Combined cycle natural gas plants also provide reasonably fast response. It is also possible for certain kinds of power plants, particularly hydroelectric and natural gas “ peaker plants,” to ramp production up or down quickly. If additional adjustment is needed, it is possible to take some commercial facilities offline, based on agreements offering lower rates for interruptible supply. These operating reserves typically handle fluctuations of 10% to 15% in the electricity supply. The apparent “lid” on intermittent electricity at 10% to 15% of total electricity consumption is caused by limits on operating reserves.Įlectric grids are set up with “ operating reserves” that allow the electric grid to maintain stability, even if a large unit, such as a nuclear power plant, goes offline. is the sum of other non-intermittent sources, including geothermal and biomass burned for electricity generation.Įven with growing wind and solar production, California is increasingly dependent on non-intermittent electricity imported from other states. California electricity consumption, based on EIA data. Even at this low level, Hawaii is encountering sufficiently serious grid problems that it has needed to stop net metering (giving homeowners credit for the retail cost of electricity, when electricity is sold to the grid) and phase out subsidies.įigure 2. In 2015, wind and solar PV amounted to only 12.2% of total electricity consumed in Hawaii, based on EIA data. Grid issues become a problem at low levels of intermittent electricity penetration. Let’s look at some of the issues that we are encountering, as we attempt to add intermittent renewable energy to the electric grid. This is basically another example of a problem I wrote about earlier, Overly Simple Energy-Economy Models Give Misleading Answers. They also miss the point that timing and the cost of capital are very important, as is the impact on the pricing of other energy products. A few simple calculations were made, such as “ Life Cycle Assessment” and “ Energy Returned on Energy Invested.” These calculations miss the fact that the intermittent energy being returned is of very much lower quality than is needed to operate the electric grid. ![]() Leaders around the world have demanded that their countries switch to renewable energy, without ever taking a very close look at what the costs and benefits were likely to be. The tiny contribution of wind and solar to grid electricity cannot make up for the loss of more traditional electricity sources due to low prices. Also, the presence of intermittent electricity disrupts competitive prices, leading to electricity prices that are far too low for other electricity providers, including those providing electricity using nuclear or natural gas. It is these secondary costs that are problematic. There are too many costs outside building the devices themselves. ![]() In fact, I have come to the rather astounding conclusion that even if wind turbines and solar PV could be built at zero cost, it would not make sense to continue to add them to the electric grid in the absence of very much better and cheaper electricity storage than we have today. Is this really possible? Is it really feasible for intermittent renewables to generate a large share of grid electricity? The answer increasingly looks as if it is, “No, the costs are too great, and the return on investment would be way too low.” We are already encountering major grid problems, even with low penetrations of intermittent renewable electricity: US, 5.4% of 2015 electricity consumption China, 3.9% Germany, 19.5% Australia, 6.6%. Many people are hoping for wind and solar PV to transform grid electricity in a favorable way.
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