Community Finance: An Essential Element of a Wealth Sustaining Society

A reasonable standard of consumption is a prerequisite of an economic system with long term productive stability. Many people now recognize this truth, and calls for voluntary simplicity and the end of consumer society meet a positive response from many people. However, the social systems implications of a reasonable standard of consumption have not been clearly thought through, partly because social systems thinking is a difficult discipline, and partly because a strong bias in favor of certain cultural norms strongly discourages any thinking which would challenge those norms. I call this bias the Social Will. The ability of the Social Will to produce conformity of thought on key social institutions is quite powerful.

The french historian Jean Michelet in writing about the Maillotin tax rebellion (named after the mallets or Maillots that were carried by the leaders of the rebellion) under the reign of the mad king Charles VI in late fourteenth century France explains how the leaders of the rebellion demanded audiences with the Dauphin (the future Charles VII) and lectured him about how a good king should treat his faithful subjects. Michelet explains that it never crossed the minds of the rebels that they could do without kings altogether, because the religion of royalty was still in full flower. If anyone had suggested to the Maillotins the elimination of royalty, they would have rejected this advice as the ravings of a radical mad person who wanted to destroy the natural social order and bring chaos and anarchy down upon the world. The Social Will of the France of that time had ordained a hereditary monarch as an essential element of good social organization. The suffering bourgeoisie wanted a good king who would rule wisely, but the idea of replacing monarchy by some other form of government was not within the event horizon of fourteenth century France.

Similarly many people are dissatisfied with the performance of private credit markets in wake the great recession of the last decade, but the percentage of these people who recognize that fundamental structural problems exist in this system which require new forms of credit is still quite small. The Social Will of modern global society has declared private credit markets to be an eternal and perfect form. John Mavrogordato summarized this resistance to new thinking on economic organization in the following terms in his 1917 book The World in Chains: Some Aspects of War and Trade:

The distribution and exchange of commodities are necessary to the existence of the State; so necessary that it might be supposed that their regulation would be one of the primary functions of government. Proper systems of distribution and exchange correspond to the digestive processes of the body, on which depend the proper nutrition of all the parts and the real prosperity of the State as a whole; yet any comprehensive plan for their control is still regarded as the most unattainable dream of Utopia, and they are left to carry on as best they can in the interstices of private acquisitiveness.

Unless we are planning to go all the way back to neolithic villages as the fundamental social unit credit cannot be dispensed with. Any time someone proposes to spend a large amount of resources in the present in order to produce economic value over long period of time in the future (e.g. building a bridge, a university, a semiconductor manufacturing plant, a solar PV farm, a nuclear power plant etc.) someone must evaluate the likelihood that this present expenditure of resources will produce in the future a sufficiently large flow of goods and services and a small enough amount of negative externalities to justify the expense. This evaluation of the future consequences of spending on infrastructure development is the process of granting credit.

To me it seems clear that leaving this process primarily in the hands of private credit markets whose raison d’etre is to turn money into more money is inconsistent with ecologically sound economic development. The people making decisions about credit should be public servants whose purpose is to create and maintain useful infrastructure rather than to turn money into more money. These community financiers should be paid salaries for services rendered rather than making money in proportion to the amount of debt they create. This not to say that community financiers should not be concerned with monetary flows and the economic viability of the enterprises to which they grant credit. Quite the contrary. But a significant difference exists between trying to create and maintain valuable infrastructure and trying to create as much debt as you can because your personal wealth is proportional to the size of this debt.

Of course if ‘public servant’ and ‘Marxist vampire’ are inescapable identities in this context then no useful reform of the credit system can be made, and we should quit wasting our time yakking about ways to save a form of social organization which is an evolutionary dead end.

Lawrence Berkeley Laboratory Scientists Develop Low Temperature Sodium Sulfur Battery

The most widely used battery technology for multi-hour grid energy storage is NGK Insulator’s high temperature (300 to 350C) sodium sulfur (NAS) battery. The high operating temperature is required to obtain adequate mobility for the sodium ions through the solid ceramic beta-alumina electrolyte. The largest installation of such batteries is 204MWhr installation supporting a wind farm in Rokkasho Japan. This installation opened operations in 2008. The sodium sulfur chemistry is attractive from a scalability point of view since both sodium and sulfur are earth abundant elements.

High temperature operation creates safety concerns, and, in fact, a battery fire occurred on September 21, 2011 at one of NGK installation’s in Japan, leading to a shutting down of all NAS battery storage installations world wide for a long period of time. In June of 2012 NGK Insulator’s published a report describing the causes of the fire and safety enhancements which they felt provided sufficient operating margin to justify reopening their battery factory. This presentation mentions two California installations (One in San Jose and one in Vacacville) of NGK’s NAS batteries which have occurred since the safety enhancement were announced. This technology is not dead, but my sense is that enthusiasm for it has waned in spite of the enhanced safety features. These batteries are too expensive ($320/KWh) to truly revolutionize grid operations but they have found some niche markets.

From time to time I stumble upon research work exploring options to lower the operating temperature of NAS batteries. If these ideas introduce rare elements to the battery chemistry they may not have the same long term scalability as the current chemistry. For example this abstract claims that adding cesium to the liquid sodium cathode will allow the operating temperature of sodium sulfur batteries to be lowered to 150C. Unfortunately cesium is a rare element which cost about $40,000/Kg. The effect of the cesium is to enhance to wettability of the sodium on the solid beta-alumina electrolyte. Conceivably some other lower cost metal can be found which produces the same effect, but such an option awaits future research.

Recently an interesting low temperature NAS battery design has emerged from scientists (Dr. Gao Liu, Dr. Dongdong Wang, and Dr. Kehua Dai) at the Lawrence Berkeley Laboratory. They claim that this battery can operate at a temperature of 80C. This temperature is below the melting point of pure sodium (97.7C). A liquid metal anode avoids the problem of dendrite formation by solid sodium and is a key enabler of the long cycle life (4500 cycles) of current NAS batteries. Liu et al maintain this feature of the NAS battery by using an alloy of sodium and potassium which has low melting temperature. The solid beta alumina electrolyte is replaced by a solid polymer which conducts sulfur ions (rather than sodium ions) at low temperature. Their battery design also includes a new cathode which is a mixture of sulfur and a conductive polymer. Some details of the cathode and electrolyte chemistry and structure can be found in this patent

As this application for Cleantech to Market funding shows, Liu et al seem to believe that this battery architecture is not just a laboratory curiosity but has the potential to be manufacturable. I believe that the manufacture of the tubular solid ceramic electrolyte for the current high temperature version of the NAS battery is an expensive process, so that the replacement of this component by a polymer electrolyte potentially represents a significant cost savings. Some information about projected development time lines manufacturing costs for of these batteries is given in this presentation. The numbers in the presentation are probably highly speculative. Furthermore the LBL scientists themselves will probably not follow this technology to maturity but will attempt to license it to a private company. I would not hold my breath waiting for these batteries to start rolling off the assembly line in large quantities, but I am always interested in technologies which have potential long term scalability.

Silevo Produces High Efficiency Low Temperature Coefficient Silicon Solar Cell Using Thin Film Tunnel Junction Architecture on Top of an N-type Silicon Substrate

The free charge carriers in so called intrinsic semiconductors such as silicon are the result of the thermal excitation of electrons from a valence band into a conduction band. The excitation of the electron leaves behind a positively charge hole in the valance band which can also act a charge carrier. Because the free charge carriers are created by thermal excitation, the colder a semiconductor becomes the less free charge carriers are present and the electrical resistance become higher. This behavior is in contrast to metallic conductors which have free electrons in the conduction band at all temperatures and which actually have lower resistance at lower temperature because thermal lattice vibration do not interfere as much with the free motion of the conduction electrons. The density of free charge carriers in pure silicon at room temperature is low compared to metallic conductors, and the electrical resistivity is high.

The number of free charge carriers in silicon can be greatly increased by adding a small amount of another element called a dopant. Silicon has four electrons in its out shell. If the dopant atom has 5 electrons in its outer shell (e.g. phosphorous) then one of these electrons can easily be excited into the conduction band of silicon. The positively charge ionic core left behind is bound to the site the dopant atom and therefore cannot act a current carrier. Thus silicon doped with phosphorous has an excess of negative charge carriers and is therefore called an n-type semiconductor. If an atom with 3 electrons in is outer shell (e.g. boron) is added to silicon then one of the electrons in the valence band can easily become attached to the atom leaving behind a positively charge hole which can act as current carrier. The electron attached to the dopant atom is immobile and cannot act as a current carrier. Thus silicon doped with phosphorous has an excess of positive charge carriers and is therefore called a p-type semiconductor. Both of these types of doped silicon are called extrinsic semiconductors. Extrinsic semiconductors have much higher densities of free charge carrier and much lower resistivities than intrinsic semiconductors.

Pure silicon is capable of a absorbing sunlight and exciting electron/hole pairs, but no electromotive force exist which can drive the free electrons through an external circuit as an electrical current. In order to produce such a current a P-N junction is required. A P-N junction is an interface between two volumes of silicon one of which has an excess of negative charge carriers and the other of which has an excess of positive charge carriers. The most common method of producing such a junction is to take a wafer of p-type crystalline silicon (most commonly doped with boron) and exposing one surface of the wafer to phosphorous at high temperature. The phosphorous diffuses into the silicon and forms a thin layer of n-type silicon. The boundary between this layer and the bulk of the wafer is the p-n junction.

When electron/hole pairs are excited by light absorption in the vicinity of the p-n junction the electron moves to one side of the junction and the hole to the other side and they can recombine only after the electron has moved through an external circuit an back into the other side of the junction. This movement of the photo excited electrons is the source of the electrical current produced by PV cells.

Silicon PV cells can be produced starting with either p-type silicon or n-type silicon. It turns out that controlling the electrical resistivity of n-type silicon crystals is more difficult than controlling the resistivity of p-type silicon thus making n-type silicon with will controlled resistivity more expensive to produce. However PV cells utilizing n-type silicon wafers can achieve higher light to electricity conversion efficiency than PV-cells utilizing p-type wafers. P-type solar cells still dominate the market, but high efficiency n-type cells have found a niche in applications where space is at a premium so that the higher efficiency allows more energy production in a give area of rooftop.

Silevo is a player in the high efficiency n-type PV solar cell field. The typical method of producing a p-n junction in a n-type wafer to expose is one surface to boron gas at high temperature. The boron diffuses into the silicon and converts a thin layer of the wafer into a p-type semiconductor. Silevo creates an ultra thin p-type layer at one surface of the wafer not by doping but by allowing one surface of the wafer to become oxidized and then depositing thin film layers on top of the oxide. The actual physics by which by which the so-called inversion layer with a majority of p-type carriers is created is a mystery to me, but it obviously works. I believe that the high temperature boron diffusion process is fairly expensive so that Silevo’s thin film deposition process may represent a significant cost reduction.

PV cells of this type have a lower temperature coefficient of performance (% loss of efficiency per degree increase in temperature). The Silevo cells have a temperature coefficient of -0.22%/C compared to -0.45 to -0.50%/C for diffusion based solar cells. Silevo claims that this lower temperature coefficient leads to 5% to 12% increase in energy production under real world conditions. Obviously hot desert conditions will get the most benefit from the lower coefficient.

Silevo does not manufacture n-type silicon wafers itself. They are depending on general industry progress for lower costs in this aspect of the solar modules.

Silevo has garnered media attention recently because it was acquired by Solar City, a major player in the residential PV market. This attempt by Solar City to become a vertically integrated company who manufactures it own solar panels is somewhat risky, but if Silevo can really deliver a high performing low cost product the payoff could be very substantial.

Carnot Compression Has Developed a Centrifugal Isothermal Gas Compressor that can Achieve a 200 to 1 Compression Ratio in a Single Stage

As I have mentioned before several different companies are developing near isothermal gas compression systems which inject water vapor into the compression chamber in order to remove heat from the compressed gas. I have recently read about another company called Carnot Compression which has developed an isothermal gas compressor which injects gas into water. The compression fluid is a gas/water emulsion (i.e. a mixture of gas bubbles in water matrix). The emulsion is contained inside a spinning cylindrical chamber where the gas bubbles are compressed as they migrate to the outer surface of the cylinder. The water absorbs the heat generated in the gas by compression which the compression nearly isothermal. Exactly how the gas gets out of the rotating compressor chamber into the pressure vessel is not clear from the limited description given on Carnot’s web site. Apparently only gas gets out and not water, since Carnot claims that the compressed gas is very dry and does not require further drying steps as do other varieties of gas compressor.

I am not really sure how this technology differs from that of a company called Oscomp which has also developed a multiphase (i.e. water + gas) rotary compressor. Oscomp claim that their compressor can achieve 60 compression ration in a single stage while Carnot claims that they can theoretically achieve a 200 to 1 compression ratio. I assume that the use of the word theoretical in this claim implies that the real world implementation of this technology will not actually reach this compression ratio.

In discussing possible applications of their compressor Carnot does mention energy storage, although this use is at the bottom of their list. Carnot’s view is that they have developed an efficient, low energy use, low cost gas compressor which is suitable for a wide variety of existing applications, so they are chasing obvious markets and obvious money making opportunities. If a compressed air energy storage market comes into existence they will be positioned to support it, but they themselves are not pursuing this rather risky business opportunity.

As far as I can tell their compressor is not reversible, so that a compressed air energy storage system based on their technology might require a separate expander stage, which might be a disadvantage compared to the technology of energy storage companies like Lightsail Energy and SustainX. Nevertheless, Carnot’s technology is new in the field of gas compression and could conceivably play a role in commercializing compressed air energy storage.

PV/Solar Thermal Hybrid Systems Utilizing a Bulk Material Spectral Beam Splitter

Silicon photovoltaic cells are capable of capturing and converting to electricity only a fraction of the available solar frequency spectrum. This limitation is part of the reason that the light energy to electrical energy conversion efficiency is limited to a little over 20%. More efficient solar cells can by manufactured from multi-layer thin film semiconductors (typically gallium arsenide compounds). Different layers are optimized to capture different part of the solar spectrum. Triple junction cells have achieved sunlight to electricity conversion efficiencies of more than 40%. In spite of the high efficiency compared to silicon PV cells the triple junction cells have made very little market penetration because of very high manufacturing costs.

An alternative method to capture a larger part of the solar spectrum is to make a combined heat and power system where silicon PV cells convert part of the spectrum to electricity and part of the spectrum is used to heat up a heat transfer fluid which can be used for hot water, space heating, or industrial process heat.

A relatively low tech version of such systems called PVT panels are already available from a number of manufacturers. These systems take advantage of the fact that PV panel naturally heat up (up to 70°C to 80°C under optimal conditions) when exposed to the sun. The solar panels are installed on top of a solar collector which contains a circulating fluid which absorbs heat from the solar panel and stores it in a tank where it can be used later for water or space heating. These systems cool down the solar panels to about 30°C and thus increase the efficiency of electrical generation by about 6%. Since residential hot water systems deliver water in the temperature range of 50°C to 60°C a heat pump is required to make this system useful for providing hot water. A heat pump can provide an energy lift of four or five. That is the amount of heat delivered is four or five times greater than the energy consumed in running the pump.

I don’t know what the economics of such systems are, but an number of companies are marketing these solar PV/thermal hybrid products (e.g. Sundrum, Solimpeks, SolarWall, TES, Northburn Solar)

Higher temperature for the thermal collector could be achieved by using concentrating optical systems such parabolic troughs, but unfortunately the high temperature would degrade the performance and reduce the life expectancy of the silicon solar cells. I recently came across an article published on the web site of SPIE (the International Society for Optics and Photonics) describing a design for concentrating solar PV/thermal hybrid system which overcomes the silicon cell heating problem. This design uses a spectral beam splitter which splits the incoming sunlight into two frequency bands one of which is fed to the silicon solar cells and the second of which is fed to a thermal receiver which is insulated from the solar cells.

The frequencies which fall on the PV cells are ones which can be successfully converted to electricity so that their energy is converted to electrical current which does not significantly heat up the silicon cells. The concentrated light which falls on the thermal absorber can produce temperatures of 150°C or higher without degrading the performance of the solar cells.

Spectral beam splitters have existed for a long time but they are fairly expensive devices which require costly thin film processing. The inventors of this particular solar pv/thermal hybrid system claim that they have developed a low cost beam splitter based on bulk materials.

The the real economics this solar design remain to be seen. 150°C temperatures are not really need for domestic energy needs, so this system will be aimed at industrial roof tops. Also motorized parabolic troughs do not seem like a good match household installations. The advantages of this system are lower silicon use due to the solar concentrator and the extra value stream of thermal energy. The disadvantage is the cost and complexity of motorized parabolic troughs.

Solar concentrators do not work well with diffused sunlight, so these kinds of systems will have the most attractive economics in locations with lots of clear skies (e.g. the American Southwest, the Mediterranean, Australia, etc.). This design is certainly not a miracle system which will transform renewable energy use, but it might find some effective economic niches.

Lithium Ion Capacitors

The most common negative electrode or anode used in lithium ion batteries is made of graphite, the same material used for pencil lead. The electrodes are comparatively cheap, have high round trip charging/discharging efficiency, and have very good cycle life. The positive electrode or cathode is substantially more expensive and has a shorter cycle life. A new class of electrochemical storage devices has emerged called lithium ion capacitors. They are not true capacitors because the anode is the same graphite anode used in lithium ion batteries and undergoes a chemical reaction with lithium. However, the cathode is replaced by the same high surface activated carbon used in ultracapacitors. This electrode does not interact chemically with lithium but stores energy in the electric field between two layers of charges.

Ultracapacitors using high surface area activated carbon have very high power density (they can be charge and discharged very quickly) and very long lifetimes. Maxwell Technologies, a prominent manufacturer of ultra-capacitors claims that their capacitors can last up to one million duty cycles. Lithium ion capacitors are intermediate in performance between lithium ion batteries and ultra-capacitors. They have 4 to 10 times higher energy density than ultra-capacitors (at the high end the approach the energy density of lead-acid batteries) and they have higher power density and longer cycle life (100,000 duty cycles) than lithium ion batteries. They also have a higher fully charged voltage than ultra-capacitors (3.7V as opposed to 2.7V) which is an advantage for some applications. In addition lithium-ion capacitors have much lower self discharge rates than ultracapacitors; Even after 2000 hours nearly 98% of the original charge remains in the capacitor.

Among the manufacturers and developers of lithium ion capacitors are Taiyo Yuden, and JSRmicro.
A key question relating to the application potential of these devices is cost. If the higher energy density relative to ultra-capacitors translates into lower cost then the field of application might be very large. I looked on line for lithium ion capacitor and ultracapacitor prices. I found an offer for a 350F 2.7V Maxwell technologies capacitor for $10.75. I also found an offer for Taiyo Yuden 200F 3.8V lithium ion capacitor for $46.09. The energy stored on a capacitor is ½CV². Therefore the energy storage capacity of the Maxwell Technologies capacitor is somewhat less than the Taiyo Yuden capacitor in spite of the higher capacitance. If I scale the price of the Taiyo Yuden capacitor by the ratio of the energy storage capacities I get a price of $40.72 for equivalent energy storage.

There may be certain application for which the higher voltage, the smaller size, or the longer charge retention time make lithium ion capacitors the preferred solution, but if the price quote I found above is reflective of real costs then lithium ion capacitors then the field of applications which they can take over from ultracapacitors may not be that large.

It’s about a reasonable standard of consumption: People are starting to get it.

Discussing the need to move beyond the Sell More Stuff paradigm of our modern system of economic production and distribution can be very frustrating because of strong resistance to changes in familiar social norms. However, I am beginning to see evidence that this resistance is breaking down, and a substantial group of people exists who understands the importance of developing a reasonable standard of consumption as a central part of any solution to our economic and ecological problems. This fact was strongly impressed upon me during the recent Thanksgiving holiday by two articles I read in a single issue of the Minneapolis Star Tribune while visiting my sister in Minnesota.

The first article was an advice column in the style of Dear Abbey. The person seeking advice had been interacting with her niece primarily by going shopping with her and buying her presents. The mother of the girl had put her foot down and mandated that this stream of gift giving should come to an end. The letter writer wanted advice on how to overcome this resistance. The the first suggestion made by the advice columnist was that in a world filled with stuff, stuff, stuff, the aunt might be able to find some better way to interact with her niece than by going shopping with her.

The second article was an editorial written by a conservative journalist complaining about certain aspects of the standards for the core curriculum of American history being developed by high school educators. The conservative writer felt that the proposed curriculum was far too critical of American capitalism in the post WWII era. The excesses of consumerism and growth at all costs was criticized, and the editorialist even suggested that the standards creators were following in the foot steps of Karl Marx by suggesting that consumer culture is entering a terminal phase in which its inherent destructiveness is undermining the basis of its own existence.

If advice columnists and secondary education bureaucrats understand that developing a reasonable standard of consumption is a prerequisite for creating a sustainable economic system and that our economic system as it currently exists is structurally resistant to the development of such a standard, then significant progress is being made in undermining existing cultural norms. The people who understand this reality are probable still a minority, and very few of them have clear ideas about what sort of structural changes are required to bring about a reasonable standard of consumption without creating a major economic recession or worse. Nevertheless it appears that the day when an intelligent social conversation about this issue can take place is much nearer than it appeared to be just a few years ago.

Water Free Solar Panel Cleaning

I just read an interesting article on Triplepundit about a robotic system for cleaning solar panels without water. While the high tech aspects of the system (the robots are themselves solar powered and are controlled by a cloud computing system) are interesting I was mainly struck by the water free aspect of this cleaning methodology. The cleaning depends on a combination of air flow and and mechanical scrubbing by microfiber cloth. An Israeli company Ecoppia are the manufacturers of this cleaning system. In addition to not requiring water Ecoppia claims that overall costs are lower than for systems that rely on spraying water and manually squeegeeing the panels.

High insolation deserts are a good locations for utility scale solar PV installations, but using water for panel cleaning may create an economic battier to scaling this form of electricity generation. Therefore the development of a water free cleaning system is potentially good news for the future expansion of such installations. Test