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Residential solar is cheap, but can it get cheaper? Paths to $0.05 per kWh
The price of solar panels has fallen far and fast. But the Energy Department (DOE) wants to bring those costs down even further, especially for residential homes. After all, studies have shown that if every inch of useable rooftop in the US had solar panels on it, the panels could provide about 40 percent of the nation's power demand. Right now, the DOE's goal is residential solar that costs 5¢ per kilowatt-hour by 2030.
In a new report from the National Renewable Energy Laboratory (NREL), researchers mapped out some possible pathways to that goal. Notably, the biggest barriers to cost reduction appear to be the stubborn "soft costs" of solar installation. Those soft costs include supply chain costs, labor costs, and sales and marketing costs that aren't related to the physical production of solar cells at a factory.
NREL wrote: "Because the 2030 target likely will not be achieved under business-as-usual trends, we examine two key market segments that demonstrate significant opportunities for cost savings and market growth: installing PV at the time of roof replacement and installing PV as part of the new home construction process."
The report mapped out two "visionary" pathways (as well as two "less-aggressive' pathways) to achieving those cost reductions within the roof replacement and new home construction markets. The result? The only way NREL found it could achieve the "visionary" cost reductions was by assuming that solar installers would start selling low-cost solar-integrated roof tiles before 2030, "which could significantly reduce supply chain, installation labor, and permitting costs."
[...] [It's] not just Tesla working on this: the Colorado-based lab cites CertainTeed's solar shingle product and GAF's solar panels as examples of products breaking the divide between roof and solar panel installation.
(Score: 2) by requerdanos on Wednesday February 21 2018, @05:03PM (5 children)
Some questions occur.
Is that every inch of residential rooftop that would provice 40% of the nation's power demand, or every inch of commercial, industrial, cultrual, residential, etc. roofing that would provide the 40%?
TFA offers us "you would produce about 1,400 terawatt hours of electricity each year—about two-thirds of which would come from small residential buildings. The total production is equal to nearly 40 percent of the total electricity currently sold by utilities in the US" after unsuitable building roofs (too small/steep/shaded) were discarded. I would guess that that includes all roofs, not just residential, but guessing's often a bad method.
What percentage of the nation's power is used by those buildings whose roofs we are planning to top with solar? 40%?
This is important because it determines whether they are generating excess power, just holding their own, or not even keeping up with their own energy needs. "The total production is equal to nearly 40 percent of the total electricity currently sold by utilities in the US" again from TFA is a nice figure, but "the electricity that US utilities sell" != That nation's power demand. Lots of power is bought and sold in other ways. How much? (I have no idea)
I know I pay retail 10c per kw/h for my home, but my electric utility buys a lot of that power from Duke Energy's nuclear plant a few miles north of here and so they surely pay a lot less than 10c/kw/h for it. If the solar was 5c per kw/h is that cheaper than the power we use now, or more expensive that the power we use now? By how much?
The eco-overeager assume the most optimistic answers without troubling about facts, the oil barons the most pessimistic with same terms. I'd rather look at what's actually facing us.
Solar is exciting in that it's getting cost-competitive with fossil fuels in many areas. Its cost really isn't energy cost so much as equipment and maintenance cost (because the sunshine is gratis).
(Score: 1, Insightful) by Anonymous Coward on Wednesday February 21 2018, @05:19PM (2 children)
Everything else would be energy negative.
High density residential because the roof square footage doesn't like up with the power consumption of the livable square footage.
Commercial/industrial/electric cars similarly, but also due to much denser energy demands.
I did calculations on the low density residential a few years back and a house and deep standalone 2 car garage provided enough roofspace for up to 20kW, depending on the surrounding terrain/flora maybe as low as 5kW out of the same panels. Having said that, even the 5kW number would be enough to provide emergency heating during the winter, and with the 20kW number, you would have enough to run basically everything in the house 24/7 plus have some left over for either charging an electric car, or running a shop out of the garage.
The real trick to solar power however is neither of those: It is the opportunity for energy independence from corporate/government control. With solar and wind it is now possible to run entirely off-grid, and so long as you don't install a Tesla powerwall, you should be safe from energy reporting telemetry.
(Score: 3, Interesting) by Grishnakh on Wednesday February 21 2018, @08:20PM
with the 20kW number, you would have enough to run basically everything in the house 24/7 plus have some left over for either charging an electric car, or running a shop out of the garage.
No, with a properly set up power grid that pays people properly for their excess, you'd put the excess electricity back on the grid for other customers to use and so the electric utility doesn't need to generate as much overall. Then when you start up a big power tool in your garage, it doesn't matter if there's some clouds overhead because the grid is supplying whatever your own panels can't at that instant. If you're consistently producing more power than you need, you end up getting a check from the utility every month, and your excess power goes to your neighbors who have too many trees, too many electric cars for their roof size, or to the high-rise a few blocks away.
Commercial/industrial/electric cars similarly, but also due to much denser energy demands.
It seems to me that a lot of commercial should be able to generate all or most of the power it needs, if not more, if it's retail. How much power does a Walmart need? It has a *huge* flat roof, there's only one story underneath, and all they need power for is lighting and HVAC, and some refrigerators in the grocery area. They're not running any industrial equipment in there (aside from the big HVACs), there isn't even an elevator. If anything, it seems like their energy usage per square foot of rooftop should be lower than a typical single-family home; maybe it isn't because the ceilings are very high and that requires a lot of HVAC.
(Score: 2) by c0lo on Wednesday February 21 2018, @09:40PM
The true libertarians should salivate in anticipation of such a scenario.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by frojack on Wednesday February 21 2018, @07:39PM (1 child)
What does that matter?
If you free up 40% of the power being consumed NOW, you can use that for electric cars.
The point is 40% more power is significant, as long as you can economically use it SOMEWHERE.
If not your house, then your neighbors. If not your neighborhood, then in somewhere in the same city, state, country.
If you can't economically use it anywhere you have built excess capacity. Poor planing, but not fatal to the over all discussion. There's no point in getting into micro-analysis here.
No, you are mistaken. I've always had this sig.
(Score: 2) by requerdanos on Wednesday February 21 2018, @08:00PM
soylent ate, and I missed in preview, the "Less than 40%? About 40%? Greater than 40%?" part of the question because I used < and > without escaping them somehow.
Even so, quoting the very next sentence:
What I was referring to was that where that number falls affects how you market it, and to whom, both issues of some import if a program promoting such unprecedented solar adoption is to be successful. I apologize for the >/< mix-up and for being (more) unclear as a result.