Final Showdown; modern bioreactor vs. open ditches, raceways,etc. 57November 26 2010 03:00:15 PM
I will spend some time and see how far I get along the road looking for an answer for the question: Which is better a modern PBR system or an outdoor raceway or ditch system?
Here are some figures put forth by several Universities and national Labs.
Algae biofuel costing -
Energy Biosciences Institute
The estimated capital costs for a 250-acre biofuel production system emphasising oil production were about $21 million, with annual operating costs at around $1.5 million, to produce about 12,300 barrels of oil, giving a break-even price per barrel of oil of $330 (based on an 8 percent capital charge).
I think that many PHDs had a hand in putting this report together. I am sure their math is correct. The point I might question is their annual operating cost. I just wonder if they added in their depreciation cost. If their construction cost is $ 21,000,000 for 250 acres of ditch or raceway or pond, we really don't know exactly what they are spending that money on, all we know is they are spreading this out over 250 acres. Any plastic will have a limited life out in the sun. I will be kind and give it a life of 12 years. So lets say of the 21 million spent 18 million went into plastic ditch liners. So, 18 divided by 12 years equals 1.5 million per year for depreciation cost. Hmmmmm?
They claim that their system of 250 acres will produce 12,300 barrels of oil per year.
An emitter of 25,000 scfm of CO2, will produce 912,500 barrels of oil per year if it is processed through 6 modern bioreactors of 1,000,000 gallon capicity each and each one is processing 4,000 scfm of CO2, 24/7/365. (that is being very liberal in allowing 2.8 lbs. of CO2 to produce 1 lb. of dry algae. Most good bioreactors will produce 1 lb of algae with 2 lbs. of CO2 or even less CO2.
6 reactors times $3,000,000 each = $18,000,000 For an enclosed system that works 24 hours every day.
912,500 barrels/year (our system) divided by 12,300 barrels/year ( UCB et.al.) = 74.18 systems to equal enough productivity to convert 25,000 cfm of CO2 into 912,500 barrels of algae oil.
Now we get down to the 'nitty gritty'.
acreage covered by the ditch system: 250 acres/system X 74.18 systems (to equal 6 one million gallon bioreactors) = 18,545 acres.
acreage covered by bioreactors 1 bioreactor covers .4166 acres X 6 reactors = 2.5 acres.
Ditch system, their cost estimates. Remember it will take 74.18 of their 'systems' to produce the tons of algae to "eat up" 25,000 cfm of CO2. This is their figures.
74.18 systems X $ 21,000,000 each = $ 1,557,780,000. to equal the output of our 6 bio-reactors.
6 bio-reactors X $3,000,000 each = $ 18,000,000
Cost for 25,000 cfm cost land footprint
modern bioreactor $18,000,000 2.5 acres
outdoor ditch system $1,557,780,000 18,545 acres
Now where is the problem?