Solar PV and Solar Thermal
There are two main technologies; Solar Photo-voltaic (PV) and Solar Thermal. Both are not competing or mutually exclusive. Solar PV converts incident sunlight to electricity directly into a DC current which has to be converted to AC and often there is requirement for storage batteries. A significant portion of cost (up to 40%) can go towards these extras which are called Balance –of-the –System (BoS) costs in the technical jargon. There are to day mainly three technologies in PV; a) Mono-crystalline Silicon b)Poly-crystalline c)thin film. Mono-crystalline Si has been most popular with the highest efficiency that has reached almost 18%.It is also the most expensive but competitive. Poly-crystalline Si is a variant of how Silicon ingots are made.
In Mono Crystalline, one crystal is grown as an ingot, which is fairly expensive and energy intensive task. In Poly-crystalline, larger multi crystalline ingots are cast and then sawn into smaller cylinders. There is no scope here for going into full details and we restrict the detail here to its relevance with the issues we are dealing with. Only about ten companies are reportedly into the highly capital intensive upstream portion of this business. But there is a downstream component, which is labor intensive and where countries like us have a long term potential comparative advantage. This is of fabricating/assembling the solar panels from imported solar cells. Almost half of the cost (60%) of solar panel is other than solar cells. Other supplier industries like sheet or plexi Glass and backing material like plastic sheets and structural framing components and materials are going to be energized from such local assembly of Solar panels. From the perspective of developing countries mono or multi-crystalline Si technologies are the best bet . This would be one of the ala-garment industries of the future with a potential for very significant employment. It is quite simple to assemble panels. There are many DIY approaches and even in
Apart from local employment perspective, there is another imperative for local production. Once Solar Power becomes really competitive, the domestic demand in the producer countries may get so heated up that developing countries like
Let us pray Thin-film technology does not prosper
There are other Solar PV technologies fast coming up where there would be total automation, and no scope for labor surplus countries. Flexible Thin-Film continuous sheets are being produced in a roll-to roll environment; a roll of web material, as in a printing press, is fed in at one end and a role of PV panel taken out at the other end. It has only to be framed as one frames a painting. These are also flexible and can be mounted on curved surfaces.
Solar PV cells mainstay would be in stand alone distributed domestic and commercial lighting system, although many grid connected solar PV farms of exceeding 100 MW are already in operation and more are coming up every day. The jury is still out if PV would be able to supply the volume of utility power that is required. Besides industries require energy in primary form as heating or cooling, where PV is less competitive, although there are split AC systems in the market of 18000 btu per hour working directly on Dc power produced by solar PV.