Biofuels

[Prime-Evil]

What's up with biofuels. Seems to me to be the wrong way to go, except perhaps in specific situations. I am thinking specifically about growing corn to make ethanol or growing canola to make biodiesel, or even the way we manage woodlots for cordwood, which is often no better than clearcutting, but on a smaller scale.

 

Reasons I am opposed to biofuels:

1. The yield per acre is very poor compared to wind energy and solar energy.

2. We tend to burn alot of fossil fuels growing and processing these biofuels.

3. They are often grown in such a way that reduces biodiversity, reduces total biomass, and leads to soil degradation and ultimately erosion, desoilification, and desertification.

4. Often risk of forest fire is cited as a reason for removing more biomass from the woods. I believe this is a mistake. In many cases I believe the woods are dry because they have been managed to intensively. The challenge is in finding a way to return it to a more natural state of moisture content before it burns extensively.

 

Exceptions:

1. If in a good year there is a bumper crop, then perhaps turning the surplus into biofuel as opposed to having it go to waste is a good option.

2. For the small woodlot owner that manages there land in such a way that the total biomass and biodiversity is increasing over time and the soil quality and biomass is ever increasing, then perhaps a certain amount of biomass could be harvested by selective cutting, or even fairly intensive coppice management in some areas, such as hedgerows, while allowing other areas to grow, and decay, naturally.

 

Summary:

In general I thing the agricultural land and forest lands of North Americal are already managed to intensively and we should not look to them as a source of alternative energy. Instead of using more fossil fuels to growing more corn to produce ethanol, we should instead find ways to grow our food using less energy. If we eat less meat we can return more land to forest land, and with more forest land, and by using less paper, we can manage our forests less intensively and grow more mature lumber products with less energy. Wind power is very compatible with agriculture. This should be the alternative source of energy from agriculture, not ethanol or biodiesel or cordwood. Finally, we should grow more trees and less grass in our suburbs. Instead of connecting our cities by cutting roads through our forests we need to start reconnecting our forests and wetlands by growing forests and reestablishing streams and marshes through our cities and suburbs.

[daneeka]

Yeah I agree that biofeuls aren't much of a solution to the whole energy problem. I mean most intensive agriculture is not sustainable so it seems kind of daft to replace one unsustainable activity with another.

 

It's all to do with consumption habbits though. We have essentially been conditioned into thinking that consuming excessively is entirely appropriate; and we keep trying to dream up ways that will allow us to continue living the life-styles we are used to. You'd think, with all the insight we've developed over the years regarding all the problems created by gross-comsumption, that we would make a conscious effort to change.

[Prime-Evil]

I agree.

Our whole economy is geared towards inefficiency and waste.

Oil is just the fuel and the lubricant.

 

It isn't enough to replace the oil.

We have to change gears also.

[Yggdrasil]

It's still questionable whether biofuels are an efficient use of resources. Some have made claims that biofuels require a net input of energy greater than the energy obtained from the biofuels (e.g. Pimentel and Patzek, Natural Resources Research 14 (2005), 65-76). However, others say that biofuels do have positive energy return (e.g. Farrell et al. Science 311 (2006), 506-508). However, Farrell et al. do say that, using the current methods of producing ethanol from corn, only 21% of the energy from the ethanol is renewable and that these methods decrease net greenhouse gas emissions by only 13% compared to the equivalent amount of gasoline.

 

However, based on hypothetical technologies which will allow the production of ethanol from cellulose, Farrell et al. estimate that such cellulosic ethanol would have a positive energy return of 90% and would decrease net greenhouse gas emissions by 88% compared to the equivalent amount of gasoline. Such technology could be implemented without creating more farmland as it would use agricultural waste as the feedstock for biofuel production. However, the concerns about the water pollution and other environmental damages from farms and biorefineries are valid points which need to be counterbalance against any potential benefits of utilizing biofuels.

 

I haven't read anything comparing the efficiency of the conversion of solar energy between biofuels and solar pannels, but biofuels offer one big advantage over solar panels: biofuels allow easier storage and transportation of energy (since ethanol is a stable liquid which can be transported and dispensed to cars using current technologies) wheras solar energy goes into the electric grid and therefore cannot really be stored and dispensed to cars efficiently. Whereas there are commercially available cars capable of running on E85, electric cars (which would be needed to use solar energy for transportation) are less attractive to consumers because of the short range and high cost.

[Prime-Evil]

Solar power can be used to produce hydrogen directly by electrolosis. The yield per acre is considerably higher than wind and biomass, but the capital cost is also correspondingly higher. Also, I think the life cycle energy cost of producing the solar cells is about 60% to 75% of the energy obtained over a 20 year life span. Not great, but comparable to ethanol from corn and uses less acres and therefore make more area available for forests.

 

Relative yield/acre/year

 

Biomass Heat: 4 ( 1-10, ie 1 cords wood, 3 tons of corn or canola, or 10 tons switchgrass)

Biomass Fuel: 2 ( 50% conversion )

Biomass Power: 1 ( 25% conversion )

Wind Power: 10 x the power at perhaps 20 times the cost per acre

Solar Power: 100 x the power at perhaps 400 times the cost per acre

 

e.g.

Biomass Heat: 1.5 cords of wood sustained yield = 24 MillionBTU/acre

Biomass Fuel: 3 tons of dry corn converted at 50% = 24 MillionBTU/acre

Biomass Power: 6 tons of biomass converted at 25% = 24 MillionBTU/acre

Switchgrass Fuel: 10 tons converted to ethanol at 50% = 160 MillionBTU/acre

Wind Power: 30kw/acre x 0.36 = 92,000 kwh/year = 320 MillionBTU/acre

Solar Power: 3000 m2/acre x 4kwh/m2.day x 15% = 2,200 MillionBTU/acre

Solar Hot Water: 3000 m2/acre x 4kwh/m2.day x 50% = 7,500 MillionBTU/acre

Solar Passive Heat: 3000 m2/acre x 4kwh/m2.day x 85% = 12,500 MillionBTU/acre

 

I think the cost goes up more than linearly, but you save on land. Also, traditional biomass heat and passive solar heat are considerably cheaper than producing liquid fuel or electricity, but of course the 'available energy' is correspondingly less. I think a combination of all of these technologies is best, but some particular attention needs to be put on re-storing and sustaining higher levels of biomass and biodiversity. The bottom line no matter what you do is that you need fewer people, and they need to consume less energy.

[Prime-Evil]

I never had much faith in this hydrogen economy nonsense, since to my hydrogen is just an energy storage medium and not an energy source. But when you consider the yield per acre of Wind Power vs Biomass, and the problems associated with land use, and the fact that Wind Power is compatible with agriculture, I think a hydrogen economy combined with electric power generation does make more sense. I think solar power will be more useful in the lower latitudes below 30-45 and wind power will be more useful in the higher lattitudes above 30-45, with both useful in between.

 

It is true that wind power will kill birds, but if it allows more natural habitat to left alone from forestry and agriculture then this cost can be mitigated and corrected. The important this is that 'alternative' energy is not used as 'additional' energy, which currently it is.

[Prime-Evil]

So then roughly:

Biomass Heat ===== $0.03/kwh ~ $10/MillionBTU ~ $150/cord ~ $1.25/gallon gasoline

Biomass Fuel ===== $0.06/kwh ~ $20/MillionBTU ~ $300/cord ~ $2.50/gallon gasoline

Biomass Power ==== $0.12/kwh ~ $40/MillionBTU ~ $600/cord ~ $5.00/gallon gasoline

Wind Power ====== $0.12/kwh ~ $40/MillionBTU ~ $600/cord ~ $5.00/gallon gasoline

Hydrogen Fuel ==== $0.12/kwh ~ $40/MillionBTU ~ $600/cord ~ $5.00/gallon gasoline

Solar Power ====== $0.24/kwh ~ $80/MillionBTU ~ $1200/cord ~ $10.00/gallon gasoline

Solar Hot Water === $0.12/kwh ~ $40/MillionBTU ~ $600/cord ~ $5.00/gallon gasoline

Solar Passive Heat = $0.06/kwh ~ $20/MillionBTU ~ $300/cord ~ $2.50/gallon gasoline

 

One of the downsides of hydrogen fuel from wind power is that even though it is a fairly efficient conversion, there is an exergy loss, since hydrogen is only about 50% as efficient as electricity in producing work. They do generally outperform batteries however, in efficiency, weight, and cost, expect perhaps in very small and short duration applications. It might be difficult for hydrogen to be cheaper that ethanol and biodiesel in the long run however, unless hydrogen engines prove to be more efficient, or simply more available.

[DV8 2XL]

'Corse the biggest issue is that none of these will ever beat liquid fuel made from coal price-wise and coal is big enough to invest in the fixed plants to make syn-fuels before anyone else can get their (competitive) feet on the ground.

[Prime-Evil]

Sure Enough.

 

With all that coal about I would like to know where I could get myself a ton or so of the stuff. Not exactly environmentally friendly, but perhaps no worse than using electricity for heat and hot water. I think if you were careful, and frugal, and used a combination of coal and wood, you could get very good use of both and use the money you saved to add some more insulation and solar heating. Where can a person buy coal?

 

It would be interesting also if you could produce liquid fuel for you car from coal at home and recover heat from the process to heat your home and hot water, and perhaps generate some electricity along the wat also. It is interesting to research what can be done on a small scale, because most research is done for applications on a large scale.