The pioneer: Dr. Emanuel Sachs, founder and Chief Technical Officer of 1366 Technologies, Inc.

The concept: Silicon-based solar at the cost of coal. Right now, more than 80 percent of all solar panels sold worldwide are made with high-cost crystalline silicon. Next-gen, thin-film technologies show some promise, but those depend on rare elements such as indium and tellurium. Silica — the principal component of sand and the second most abundant element on earth, after oxygen — could be the ticket to affordable solar. Making solar panels from silicon is wasteful; thin wafers are shaved off large cylindrical columns of refined silicon, which means that half the silicon ends up as dust. With his new “direct wafer” method, Sachs solves the problem by using molten silicon — no sawing needed. The single-step manufacturing process uses much less energy too, which cuts the cost of each wafer by more than 70 percent. If successful, “direct wafers” would open up a market for solar that’s unconstrained by cost or materials.

The payout: $4,000,000.00

The goal: Sachs’s prototype wafers are four inches square with efficiencies of roughly 12 percent. That’s a bit higher than thin film solar, but not as efficient as the 15 to 21 percent range of standard crystalline silicon panels. Sachs plans to produce six-inch square wafers — the commercial standard — with 16 percent efficiency by the end of 2011. Long term, he aims for 21 percent efficiency at one-third the cost of today’s installed silicon-based panels.

The hurdles: Efficiency and mass production. Currently Sach’s molten direct-wafer technology is about 20 to 50 percent less efficient than the standard. The more efficiency you strive for, the more difficult the challenge becomes. In other words, it’s a lot harder to get from 18 to 20 percent efficiency than from 15 to 18. One efficiency-boosting approach Sachs is trying is to introduce textures into the molten crystalline wafers in order to trap more light. He also has to develop commercial-scale production methods. It’s not clear yet that his molten wafer method can make that leap.

The promise: “Sunlight is the original, omnipotent form of energy — fossil fuels themselves are a product of plants grown by sunlight. The question is how to capture this diffuse resource. We are trying to harness the primordial power of nature with the least effort — to find out what nature wants to do and help it on its way.”