to precisely match the rate of the water coming out of the bucket. If there is only one person drawing water from the bucket this can be difficult to do. One person is fairly unpredictable. What if he all the sudden decides he wants a lot of water, or what if he all the sudden decides he doesn't need any for a while. This makes load following (i.e. making sure the right level of water is always present) more difficult and less efficient.  Lucky the actions of a lot of people average out into something much easier to predict. So in order to deal with the problem they made the buck wider (but still just as deep) so many people can draw out their cups of water at once.

This system worked well enough (most of the time). Then one day some new people (i.e. wind and solar advocates) decided that they wanted to put their cups of water into the bucket as well, but other people didn't want them to because they couldn't control when they put the water into the bucket, and because they also couldn't predict it with perfect accuracy. The new people said it would be fine, and that just like with people taking water out of the bucket things would become more predictable if they just made the buck wider so more people could put their cups of water into the bucket at once. Then once things became predictable the people that could control the rate they put water into the bucket would help match everything up.

So how well does this new way work?  Opinions vary, but personally I am very sceptical that adding different types of unpredictability together will somehow make things more manageable. One thing’s for certain, the electric grid is not really a bucket. It is an expensive complex machine, and making it do what the renewable energy advocates want makes it even more complex and expensive. I think that’s why they are always saying things like “we need to upgrade our archaic electric grid” or “we need a smart grid”. Sure the electric grid (just like roads) needs maintenance, occasion expansions and even upgrades; but I believe that the biggest reason they are pushing so hard is because they want the money needed to integrate more solar pv and wind without having to included that money in the costs of those technologies.

So what happens when things don't match up?  Well larger difference cause Power outages while smaller differences cause other power quality issues.  Both of these things have costs.   A Berkeley Lab Study estimates that power interruptions cost the US $80 Billion annually.

Lets talk a little bit more about power quality.   What is power quality?  Opinions vary but here is one definition I found useful.

"Power quality is simply the interaction of electrical power with electrical equipment. If electrical equipment operates correctly and reliably without being damaged or stressed, we would say that the electrical power is of good quality. On the other hand, if the electrical equipment malfunctions, is unreliable, or is damaged during normal usage, we would suspect that the power quality is poor."

We have standard for voltage, frequency and phase.  Then we make devices that run off those standards.  If the power difference to much from the standard then devices won't work properly or they can even be damaged.  Both Solar pv and wind can cause power quality issues (e.g. can deregulate line voltages and sometimes in extreme circumstances even shifting the line phase ).  Google the words wind and solar along with power quality and you can learn about the various issues and proposed solutions, or you can watch this video (I highly recommended it).  There are sighs Germany is already having problems  with it’s level of penetration.

"short interruptions in the grid has increased by 29 per cent in the past three years – resulting in some firms on the grid reporting damage running into hundreds of thousands of euros as a result of unexpected stoppages."

Manufacturing requires good power quality which solar/wind can have trouble supplying. This is especially true for manufacturing high tech things like solar panels. There have been attempts to deal with the problem with things like battery back up at the source, but there are still signs that large amounts of wind and solar can cause problems.  In order to cope with these problems  manufactures need to spend money on special systems (for example system that use battery backup), but such things have costs.  However the problem is dealt with (e.g. at the source, smart grids and/or making the end users deal with it) there are costs that should be included in the price of wind and solar.

The variability of wind and solar means that other types of energy generation have to ramp up and down more often in order to match electric production with use.   This creates inefficiencies which have costs that should be attributed to wind and solar.

A good way to understand these inefficiencies is to compare electric generation to something  most people are familiar with.   Cars are more efficient when they are driven a certain way.  For example.

"While each vehicle reaches its optimal fuel economy at a different speed (or range of speeds), gas mileage usually decreases rapidly at speeds above 50 mph."

Power plants also have an optimal fuel economy when operated at a certain continuous output.   They call plants made to operate at their optimal fuel economy Base load Power Plants and anything that causes them to very from their continuous optimal output  creates inefficiencies that have costs.  Some of that cost should be attributed to wind and solar (The rest of it should be attributed to things like changing demand).

It's important to note that power plant not operating at their optimal output because they are being used for load following(i.e. being used to help match electric production with use) are performing a service for the gird.  This service is called spinning reserve and studies have been conducted to try and estimate how much it costs.  One such study is quoted below.

"An expected finding from case studies made to date is that the specific cost of power generated in spinning reserve mode is quite high compared to the optimum cost of power from the same unit. This is, of course, due to the poor heat rate of most thermal power units at low load. If the unit could have operated at high load instead of spinning reserve, there is a lost opportunity cost which may double the cost of the spinning reserve service."

Next is another comparison between cars and power plants.

"Idling can use a quarter to a half gallon of fuel per hour, depending on engine size and air conditioner (AC) use. Turn off your engine when your vehicle is parked. It only takes a few seconds worth of fuel to restart your vehicle. Turning your engine on and off excessively, however, may increase starter wear."

Unlike internal combustion engines base load power plants can't start up that easily (Some can take more than 12 hours to reach full load).  How long it takes to start a base load power plant varies based on numerous factors.  One such factor is how hot it is.  Cold starts take the longest while warm and hot starts take less time.  Trying to get the plant online too fast can result in unnecessary plant failure or wear.  This bring us to another cost that is increased by intermittency.    Intermittency increases Power Plant Cycling Costs.   Power Plant Cycling Costs are the increased costs of maintenance and forced outages caused by things like turning the plant on/off, load following, and minimum load operation, in response to changes in system load requirements.  There are ways to reduce these costs like keeping the plants hot, but such things also have costs.

Another costs of intermittency is as the cost of underutilized capital assets.  A good example of an underutilized capital asset would be a power plant that only runs a few month out of the year when its too cloudy for solar pv, or a transmission line going to a wind farm that has to be build to handle that wind farm’s maximum capacity even though on average the wind farm only delivers 30 percent of that.  Here is a good example of the problem from Germany.

As you can see there are days in January with almost no wind or solar production.   The question you might be asking yourself is how do they get power when wind and solar aren't there for them.  What happens is that people end up having to have two power systems.  The conventional power system (mostly coal in Germany) which is able to meat all of the countries needs plus an extra wind and solar system which can't be relied upon.   Both of these systems have to be paid for which as you can imagination is quit costly.   A lot of people seem to think that some costs don’t count, but if people want to continue to enjoy electricity on demand 24/7/365 then they do count and they need to get paid.

In conclusion there are reasons why electric prices are higher in places that embrace solar and wind.  The sticker price they show you isn't even close to all that you'll have to fork out.  This shouldn't be allowed to go on.  There need to be a better accounting of the true costs of producing electricity with different methods.  Some people have already started on it, but a lot more work need to be done.

Update Mar 4 2015:  Made some changes on things I didn't like. 

The Hidden Costs of Wind and Solar: Part I Power Density

Renewable energy is a strange term. What does it really mean to be renewable when even that giant nuclear reactor is the sky will burn itself out eventually? Looking at a dictionary we get this.

“Any naturally occurring, theoretically inexhaustible source of energy, as biomass, solar, wind, tidal, wave, and hydroelectric power, that is not derived from fossil or nuclear fuel.”

So renewable energy has to not be derived from fossil or nuclear fuel, yet the sun uses nuclear fuel, and most thing that go under the title renewable energy (i.e. biomass, solar, wind, tidal, wave, and hydroelectric power) are derived derived from sunlight so this definition contradicts itself.

Personally I think that “renewable” is just a rhetorical device used to try to make certain types of energy seem better than the alternatives, but my purpose here isn’t just to criticize people’s terminology. Really when people are talking about switching to renewable energy they are talking about wind turbines and solar pv. These are the two ‘white knights’ that people think are going to save us all from the evil nuclear and fossil fuel industry, so these are the two energy sources I’m going to talk about.

The cost of wind, and solar can be placed in two categories. One category includes things like the cost of things like wind turbines, solar panels and grid tied inverters. There are plenty of sources that talk about those costs so I’m not going to. Instead I’m going to talk about the second category which is the hidden costs of wind and solar pv.

The two biggest sources for the hidden costs of wind and solar are their low power density, and the intermittency of those sources.

Power density is the power per unit of area. It’s an important consideration because it describes how much space you need to fill your energy requirements. The power density of wind and solar are low, which means that to supply most of our power from such sources would require a lot of land. To give you an idea of how much consider this. One estimate of the power density of solar pv is 10 w/m^2(see page 41), and in 2011 the U.S. Generated 4,100,656 Gwh. These two facts taken together tell us that if we generating all of our electricity with solar pv in 2011 then it would have taken 46,811 square kilometers ( or 18,074 square miles). That’s roughly the area of all the roads in the US (roads occupy 17,879 square miles of the land in the contiguous 48 states). Those roads weren’t easy or cheep to build or maintain; can you imagine how much harder such a massive solar project would be? Of course this is all academic. You can’t really power the whole country with solar pv because solar pv doesn’t work at night.

Estimates for the power density of wind have been around 2 to 7 w/m^2, but new research suggests that the power density of large wind farms may actually be as low as .5 to 1 w/m^2 (Imagine wind turbines covering an area that is 10 to 20 times the area of all the roads in the US).

 “Energy from coal can also be made almost anywhere. But to make electricity from wind, the generator has to be where the resource is, and for wind, that means places with few major power lines. “ Matthew L. Wald in New York Times article. 

Power density is important (especially for wind) which is why people try to situate wind and solar in places where the power density is highest. This means a lot of transmission lines are needed to get the power to where it’s used and those transmission lines have a cost that needs to be accounted for. One source estimates that in the US between 2010 and 2030 the cost of without "renewables" would be $18.5 and the cost with "renewables" would be $115.2 billion.   Also, some people argue that there are aesthetic costs (i.e. it lowers property values) to having wind turbines, solar panels and transmission lines all over the place.

If you wish to know more about Power density please read this PDF Sustainable Energy — Without the Hot Air.   It is written by David J.C. MacKay FRS Regius Professor of Engineering Cambridge University Engineering Department. In it he explain many of the important issues in detail in a very reader-friendly way. I would recommend it to anyone interested in the subject. It’s a bit long, but it really is worth it.