Good questions, and I certainly don't know all the answers myself. But! It's certainly not "crappy knock-off" power, its every bit as good as what comes from the crusty old coal plant. My neighbors all easily absorb the extra daytime power my PV array puts back onto the grid, without a hiccup.
It's not every bit as good.
Why rooftop solar is disruptive to utilities -- and the grid
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Diane Cardwell reports in the NYT that many utilities are trying desperately to stem the rise of solar power, either by reducing incentives, adding steep fees or effectively pushing home solar companies out of the market. The economic threat has electric companies on edge. Over all, demand for electricity is softening while home solar is rapidly spreading across the country. There are now about 600,000 installed systems, and the number is expected to reach 3.3 million by 2020, according to the Solar Energy Industries Association. In Hawaii, the current battle began in 2013, when Hawaiian Electric started barring installations of residential solar systems in certain areas. It was an abrupt move — a panicked one, critics say — made after the utility became alarmed by the technical and financial challenges of all those homes suddenly making their own electricity. "Hawaii is a postcard from the future," says Adam Browning, executive director of Vote Solar, a policy and advocacy group based in California.
But utilities say that solar-generated electricity flowing out of houses and into a power grid designed to carry it in the other direction has caused unanticipated voltage fluctuations that can overload circuits, burn lines and lead to brownouts or blackouts. "At every different moment, we have to make sure that the amount of power we generate is equal to the amount of energy being used, and if we don't keep that balance things go unstable," says Colton Ching, vice president for energy delivery at Hawaiian Electric, pointing to the illuminated graphs and diagrams tracking energy production from wind and solar farms, as well as coal-fueled generators in the utility's main control room. But the rooftop systems are "essentially invisible to us," says Ching, "because they sit behind a customer's meter and we don't have a means to directly measure them." The utility wants to cut roughly in half the amount it pays customers for solar electricity they send back to the grid. "Hawaii's case is not isolated," says Massoud Amin. "When we push year-on-year 30 to 40 percent growth in this market, with the number of installations doubling, quickly — every two years or so — there's going to be problems."
From someone on another board...
"EE working for a utility here, and I agree with all of this. The utility I work for, and a lot of others, don't even generate any power, we just do transmission and distribution, i.e. "poles and wires". Solar still causes us headaches. Don't get me wrong, I love solar, and I want reduced fossil-fuel usage, but the issue really is more nuanced than the public perception of "the utility just doesn't want us making our own power so they can keep charging us money".
Most people seem to operate under the assumption that power distribution is a network, where it flows in any direction. On the transmission side, yes, this is true. For distribution, it's generally false, except in large cities. More common are radial feeds, where several circuits, also called feeders, come out of the substation, each one typically having multiple branches and serving a certain area. Think of it like an artery system. The main trunk of the feeder has larger size wires that can handle more current, the branches have smaller sizes, etc. It's designed for power flowing from the substation to the customers, and not vice versa. There are a number of issues that arise when this expectation is violated. As a few examples:
If the homeowner at the end of the branch puts in a large solar installation, the wires and distribution equipment may not be sized to handle the power he's producing.
The variability of generation and inability to measure it is definitely an obstacle. Let's say there's an area with 20MW of load, and 15MW is being provided by solar. The solar output is unpredictable, but to the utility, who probably only has real time metering at the substation, it just looks like 5MW of load, so they don't know that when the sun goes down or a storm passes through they're going to see a major load increase.
It's a safety issue. The utility does not, and absolutely never will, assume that a customer has a properly functioning transfer switch that prevents backfeed during outages, which can be hazardous to both linemen working to restore power. There are certainly safety precautions that linemen can take, but it's still a danger.
On the billing side, the utility still needs to maintain equipment to provide whatever class of service the homeowner has. They need to be able to provide, for example, 400 amps, even if the homeowner gets solar and winds up having a bill of $0 from the utility. The O&M costs for such customers wind up being effectively subsidized by people who don't have solar.
I like solar, and I'm not afraid of it putting me out of a job, at least in my lifetime. I think when battery technology is more mature, it could help alleviate a number of issues that currently exist. But the public perception that its conspiracy by big bad utility is just trying to stifle competition is untrue. I'm not going to say that anticompetitiveness could never be the motivation for a utility to fight the proliferation of solar, but from an engineer's perspective, there are real obstacles that exist that many people don't realize or appreciate."
