Solar cells are continuing to improve in efficiency. My best source tells me that within a few years, we will likely be seeing solar arrays of multiple layers, each layer tuned to a particular wavelength emitted by the sun. Why is this important now? If a company is looking at the life of existing boilers and planning replacements, we just may be reaching the point that a new boiler's life will encroach on the possibility of replacement by solar. Not that I have ever seen management worried much about what might happen to their current investment in five to ten years! Such a scenario may leave future managers with the decision of whether to retire an asset early due to (at the time) much lower operating costs with new technology.
Solar is already at use in our industry, often with subsidies to make it attractive. The Pratt Industries' box plant on Staten Island has its entire roof covered with solar cells. To see this, go to Google Earth and search for "Victory Boulevard, Staten Island, New York." Scroll to the western end of Victory Boulevard and this array is plainly in view.
One of the biggest problems with solar energy, besides its history of inefficiency is the land it occupies. A current real concern here in the United States is a plan to build a solar farm in my home county, Highland County, Ohio, to supply power to Cincinnati. It will occupy some nice farmland (see here).
There are many places solar can be placed to avoid this conundrum. The Pratt Industries example mentioned above is an obvious one. There are many industrial roofs that could be used for solar arrays. Warehouses are particularly attractive, although paper machine roofs could be used, too.
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One place I have been thinking about recently is the space between railroad tracks. This is necessary space for railroads to function, but it is really not used for any productive activity other than to keep the rails properly spaced. If you run the numbers, this space represents about 46,000 acres in the United States. This does not include any other land on railroadrights-of-way which must be kept clear for the functioning of railroads. (There have been some nascent attempts to use this other land for solar arrays).
This is enough land to be worth considering. It just may also be of such a configuration to help supplant the overburdened electrical grid in the US. Even more interesting, if one thinks of it as a contiguous array, the overall exposure to sunlight will be considerable on any given day of the year due to its massive spread. This is certainly a possibility far beyond the scope and interest of the pulp and paper industry, however if one thinks about all the mills that have railroad sidings, connections to this solar grid would be easy.
My main point, however, is this: solar is maturing to a point that some fossil fuel fired boilers installed today may be retired before their useful life is over due to the advancements just around the corner in solar.
For safety this week, it is important to remember that if you are around solar, it must be in your LOTO (Lock Out Tag Out) procedure just like any other energy source when it comes to maintenance. We have solar on our house and the local utility has stickers all over the place on our junction boxes warning service techs of this hazard.
Be safe and we will talk next week.
