Five northern Nevada companies that are developing products ranging from plant-based lubricants to building-automation systems that save energy are in the midst of an intense summer-long training regimen.Their goal: Prizes that range from $20,000 to $250,000 in cash and services in a national competition known as Cleantech Open.This marks the first year that the competition has specifically targeted Nevada companies, although several startups from the state in the past traveled to Cleantech Open events in California.Chip Evans, Nevada director of Cleantech Open, says he was surprised at the strong response the event drew in its first year in Nevada, especially …