Since the train is electrically powered, I am not terribly disturbed by the use of the kilowatt-hour as a unit of energy. Even the SI Brochure (reluctantly) accepts it for electrical energy. I am baffled by some fool converting it to BTUs, which are customarily used only for thermal energy. I wonder if there was some attempt to take into account the thermal efficiency of the power plant, and calculate thermal energy at the plant to power the train. In any case, like most oranges/apples comparisonns, it went awry.
Since it was promptly converted back (wrongly) to kilowatt-hours, the entire BTU conversion can only be judged as stupid and unnecessary. Given that the raw data from a German study was in kilowatt-hours, I am sure the consultant would have converted to joules as badly as he did BTUs ( as 1 BTU ~ 1055 J, using the international table BTU). ________________________________ From: Pat Naughtin <pat.naugh...@metricationmatters.com> To: U.S. Metric Association <usma@colostate.edu> Cc: USMA Metric Association <usma@colostate.edu> Sent: Fri, December 31, 2010 7:35:44 PM Subject: [USMA:49368] High speed rail error Dear Carleton, I think you will be interested in this train story at http://www.cahsrblog.com/2010/12/hsr-emissions-paper-was-wrong/?utm_source=rss&utm_medium=rss&utm_campaign=hsr-emissions-paper-was-wrong where they say: Berkeley’s numbers are undone by a simple unit conversion error committed by a CHSRA consultant. Conversions between metric and imperial units are prone to errors and misunderstandings, most famously in the case of NASA’s $300 million Mars Climate Orbiter mission, which was inadvertently crashed into Mars because of an overlooked conversion between pounds and Newtons. In the case of the high-speed rail study, the CHSRA consultant’s unit conversion error leads to an overestimate of HSR energy consumption by a factor of nearly four–not just in the Berkeley study, but also in the CHSRA’s program level environmental reports. The energy consumption figure cited in the Berkeley study and its supplementary data is 170 kilowatt-hours per vehicle kilometer traveled, or kWh/VKT, a measure of how much energy a high-speed train consumes on average when traveling one kilometer. This number is correctly converted by Berkeley from a figure of 924,384 BTU/VMT referenced in the energy chapter of the 2008 CHSRA program-level EIR. That chapter in turn references a peer-review study performed for CHSRA by the German firm DE-Consult in 2000, which evaluated the energy consumption of a hypothetical 16-car trainset with a seating capacity of 1200 and a design speed of 385 km/h (240 mph) and an operating speed of 350 km/h (220 mph), essentially a souped-up German ICE3. The DE-Consult study (unavailable online) contains detailed performance simulations for the proposed California system that give the average energy consumption of such a train as 74.2 kWh/VMT, or 46 kWh/VKT (see copy of Annex 4-11). And therein lies the error: CHSRA’s consultant botched the conversion from kilowatt-hours to British Thermal Units, feeding Berkeley a figure of 170 kWh/VKT instead of 46 kWh/VKT. I wonder why they were converting from British Thermal Units (no temperature specified) to kilowatt hours instead of (say) megajoules per kilometre (MJ/km). Clearly none of the consultant engineers has any sort of firm grasp on metrology -- VKT for vehicle kilometre travelled doesn't impress me as coming from a knowledgeable person who knows his SI from his toothbrush. Cheers, Pat Naughtin LCAMS Author of the ebook, Metrication Leaders Guide, see http://metricationmatters.com/MetricationLeadersGuideInfo.html Hear Pat speak at: http://www.youtube.com/watch?v=_lshRAPvPZY PO Box 305 Belmont 3216, Geelong, Australia Phone: 61 3 5241 2008 Metric system consultant, writer, and speaker, Pat Naughtin, has helped thousands of people and hundreds of companies upgrade to the modern metric system smoothly, quickly, and so economically that they now save thousands each year when buying, processing, or selling for their businesses. Pat provides services and resources for many different trades, crafts, and professions for commercial, industrial and government metrication leaders in Asia, Europe, and in the USA. Pat's clients include the Australian Government, Google, NASA, NIST, and the metric associations of Canada, the UK, and the USA. See http://www.metricationmatters.com/ to subscribe.
