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A humorous story about northern Ohio I have heard indicates that, in 1796, the famed explorer and surveyor Moses Cleaveland pulled his expedition’s boats into the mouth of the Cuyahoga River and told his party “We’ll camp here until the clouds clear.” Thus the permanent settlement of Cleaveland, later spelled Cleveland, was founded. This, of course, is not necessarily historical fact; however, Ohio’s reputation for cloudiness and limited sunshine is well founded and documented. One would think that this would, at least, give pause to the proponents of massive subsidized expansion of solar power conversion projects in the area.
Solar power basics:
The University of Oregon offers a good explanation of the basics of solar energy. The basic mechanism of photovoltaic (PV) cells is that photons from sunlight striking silicon liberate bound electrons and induce an electric current. Per the information presented by the University of Oregon, 77% of the energy from the sun is carried in photons containing sufficient energy at the appropriate wavelength to move electrons in the silicon, and 47% of the energy from the sun makes it through the atmosphere to the Earth’s surface. As an average over the entire surface of the Earth, 164 watts/m2 from the sun reach the surface over a 24 hour day.
As another reference, Wikipedia’s entry on Solar Cells offers a good explanation of energy conversion efficiency and Standard Test Conditions (STC). The Standard Test Conditions, which are used to test and rate solar cells, are intended to approximate solar noon near the spring and autumn equinoxes in the continental United States with the surface of the cell aimed directly at the sun, and specify that testing takes place at 25°C (normal room temperature). This needs to be remembered when reviewing and comparing power capacity and energy rating for various cells; and we need to understand that deviation from these conditions in the real world will obviously cause the cells to perform differently.
To relate this to Ohio, NREL offers information on the average annual power that we can expect from the sun. Per the solar resource maps offered by NREL, it can be seen that Ohio generally receives 4.0 to 4.5 KWh/m2/day, which translates to 187.5 watts/m2. Also, when determining the actual average power or energy output of solar cells, it is important to remember that efficiency of conversion to electricity for PV cells is quite low (generally around 10%).
It is also worth noting that some of the same concerns raised in previous articles regarding Critical Analysis of Wind Turbines, will also be concerns regarding the efficacy of solar power generation. In particular, the simple economic analysis does not account for the cost that will be incurred to maintain and operate a traditional back-up system for generating power when the sun is not shining adequately, and for the added cost and inefficiency of cycling this back-up system on and off to balance the supply load against the variability of the sun generated power.
Solar panels at the Akron bus garage:
A more detailed analysis of the project to install solar panels on the roof of the Akron Metro Bus Garage is included in the two simple images attached to this article. Information was taken for the Ohio Government press release and a similar press release provided by Sharp, the manufacturer of the 235 Watt solar panels being used, model NU-U235SF1.
To conduct the cash flow analysis information regarding the average commercial price of electricity in Ohio was taken from the DOE EIA, and information regarding the expectation that the efficiency of the solar panels will degrade approximately 1% per year was taken from Geoffrey Styles and his opinion of the Akron project on Energy Outlook.
The more detailed analysis, taking into account inflation and the average commercial price of electricity, indicates that the investment of $2,500,000 will not be paid back during the expected life of the solar panels. Further, note that two very generous assumptions were made that actually err on the side of the solar panels; (1) since Operation & Maintenance costs are not documented, it was assumed that there will be no such costs; and (2) the full credit for the commercial price of electricity is applied to the entire expected annual energy output of the solar panels. It is known, however, that any electricity not used by Akron Metro RTA will be sold back onto the grid, and the RTA will be paid far less than commercial price for this electricity.
Turning Point Solar array planned for southeast Ohio:
Information regarding the 500 acre solar array to be installed in southeastern Ohio, beyond the initial Ohio government press release, is proving harder to find.
We know that the entire array will be comprised of 239,400 solar panels, will be rated at 50MW, and will cost $250,000,000. This makes it roughly 100 times the size and 100 times the cost of the Akron Metro RTA project. It is fairly easy to guess that performance and pay back will be equally dismal.
One thing we need to consider, however, is that the Turning Point Solar array is a commercial power generation venture, which means it will need to sell its power to distributors like AEP on the wholesale market. The annual average wholesale price of electricity is far less than the commercial retail price which the Akron RTA pays, making any return on investment for the massive Turning Point Solar Array even less likely; unless someone raises the price we pay for electricity.
Unfortunately, the move to deliberately raise the cost of electricity is already happening. The press release notes that AEP is already negotiating a Power Purchase Agreement (PPA) to buy electricity from the array at elevated cost. They need to do this to meet the requirements of the mandates imposed by Ohio Senate Bill 221. So far, there is no specific indication regarding how much more AEP will pay for electricity from the solar array, or how much Ohioans can expect their electric bills to increase.
