Ice cream freezers chilled by propane and soft-drink vending machines cooled by carbon dioxide represent two concepts designed to be more environmentally friendly. (See Rethinking Refrigerants, page 29.) Those approaches may or may not become more widespread, but what's important is that the two companies behind them are doing their homework, performing extensive comparative testing, carefully evaluating the data, refining the technology. They aren't moving forward with the projects just because it seems like the green thing to do. They are achieving genuine technical and economic benefits. And that's exactly the right approach - test and validate new technology before widely deploying it. Unfortunately, producing hard facts may not always be enough when green-mania simply chooses to ignore them. For example, a recently concluded three-year test of hydrogen fuel cell buses in the San Jose area found that the operating cost for a fuel cell bus was $51.66 per mile, compared to $1.61 per mile for a conventional diesel bus. The "green" buses also broke down much more frequently. The technology is clearly not ready for prime time, but, undeterred, the California Air Resources Board plans to spend another $36 million to put more of those babies on the road.
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