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Retired electrical engineer with 30+ years experience in designing instrumentation and switching power supplies. I understand ICEs, electric motors and electrical grid transmission. General Physics background. I worked for many years in the semiconductor equipment business in Austin, Texas.... More
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  • Storing solar energy as chemical energy
    The following is an "off the wall" idea.

    When the sun is shining bright, the electricity generated from PV panels could be used to drive an arc furnace to produce calcium carbide ( CaC2 ) from limestone and carbon (coke).  CaC2 is a hard, grey black material that produces acetylene gas when added to water.  It has been used for making Acetylene for welding and  chemical synthesis and as fertilizer, since the early 1900s.  If kept sealed in an air (moisture) tight container, CaC2 will keep for years at any temperature.

      Acetylene is a fuel that burns very hot because of the high carbon content in the molecule.  Very nice for welding with oxygen.  When burned with air it produces temperatures excellent for moderate temperature metal soldering/brazing.

      A small arc furnace would only be useful for making small batches of CaC2, not any sort of continuous flow processing.  But the materials are so cheap that if a batch is ruined by the sun ducking behind clouds, it's not a big economic loss in materials wasted. 

    Sure it's a crazy idea.  I said that at the beginning :-)
    Sep 06 8:53 PM | Link | Comment!
  • Stocks for the Renewable Energy Reaction
    In many places, renewable energy has become synonymous with "higher electricity prices".  Where Wind or Solar PV electric generation has been subsidized, electric energy prices have inevitably risenSometimes more than politicians expected or likeBut removing long term subsidies can cause political problems from business and the noisy "green lobby".  Consumers just grit their teeth and vow to vote their pocketbook when possible.

      However, some larger electricity users have other optionsOne of the best is to use Natural Gas that is already purchased for heat generation to run an in-house electric generatorTen years ago that option was only for the very large users because of the expense of the capital equipmentToday there are several options for even modest users; as low as 10MWh / month.

    Two companies in this business are Capstone Turbine, CPST and Fuel Cell Energy, FCEL

    Capstone uses a 100k rev/minute gas turbine, directly coupled to an alternator, to produce electricity that is converted to local line format by an ancillary electronic power switching systemThe turbine is quite compact for it's power outputIt uses an exhaust heat regenerator for improved efficiency and can easily accept a secondary heat exchanger to heat water or make steam. It requires very little in the way of auxiliary inputs; a fuel supply and an exhaust stackElectrical efficiency runs about 35 to 40%, depending on size and optionsCost is about  $1k/kW, uninstalled.

    Fuel Cell Energy sells fully developed, molten salt high temperature fuel cells for stationary energy generationThere FCs can accept clean natural gas and operate at an electrical efficiency of near 50%.  They can also have their waste heat routed thru a heat exchanger for hot water or steam generationTheir advantages are superior electrical efficiency and quiet operationHowever, they tend to require more maintenance and have a substantially higher purchase cost per kW

      Their exhaust is very clean, assuming the fuel source doesn't have any contaminants such as sulfur oxides. These fuel cells also use electrical converters to change their DC output to line frequency AC power, so that added cost is similar to a turbine generation system.

      Considering that both systems produce "free" electricity if you already burn the NG for heat, the cost of money is the main impediment to their useAt today's interest rates the Capstone turbine payback period can be 4 years or lessI foresee many companies who are suffering from rapidly rising utility electricity prices adopting one of these technologies to avoid involuntarily joining the "green revolution" at the cost of their competitive position.
    Jul 10 4:18 PM | Link | Comment!
  • Axion Power International, AXPW.OB, for trade and investment
    If an expected DOE research grant gets final approval in the next month or two, I expect a significant jump in the price of AXPW.OB (Axion technologies).  I have been slowly building a position in this battery development "tech" stock for over 6 months.  All the elements for ultimate success seem in place and Norfolk Southern (NYSE:NS) has publicly acknowledged a purchase order for about $500k worth of batteries and battery management system.  This equipment will be used in a prototype railroad hybrid
    diesel-battery switcher locomotive.  The hybrid RR engine concept was proven out several years ago, with 50% fuel savings, but the Lead Acid batteries of the time couldn't take the high cycling activity and died after some months of use.
       Axion's PbC battery is really a hybrid of an AGM lead acid battery and carbon electrode supercapacitor.  It thrives on frequent, rapid cycling.  It has run, without meaningful degradation, for 70,000 shallow discharge cycles with rapid (100A) recharging. Whether this will translate into a deeper discharge, 10k+ cycle reliability in the RR switcher hybrid will be the subject of testing starting later this year.

      Having looked at the technology, I am confident it will be a cost effective solution for the locomotive diesel-battery hybrid.  It might also work for a pure battery yard switcher engine, producing zero point-of-use air pollution.

    Disclosure: I am long  AXPW.OB

    Jun 03 4:14 PM | Link | 2 Comments
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