Can bioenergy replace coal?

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GRA

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I'm on McKinsey's mailing list, and this is the most recent article they notified me about:

"Can bioenergy replace coal?"

This refers to the EU. Currently, the answer is not at current prices, but possibly by or shortly after 2025, assuming continued improvements that lower cost.

http://www.mckinsey.com/insights/sustainability/can_bioenergy_replace_coal?cid=other-eml-alt-mip-mck-oth-1409" onclick="window.open(this.href);return false;
 
There isn't enough biomass generated on earth to displace current FF consumption.

As a feedstock for plastics and chemicals, yes. Fuel, no.

Right now the EU is importing tons of wood pellets made in the US to burn there. They get incentivized for a non-FF source, but its completely non-sensical given the shipping energy/cost.
 
woodgeek said:
There isn't enough biomass generated on earth to displace current FF consumption.

As a feedstock for plastics and chemicals, yes. Fuel, no.

Right now the EU is importing tons of wood pellets made in the US to burn there. They get incentivized for a non-FF source, but its completely non-sensical given the shipping energy/cost.

Got some numbers, woodgeek? I'm very interested in the assumptions and data behind your belief. Thanks man! (BTW - there's a large difference between your "FF consumption" 'line in the sand' and the subject of the report...

As for the EU importing pellets, that's a function of globalization. It's less expensive for them to buy pellets from us, and they learned (actually learned, not forgot the lesson... ;) ) the hard way about keeping their forests. We, on the other hand...not so much.
 
AndyH said:
Got some numbers, woodgeek? I'm very interested in the assumptions and data behind your belief. Thanks man! (BTW - there's a large difference between your "FF consumption" 'line in the sand' and the subject of the report...

Let's see:

http://onlinelibrary.wiley.com/doi/10.1029/94JD01832/abstract" onclick="window.open(this.href);return false;

http://www.rainforestconservation.org/rainforest-primer/3-rainforests-in-peril-deforestation/c-human-use-of-biological-productivity-the-diversion-of-net-primary-productivity/" onclick="window.open(this.href);return false;

tells us that the net productive potential NPP of the entire earths terrestrial biosphere (photosynthesis) is ~60 Gt C/yr. A couple other sources give similar estimates.

We currently take a lot of that NPP for food/animal feed/energy/building materials, estimates that we are using 31% of the Earths terrestrial NPP now, call it 20 Gt C/yr, in addition to FF. It also suggest we already use 50% of current forest NPP, for building materials and energy. BTW, burning biomass currently yields 10% of human energy use, more than solar, wind, or hydro.

Coal consumption looks to be something like 8 Gt/y globally.

A lot of biomass needs drying energy input to burn as efficiently as coal, so it would prob take about 10 Gt /yr C of biomass, (about 20 Gt of dried biomass) to replace Coal. This would require us to add a load on the biosphere roughly 50% greater than we currently do already. This sounds pretty infeasible.

Since coal is ~30% of current global energy, replacing all FF would require 3x the number we just came up with (given the fact that biomass can be pyrolyzed in principle to form liquid and gaseous fuels). Replacing FF at current rates of consumption would require processing an additional 60 Gt of dried biomass per year, 30 Gt C/yr, and the human share of terrestrial NPP going from 20 Gt C/yr (30%) to 50 GT C/yr (85%).

In other words, there would be no nature left, nor room to grow more to satisfy future demands.

RE the US pellets going to EU: it might make financial sense (due primarily to incentives there, not market energy prices), but poor engineering sense. Biomass has low mass energy density....if it will be burned for energy, let's do it close to home.
 
woodgeek said:
There isn't enough biomass generated on earth to displace current FF consumption.

As a feedstock for plastics and chemicals, yes. Fuel, no.

Right now the EU is importing tons of wood pellets made in the US to burn there. They get incentivized for a non-FF source, but its completely non-sensical given the shipping energy/cost.

There's certainly plenty of solar energy available. Trapping that as biomass is one approach. To me this implies net-new biomass, not harvest of current terrestrial plant growth. Growing oil-rich algae in closed systems would seem to be one avenue to provide energy storage without diverting existing biomass. Growing Corn for fuel is a hideous waste of farmland.
 
woodgeek said:
AndyH said:
Got some numbers, woodgeek? I'm very interested in the assumptions and data behind your belief. Thanks man! (BTW - there's a large difference between your "FF consumption" 'line in the sand' and the subject of the report...

Let's see:

http://onlinelibrary.wiley.com/doi/10.1029/94JD01832/abstract" onclick="window.open(this.href);return false;

http://www.rainforestconservation.org/rainforest-primer/3-rainforests-in-peril-deforestation/c-human-use-of-biological-productivity-the-diversion-of-net-primary-productivity/" onclick="window.open(this.href);return false;

tells us that the net productive potential NPP of the entire earths terrestrial biosphere (photosynthesis) is ~60 Gt C/yr. A couple other sources give similar estimates.

We currently take a lot of that NPP for food/animal feed/energy/building materials, estimates that we are using 31% of the Earths terrestrial NPP now, call it 20 Gt C/yr, in addition to FF. It also suggest we already use 50% of current forest NPP, for building materials and energy. BTW, burning biomass currently yields 10% of human energy use, more than solar, wind, or hydro.

Coal consumption looks to be something like 8 Gt/y globally.

A lot of biomass needs drying energy input to burn as efficiently as coal, so it would prob take about 10 Gt /yr C of biomass, (about 20 Gt of dried biomass) to replace Coal. This would require us to add a load on the biosphere roughly 50% greater than we currently do already. This sounds pretty infeasible.

Since coal is ~30% of current global energy, replacing all FF would require 3x the number we just came up with (given the fact that biomass can be pyrolyzed in principle to form liquid and gaseous fuels). Replacing FF at current rates of consumption would require processing an additional 60 Gt of dried biomass per year, 30 Gt C/yr, and the human share of terrestrial NPP going from 20 Gt C/yr (30%) to 50 GT C/yr (85%).

In other words, there would be no nature left, nor room to grow more to satisfy future demands.

RE the US pellets going to EU: it might make financial sense (due primarily to incentives there, not market energy prices), but poor engineering sense. Biomass has low mass energy density....if it will be burned for energy, let's do it close to home.
Thanks woodgeek - I appreciate your view. It seems reasonable from the perspective of using existing biomass materials, methods, and processes to power existing thermal power plants. I'd like to offer a different view. Let's start with some example processes/assumptions behind the NPP numbers.

- Tree farming: clear cut, plant hybrid trees, wait x number of years, repeat. Productivity continues to fall as the land is degraded; land-owner sells spent property when the trees are no longer profitable.
- Industrial agriculture: Land is bare much of the year with zero photosynthesis. Corn is planted, does its thing for 60-100 days, then is harvested. This is an amazingly inefficient way to convert sunlight into biomass.
- Thermal power plants are not efficient users of heat energy regardless of what's burned, and too much of the resultant electricity is lost in transmission.

Based on these and other similar practices, I'd have to agree - there aren't enough trees or cornstalks to cut, split, gasify (or not) and burn.

We have a way to rapidly produce biomass that 1. does not kill the tree (it normally doubles the life of the tree) and uses all available photosynthetic potential during the entire season and works better in efficient burners. It was used very successfully all across Europe even after they had clear-cut the entire continent to make wooden ships. It's called 'coppice'. A tree is cut above the ground, new branches quickly grow out of the trunk, and they are harvested when they're at the correct diameter. Coppiced trees will produce for hundreds of years.

One example of using this pole wood efficiently provides heat and hot water for a 24 hour period with one or two 30 minute firings per day even in Siberia is the masonry stove. This scales well to provide district heat/hot water. District heating such as this reduces the electrical and fossil fuel demand.

Biomass does not need to be burned to provide energy. It can (and probably should) be shredded and fed into anaerobic digesters. Instead of inputting wood and getting heat and ash, we can feed a digester and get biogas to burn in a conventional gas-fired generator, plus a nutrient-rich liquid fertilizer to be returned to the land. This closes the nutrient loop so that the biomass production is truly sustainable/regenerative and not simply another example of mining and degrading the soil.

Finally, some context might be useful. None of the existing energy transformation projects underway on the planet leave wind/PV/solar thermal production at their current volumes and look for ways to grow more trees to burn in coal power plants. Even though it's been clearly shown that we don't need to burn anything to have a 100% fossil-fuel free power grid, there's still some potential cost savings if a small amount of thermal generation can be available if necessary. So - nobody's suggesting that we replace coal with trees at our current ~45% use rate - it's more like 1-5%. That changes everything. ;)
 
Part of the 'peak-oil' doom scenario was always that without oil there would be no plastics, petrochemicals, etc. When I looked up the numbers for what fraction of oil goes to that stream, it was quite modest (a few % IIRC). The amount was somewhat less than the amount of woody biomass being burned globally at this time.

So, if we really want/need sustainable, non-FF plastic, the biosphere will give us plenty, especially if we recycle it. A lot of the process heat/energy for production would come from burning side products.

Coppice would be a great way to get the feedstock. Likely amenable to large-scale mechanization.

For energy, I would much rather go PV rather than photosynthesis, just for the much lower land-use factor.
 
woodgeek said:
For energy, I would much rather go PV rather than photosynthesis, just for the much lower land-use factor.
+1

I've previously posted about "The Nonsense of Biofuels", an editorial written by Nobel laureate Dr. Hartmut Michel, Director of the Max Planck Institute of Biophysics. From the editorial:
Dr. Hartmut Michel said:
As a result of the limitations described above, 4.5% is considered as the upper limit of the photosynthetic efficiency of C3 plants. However, in reality, values of only around 1% are observed, even for rapidly growing trees like poplars.
By contrast, PV can provide 20% efficiency directly to electricity with no moving parts.

It boggles the mind that so many people believe that you can take extremely inefficient processes and put them together to create a global solution. You can't, at least without killing most of the people on the planet first.
 
AndyH said:
Hey Reg - which is better: 1% of an incredibly huge number, or 20% of a very tiny number?

I'm not sure I get where you are coming from @AndyH. The huge input side to the 1% number is taking a very big toll on Earth's natural systems, contributing to extinctions, leading to side effects like ocean and great lake dead zones, etc. A very big chunk of the natural biosphere has been commandeered or replaced with artificial systems (like farms). Sometimes the replacement also has negative AGW effects, sometimes not, the science is poorly understood.

And the resulting output is only ~10% of human energy, a significant but <50% of human building materials, and nearly 100% of our food. And history is replete with human demand overloading the system to the point of local collapse.

Agriculture and biosphere harvest as practiced is a messy, creaky, poorly-regulated extinction machine. It just happens to provide all of the food we need to live.

Of course, we have no choice but to 'mend it not end it'. I also believe that we can improve yields significantly from current levels, while reducing soil depletion and fertilizer runoff. But I would like to see that capability put towards feeding humans well with less land under the plow or pasture.

So, are you proposing to put more of Earth's land into intensive production for human needs, or do you think we can get sustainable energy and food from less land than we use now??
 
AndyH said:
Hey Reg - which is better: 1% of an incredibly huge number, or 20% of a very tiny number?
Considering that the EROEI for biofuels is very close to unity (1.5:1 if you ask the extreme optimists and 0.7:1 to 1.2:1 based on studies of current practices) coupled with the fact EROEI is required to be AT LEAST 3:1 just to maintain as sustenance-level society, then biofuels are not a real option. The author of the article linked in the OP apparently does not appreciate that economics are at the complete mercy to physics. Put another way, biofuels do nothing other than damage land that could otherwise be used to grow food or, better yet, could be left in their natural state.

Solar panels, with a current EROEI of about 10:1 have the potential to provide society with renewable energy that is sufficient to run a modern society sustainably. Even then, we need to be careful to ramp up PV production in a responsible manner since EROEI of the PV industry drops dramatically (even below unity) when the growth rate is extremely high. (Sorry, I cannot seem to put my hands on the Stanford paper which discusses this effect.)
 
woodgeek said:
AndyH said:
Hey Reg - which is better: 1% of an incredibly huge number, or 20% of a very tiny number?

I'm not sure I get where you are coming from @AndyH. The huge input side to the 1% number is taking a very big toll on Earth's natural systems, contributing to extinctions, leading to side effects like ocean and great lake dead zones, etc. A very big chunk of the natural biosphere has been commandeered or replaced with artificial systems (like farms). Sometimes the replacement also has negative AGW effects, sometimes not, the science is poorly understood.

And the resulting output is only ~10% of human energy, a significant but <50% of human building materials, and nearly 100% of our food. And history is replete with human demand overloading the system to the point of local collapse.

Agriculture and biosphere harvest as practiced is a messy, creaky, poorly-regulated extinction machine. It just happens to provide all of the food we need to live.

Of course, we have no choice but to 'mend it not end it'. I also believe that we can improve yields significantly from current levels, while reducing soil depletion and fertilizer runoff. But I would like to see that capability put towards feeding humans well with less land under the plow or pasture.

So, are you proposing to put more of Earth's land into intensive production for human needs, or do you think we can get sustainable energy and food from less land than we use now??
Sorry mate - you've missed the entire point. ;)
 
Reg - along with classes in climatology and atmospheric physics, I strongly recommend a refresher of biology and the first two terms of environmental science.

On this planet, the number one energy system by a wide, wide margin, is photosynthesis. It's the system behind all of our food, the majority of our building materials, and every single drop of gas, oil, and coal that we've ever used.

Just one example of how far off the mark your belief in the superiority of 20% PV as compared with plants: How many solar panels can we stack so that all of the lower layers also produce energy? Not very many, eh? LOL Look at a forest. All of the plants are getting full use of the sun - from the tops of the 250' trees all the way down through the three-dimensional layers to the ground to the grasses.

As I asked earlier and you forgot to answer - which is larger: 1% of an incredibly large number or 20% of a very small one?
 
AndyH said:
Reg - along with classes in climatology and atmospheric physics, I strongly recommend a refresher of biology and the first two terms of environmental science.
Ad hominems ad nauseum from someone who clearly does not have training in science.
AndyH said:
On this planet, the number one energy system by a wide, wide margin, is photosynthesis. It's the system behind all of our food, the majority of our building materials, and every single drop of gas, oil, and coal that we've ever used.
And we had better leave the biosphere largely intact. The recent move toward clear cutting forests for biofuel needs to stop.
AndyH said:
Just one example of how far off the mark your belief in the superiority of 20% PV as compared with plants: How many solar panels can we stack so that all of the lower layers also produce energy? Not very many, eh? LOL Look at a forest. All of the plants are getting full use of the sun - from the tops of the 250' trees all the way down through the three-dimensional layers to the ground to the grasses.
More non-sequitur nonsense. You clearly know very little about semiconductor physics. The way that higher-and-higher efficiencies are achieved using photovoltaics is that different layers of the material convert different frequencies of light to electricity. This allows a single solid-state device to convert sunlight to electricity at extremely high efficiencies. Laboratory results are now approaching 45% efficiency and commercial products today exceed 21% efficiency.

Instead of destroying vast swaths of the biosphere to produce fuel for our vehicles, we can accomplish the same goal by covering many of our existing structures with photovoltaics. The vehicles can store this electricity in batteries for use when needed or by other loads if desired.

One strong benefit of photovoltaics is that they produce *more* electricity in the cold than they do in the heat, which partially compensates for the reduced amount of sunlight we receive in the wintertime. Plants, by contrast, greatly reduce their production once the temperature drops below a certain level.
AndyH said:
As I asked earlier and you forgot to answer - which is larger: 1% of an incredibly large number or 20% of a very small one?
You never asked this question before. I answered the one you asked. Definitively.
 
AndyH said:
Sorry mate - you've missed the entire point. ;)

My bad, @AndyH. I don't want to get in the middle of the 'thing' b/w you and Reg.

I gather you feel that it is more feasible/practical (?) to increase the planets NPP, presumably in a way that does not interfere with existing natural systems, and harvest the biomass for energy and materials, than to build out large-scale PV to power a largely electrically-driven future society??

Of course, I think it is silly to say one is better....they will both get done eventually, and each, biomass and PV will excel in some areas over others. I think biomass will excel at providing diverse and sustainable chemical feedstocks and building materials, while large-scale PV electricity will do a lot of prime moving for society.

I think we will still be using hydrocarbon liquid fuels in 2050 and 2100. I think we could easily run commercial aviation on biofuels, if needed and wanted to. If we need and want to remains unknown at this time.
 
RegGuheert said:
blah blah blah off-topic BS snipped
AndyH said:
As I asked earlier and you forgot to answer - which is larger: 1% of an incredibly large number or 20% of a very small one?
You never asked this question before. I answered the one you asked. Definitively.
Sorry. I thought I did ask you the question before. I seem to recall this:

http://www.mynissanleaf.com/viewtopic.php?p=391537#p391537
AndyH said:
Hey Reg - which is better: 1% of an incredibly huge number, or 20% of a very tiny number?
And this:
http://www.mynissanleaf.com/viewtopic.php?p=391629#p391629
AndyH said:
As I asked earlier and you forgot to answer - which is larger: 1% of an incredibly large number or 20% of a very small one?

I'll now ask you for the third and last time:

Would you rather have 1% of an immensely large number or 20% of a quite small number?
 
You seem to miss the simple point. EROEI for biofuels is close to unity. That means it is not a source of energy, it is simply an energy carrier. In your part of Texas, the EROEI for corn ethanol is particularly bad. Today, we burn liquid fossil fuels to produce an equivalent amount of liquid ethanol. The net result is biofuels simply waste cropland, but do not reduce the amount of fossil fuels consumed.

In other words, to get the 1% of whatever, you need to provide about that much energy from an actual energy source. We need to stop the insanity of subsidizing farmers to waste perfectly good farmland.
 
Thanks for your patience, woodgeek. Let me give this a shot if you don't mind.

Don't worry about "1/treehugger" - he stays on my ignore list.

I don't disagree with your points about how man has exploited and made a mess of the natural environment. In the past, most of the people here on the forum have responded in ways that confirms they see 'board feet' when they look at a tree - especially when they advocate for clear-cutting to build a nuclear power plant. ;)

I'm holding out for a 100% wind/water/solar/renewable/[carbon-neutral or carbon-negative] environment, and one that includes the wholesale scrapping of our entire chemical agriculture manufactured-food-like-substance system.

No man, at this point, after working to try to understand the huge gap between what this planet does when we get out of the way and what damage we do out of hubris and ignorance, I'm standing with the Lorax. :lol:
 
RegGuheert said:
You seem to miss the simple point. EROEI for biofuels is close to unity. That means it is not a source of energy, it is simply an energy carrier.

Not quite that bad. However, when biofuels were the source of energy for farming, the EROEI was about 3. That's based on farming by mule/horse/oxen, of course. The farms could feed the farmers, their farm animals, and about twice as many town and/or city people. EROEI from sugar cane to ethanol is around 8. Firewood is around 30. A combination biofuel and electric farm looks to me to have an EROEI of around 10, and a biological EROEI of around 20.

Of course, there are lots of complicating factors. The soil is being eroded, on the average, faster than the geologic rate of replacement, so crops and/or methods of farming need to change. Mining soil for fuel is just as short sighted as mining fossil fuels.
 
Thanks Wet. I'll leave Reg to you. I've had my fill. ;)

I re-read the subject summary just to make sure I wasn't missing something. Before we get off into a US-centric rant, I think it's really important to remember that Europe is not simply trying to replace 'business with usual' fossil fuels with 'business as usual' stuff they can burn. They're headed to a high-90% wind/solar/hydrogen economy. The portion of their total energy supply from biomass (not biofuels!) is largest today as they transition - the portion will continue to fall as the wind/solar is fleshed out.

As I've said many times on this forum - the problem with biofuels in the USA is the mindset, assumptions, and infrastructure at play in this country. The USDA has made clear that we will be out of usable soil in the farm belt in 40-60 years if we keep doing what we're doing today. Clearly something must change. Thankfully it is. The changes in mainstream ag (AKA those majority megafarmers that plant every seed under contract to ADM, Monsanto, et al) are very slow - but there are projects all over this country - some like the work at the Rodale farms that have been going for ~60 years - that are ready to 'go large' once the rest of the country wakes up. Beyond 'just organic' there are projects that prove beyond any doubt that we can provide more than twice the food we need by mimicking nature - without any fossil fuel, chemical, or fertilizer inputs. Food, fuel, fiber, medicine at twice the rate of our best industrial ag to date.

The solutions are ready for us to catch up and it's pretty clear that while bioenergy is one of the golden BBs, it's got plenty of company when replacing coal.
 
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