By Peter Asmus, Senior Analyst, Pike Research
It was the Greeks who first viewed the sun as a source of energy that could be managed and exploited by humanity. Early efforts to tap this energy source revolved around what are now called “passive solar designs”–methods that tap the sun’s light and heat to help us see and stay warm within our homes and other buildings.
Solar power technologies received a major boost from Leonardo da Vinci in the 1500s, when he conceived a parabolic mirror that concentrated solar energy for clothing dyes. This form of solar energy — now referred to as “Concentrated Solar Power” (CSP)–was first developed commercially for electricity generation in the Mojave Desert in California in the 1980s. For more than three decades, this series of parabolic troughs totalling 360 megawatts (MW) of CSP was the largest solar power generation station in the world. While there are several CSP projects on the drawing boards throughout the world, with North Africa and Spain being two major markets, many are being canceled in California and through the western U.S. and replaced with solar photovoltaics (PV), the focus of today’s solar power industry.
Modern solar PV technology was developed initially for the space program over 30 years ago and relies upon silicon transistors. Because these solar transistors were so expensive, it took the emergence of the satellite industry in the 1950s to create a demand for such wireless electricity generators to find a cost effective application. The space industry needed a remote power source that did not require copious quantities of stored fuel. Solar PV panels filled a unique though specialised market niche. Initial terrestrial applications were for remote homes and facilities not connected to any utility grid.
Today, even the conservative Institute for Electrical Energy Engineers (IEEE) now predicts that solar power will be the world’s cheapest source of power over the long-term, due to its modularity and the increasing efficiency of the panels. Future innovation should radically increase performance since efficiency can be targeted at the four-fifths of the potential solar resource that’s currently lost in the power conversion process.
A typical solar PV system consists of the actual solar modules, balance of system (BOS) components, such as inverters that convert the direct current (DC) power generated by the solar module into alternating current (AC), and other system components, such as racks and wiring, or even advanced storage systems such as batteries.
From a utility point of view, solar PV can be problematic. Like wind, power production can be variable, though wind is less predictable. (We know, for example, that the sun does not shine at night!) The key technologies necessary to integrate solar PV into utility systems are “smart” inverters and “smart” meters, technologies that can tap intelligence within the grid network to manage the increased complexity of relying upon multiple smaller sources of power. In this way, solar PV is part of an evolution transforming our grid from a one-way power flow from large centralised power plants to a two-way exchange that looks a lot like the Internet.
