Solar Technology and Cost – An Overview

Solar power technology has been around in some form or another for thousands of years and even many so called modern solar devices and designs are now decades old. Yet, they have not fulfilled the promise that many hope due to their high cost and lower efficiency.

There are approximately 1,000 watts per square meter of sunlight power falling on the surface of the Earth (at the equator) but only a small portion can get converted into usable electricity. Part of the problem is the result of internal losses of all the photons that hit a solar panel, only some will knock loose an electron – and not all of these will travel down the module and into the device before being recaptured.

The latter effect is due to something called carrier lifetime. The longer the electrons wander around loose, the more likely they are to flow out of the module and down the wires to an outlet. Most modules can only achieve around 10-15% efficiency, although several companies have raised the efficiency of their devices to as much as 20% by extending that carrier lifetime.

Solar thermal devices, on the other hand, use sunlight-heated salt water panels to generate steam that can be turned into electricity. The efficiency is often as high as 30% but such devices are high risk and expensive – the high temperature and pressure of the water means that if it escapes it can do considerable damage. Efficiency considerations aside costs remain relatively high and most types of solar panel remain fairly expensive. A 30-watt module costs around $250, while a 195-watt panel will run to almost $1000. To install a solar panel power system for even a modest home will cost somewhere around $10,000-$16,000 for the panels add to these batteries and other components and the cost rises from around twenty to thirty thousand dollars.

Fortunately manufacturers have begun to respond to the rising costs of gas and oil. As the market matures for solar technology, research dollars have been directed at finding new ways of increasing efficiency and lowering costs. Even with the relatively high price of large application panels and accounting for inflation, the cost of this technology is still much lower than it used to be.

The cost of PV (photovoltaic) cells has fallen by about 15% per year for the past 10 years. The fact that these cells can last 20 years, householders can have clean power while recouping the initial investment. Improvements continue to be made and a major European chip maker, ST Microelectronics, now has prototype solar cells that are expected to be considerably cheaper than today’s panels.

Organic compound solar panels are now found in applications such as computer keyboards and monitors. These flexible plastics mean that a computer can be folded or rolled like a magazine – although these are still expensive, the costs are coming down as the technology matures. A French-Italian company estimates that it will soon be able to produce an organic cell soon that will produce electricity at around 20 cents per watt, compared with around $4-$8 per watt for ordinary solar power.

Solar powered water heating also has variable costs. In the 1920s some municipalities used large storage tanks for storing and solar heating water that was then supplied to homes. However, when the price of electricity and oil came down these were no longer cost-effective. However these methods may well become competitive again if current research pays off. If the price of oil and electricity from gas and coal fired plants continues along the upward trend of the last ten years just a small improvement could make new applications more economically viable.