Los Angeles fancies itself the capital of the alternative-energy world. Electric car companies are clustering here along with the startups to create the new-age batteries for them. Wind farms are popping up outside the city and solar electricity is hot.

On the one hand, all that’s promising. Alternative energy is, after all, the future. But on the other hand, it’s risky. Virtually every form of alternative energy today is either unproven, expensive, limited in capacity or dangerous in its own right.

We got a good reminder of that last week in a special section in the Wall Street Journal headlined “The Long Road to an Alternative-Energy Future.” It took a look at several alternative-energy initiatives and pointed out the significant challenges of each.

Take wind technology. It may be the most promising source of relatively low-cost, low-polluting electricity. The problem is much of the entire eastern half of the United States doesn’t have much wind. What’s more, there’s likely to be political objections to huge transmission lines that will need to cross states to transport electricity from, say, the windy western Great Plains to the East. In short, wind power has the promise of supplying only 20 percent of America’s electricity demand by 2030.

Solar power is growing quickly but still only accounted for 0.1 percent of all electricity produced last year. Solar power costs roughly three to six times as much as coal-powered electricity, it’s intermittent and it’s less of a resource in places like Seattle. Big solar farms could be installed in the desert Southwest, but again there’d be big objections to the transmission lines.

The special section went on. Making oil from algae is promising, but “it hasn’t proved that it can produce fuels in sufficient quantities or at a low enough cost to make a dent in U.S. liquid fuel consumption.”

The new generation of better and safer nuclear plants will take a long time to get going, and there are supply chain problems; not many forges can make reactor containment vessels. Battery cars are expensive and may require costly recharging stations to be installed in cities. And, of course, most of the cars will be “fueled” by electricity from coal- or natural gas-fired generators, so can they really be called alternative-fuel vehicles?

The point is that a move to an alternative-energy future may be a painful one. No one knows what may happen. There’s bound to be busted companies and lost wealth and – in this area, particularly – probably a load of taxpayers’ money diverted to prop up losing propositions. Who knows? Maybe the alternative-energy magic bullet will turn out to be something that doesn’t benefit Los Angeles in any way.

The search for viable alternative-energy sources must and will go on, of course. But it’s good to remember that most of the experiments in alternative energy will prove to be failures.