To understand what is happening to solar-based energy production, one has to understand the passion of those searching for the energy Holy Grail -- limitless free energy from the sun is transformed electrochemically into limitless electrical energy at low cost with zero carbon footprint.
It is that passion that drives tens of thousands of scientists and engineers around the world, and even the solitary inventor in the proverbial garage. Energy's Holy Grail is in fact a cycle: Solar - Hydrogen - Fuel Cell -- Electricity. The energy from the sun is used to break the chemical bonds of hydrogen; the hydrogen is stored and then released through a fuel cell that recombines hydrogen and oxygen and in the process generates heat and a flow of electrons - electricity. The by-product - water.
The cycle is necessary because the sun does not shine on any one spot on the earth's surface 24/7. Its energy needs to be stored and made available as needed and the mechanism for storage is hydrogen. The fuel cell converts this stored energy into electricity.
Optimizing each stage presents unique technological obstacles in order to reach the goal of a commercially viable (i.e. affordable) process to inexpensively produce electricity.
The exciting news is that within the next six years the energy Holy Grail will be within our grasp.
The intermediate steps along this technological quest are providing their own benefits.
Implementing solar hot water has a payback period of less than seven years with a useful life of over 20 years. The cost of generating solar electricity (photovoltaics) continues to drop every year.
As stated in Wikipedia (photovoltaics): "Grid parity, the point at which photovoltaic electricity is equal to or cheaper than grid power, is achieved first in areas with abundant sun and high costs for electricity such as in California and Japan." Today, "Grid parity has been reached in Hawaii and other islands that otherwise use fossil fuel (diesel fuel) to produce electricity."
Even without subsidies, grid parity will be reached in many areas of the United States by 2015. With existing subsidies that point will be reached by 2011.
As the cost of solar electricity drops, so does the cost of producing hydrogen by using electric current to split water molecules (electrolysis). Scientists are probing the secrets of photosynthesis (the way plants convert sunlight to energy) in order to significantly reduce the costs of electrolysis. Their results should be commercially viable within four years.
Bioscientists are also making genetic modifications of bacteria and algae, and, using feedstocks of wastewater or biomass in a bioreactor, produce hydrogen. These processes are also coming out of the lab into pilot plants. (Clemson University, for example, obtains hydrogen from rotted peaches by this method.)
Significant progress is also being made to store hydrogen gas in a safe, compressed state for easy transportation and use. These methods of solid state storage of hydrogen are also reaching commercial development. Hydrogen molecules are stored in a matrix of nanostructures (tubes, hollow spheres, or layers of structures built on a molecular level) that provide remarkable surface area. For example, a teaspoon full of these nanostructures would provide as much surface area as half a football field.
Packaged in metal cylinders or cartridges of varying sizes, these hydrogen storage devices are as portable as propane tanks and perfectly safe. One California start-up demonstrated enough stored hydrogen in three cartridges, each the size of a laptop computer, to power an electric car 300 miles.
Fuel cells can range in size from large stand-alone facilities that provide back-up power for elevators in high-rise buildings, to residential boxes the size of a dorm-sized refrigerator, to even smaller units in automobiles and buses.
Two components of current fuel cells make them too costly for widespread use: platinum used as a catalyst, and a polymer membrane that separates the two sides of the fuel cell. Recent discoveries, however, should sharply reduce these costs. Other, cheaper, metal compounds can replace the platinum and a new material, said to be 100 times cheaper, can replace the membrane.
Using new technologies, two Korean companies are now developing fuel cells that are predicted to cost 10 times less, and be 40% more efficient, by 2010.
The quest for the energy Holy Grail has already produced entirely new industries. Within the next few years we will see dramatic growth that can transform many sectors of the economy, produce new companies, new businesses, new job opportunities, and local manufacturing.