Some high-quality nutball vaporware that has crossed my desk in the last year or two includes:

• The guy selling kits and manuals for "how to run your car on zero-point energy". (Zero point energy is always a favorite with the perpetual motion crowd.)
• The water-powered car (or at least water-powered welding) was a huge media hit, even getting onto mainstream papers and TV stations.
• The Beck Mickle Hydro waterwheel supposedly generates 1-2 KW of power from just a 20cm drop in a stream; many smart people I know were excited about it, but someone on PES Wiki ran the numbers and calculated that there isn't 1 or 2 kW in streams that small to begin with.
• Steorn's Orbo has a classy, professional website, but with zero content, and a planned demonstration was called off at the eleventh hour.
• The "gear turbine" engine is such a mess I don't even know what to say about it.
• And of course, there's everybody's favorite, cold fusion.

(By the way, if anyone wants to share particularly fun lunatic fringe inventions in the comments, go for it!)

Most of these inventors have notoriously poor spelling and grammar, and have extended conspiracy theories as to why their inventions are not being embraced by the public. Those are the sincere ones. The ones with the slick presentations who promise a lot and then call off their demonstrations at the last minute are the con artists, playing off people's desperation to find energy alternatives. And there's the occasional prankster like David Jones, a real scientist who claimed to make perpetual motion machines just to mess with people.

Then there's the grey-area inventions: the ones that are legitimate, and often brilliant rethinkings of how to do things, but are too difficult to feasibly produce or run. The Massive-Yet-Tiny Engine, which claims to have a power-to-weight ratio 40 times better than conventional internal combustion engines, is probably one of these. The folks at AutoBlog had a long list of reasons why the engine is probably impossible to make, yet they encouraged the inventor and his company to keep pursuing it. As one commenter pointed out, the internal combustion engine has 100 years and over a trillion dollars in R&D behind it. Fusion is still in this category, even though there's no fundamental principle of physics keeping it out of reach. Many people think that fuel cells are in this category, and decades of debate have ensued.

Should we just sit back and snicker at these fringe inventions? No. Being skeptical is good, but being cynical is bad, because cynicism is obedience. The cynic assumes nothing can be done, and so does not try to do anything. It's too late for that; the state of the world is too dire for cynicism. We need idealism and we need action. But we need to act with clear heads, and pursue the most promising leads.

So how do we decide which paths lead to massive change, and which are too good to be true?

We need a basic understanding of physics, of course, but moreover we need to ask the right questions. The best list of questions I've seen is at From The Wilderness:

1. How Much Energy is Returned for the Energy Invested (EROEI)?
2. Have the claims been verified by an independent third party?
3. Can I see the alternative energy being used?
4. Can you trace it back to the original energy source?
5. Does the invention defy the Laws of Thermodynamics?
6. Does the inventor make extravagant claims?
7. Does the inventor claim zero pollution?
8. Can I see blueprints, schematics or a chemical analysis of how it works?
9. Infrastructure Requirements: Does the energy source require a corporation to produce it? How will it be transported and used? Will it require new engines, pipelines, and filling stations? What will these cost? Who will pay for them and with what? How long will it take to build them?

Ansering question number one often requires sophisticated expert analysis. For instance, it comes up often when talking about biofuels, because some studies show that corn ethanol has an EROEI of only 0.8, so you have to put in more energy than you get out, while other studies put it at 1.3, making it a (barely) green alternative to gasoline. (Incidentally, the EROEI of Brazilian sugarcane ethanol is usually quoted at over 10, and biodiesel ranges from around 3 for US crop-based production to a theoretical 10 for algae-based production.)

Questions two, three, four, six and eight above should raise your scam-alert flags: any inventor who refuses to tell you how their device works or let skeptics test it is obviously a fraud. Quesion five is the downfall of the classic crackpot perpetual motion-ist, and is usually easy to spot as long as you have enough information to run the numbers; it's not nearly so difficult as calculating EROEI. Finally, question nine is the killer for many of the grey-area technologies (including, so far, fuel cells).

So keep your mind open to new inventions and wild claims, but know how to evaluate them. And likewise, don't forget to be skeptical of established and well-funded technologies that still don't have a chance in the long run. Bet your time and money on the most promising leads.

Source: http://www.worldchanging.com/archives/007224.html