by John Farrell, via the Institute For Local Self-Reliance
A new study for the California Public Utilities Commission explores the “Technical Potential for Local Distributed Photovoltaics in California.” Basically, it’s one of the more in-depth analyses of local solar power in the country, suggesting that California has the capacity to add 15 gigawatts (GW) of local solar (20 megawatts and smaller) to its grid by 2020. The study pushes the boundaries of distributed generation by assuming that local solar can be installed sufficient to meet 100% of local demand, far beyond the conservative “15% rule” that utilities typically apply.
There are the usual caveats about the technical limitations of the current grid, but a few graphics from the report provide a glimpse into the implications of a distributed generation future.
This first chart shows supply curves for various types of distributed solar under their 15 GW scenario. What I find interesting is that the biggest chunk of distributed solar is not on the ground or on commercial roofs, it’s residential rooftops. Half of the state’s distributed solar potential is on residential rooftops.
This next chart illustrates the cost and benefits of residential solar PV for a PG&E substation in Fresno, CA. What I find interesting is that 6-7 cents of the levelized cost of solar (which includes the federal tax credit) are offset by electric system benefits and greenhouse gas reductions. Energy provides another 5-6 cents. Presumably, state incentives (the CSI, net metering, etc.) fill the gap.
This next chart of interconnection costs for distributed solar has two interesting findings. First, interconnection costs (for the utility) are lower for residential solar than for other small-scale (< 1 MW) distributed solar. Costs fall off as projects increase in size to a sweet spot of 3-5 MW and then rise again. Divided over the projected output over 25 years, however, these costs are in the hundredths of a cent per kilowatt-hour.
This chart shows what it will mean to have a significant amount of solar on the grid. It will effectively shift the peak demand period on the electricity system from the mid-afternoon to the early evening (when solar PV no longer produces much electricity). This could have interesting implications for net metering customers who count on high peak prices to pay off their PV investment.
The last item of interest is their cost projection for maximizing local solar power. Reaching the 15 GW distributed solar potential would increase the state’s renewable energy supply from 33% in 2020 to 48%. The marginal cost is about $6 billion, or about $0.15 per kWh. That’s not bad when the avoided cost (e.g. “market price referent”) in California is around $0.12 per kWh, especially when we’re talking about 2.5 GW of additional local solar power with $750 million in economic benefits and new jobs.
John Farrell directs the Energy Self-Reliant States and Communities program at the Institute for Local Self-Reliance. This piece was originally published at the Institute For Local Self-Reliance and was reprinted with permission.
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As a California homeowner with 16-panel grid tied system (with excellent exposure), here is my take on solar vs. baseline sources.
When they are operating at full power, just one of California’s four nuclear reactors (two at San Onofre, two at Diablo Canyon) cranks out over a gigawatt. Of course, San Onofre is down now, but over the last several years, these reactors have run at capacity factors of around 90 percent (you can sub a large natural gas plant if you like).
My solar power system produces 3.7 megawatt hours annually. For now completely ignore the hard problem of intermittentcy, and just ask how many of my home solar systems would be needed to produce the same amount of power annually as one reactor. The answer is two million.
So that’s 8 million home systems to replace all four reactors, which supply about 20 percent of California’s power. So you would need 40 million home systems to produce all of California’s power. My system uses 16 panels, so 40 million systems require 640 million solar panels (ignoring the possibility of solar thermal).
OK, so let’s say PV solar only supplies half of California’s power. I guess then we would only need 320 million panels and 20 million home systems.
And that’s ignoring the problem of building a grid that could handle the intermittency problem, and it ignores the reality that many potential sites don’t have good exposure.
Realistically, how long would it take to build this out?
It appears to me that what you have done in your comment is to entirely ignore the findings of the in-depth analysis by the California Public Utilities Commission discussed in this article, and in their place substitute some back-of-the-envelope guesstimates and assumptions and misguided comparisons between so-called “baseload” power sources and peak-matching power sources.
With all due respect, it reads like the usual “analysis” one sees from fans of nuclear power, who typically exaggerate the supposed “problems” and costs of expanding solar power and underestimate or ignore the costs and the very real problems of nuclear power.
Agreed, he just ignored the study and pushed Nuclear as the alternative. The thing big energy fears is a repeat of what has gone on in Germany. Germany added 25 GW reducing the large producers profits during peak hours. Once energy storage becomes inexpensive it will eat into their off peak profits.
With the PV efficiency going up, cost going down, and storage just around the corner. The trend is towards local/home rooftop solar with energy storage.
Local energy production will take over from large scale producers for one very simple reason. It will eventually become cheaper to produce your own power than the electrical companies can provide it. They are financially hampered by the need to maintain the distribution grid, and local production is not.
Renewables require more transmission not less.
Energy storage costs swamp grid costs in both $ and kwh terms.
Hey SecularAnimist,
I am very pro-solar power. I put my money where my mouth is. The figure I use for my home system is based on my own historical readings, but is very similar to NREL estimates. As I said, if you don’t like nuclear, substitute I big natural gas plant.
I’d be happy to be proven wrong, which is why I provided these numbers. If someone can point out a mistake, I’d love to see it.
You calculation seems correct to me, but it misses the point for a couple of reasons.
If you consider the peak power that the panels produce then it is roughly 250 thousand rather than 2 million homes per GW. Solar PV reduces the peak power demand much more than the base power demand and is very useful when viewed that way.
It appears that your PV system was designed to roughly equate to your home power demand. I expect that it is roughly 20 m2 which may not be your total available roof space. My home would require about 20 m2 as well, but I actually have about 100 m2 available. When it makes financial sense for home owners to cover their entire roof, garage, patio etc spaces then the available PV generation will be several multiples of what you calculated.
Bernard,
My numbers were in response to the following quote from the article:
“The study pushes the boundaries of distributed generation by assuming that local solar can be installed sufficient to meet 100% of local demand.”
I agree with you that California is blessed in that solar PV output is correlated with demand. Basically, PV runs air conditioners. The picture is not so rosy for Germany or England, however.
PV during day and recharging EVs and PHEVs at night is a great combination for smoothing demand. No doubt. Personally, I don’t need an EV, since I have an even more efficient vehicle available, my commute bicycle.
Breaking even? Will never happen for me. You are right about size of system. But I only use 2400 kwh annually, produce 3700 annually, and get to sell back to PGE 1300 KWH annually at wholesale price of about 3 cents per KWH. I’d be nuts to add any more panels, and I caution neighbors who are considering PV that simple conservation and a TOU meter are much more cost effective, at least in cool, foggy parts of Bay Area where we don’t need air conditioning.
Did you yourself read the the findings of the “in-depth analysis by the California Public Utilities Commission discussed in this article?”
I assume you did. Please tell me what conclusions you draw from fig. 18 on page 69?
According to the study, CA can add 16 GW (nameplate) of solar capacity by 2020 without grid changes (see the study’s ground rules for an explanation).
The installation type and volume of PV installation discussed in this study is really better thought of as a demand management system, rather than an electricity generation system.
Can we please have the images scaled up? Clicking on the images doesn’t help – the target is the same size as the embedded graphic.
Some of us aren’t as young as we used to be.
Friggin wimpy headline. Here’s a “Visionary Headline”: “Report shows solar panels on California homes and businesses would power all of California”
Don’t make it more complicated. It’s a major fail of communication.
All of California’s power.
More words, less movement. Few catchy words, major impact. Follow the science.
The report doesn’t say that at all!
Are you confusing this report with the recent NREL “80% by 2050″ report?
Excellent study and the findings will help other areas also to go in for solar.
Dr.A.Jagadeesh Nellore(AP),India
E-mail: anumakonda.jagadeesh@gmail.com
It is not between solar and nuclear….. add in hydroelectric, steam, wind power….. use ALL of the alternatives…..
AA wrote: “The installation type and volume of PV installation discussed in this study is really better thought of as a demand management system, rather than an electricity generation system.”
That’s an important point, and one reason why concern about the ability of the grid to integrate large amounts of distributed PV generation is misplaced.
As far as “the grid” is concerned, distributed PV mostly “looks like” demand reduction. It means residential and small business consumers are simply not drawing as much electricity from the grid — particularly during times of peak demand — as they would if they didn’t have PV. It’s indistinguishable from demand reduction resulting from efficiency and conservation.