https://www.greentechmedia.com/articles ... as-peakers
The solar tragedy of the commons. In California solar power provides "dirty", unregulated power to the common power grid.
Think this is an exaggeration? Read on. And read "between the lines" to what is not said but implied. Solar power, at least from commercial solar power farms, can be a fully contributing "citizen" on the power grid but California government regulation and policy treats solar and wind power differently from hydro and fossil fuel generated power. The technology exists to fix the problem but it has not been applied. And solar farms would have to reduce their power output somewhat to provide the solution.
PV Plants Can Rival Power from Natural Gas Peakers wrote:First Solar Proves That PV Plants Can Rival Frequency Response Services From Natural Gas Peakers
In California, an important test for solar farms as grid-balancing agents JANUARY 19, 2017
Last summer, First Solar and California grid operator CAISO ran a set of tests to show that utility-scale solar PV , instead of being a disruptive influence on the power grid, could actually help stabilize it.
Over a series of days in August , First Solar slightly curtailed power output at a 300-megawatt solar farm in California, enabled its array of inverters, and plugged into CAISO’s [the local power grid] system. It then orchestrated the plant’s output to follow CAISO’s automatic generation control (AGC) signals, respond to its frequency regulation commands, and use inverters for voltage regulation, power factor regulation and reactive power control.
The results, according to a report released [in Jan 2017] , showed that First Solar was able to meet, and sometimes exceed, the frequency regulation response usually provided by natural-gas-fired peaker plants.
Conventional coal, gas or hydro power plants reserve about %10 of their maximum capacity for two vital reasons. First the reserve is just there in case of a sudden increase in power demands. The second is to provide what is sometimes called "grid services" - keeping the alternating current (AC) in sync and maintaining the shape of the AC waveform. The last issue, a improperly shaped waveform, is a known issue with power inverters which convert the DC power from a battery or solar panel to the AC power like you get from your power outlet at home.
Solar power farms in California are often allowed to sell as much power as they generate onto the grid. And the grids are required to buy all the power produced by home grid-tied solar panels. Meanwhile fossil fuel powered plants are providing well regulated power and helping to maintain the quality of power on the grid. That means that solar power is a kind of "free rider" on the common power grid. When solar and wind was less than about %20 of the total this wasn't too much of a problem. Now it is.
The amazing thing to me is that in California, the home to Silicon Valley, it took until 2017 to get the results of the full scale test that solar power can provide the same quality power as other power generators in the state! Why? Reading here and elsewhere the answer seems to be partly "greed" but mostly politics, a failure of regulation and requirements that the power companies buy all the power produced (this is especially true of home solar power) and requirements that large amounts of power come from renewable. Because of politics and social policy commercial and home grid-tied systems can get away with producing the quality of power they produce when they want to. And leave other generators to fill in the gaps and provide the services required to maintain stable, quality power on the grid.
The article above applies only to commercial solar farms and not to the power produced by the PV panels on homes. Grid-tied solar power from home based systems are allow to put all the power they can produce onto the grid and the grid operators in California are required to pay a premium (higher than the bulk market) price for it. This power is effectively subsidized.
Is the situation really like that? Consider this technical paper presented at a conference in 2012.
https://cdn.selinc.com/assets/Literatur ... 23_Web.pdf
Power Factor Control for Grid-Tied Photovoltaic Solar Farms
Solar farms use devices called inverters to convert the DC power from the solar (PV) panels into AC at a different voltage.
The point of common coupling (PCC) is where the output of all the inverters come to together to tied into the general power grid.
Power Factor Control for Grid-Tied Photovoltaic Solar Farms wrote:The main components of [solar farms] are solar PV panels and PV inverters that convert dc power generated from the panels to ac power tied to the electric grid. This energy conversion mechanism can potentially deteriorate the power quality of the grid, especially as the number of gridtied solar farms increases .
The common-point power factor at the point of common coupling (PCC) of multiple PV inverters can fluctuate unpredictably outside of the utility requirement range. The variation depends on the power quality and harmonic distortions injected by the inverters . Therefore, maintaining the power factor at the PCC is critical for maintaining the power quality and stability of the overall system. A power factor adjustment can improve the efficiency of the overall utility network . The power factor adjustment gives the utility greater flexibility to supply the power quality required by the loads.
Utilizing the components of a typical PV generation site, an active closed-loop power factor control system can be easily implemented. This is accomplished by utilizing the communications capabilities of the components, which allow the controller to collect the required control data and make decisions to adjust the inverter outputs. The implemented solution proves to be simple and cost-effective for achieving the desired power factor reference set point.
Once the PI controller parameters are chosen appropriately after field testing and tuning, the controller can track the power factor changes at the PCC quite well. An implemented solution proves that the controller can keep the power factor within 5 percent of the reference set point.
But wait, there's more!
http://www.latimes.com/projects/la-fi-e ... ity-solar/
California invested heavily in solar power. Now there's so much that other states are sometimes paid to take it
By IVAN PENN JUNE 22, 2017
Sometimes the next door state of Arizona, shuts down it's solar power farms, and takes excess power from California so that California's power grid doesn't burn out. California has to pay Arizona for the privilege. A similar thing is happening in Germany. Some neighboring countries have received permission from the EU to block power at the border to protect their power grids.
This story seems like something from a Dickens novel. If I get any information wrong please quote the sentence and give me a URL to the correct information.
Nuclear Power on the other provides greenhouse gas free power 24/7. It has been been able to for over 50 years.
The northern part of the state of Texas has some of the best winds for wind power in the continental US. I don't know the Texas power grid system is handling this issue. On the peak hour on the best day they have reported over half their power coming from wind. To do this the Texas grid has invested a considerable amount (over a billion $ ??) in new power lines to connect the wind turbines in the northern part of the state to the major population centers in the south.