Fuel use in agriculture..., pending

I have made the point on this blog before that depletion of fossil fuels is scary, in part, because we need fuel to grow, process and transport food. I promised that I would write a post on this topic but I have been pre-occupied with planting switchgrass and harvesting canola.

I’ve started working on this post though! Here is what I have so far.

I have constructed the following flow-chart as a way of diagrammatically expressing where fuel is utilized in the food-production chain. What should be apparent is that even this simplistic account of food production shows that trying to quantify fuel use in such a system is extremely hard. This is because fuel (and more broadly, energy) is needed in all steps of the process and the quantities used are dependent on multiple variable factors. In the end, we may not have adequate data and it will become necessary to make assumptions.

Dr David Pimentel, whom I think belongs to the College of Agriculture and Life Sciences at Cornell University, rose to prominence a few years back when he wrote a paper stating that all biofuels provide less energy than is required to grow them. The reason there is controversy regarding this is that other work says exactly the opposite. I think part of the reason for these differing opinions is that people are making different assumptions about energy use.

The good news is that various papers, extension services and statistics resources do provide some information about fuel use in the food production stream. The following PDF extract gives an example of this. So when I get some time I will work through these and try to estimate whether we are all going to starve.

John Howard and HIV

"Prime Minister John Howard has canvassed changing the law to prevent HIV positive people from being able to migrate to Australia."

....That will do nicely!

We can't believe Howard is making an issue out of this - it just CAN'T actually be an issue of any significance to Australia.

Think about it:

Australia took 131,539 permanent migrants in 2005-2006.

94,382 of these were under the migration program, 60,000 skilled migrants, 34,000 family based migrants, 12,113 humanitarian migrants, and 25,098 "nonprogram" arrivals.

If we consider that the hot spots for HIV are Africa and South Asia, we have an annual pool of less than 25,000 migrants who are from these regions (98% of the humanitarian class are from Africa/Middle East; 12% of the migrant class are from South Asia).

However, it is probably a fair assumption that educated and skilled migrants are unlikely to have a high % of HIV positive people. So the HIV rate of these migrants will not be representative of the average HIV rate of their home country and will instead be lower (probably vastly lower).

So the small number of people with HIV who will be coming to Australia are likely to be family members of skilled migrants or people we are accepting for humanitarian reasons. Assuming that there are limited grounds for objecting to families bringing infected loved ones to live with them and care for them, we can perhaps fairly focus upon the humanitarian migrants.

In 2005-2006 the major migrant-source regions were the Middle East and Africa, with the majority of migrants arriving from the Sudan and Egypt. The HIV prevalence ratio for the Sudan and the Middle East are around 2% and 0.1% respectively. Call it an average of 1%. This makes the total number of HIV positive migrants from these regions about 12 people a year, assuming that migrants are representative of demographics of the country (for instance, almost all HIV infections in the Sudan are believed to be associated with prostitutes and their clients).
The costs for anti-retroviral therapy range from 2-20,000 dollars a year, with a typical 3-drug therapy pegged at around $11,000 a year. So a worst "typical" case would result a cost of $240,000 per year.

Sure, there is a case to be made that the Australian tax payers should not have to face that cost burden... however this burden is less than a cent per tax payer per year! We are meant to be accepting these people for humanitarian reasons! Goddammit, it should be mandatory to take some folks with HIV. Call it a compulsory donation towards alleviating the horror of life for the unfortunate in the world.

On this basis, we could assume that Howard is once again targeting the most vulnerable of the migration categories, those brought in under the humanitarian program, most of which are from Africa and the middle east, purely for political reasons. He is playing the politics of division again knowing that a) Kevin Rudd won't have thought about this particular issue; b) the old "wowser xenophobes" who still think you can catch HIV by thinking about it will be completely supportive; c) that if he exaggerates the extent of HIV-carrying migrants who're entering the country, many a tax-payer will say "hey, they can't migrate here to take my money! I had better vote for Howard!" Perhaps he is also trying to divert the public's attention from other problems he is facing, such as his governments gross inaction over climate change.

Dear Australia, please tell us you are not stupid enough to fall for this!

Fuel – needed for food, and other minor things

Quite a few people were interested in my previous post about biofuels, so I hope you like this one.

One thing before I start. The reason I am focusing on North Carolina in these posts (other than the fact that I live here) is that the Eastern United States, as a region, has some of the highest per capita fuel use in the world. So if we can reduce fuel use here to a sustainable level it should be possible to do it any where.

Moving on - I am obviously interested in biofuels but the reason for this is not that I am particularly concerned about climate change, which is what most people think about in regards to reasons for using biofuels (climate change could be a major a problem, don’t get me wrong). I am interested in biofuels because our civilization is reliant on abundant fuel for its very survival.

I don’t say that to be dramatic, I really mean it. As oil becomes scarce and more expensive it won’t simply be a matter of it being inconvenient or expensive to get from point A to point B when you want to. Which is the second thing most people of think of when we talk about fossil fuel depletion. It is a lot more serious than that. When oil becomes scarce and expensive people will be unable to commute to and from work, period. This will also cause serious economic disadvantage for people with lower income and those in outer suburbs or rural areas and the functioning of the economy will be impaired.

Additionally, and more seriously in my opinion, we need fuel to grow and transport food. The large population of humans on Earth is in part due to the fact that we can use farm machinery to cultivate vast areas of land. We could conceivably grow the same amount of food with higher labor inputs but imagine, for example, planting and harvesting the entire Australian wheat crop by hand. This would probably raise food prices substantially. Then how do we move the huge volumes of produce to people? If you think about this for a moment you will start to see my point.

In the previous post I looked at the ability of different biofuels to meet our energy demands. I concluded that we will need to dramatically reduce our energy needs in the future to live within a renewable resource base. The point of this post is to look at how we can reduce our energy use. This is a complicated subject so to make things easier I will focus on petrol use.

The data for this post comes from the following US government statistics websites http://www.bts.gov/ and http://www.census.gov/ .

To begin, lets look at the annual fuel usage of North Carolina if everyone traveled 400 kilometers a week (which is our weekly average travel distance) and drove either 1) a car getting 11 kilometers per liter, which is the national average fuel efficiency of an American car, 2) a car like our little Hyundai that is more efficient, 3) a hybrid like the Toyota Prius or 4) a magic car that gets twice the fuel efficiency of a Prius. Then let’s see how much of our fuel demand we can meet using 50 % of North Carolina’s pastoral land to grow Switchgrass, using all the same assumptions from my previous post.

This is what you get:

So, even if we all drove cars with magic efficiency we are still 80 % away from meeting our fuel needs with one of our best-prospect biofuels. So even though driving fuel efficient cars is important it is not going to lower fuel consumption sufficiently.

So what other options do we have to reduce fuel use?

Of course not everyone has to drive as far as I do each day which means my estimates are not exactly correct. So let’s look at some real figures.

The following table shows the breakdown of different types of commuting for people in the US. Assuming people in North Carolina conform to the national average then you can calculate the number of people in the state who use each form of transport:

This shows that about 7 million people a day drive to work. Of course nearly a million of these carpool so lets assume there are two people in a carpool car and divide this by 2. So people undertake about 6.6 million car trips in a working week.

This tells us that a simple way to reduce fuel use is to get some of the 76% of people who drive alone to carpool. I will deal with that later though.

The average national commuting speed in the US is 51 kilometers an hour so from that you can calculate how far people are driving using average commute times. Using the average fuel efficiency of 11 kilometers a liter you can estimate the amount of fuel used by these different length trips. This is what you get:

What is interesting about this graph is that the total fuel use amounts to 6.7 thousand megaliters a year, when the average petrol use in North Carolina is 16 thousand megaliters a year. My figures are estimates which may in-part explain this discrepancy, but it doesn’t explain all of it. I think what this shows is that over half the petrol in North Carolina is not being used for commuting/domestic use. So simply reducing domestic fuel use is not sufficient to reduce total fuel use, but lets not worry about that for the moment.

What is also interesting is that over 60 % of trips are less than 30 minutes one way, which is approximately 18 kilometers or less. I personally think anything less than 10 kilometers is easy to do on a bike. Perhaps not for a trip to the shops but for regular commuting to an office, for example, where you can access showers and a change of clothes, it is easy. I used to commute 12 kilometers to work by bike with no problems. According to the previous table a paltry 0.3 % of commutes are done by bike so increasing bike use could be one way to drastically reduce fuel consumption.

Another way to reduce fuel use could be to increase public transport use. A standard diesel bus gets about 4 kilometers per liter of diesel. So if we assume a bus has an average of 20 people on it this works out as about 260 L of diesel per person annually. Diesel and petrol use are not directly comparable but that aside people catching a bus use about 13 % of the petrol of an average car, this is vastly more efficient than a Prius. A train might be even more efficient but I don’t have that data at my fingertips.

And, as I mentioned before, a big way is too reduce fuel use per capita is to increase car pooling (i.e having two people in a car uses half the fuel per head).

So, lets say 60 % of people do something other than drive just themselves to work. If only 20 % of trips less than 30 minutes were by bike, only 20 % of trips were by bus and only 20 % of people you could save about 3.5 thousand megaliters of petrol, or 50 % of total petrol used for commuting purposes. Now THAT starts to be a big saving of fuel.

If everyone else not using these alternative transport options started using cars with twice the fuel efficiency the petrol used in commuting would be around 1.7 thousand megaliters a year. We COULD potentially meet this using biofuels if we used things like switchgrass and woody waste.

Of course there is the outstanding problem of fuel used in non-commuting applications - about 9.3 thousand megaliters worth of it. Of course part of this is non-commuting car use, so it will be in part met by increases in fuel efficiency. I haven’t found any information about where else the fuel is used, so I can’t recommend how to reduce the amount used. It could also be things like lawn mowers for example, which we could find alternatives for. If anyone can tell me that would be great.

So perhaps I can conclude this post by saying that in North Carolina we MIGHT be able to meet energy requirements currently met using petrol by using biofuels. This is without using crop land needed for food and not cutting down extra forests to grow things. However this can not be done with increases in fuel efficiency! People will need to change their lifestyles (oh no!) by using alternative transport options and working closer to home. Appropriate town planning might provide one way to do this, such as by providing convenient public transport, and more urban consolidation.

Stay tuned for the next post, where I will try to get my head around fuel needed for farming and transport of goods.

Alternative Fuels

Posted by: Nic





In keeping with my current job, the purpose of this post is to examine fuel usage in North Carolina and look at the ability of different alternative fuel options to meet the demand.



A summary of fuel use in North Carolina in 2006 is provided below. For comparison I have included fuel usage for Western Australia (us being from there, and all). I am getting ahead of myself, but what is interesting is that the per capita gasoline use in North Carolina is twice that of Western Australia, even though Western Australia could be considered a highly urbanized and car-dependent society.



I am going to look at three alterantive fuel sources - Canola for biodiesel, and winter wheat, switchgrass and poplar for ethanol.

Canola for Biodiesel

Currently about 170 thousand hectares of land are used for winter wheat production in North Carolina. This land could be used for Canola production and the oil from this used for biodiesel.

Assuming a Canola yield of around 2 T/ha and a recoverable oil yield of 45 % 150 ML of oil could be produced annually. Assuming a 100 % conversion efficiency of this oil to biodiesel this would only meet 3% of North Carolina’s annual diesel requirement.

Wheat for ethanol

The winter wheat production could instead be used to produce ethanol.

North Carolina’s winter wheat yield in 2006 was about 680 thousand tonnes. Assuming a starch content of about 65 % and a starch to ethanol conversion of 75 % this would produce about 300 ML of ethanol a year. Now, ethanol has a lower energy density than gasoline so this is equivalent to about 250 ML of petrol. So this would meet about 1.6 % of North Carolina’s gasoline needs.

Switchgrass for ethanol

Switchgrass (Panicum virgatum) is a fast growing perennial bunch grass which can yield about 10 T/ha annually.

North Carolina has about 8 hundred thousand hectares of pastoral land so let’s assume 50 % of this is turned over to Switchgrass production. Work shows that the ethanol production from Switchgrass is about 280 L/dry Tonne (this figure is rubbery though and technology change could increase it). This works out as 1200 ML of potential ethanol production (equivalent to about 1000 ML of petrol) or about 7.5 % of North Carolina’s gasoline needs

Short rotation woody crops for ethanol

The option exists to use woody biomass to make ethanol. We could use forest material in North Carolina but instead let’s assume we are using short rotation Poplars grown on 50 % of the pastoral land. Poplars can get about 17 T/ha which equates to about the equivalent of 1800 ML of gasoline or 13 % of North Carolina’s gasoline needs.

Energy yield per hectare

If you look at energy yield per hectare Switchgrass yields about twice the quantity of ethanol per land area that winter wheat does and Poplar nearly four times. So woody crops are more efficient for fuel production than grains.

Summary

The diagram below summarizes how much of North Carolinas gasoline usage could be off-set using these various alternative fuel sources.

What these simple calculations show is that common biofuel feedstocks can not meet the gasoline and diesel requirements of North Carolina.

I am not implying that biofuels should not be considered, as the third pie-chart shows, with increased energy efficiency biofuels could provide a large portion of energy requirments. What this tell us is that current energy use in North Carolina is simply unsustainable and people will need to adopt lower energy use. By my estimates people will need to use 1/8th the energy they currently do in order to reach a sustainable energy consumption.

References

Fuel useage statistics for North Carolina from the Energy Information Administration (http://www.eia.doe.gov/ ).

Western Australia fuel usage statistics from http://www.abareconomics.com/ and http://www.abs.gov.au/.

Oh, look, happy reunion

Nic is here! And there shall be great rejoicing in the land. While this piccy was supposed to go on contrabandvegemite, anyone else who uses Blogger will know that it has been having a *painful* week... and so this picture is now here. Just like Nic. Hurray!

Ok, so temperatures near freezing aren't my idea of fun, but the compensation is the pretty colours...these photos were taken from the top of the Duke Forest Hardwood tower, some 45 m above the ground (and swaying!), while I clung on for dear life and tried not to drop the camera.

We were at the forest to help Kim fix up the telescoping tower on the new Katul lab van...pretty cool...

The other side of Durham

Yeehah!

Just experienced a very revealing Friday Night in supposedly sleepy old Durham...and discovered the seething underbelly of this town is crankin'.

What was supposed to be merely a very funny night in company of the wryly domestic Amy Sedaris (local Comedienne extraordainaire) morphed into a tour of the Durham independent music scene at a bunch of local nightspots none of our party had really known existed, thanks to a local music festival called Troika (http://www.troikamusicfestival.org/).

Our $10 multi-venue tix lead us to see a local punk-lesbian-smash your drums type act at the very funky Jo and Joes; followed by the Mountain Goats (yeehah again!) at 304 Southern, and finally local gothic act Veronique Diabolique at Ringside, a wonderfully eclectic four story venue with two stages and topped off by a quiet bar that is decked out like the opium den of your dreams.

Waking late on Saturday morning I stumbled from bed and began the long walk back to where my bicycle had spent Friday night. Fall colours on the trees, soft sunlight and the feeling that I'd finally started to work out why so many locals say: "I love living here".

Oh, and Amy Sedaris is my new heroine. When I grow up, I'd like to be just like her... or at least to have a wardrobe just like hers.