Is solar power viable now?
by William Papolis, Monday Mar 26, 2007 10:34AM EST
OK, it’s credible, and technologically feasible, but is it economically viable?
A wise old owl once shared with me, “… sure, it may sound good, but it all comes down to the money.”
Before I answer that question let’s look at a current proposal for power generation.
Example 1 – Coal Power
The province of Saskatchewan, Canada wants to build a 300 Megawatt clean coal facility for 1.3 billion US. You can read about it here … SaskPower 300MW clean coal
The goal of this facility is to capture carbon dioxide and sequester it deep underground with the hope that it will never leak into the atmosphere. They claim about 90% carbon capture, and a use for sequestering CO2 includes: pumping it into oil fields to help with oil extraction from the ground, perhaps in the Alberta Tar sands?
A coal plant will require a local mine, usually a strip mine, that some argue creates more environmental damage during the mining process than during burning of the fuel. The cost of operating a coal plant is much higher compared to a solar power facility. (I don’t have numbers to back this up, but I will explore it further in a future article.)
The typical life span for a coal fired plant is 60 years.
One final critical point. When a plant claims a certain capacity to deliver power (in this case 300MW/hr) the real amount of power created is much less. In fact, according to this MIT article from (2003), here are the numbers ...
Coal plant efficiency ...
- 33% = average plant
- 39% = excellent plant
plus note the following ...
- 300MW per hr
- 24 hrs per day
- 365 day per year
So how much power will a 300 MW coal fired plant generate per year?
Power generated per year by coal = 867,240 MWhrs = 300MW * 33% * 24 * 365
Our coal fired plant will generate 867,240 MWhrs per year in usable electricity.
Example 2 – Solar Power
Separately consider a small solar power plant that can produce 10MW. I estimate the cost at $55 million US. (A future article will explore this number further, with details. Assume for the moment it’s accurate.)
A solar power plant requires very little maintenance and no fuel. The sun is the fuel and it won’t run out. Once the plant is setup, it can generate power for decades, producing zero emissions. Solar panels come with a 25 year warranty and can effectively operate for 50+ years.
Now, getting back to how much it costs to deliver the equivalent of a 300MW coal fired power plant of electricity using the example of the 10 MW Solar power generating station mentioned above.
Assuming the following for a 10 MW station solar power facility ...
- .1909 kWhrs/day per panel
- 6 hrs average of direct sunlight per day
- 52,500 panels on 50 acres of land
- 365 days per year
How much power would a 10MW solar power station generate?
Power generated per year = 21,948,727.5 kWhrs = .1909kWhrs * 6 * 52,500 * 365
Converting to MWhrs (divide by 1,000) we get ...
Converting to MWhrs = 21,948 MWhrs per year = 21,948,727.5 kWhrs per year
How many little 10MW power stations do we need to deliver the same power output of the coal fired plant above ...
# of 10MW solar power stations ~ 40 = 867,240 MWhrs / 21,948 MWhrs
We would need about 40 x 10MW solar power stations, and at $55 million per station that will cost ...
Total cost for 300MW solar power ~ $2.2 billion = 40 * $55 million
Bottom line, we would need $2.2 billion to produce the same power output as the coal fired plant.
But remember these key points
- The coal plant price does not include the fuel cost for the next 60 years (many more millions per year)
- Annual operating expenses for the coal plant are much higher (millions per year)
- The environmental damage caused by the coal plant is not factored into the cost (hundreds of millions more)
When these additional costs are factored in, I estimate the difference between coal and solar power becomes negligible. If the price is the same, why aren't we doing more solar power today?
Going back to our previous calculation for Connecticut ...
Now to produce 6,342.5 TWhrs per year how many 10 MW solar power plants @ $55 million do we need to completely replace our coal fired plants?
Converting 21,948 MWhrs per year from our 10MW solar plant to TWhrs is ...
Converting to TWhrs = 0.021948 TWhrs per year = 21,948 MWhrs per year
Now how much will it cost?
Cost to replace coal = $15.892 trillion = (6,342TWhrs / 0.021948TWhrs) * $55 million
Hmm … that seems like a lot of money. Putting that number into perspective the US GDP for 2006 was $12.98 trillion dollars, so replacing all coal power with solar power is equivalent to a bit more than 1 year of our Gross Domestic Product.
We can build it now, it can easily generate enough power to replace coal, we would need the area of Connecticut, we can put it in the desert if we want, but it does cost a bunch of dough.
Granted this is a big idea, a VERY BIG IDEA, but we have to remember a few things.
- We don’t have to build it all at once
- It will get cheaper over time to build (prices will go down as volume increases)
- The technology will get better over time (at least double in efficiency)
- Currently we aren’t paying the full cost for all the environmental damage of burning coal (frankly we are subsidizing burning coal by pushing those environmental costs into the future)
- That $15.892 trillion cost is a one time cost. Spread over 50 years it works out to $.40976 Trillion or 3% of current annual GDP. (That doesn't sound so bad.)
- We have already spent $1.2 trillion on the war in Iraq. I am all for the war, and I believe Sadam was a "bad man" that had to be removed, but if we are trying to secure our energy future it seems solar power is an alternative. SOURCE: New York Times (Jan 2007)
- The environmentalists are claiming that in order fix the environment we need to contribute 1% of GDP. Why not pay 3% to build solar panels and stop burning coal. We fix both problems at the same time, don't we?
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