Discussion regarding the art and science of creating holes of low entropy, shifting them around,
and then filling them back up to operate some widget.
30 July 2005
Sweeping CO2 Under the Rug
The USA still stands above us at 20.3 tonnes per, but the numbers are surprising because 70 % of Canadian electricity is from hydroelectric and nuclear -- non-CO2 emitting sources. In comparison only about 25 % of US electricity doesn't come from carbon fuels. So where's the extra CO2 coming from?
It's not the transportation sector. The source is, in fact, industry. Canada's industry is one of the most energy intensive in the entire world. This is largely due to the fact that Canada has a heavy resource-based economy. Canadians consume about 23% more energy per person than even our energy hog friends to the South.
Pulp and paper, smelting, steel, cement, fertilizer, and bitumen (tar sand) production compose the bulk of energy consumption by Canada's industry. However, not all industries produce equal CO2 emissions for a given energy input. Alcan's Aluminium consumes large amounts of electricity for electrolysis -- it cannot use heat directly from a carbon fuel, it can only use low entropy electricity. Steel, on the other hand, is dependant on high quality coke for reduction reactions to remove impurities. Most of the other industrial processes require either heat or steam.
The Alberta tar sands are a special case. Large amounts of hot steam are needed to separate out the valuable volatiles from the sticky mess. So how are we getting oil from the tar sands? We burn natural gas of course. This makes tar sand gasoline extremely intensive in C02 terms. One possible solution is to build a nuclear steam plant up in Fort McMurray. However, using nuclear to provide heat and steam only really works in that one place, because all the refineries are pretty much lined up in a row. Saskatchewan's potash plants, in comparison, are not close together.
This leaves us at the possibility of recovering CO2 emissions at the source and pumping it underground. Recovery can be done by either physical means (liquefaction of C02 from the exhaust) or chemical means. A technical discussion of CO2 recovery can be found here:
Pumping CO2 underground is a relatively well established technology for oil wells. The Saskatchewan Weyburn field project is representative of the concept. As a side benefit, liquefied C02 is actually a superior agent for forcing the remnants of oil from a nearly exhausted field than water. Hence, there might actually be some real economic value in liquefied CO2.
There has been a recent surge in interest in CO2 sequestration by some of the Kyoto opponents in the world. This is of course, somewhat amusing because Kyoto is a purely carbon metric, and it is difficult to not be somewhat cynical of their motives. The real value of Kyoto is that is creates a carbon pollution trading system. Unfortunately, the voluntary system proposed by the USA is likely to be far less successful than the capitalist Kyoto system.
If we can't put a dollar value on liquefied Carbon Dioxide, industry will continue to deal with it the way they know how: with an exhaust.
27 July 2005
Oil to Electricity
It used to be that we had a coal economy. Industry ran on it, trains and ships burnt it to supply transportation.
With the introduction of the automobile, we saw a demand for a portable liquid energy source. That led in turn to a shift in the energy industry away from coal to oil.
Currently we appear to be in the transition from an oil to a natural gas economy. It represents a fairly small economic potential gap to jump. There is a fairly large amount of natural gas available for consumption, especially if you consider gasified coal. Natural gas can be liquefied at about 100 K, which is cryogenic but fairly easily reachable with conventional and established refrigeration technology. Natural gas is already routinely liquefied for transport in ships.
Because I foresee this upcoming shift to natural gas, I would regard myself as a peak oil optimist. The peak in oil production may be here already, but I don't think our economy is about to collapse on itself.
Of course, switching from oil to natural gas does almost nothing for the global warming problem. As a Canadian, global warming is not a major negative for my own self-interest. Countries with vast artic territories like
The only real solution that I can foresee is switching from carbon-based energy to some other means of energy storage. Hydrogen is a straw-man, but I can see electricity becoming our new means of energy trading. Electricity infrastructure, obviously, is already very strongly established. What is patently missing is a means of electricity storage. This is especially necessary to make intermittent renewable sources more economical. To this, I look to the proliferation of (non-hydrogen) electricity storage methods: pump hydro, compressed air/natural gas, flywheels, solid oxide batteries, flow batteries, and our standard electrolytic cells. Plug-in hybrids will allow us to shift much of our transport energy consumption from oil/gas to electricity as well.
For this reason, I think the best step any government could take today to move towards carbon independence is the construction of a large DC transmission grid. In order to operate an electricity economy, we will need to be able to transmit electricity from one side of the country to the other. DC transmission losses are usually on the order of 0.6 % per 100 km. Currently, our grids are not well connected. Some grids, like
This is a step that we can take now, without relying on vapourware. We know it will save money. It may end up not being the most efficient investment, but we can be confident it will have a higher rate of return than PV or biofuel subsidies.
01 July 2005
Renewable Red Herrings
One of the great dangers environmentalism faces in reaching for technological solutions to existing pollution problems is that they've got it wrong. Let's face it, environmentalists tend not to do the math. When environmentalists overreach or exaggerate, they damage the credibility of the green movement as a whole.
In the current landscape, megatonnes of Carbon Dioxide have become the conscience of environmentalism, with leaders like Tony Blair championing the danger of climate change while the US administration hires Exxon to redact its scientific reports on the subject. One of the possible solutions to the consumption of carbon fuels put forth by environmentalists is the development of renewable energy: solar (specifically photovoltaic), wind, biomass, and reservoir hydro.
Of these technologies, the only proven one is hydro-electric dams... Wind has made strides in installed capacity, but its volatile power output make it a liability to the grid. It is cost effective when the wind is blowing, but the fickleness of mother nature puts an excessive stress on gas-fired load-following plants and voltage regulation. Currently the fate of wind hangs in the balance. With increased decentralization, better coupling to strong load-following power providers like hydro, and the introduction of utility-scale electrify storage like flow batteries, it will be able to provide a significant reduction in CO2 emissions.
That leaves photovoltaic and biomass as underdeployed, but potentially promising solutions. Unfortunately, I believe both of these technologies will be failures over the next 25 years.
Photovoltaic cells are energy intensive to manufacture. Optimistically, the energy return ratio of PV cells is about 20:1. This means that for every Joule used in the manufacturing process, the solar cell will only return twenty times that over the lifetime of the cell. Of course, most cells aren't installed in an ideal clearness index climate, oriented to the sun. Installations on home roofs are usually installed at the wrong angle, and may not be south facing. A ratio of 10:1 is more common in the literature. Compared to wind at 40:1 and hydro at 100:1 , PV is not economically feasible.
Furthermore, all current PV production is done using silicon recycled from the microchip industry. This reduces the material cost of photovoltaic manufacturing. The current prices of solar electric cells, expensive as they are, are not sustainable if demand increases substantially.
While decentralization has its advantages, I think solar has picked the wrong method for gathering power. Photovoltaic, realistically, should stay off the grid for the time being. Centralized concentrated solar-thermal collectors seem to have much greater potential for providing peaking power to the grid. However, it should be noted, concentrated solar performs poorly in the diffuse lighting conditions of overcast skies. Concentrated solar, like wind, often requires the installation of expensive transmission lines to bring power from the boondocks to urban areas.
Biomass is a net zero carbon emitter, since plants consume CO2 from the atmosphere and then we later burn them to liberate energy. Compared to other renewables, biomass is storable and portable. As such, it can be used for transportation.
Unfortunately, photosynthesis is an inefficient solar cell. The amount of arable land necessary requires a lot of energy to fertilize, plant, irrigate, and harvest. The energy return of ethanol is terrible, typically around 1.1:1 if it is even positive. Turning over huge tracts of land for biodiesel and ethanol production will have to come out of land being used for food production. While the world is currently feeding itself, we can't do both food and biomass production at the same time.
PV subsidies in Germany and California, along with ethanol and biodiesel subsidies in America and Europe are essentially cases of government picking the winners. Given the historical success rate of government investment in technologies.