Solar start-ups are hot again — especially those that address the “downstream” part of the value chain: installer services, customer acquisition, system design tools and analytical systems. And as in years past, there are a dozens of companies showing new types of types of solar panels, trackers, racking systems and integrated systems.

If these products can deliver on their promises, we can look forward to further reductions in both hardware and soft costs for systems. And not surprisingly — after a few successful IPOs and acquisitions — VCs are investing again in solar deals.

At this years Solar Power International (Chicago, October 22-24th), many of these promising startups are highlighted in a new section called “Start-Up Alley.” Here, 20 early stage solar companies will be demonstrating their products and services, and will be presenting their business proposals to potential investors. But Start-Up Alley is not the only place to learn about ways to improve your solar business — industry stalwarts like UnThink Solar, OnGrid and Solar Marketing Group will be at the show.

This is the 10th year for Solar Power International. We’ve watched the show grow from a few aisles of hippy-eco solar products on the ground floor of a San Francisco office building — to a major international trade show. So listen to this week’s Energy Show for a preview of the hottest solar start-ups, and a picture of where the industry is going for the next ten years.