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The portable energy options market has been one of the most disappointing areas of the green tech space. Millions of dollars have been poured into the space but, even after years of trying, most of the firms investing in portable energy technology have yet to build a real business.

This is true in everything from consumer applications to business equipment. For instance, Ballard Power (NASDAQ:BLDP) is one of the big names in this arena and is focused on fuel cells. But to date, despite rabid enthusiasm from many retail investors, the stock has been, at best, neutral for most investors. Plug Power (NASDAQ:PLUG) is another firm with a similar story.

On the consumer side, the problem is that many of these products are in search of a solution rather than having been created in response to a real pressing need. Most of the products on the consumer side are too expensive to add value for the average user, and they haven't picked up enough traction to benefit from production efficiencies from scale. As a result, investors have mostly given up on this space.

There are, of course, firms that make consumer batteries, but that's very different from fuel cells and portable generators. Generac (NYSE:GNRC) makes generators for home use, but these are really old technology and are run on conventional fossil fuels for the most part.

Instead, a large part of the investment community in the portable energy tech space has now turned their attention to Business to Business (B2B) applications. Tesla's (NASDAQ:TSLA) new Powerwall is perhaps the most notable opportunity here, but the press around that has been intense and so the opportunity is certainly well known at this stage. One less well known option in the B2B space though is Toshiba.

Toshiba is not a U.S. company of course, but the firm does have an ADR trading on the pink sheets in the U.S. under symbol TOSYY and TOSBF. Normally, pink sheet investments are very risky and have to be approached with extreme caution. That rule is not really as relevant though when dealing with enormous multinational firms like Toshiba. While the issues are still not as liquid as most exchange traded stocks, at least with an ADR for a sizable firm, investors get the comfort of knowing that their investment is based on a stable company with real profits.

Toshiba has a wide variety of products, which is part of the reason its pink sheet issues are a bit safer, but in the context of portable energy tech, the firm has an interesting new product focused on disaster recovery efforts. Disaster recovery is a lucrative, if sometimes sporadic, business and certainly it's an area where portable energy tools have obvious value. This is a market where companies like Clean Harbors (NYSE:CLH) have created very effective business models, but Toshiba's system can help to enhance those business models. To that end, Toshiba's product probably represents a good opportunity for investors. Again, given the size of the company, the product is not going to cause the stock to double overnight, but over time it could move the needle.

The broader point for investors is that it's time to rethink portable energy technology investing. Most of the systems that have been pushed in the past are simply not useful enough to disrupt the existing status-quo. Investors have latched onto too many stories of disruptive innovations where there was not much evidence backing the firm. Rethinking that model means investors should look for areas where portable energy technologies can fill a real need that is currently woefully underserved by existing products. Disaster recovery is one such area, and military operations are another. Sun Edison (NASDAQOTH:SUNEQ) is a good choice for investors in that arena.

Regardless, smart investing means knowing when to pass on an investment as much as jump at it, and good investors will be carefully scrutinizing firms to discern who has a specialized niche and who is trying to bite off more than they can chew.

By Michael McDonald of Oilprice.com. The Motley Fool recommends Generac Holdings and Tesla Motors. The Motley Fool owns shares of Clean Harbors, and Tesla Motors. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.