Re: Reducing CO2 Emissions


Michael Tanzer

".. Even the most optimistic projections for use of non-carbon energy sources still see carbon-based energy providing the vast proportion of our energy consumption in the year 2030." 

 "…And this will require painful sacrifices, because among other things, as noted, there are no quick technology fixes which can be widely deployed in the 2020-30 time frame. "

  ".. Others propose to "solve" the problem in the relevant time frame by making wildly optimistic projections of the time required to replace existing fossil fuel technologies by renewable energy sources, or for making fossil fuels "clean" by means of technologies which are still in the dreaming stage."

 Leaving dream technologies aside, there is no reason technology could not be deployed quickly if we stopped depending on markets. There are commercial wind farms all over the world, including several a few miles from my home. Thermal generation of solar electricity in the desert exists in California and Nevada, and is being constructed elsewhere. (And unlike wind or solar cells, the heat that drives thermal engines in those plants can be stored cheaply.) For that matter, while electricity storage is expensive it is not that expensive. VRB associates sold a flow battery that had a long lifespan for $325 per kWh of storage capacity if bought on a large scale. It went bankrupt, both because a lot of companies have and because there is not a lot of market for storage that expensive when utilities can buy comparatively cheap fossil fuel and generate power as it is demanded. But that is not a case of being physically or economically incapable of replacing fossil fuels with wind. It is, as Tanzer says, a case of markets not being able to respond. Let’s do a rough quantitative analysis for the U.S.

While it would be absurd to replace all U.S energy consumption with wind electricity (and impossible since some needs can’t be met by electricity) it is not a bad first approximation. And in fact we have more ability to generate renewable electricity than any other form of energy. Further, quite often we can use electricity more efficiently than we can use other sources. (The net efficiency may not be high if the electricity is generated from fossil fuels, but if it is renewable electricity then comparing kWh to BTUs is reasonable.) For example, electric cars and trains can move a lot further on a kWh of electricity than gasoline cars or diesel trains can on the equivalent amount of fuel. Just as importantly freight in general can move more efficiently on rail than on heavy trucks. (It is true for passenger transport too, but only with sufficient utilization.) Similarly, we can get 3 to 5 times the heat out of electricity driving a ground source heat pump than we can out of natural gas driving a gas boiler. In general it would be very conservative to assume we cut energy consumption by about 40% without losing many of the services that energy provides.

In round numbers, the U.S. consumes less than 3.35 Terawatts annually. (That is: take all U.S. consumption and convert it to kWh per year. Calculate what size generation capacity running at 100% would produce that number of kWh. U.S. consumption is 3.35 million megawatts by that calculation. Terawatts tends to be used in this type of discussion, probably because it was the key measure in several of the major peer reviewed articles on the subject.) 60% of that is slightly more than 2 Terawatts.

According to the page 21 of the Annual Report on U.S. Wind power Installations 2007 (the latest official numbers available) cost per kW for wind plants averaged around $1,700 per KW in 2007, but costs are expected to approach $2,000 once 2008 numbers are in. On the positive side, the long term trend in capacity factor for wind power is upward. Today capacity averages from 33% to 35% in various regions, with 40% not uncommon in the best sites. Let’s take 33.33% as a capacity factor for new generation. That lets us be conservative and keeps our arithmetic simple. To translate nominal capacity to the kind of capacity used in the Terawatt measure we simply multiply by three. This produces an average cost of $6,000 per kW. However wind power is variable, so we need to add 20% extra capacity to compensate for storage and transmission losses. That brings cost to $7,200. Capital costs for storage add another $1,000 per KW, and capital costs for transmission lines add another $800. Even with connecting distant wind farms by long distance High Voltage Direct Current (HVDC) transmission lines, and adding storage, we will have some occasions where we don’t have enough wind when we need it. Thus, we add natural gas generation for occasional backup, at high percent of capacity even though it would provide less than 2 % of total kWh generated. That is another $350 per KW. The total rough cost is $9,350 per KW.

Less than 19 trillion dollars would replace 98% to 99% of reduced energy consumption with wind electricity. If we borrowed that money for 20 years at 5% that cost would be slightly over 1.5 trillion dollars annually. But we spend more than 1.2 trillion dollars annually for energy now. So the difference between the cost of this rough and ready estimate and what we spend now is 300 billion dollars a year, which is a great deal smaller than the U.S. military budget or than the U.S. war on drugs or any of great many absurd and deadly ways we spend U.S. money today.

Jon Rynn and I put together a spreadsheet that provides a more comprehensive set of and realistic scenarios for this transformation, looking at various degrees of success in making efficiency improvements, and various levels of technical improvement from zero technical breakthroughs, to minor breakthroughs to major (put still maybe possible) breakthroughs. It calculates a mix of renewable energies rather than depending on just wind, and also documents much more extensive possibilities for efficiency gains, far beyond the 40% I suggested in this brief reply. Every bit of energy we save via efficiency improvements provides the same services we get now while reducing the number of expensive wind generators or solar plants we have to build.

Beyond the spreadsheet, while we could simply run the same size economy with renewables, it is quite true that a lot of what we do is not worth doing. Most money spent on the US military and on U.S foreign policy establishments is directed toward aggression, not defense. Most of our law enforcement, especially but not limited to the war on some drugs repress rather than protect. A good argument can be made that automobiles create much more harm than is made up for by individual convenience to drivers. You can extend the list, but I don’t think we would disagree that many of our "goods and services" are really "bads and disservices". And the bottom line is also one that I don’t think we would disagree on. No "market" will do what needs to be done. If we want wind generators and solar power plants to replace fossil fuel based generation, we need to start with a five year program of building factories to produce those generators, while surveying sites to discover the best locations to put them. At the same time we can plan where the HVDC lines need to go and storage and backup and so on. Then we can spend the next 15 years producing a wind turbine and solar mirror every few seconds or so, and installing them along with storage and HVDC lines. Similarly we need to create a comprehensive plan for conversion of about 85% of freight and as much passenger travel as possible to rail or to trolley bus lines, where modified conventional buses run on electricity from overhead lines. Electric cars can also be used. With today’s technology that either means cars comparable in cost to conventional automobiles with a top speed of 40 mph (or less)  and a 50 mile range (or smaller), or electric cars comparable to today’s internal combustion monsters but about three times as expensive. To the extent we have to use the latter, having a decent mass transit system in place will allow them to be part of car sharing rather than individually owned. Car sharing will let us get more use out of the more expensive electric cars, bringing per mile cost closer to that of internal combustion powered monsters.

I will add that to the extent we can’t simply improve the efficiency of industrial processes and then run them on electricity we can supply processes that absolutely require hydrocarbons with feedstock derived from small amounts of waste or agricultural fibers, nothing like the huge amounts currently being considered as oil replacement in transport. This is also a valid place to use really tiny amounts of fossil fuels.

For more detail, look at the spreadsheet. But the bottom line is we do have the means to bring emissions very close to zero very quickly. If we do this over 20 years, the difference between the cost of renewable and the cost of a fossil fuel system will be trivial, something we can cover out of various types of waste such as repealing tax cuts for the rich. Because of various positive externalities in replacing fossil fuels and emitting sources with renewables and efficiency, the net effect on GDP will probably be positive even before we consider global warming effects. If it has to be done over the course of ten years, then we probably will need a temporary contraction of GDP, but not on anything like the level Tanzer suggests.

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