Monday, December 01, 2014
More on the Ivanpah boondoggle
Overlooked: Deserts have lots of sand
Dr Klaus L.E. Kaiser
In California’s sunny south is the Ivanpah Solar Power Facility (ISPF). It’s a massive structure in the Mojave Desert that was supposed to deliver an energy output of approximately 1.7 million MWh (megawatt-hours) of electric energy annually. ivanpah The ISPF uses 173,500 heliostats (adjustable mirrors to follow the sun) that reflect the sunshine onto boilers located on centralized power towers.
The facility covers 4,000 acres (1,600 ha) of public land and received $1,600 million in government-backed loan guarantees. Another $600 million came from private investors with nearly one third of that from Google.
This super-duper solar power plant was to be THE solar power plant, not just in the USA but in the entire world. (Source of photo) As it turns out though, the grand hopes for “alternative energy” were premature. There ought to be at least one lesson from this project: the desert environment is simply not quite as benign and suitable to solar power generation systems as many people hope.
To begin with, ten square kilometers of room-size individual mirrors do not all reflect the sunshine to one point, even with the best intentions and computer control of the mirrors’ angles. There are always some parts of the associated machinery that do not function due to grit in the gears and on the mirrors. As a result, sunlight is reflected into many directions causing birds flying across the field to become disoriented. Others that get into the main path of light have their feathers singed or they get fried. Even airline pilots high above the ground have complained about glare from the mirrors.
Low Power Output
However, the power facility has another even bigger problem: its power output is nowhere near the design value and that’s not because of a lack of sunshine since the facility began operating in December 2013.
Obviously, the power output of the plant varies with the seasons and number of daylight hours at the site. In the eight-month period of January-August, 2014, it produced only 250,000 MWh of energy, roughly one quarter of the expected output. Even in the high irradiance and long-day four-month period of May-August, 2014, it delivered less than 200,000 MWh of electric energy – less than one half of the design value. As there was no particular lack of sunshine that underperformance could not possibly be blamed on unusual natural conditions.
One can only speculate as to the reason for the lower than expected power output at this time but there is at least one obvious cause—namely sand and dust. A decade or so ago the Siemens company installed solar (photovoltaic) power panels in the Mexican sierra that got sand-blasted into oblivion in short order. In any event, in order to salvage the plant the ISPF owners decided on a two-pronged approach: borrow more money and use more natural gas.
The first approach of borrowing more funds is still under consideration. It’s commonly known as the rob-Peter-to-pay-Paul principle and is frequently to be found in government circles.
Pete Danko of Breaking Energy reports that the Platts trade newsletter Megawatt Dailydiscussed Ivanpah’s status. It noted that the trio of Ivanpah owners had sought extensions on repaying their current loans as they waited to receive a hoped-for cash grant from the U.S. Treasury worth 30 percent of the Ivanpah plant’s total cost of $2.2 billion to repay the current part of the (California) loan guarantee.
Use More Natural Gas
The second approach to ISPF’s problems is even more insidious in terms of the underlying idea of “green” power generation.
In March of this year the ISPF’s owners decided to apply to the California Energy Resources Conservation and Development Commission for permission to “upgrade” the system by doubling the amount of natural gas usage permitted for “preheating” of the solar towers. This request was approved in August 2014 and the ISPF can now use up to 525 million standard cubic feet of natural gas per year for that purpose. It is important to put that amount of natural gas into perspective vis-à-vis the overall energy generation by the facility.
Fudging the Numbers
To investigate the real contribution of natural gas to the plant’s output, one has to ask how much electric energy a regular power plant delivers with the consumption of 525 MCFT of NG. Using a heat-energy to electric-energy conversion rate of 60%, or 0.2 kWh/cft of NG, that amount of NG alone produces roughly 100 million MWh of electricity.
In terms of ISPF’s design output, these 100 million MWh of NG-sourced energy appear small; however, it really ought to be compared the amount of true “solar” energy produced.
To do that one also has to deduct the energy amount of the already used NG of roughly 30 million KWh (up to end of August 2014). That would leave then only in the order of 250 million MWh for the entire January to September period or somewhere in the neighborhood of 50% of the entire ISPF output. Therefore, doubling the amount of natural gas use will make the total “solar” energy output appear to be yet larger than it really is. It will be easy to fall for such claims – unless you know how numbers can be fudged.
Look for the Spin
Undoubtedly the solar power industry, many politicians and, I guess, most certainly all anti-carbon activists will try to spin this anticipated increase of the ISPF power output as a great success story of solar power generation in general and the Ivanpah plant in particular. In the end though, I surmise it will all be in vain and Ivanpah will eventually become another giant “green energy” boondoggle.
Posted by John J. Ray (M.A.; Ph.D.).