Posted on 01/05/2009 5:12:17 PM PST by WayneLusvardi
Sempra Energy is reporting today in the Los Angeles Times that its new solar farm near Nevada has achieved price parity with coal power at about 7.5 cents per kilowatt hour. This is good news except for the fact that the Times merely regurgitated a Sempra public relations release puff piece and left some stuff out; like the cost of back-up coal fired electricity when the sun isn't shining bright enough.
Another apparent cost left out is the cost to buy land. The small 10 megawatt solar farm that Sempra has recently built is apparently on land Sempra owns next to its coal power plant near Nevada. A larger plant may have to buy land and factor that into the cost.
It also doesn't break out the added cost, if any, for transmission if the transmission lines do not have capacity to handle additional load or if new regulators are needed due to the irregular pulsing of solar power. There may also be costs once the panels start to degrade that are not as yet factored into the price. Sempra is refusing to release documentation of costs citing proprietary information.
But solar power is a better bet than wind energy at this point in time.
It is interesting to note that concurrently with the above announcment what is called the Solar Geomagnetic AP Index, the amount of light energy generated by the sun, is at the lowest in recorded history since 1932. SEE TABLE AT FOLLOWING LINK WHICH SHOWS THE SOLAR GEOMAGNETIC AP INDEX FROM 1932 TO 2008
http://wattsupwiththat.com/2009/01/04/solar-geomagnetic-ap-index-now-at-lowest-point-in-its-history/#more-4817
So much for "global warming" which is what solar power is supposed to reduce or eliminate.
The newspapers are merely publishing public relations releases these days without any apparent scrutiny or questioning, especially if it is something they are advocating. Read the whole thing LA Times puff piece here: http://www.latimes.com/business/la-fi-thinsolar5-2009jan05,0,2265033.story
That’s the biggest fly in the ointment. You still have to have full backup coal/gas/nuke-powered generating capacity for when the sun isn’t shining or the wind blowing.
When one adds the fact that said generating plants can’t be switched on or off like a lightbulb but must always be running at a certain capacity the full insanity of “renewable” energy becomes readily apparent to even those of us from Rio Linda.
I have a friend that works in residential solar in California. He said the cost of residential-on the grid (no batteries) solar was still 20 cents per kilowatt hour meaning that it only made financial sense in certain California markets after considering subsidies.
To USNBandit
Thanks for the first hand report. Any more people out there with first hand information on actual real time solar energy costs?
Show me a coal plant that costs 7.5 cents/KwH to run, and I’ll show you a coal plant that won’t be in business for very long. Most bulk producers/retailers aren’t going to buy at $75/MW. At most, you’ll be lucky to get $27-30/MW on a long-term contract.
“That’s the biggest fly in the ointment. You still have to have full backup coal/gas/nuke-powered generating capacity for when the sun isn’t shining or the wind blowing.”
Or, as another poster suggested on another thread, you could build a nuclear plant and generate electricity. Use the electricity to run huge sun lamps that point at the solar panels. And then collect cheap, consistent energy from the solar panels.
Thermal power stations
Conventional power stations fission a material or burn a fuel to obtain heat that is used to boil water and superheat the resulting steam which is fed to the steam turbines (some power stations also use gas turbines in combination with steam turbines). The turbines drive turbogenerators that make electricity.
A power station takes days to start producing electricity from a cold start. Time is needed to boil the water, to superheat the steam, to warm all the components of the power station, and to spin the turbogenerators up to operating speed.
Each power station is designed to provide an output of electricity. It can only provide very little more or very little less than this output (i.e., a power station has a "low turndown ratio").
Electricity demand matching
Electricity is wanted all the time but the demand for electricity varies from hour to hour, day to day, and month to month. The electricity grid has to match the supply of electricity to the demand for it at all times. This is difficult because power stations cannot be switched on and off as demand varies.
The problem of matching electricity supply to varying demand is overcome by operating power stations in three modes called "base load," "generation," and "spinning standby."
Some power stations operate all the time providing electricity to the grid, and they are said to provide "base load."
Other power stations also operate all the time but do not provide electricity all the time. They burn (or fission) their fuel to boil water and superheat the resulting steam which is fed to the steam turbines that are thus kept hot and spinning all the time. Of course, they emit all the emissions from use of their fuel all the time. But some of this time they dump heat from their cooling towers instead of generating electricity, and they are then said to be operating "spinning standby."
One or more power stations can be instantly switched from spinning standby to provide electricity to match an increase to demand for electricity. It is said to be operating "generation" when it is providing electricity. Power stations are switched between spinning standby and generation as demand for electricity changes.
Thus the grid operator manages the system to match supply with demand for electricity by switching power stations between "generation" and "spinning standby."
Windfarm input to electricity
Windfarms only provide electricity when the wind is strong enough and not too strong. So, they suddenly provide electricity when the wind changes. The grid operator must match this changed supply of electricity to the existing demand for electricity. Of course, the grid operator achieves the match by switching a power station to spinning standby mode. That power station continues to operate in this mode so it can provide electricity when the windfarm stops supplying electricity because the wind has changed again.
Windfarms only force power stations to operate more spinning standby. They provide no useful electricity and make no reduction to emissions from power generation. Indeed, the windfarm is the true source of emissions from a power station operating spinning standby in support of the windfarm.
Windfarms have capital, maintenance and operating costs that add to the cost of electricity. These costs are their only contribution to electricity supply.
When you are ordered to lower output do you also lower the generating capacity of the plant by lowering the energy needed produce 100% output? Or are you still using 100% of the energy required to keep the plant running 100% and just venting the percentage of the energy not needed when producing, say 95% of the output? You have got to be prepared to add that extra 5% load when they ask you to go back to 100%.
It finally dawned on me what the trick Sempra is trying to pull off by claiming 7.5 cents per kilowatt hour ($75/megawatt/hour) is at “parity” with natural gas and coal-fired energy. The plant they are claiming generated 7.5 cent power ($75/MW/Hr.)is near Nevada and ships electrons to California. California is loaded up with old long-term contracts from the energy crisis of 2001 at, say, $75 to $100 per megawatt hour (7.5 cents per kw hour). So Sempra is not comparing their new solar power at 7.5 cent kW hour to the current market rate, which is about 2.5 to 3 cents per kW hour ($25 to $30 per mW hour); instead they are comparing their cost to the puffed up price of long term contracts from the energy crisis of 2001. What will happen with this overpriced solar power if, and when, Mike Peevey, the Cal Public Utilities Commission President, is successful in getting “open access” for large utility users (schools, industries, etc.)?? Solar will go poof! And solar will become a stranded asset the rate payers will have to pay off. In other words, look for another California energy crisis down the road due to the shift to “Green Power.”
A lot of the people doing it in California evidently are rolling the cost into their mortgage on new construction.
No, when you reduce electrical output you almost always reduce thermal (steam) production by a corresponding amount. The generator excitation will be reduced which reduces current output but keeps the turbine spinning at the same speed. Steam overcomes the counter-torque generated by the intensity of the field when generating. Lower power output—lower counter-torque—less steam needed to spin the turbine at rated speed. However, there are cases in which a small amount of steam might be released at barely self-sustaining power or keeping the plant up without rolling the turbine.
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