Copyright (c) 2011 Scionix Consultants
Whenever I discuss solar energy, either among friends, or at public presentations, I often hear a number of genuine concerns about solar. Some were true a few years ago but have already been addressed by the fast pace of technology. Some of the concerns might have their origin in our own knowledge from misinformation or disinformation, and others are free floating urban legends. Some concerns continue to be true, standing in the way of widespread adoption of solar electric energy use. Here I have briefly covered a few of these issues. It is good to remember that every change in technology has generated concerns and controversies in the past.
1. Is there enough electric energy that can be generated from solar? [Definitely yes]
To most of us it seems that there is not much energy in sunlight. If you had thought this way, you would be surprised by the numbers below. These numbers are somewhat different from different sources, because of the assumptions made. Please also see slide 16 in my 2010 INGCORE presentation (Reference 3 in the right bar).
Of the average solar radiation intensity of 342 W/m2, about 58% reaches the Earth's surface. As a simple case, suppose we could use 10% of the so far unused land areas. The energy received in that area is about 24000 exa joules per year, which is 6,648,000 TWh (Tera WattHours). Let us assume (a lower than available now) solar panel efficiency of 10%.
In 2005, our global yearly consumption of electricity was 15,182 TW; of which 9,541 TWh from fossil fuels and 2,555, TWh from nuclear power.
So solar cells can produce 35 times more electricity than produced by fossil fuels and nuclear power in 2005. Even if we use only 1% of unused land area we could produce nearly 4 times the total needed. And we are not even talking about going to all solar; to get to a 30-40% of energy requirements, we need to use less than 1/1000 of unused areas, ignoring that solar cells will reach 15-20% efficiency in the near future.
In more common terms, the average residence in India has a lot more roof area than is needed to get all of its electricity use from current solar panel technology.
2. Solar panels take so much energy to manufacture, the total energy generated during its lifetime of use, does not recoup it [ Absolutely Wrong. ]
Even 20 years ago, before solar cells were produced in any quantity, this may not have been true. Considerable independent scientific studies have been performed and published analyzing the total cost of producing everything needed for a full grid connected solar electric system, including the cost of producing the required machinery to make the solar parts and the other components in addition to the raw materials [Reference will be added on the right bar]. In 2001 studies estimated the time needed to recoup the energy used in production of the system between 4 to 10 years. But the vast improvements in efficiency of panels, newer materials, and cost reduction from mass production and adoption has made this number in 2011 come down to about 1 year.
Most good quality modern solar electric systems come with a 20 to 30 yr manufacturers' warranty already, during which period they will produce many times the energy used in their manufacture. Incidentally, my own research indicates that a well designed solar system could be operating for 50 years with only 15% reduction in output, and possibly continue to produce useful energy for many more years after that. This is discussed in detail in item 3 here.3. The useful life of solar panels is rather short [Not at all true]
The above, unfortunately, is a prevailing view, but is a misconception. This might have originated from manufacturing defects in the earlier panels, or the lower quality control of some manufactures. Another reason for the misconceptions might be from the very limited life of rechargeable batteries used in the smaller systems. Batteries indeed have very limited life, however we are considering here grid connected solar systems without chemical batteries.
All modern solar manufacturers are giving warranties better than 80% electricity production after 30 years. It turns out that 80% is a rather conservative stand, and that is used because many standards now require that minimum. Most degradations or failures are as a result of moisture leaking through seal breaks in earlier models, not from the degradation of the silicon component.
A very recent study (Reference 8. Performance of Silicon Solar Panels after 20 year use) shows even better results. After 22 years of usage the energy production continues to be above 92%!! My own experience with my 17 year old system (admittedly a rather small sample of 8 panels) is that at this age the production is better than 95% of the original. Note that furthermore, the solar panels require almost no maintenance at all, it is much like the electrical wiring in a building.
The panels manufactured now in the better quality production lines may have even longer life. Even after degrading to 80% of the initial, the production is still quite useful. That may mean that modern panels may last 60 to 100 years or more of useful energy production!!
4. Are solar electric systems safe? Do they emit toxic or green gases? [It is the cleanest comparatively]
Solar electric generation maybe one of the most clean and safe of all energy productions we have. However, there have been fears that making solar cells might release more hazardous pollution than fossil fuels would. To ease those concerns, concerned world-class scientists studied the matter closely and and have concluded that manufacturing solar cells produces far fewer air pollutants than conventional fossil-fuel-burning power plants.
See the Reference 10. Study: Solar Power 'Surprisingly Green' Despite Toxic Materials. Also see the Reference 7. Comparison with nuclear energy -- life cycle production costs, safety, greenhouse gasses, subsidies .
5. Is solar cost effective now? Is it viable? [The emerging facts are surprising even to experts]
This involves some subjective assessments as well. We have to consider the cost of money (interest rates, which change with time), the cost of energy from other fuels (region dependent), the power shortage condition of a given region, the relative subsidies available for various forms of energy production, and the lifetime cost of pollution effects or that of decommissioning power plants, global warming effects, to mention a few. Most calculations of energy costs are very often simplistic in that they ignore some of these factors. I will give some related points.
We often hear that solar energy needs subsidies to be competitive. This is currently true. But the cost of producing solar is decreasing faster than all other forms. Moreover, the costs of all the energy sources are going up, but the solar energy source itself is totally free and will remain so for ever. And a very interesting and least realized aspect of our industrial energy production is that pretty much from the beginning of organized energy production for widespread use, every form was subsidized by the government in every country. It turns out that even now the energy subsidy currently for solar is less than that for other forms! See Reference 11. Energy subsidies are as old as the Republic.
The scientifically accepted best measure of the cost of energy is the Levelized Cost of Energy. This takes into account the lifetime cost of producing, using, the costs to mitigate the secondary effects from the use of a particular form of energy, and decommissioning of the plant at the end of life. The preeminent, impartial global organization which studies such matters is the Renewable Energy Network for the 21st Century. The following graph is from the REN21 2009 Global Report.
Another measure is how fast solar energy use is growing and adopted all over the world. It is the fastest growing segment of the alternative energy sector. The following graph from the REN21 2011 report shows the dramatic increase in solar.
The cost of a new energy source is often talked about in terms of Grid Parity, which is the cost of energy produced currently for the electric grid. This is region and subsidy dependent. Solar Electric has already achieved grid parity by mid 2011 in many parts of the world, and its cost continues to come down dramatically.
Solar appears more expensive at first look than the subsidized energy from the grid in many parts of the world. One should look at what it would take to put in a new plant of any type to get the extra energy, the availability of the resources to produce the energy, and the normal and expected inflation of these sources in the future. Solar is abundant, and a free resource.
One of the most compelling reasons for solar electric energy is that the efficiency of production is almost entirely independent of the size of the plant. This, coupled with the distributed availability of it very close to where energy is needed, and that even a single user can very effectively produce solar energy safely is what is going to make solar the big winner and major energy source in the very near future. In the industrial age, energy production had to be centralized (and then the fuel or energy distributed through vast expensive networks, as for petroleum and electricity) for safety, and because of the large plant capacities, cost and difficulties of operation. This is a total paradigm shift for solar electric generation. Of course for the individual producer to benefit from this, compensation needed to be provided through regulatory environment in the form of feed in tariffs or other mechanisms.
Governments in many parts of the world, realizing the economic benefits of harvesting solar energy have started providing such compensation. The beneficial results from feed in tariffs have been just dramatic. Partly because of pressure and influence from the other sectors of production, some governments even scaled back the relative subsidies for solar as a result. For a sample of this rapid development see Reference 4.Some medium scale solar projects.
Governments in many parts of the world, realizing the economic benefits of harvesting solar energy have started providing such compensation. The beneficial results from feed in tariffs have been just dramatic. Partly because of pressure and influence from the other sectors of production, some governments even scaled back the relative subsidies for solar as a result. For a sample of this rapid development see Reference 4.Some medium scale solar projects.
6. Energy production is simply an issue of economics and one of demand [Not so! It is a national/regional security issue!!]
This has been the prevailing view that most areas, states or countries would continue to find the required energy from new sources as the demand increases, or would be able to procure the required additional resources from neighbours. However, some areas like Kerala have already maxed out on the primary resource like the hydro, and the expected growth of energy needs are much higher than that can easily be handled.
Energy is really a national and regional security issue! The shifting local or geopolitics could leave a particular region or country short of energy unpredictably. On a very simple scale, the current shortage of energy in Kerala is a case in point. However even international pipe lines and shipped energy sources could be cut off on short order. This is why we need to develop energy self sufficiency. Solar is the most abundant form of energy available. It is locally available everywhere. It practically unlimited source of energy at zero cost (after the initial equipment purchase).
No comments:
Post a Comment