Is solar powered energy reaching maturity or is it in its infancy

Great Debates
1

I thought of putting a bunch of charts and statistics in this, but decided not to.

My question is basically this.

Is solar energy reaching a point of maturity a few years down the road, where growth in solar installations will start to slow, level off and decline and prices will stop declining rapidly (maybe starting in a few years)? Solar will make up a form of energy generation the world used, but probably less than 20% and the world will still use nuclear, fossil fuels, wind, etc.

Or is solar still in its infancy (like the internet in 1995), and in 20-50 years will 70-100% of people’s energy needs be met with solar and cheap batteries because the cost of solar will continue to decline by 10-30% a year until it eventually costs $500 to install a rooftop solar system on your house to provide free energy for the next 30 years?

I’ve seen panels for $0.25 a watt now. That is an amazing decline from a decade ago when they were $5 a watt. But you still have all the other hardware costs and soft costs, and those are not declining by anywhere near the same rate. The panels may be 90%+ cheaper than a decade ago, but all the other costs of setting up a solar system have not declined by 90%.

But who is to say someone won’t invent some method of easy to install solar panels that will keep the price depreciations going.

I’ve heard some people predict solar will make up nearly 100% of our energy by the 2030s. And I’ve heard other people say it’ll max out at 10-20% (right now it is at 1%).

Obviously, if it is going to make up more than 20-30%, we need better battery technology. And right now the price bottlenecks are the soft costs, not the costs of the panels anymore.

2

There’s always the possibility that a new technology will replace silicon cells. Perovskite-based cells are being improved all the time. They’re cheaper to make and more efficient on a per weight basis. And unlike silicon, they can be flexible. They do have problems with long-term stability, but they’re working hard on that.

3

I think there’s potential in utility-scale solar-thermal that is yet to be explored. The parabolic SEGS facility in California is capable of generating over 350MW in a lot less space than the equivalent photovoltaic setup would require.

4

I think we’re at least approaching the point of diminishing returns, even if we’re not quite there yet. Improvements in efficiency do improve installation costs–if you need half the panels for a given power output, then your installation costs are halved. There might be another doubling here, but I doubt there’s more.

Where there is still a ton of headroom is in energy storage. Solar is already cheaper than coal without storage ($1/W, 2200 hrs/yr, 5% interest rate is 2.3 cents/kW-h), but as you say, if solar is ever going to get in the double-digits, it needs to be backed by storage. There are good indications that current li-ion tech can be scaled up, plus there are chemistries that may just be fundamentally cheaper. We’ll have to see, but Tesla is already making grid-scale storage work in high-cost areas (like Kauai), and if they can cut costs by another factor of 2 or so, it’ll start to make sense almost everywhere.

I’m fairly optimistic. Also, with smarter usage we can get away with less storage, making it relatively cheaper. Charging EVs during the day, doing high-power activities like aluminum smelting at peak hours, chilled water systems for cooling, etc. all help out, but don’t make sense right now when the cheapest power is at night.

5

NREL
U.S. Solar Photovoltaic System Cost Benchmark: Q1 2016

Module costs have been relatively flat since 2012.

But cell costs are the minority of the total system cost, which comprises:
Module
Inverter
Hardware Balance of System (Structural and Electrical Components)
Soft Costs - Install Labor
Soft Costs - Other (permitting, inspection, and interconnection, land acquisition, sales tax, overhead, net profit)

The module cost is pretty much the same across different generation scales, but the other costs scale inversely with size, such that grid-scale >100 MW was already below $1.43/W over a year ago.

Of course system cost is not cost of electricity. And cost of electricity depends on capacity factor, curtailment, T&D, storage, etc. PV is more peaky than wind, so on its own leads to more curtailment. But combined PV and wind leads to less than either on its own. I forget if it was NREL or ERCOT who found an ideal wind:PV ratio of about 2.2. Obviously YMMV depending on local grid specifics.

But it sure looks like the actual PV technology in use now is pretty darn mature. There are still impressive improvements being made to efficiency with other chemistries,

but their costs don’t compare.

As mentioned by others, there are still improvements to be made on how to best integrate intermittent power sources into the grid.

6

Also see hybrid CSP + PV. But CSP has very high capital costs. It’s hard to take advantage of economies of scale with fewer large installations. But as you say if land use is a concern, CSP takes up much less of it.

7

Storage is not synonymous with the batteries only.

8

Nope, there are various other ways that people are looking into. I read an article about a Swiss(?) group looking into using mountains as pressure vessels for energy storage from solar systems. Basically, you dig a really big chamber into a mountain, seal it, use solar to pressurize the inside, then when it’s dark you use that pressure to run turbines and the like. I’ve seen similar proposals using water and gravity systems (i.e. pump water up to the top of a tower during the day, then at night allow the water to come back down through a turbine, producing electricity). I don’t know how feasible any of these really are, but certainly, there are other ways being looked at.

As to the OP, I’d say that solar as it is today is closer to mature than infancy. While we haven’t reached the limits of the current technology, I don’t think there is a whole lot of additional scale that you can get from it as things stand (obviously an energy storage system is going to be key and will leverage a lot of the technology wrt utility).

9

There are a couple pumped hydro systems in the US. And there was a company, General Compression, working on compressed air storage. I see they have a linkedin page but their website doesn’t appear to be working so I’m not sure what happened.

10

First of all, it should be understood that essentially all energy except for nuclear fission and geothermal is derived from solar power. The Sun’s energy drives the hydrological cycle that moves water, allowing for river flows from which power can be produced by dams; it causes currents and uplifts in the atmosphere that move wind which can drive wind turbines; and of course it is the source of energy for all photosynthetic plans and algae which produce phytomass for combustion and nutrition, which can be viewed as being delayed and immediate energy sources.

Phytomass, in the form of so-called ‘fossil fuels’, e.g. gaseous and liquid petrochemical (oil, natural gas) and solid carbonaceous (coal, peat, oil shale), is what drove our collective society from being powered primarily by animal husbandry and very crude renewable sources to an industrial society supporting very dense populations with complex logistical and transportation networks. However, all of the ‘solar’ energy of that phytomass was concentrated into very dense forms over the span of tens of millions of years, largely by geological forces, and we’ve managed to consume a large portion of the readily accessible amount of it in the span of somewhat less than two centuries.

The question becomes whether we can use immediate sources of solar energy, irrespective of their specific conversion methods (photovoltaic, solar thermal, biofuels, et cetera) to replace the delayed sources (fossil fuels). When the problem is examined from this overarching perspective, the scaling problem becomes very clear; as can be seen from this chart, there are order of magnitude differences between the necessary power density requirements to sustain cities and other industrial capabilities such as steel production and transportation compared to the power density and required footprint of PV solar, biofuel, and other renewable resources. Such resources are renewable (with certain caveats) but not sustainable in the sense of being able to keep up with energy demand. (The chart I was actually looking for was from Vaclav Smil’s Global Catastrophes and Trends, pg 85, Figure 3.5, but I can’t find it online.) This is irrespective of incremental improvements in solar power efficiency and energy storage methods; the scale of the gaps would require near-magical improvements to even be viable as a replacement.

Does that mean that we shouldn’t invest in renewables? Absolutely not. Although solar is not going to scale up to replace all fossil fuel production, it is readily deployable and more cost effective than carbon sequestration of coal-fired and fuel oil, plants, and so can be used to offset and retire those sources to reduce atmospheric carbon output. It can also be used to provide peak daytime power production or stored for surge production, and solar has the potential to provide for essentially all dispersed residential use at less than 40 degrees latitude. What it cannot replace is transportation energy (though it could offset commuter demand through electric vehicle and synthetic fuel production) and high power demand for industrial uses without enormous physical footprints for energy collection and the associated environmental impact and maintenance costs. And it is certainly possible that advances in biotechnology will allow us to produce power directly from glucose through biomolecular mechanisms, thereby removing the inefficiencies inherent in either extracting energy from rich plant oils or producing alcohols for combustion.

So, I wouldn’t say that solar energy as a general for is “reaching maturity”, but the scaling issue is one that won’t disappear with incremental improvements in existing or prospective solar power production technologies, nor in improvements in energy storage, and we’re going to have shift to other dense power production sources (Generation IV nuclear fission, nuclear fusion, hydrocarbon fuel synthesis, et cetera) for future industrial demand, particularly as developing nations engage in more heavy industry and per capita energy demand.

Stranger

11

How is this even remotely relevant? The amount of agricultural land needed to feed a city is also vastly higher than the area of a city. And yet cities still exist.

Covering 1% of the US with PV/storage would serve virtually all our energy needs. Compare to agriculture where a whopping 40% of land is already being used.

Now, it probably doesn’t make sense to use PV for absolutely everything, but the density argument is nonsense. Cost is the main issue, at least up to perhaps 80% utilization (past that, you start needing hydrocarbon synthesis, etc.).

12

And we move food with trucks. I just had a vision of giant battery trucks charging up at sun farms and driving to the city. :smiley:

13

The technology is somewhere beyond infancy, and not quite mature.

It’s in it’s young adultery.

14

True. However if solar does undergo dramatic depreciation in price, you’ll reach a point where the cost to maintain the grid becomes more expensive than the higher cost from local rooftop solar vs utility. In that case, it won’t make economic sense to get utility scale solar and only residential systems will make economic sense. I don’t know what forms of storage there are that you can have at the household level other than batteries. Salt, ammonia, water, etc seem like they’re more for utility scale storage.

15

Right now, the cheapest power is at night precisely because the demand is already higher during the day. You don’t need to store solar power during the night: You just use solar plus something else during the high-demand day, and just the something else during the low-demand night. You would still need at least some smart usage to account for clouds and such, but one of the major consumers is air conditioning (which also has greatest demand in the summer, when solar is more productive), and air conditioning is very well-suited for smart usage.

We have all the technology we need for smart usage right now. All we need is for someone to put the pieces together and get folks to accept it.

16

You can’t ignore supply, though–power is cheap at night because demand is low and supply is (relatively) high, due to base-load generation.

In some hypothetical all-solar future, there isn’t *any *generation at night. So the difference will have to be made up with storage and smarter usage.

That said, clearly things won’t be truly all solar. We’ll have wind, hydroelectric, and maybe even some nuclear. This will likely be more than enough, combined with grid enhancements, to reduce the storage requirements to something reasonable.

Anyway, I agree with your conclusion. A lot of projections are based on demand staying exactly where it is forever, which is nonsense. Consumers and industry are happy to change their behavior with the right incentives. When daytime energy is virtually free compared to nighttime, they’ll be happy to run their drier or whatever during peak solar hours.

17

One thing I don’t see addressed that often is that solar can “win” even if the full cost (+storage) is higher than coal. The reason is that the (already cheap) daytime rates reduce the value of baseload generation. If solar undercuts your coal generation prices during the day, then suddenly you’ve lost a good chunk of your profits. You have to raise prices at night to stay profitable, but then you’ve left an opening for alternatives (gas, wind, solar+storage). Not to mention timeshifting of demand. You end up in a death spiral where a player in one niche makes it progressively more difficult to compete in other niches. And all the while, the popularity of solar drives investment up and prices down, making it even more difficult.

Put another way, the “game theory” around baseload generation doesn’t put a high price on it. So while 24-hour generation clearly has some value, if the market can’t price it then niche players can squeeze in. The same thing may happen to the grid itself, without intervention: as more individuals disconnect (because it’s economic for their particular situation), prices go up for everyone else. As prices go up, it’s cost effective for yet more consumers to disconnect. This could continue until the entire grid is impossible to maintain.

18

Energy return will go up but not much, and very likely not enough to meet demands for global industrialization.

19

The history of solar predates the internet by a wide margin, depending on how you view it. From here:

There is still some room to run, but I bet there won’t be another “50 million” comparison.

20

I would say it is still in an early stage of development.

The efficiency of solar panels only reached 20% in the past couple of years, it has a way to go. Then there is temperature sensitivity and various ways of angling the elements to capture more light and keeping the darn things clear of dust. The efficiency and cost of inverters and control systems and integration with smart metering is also at an early stage. Domestic battery storage may soon become viable. Grid batteries are still in the prototype stage.

A technology requires a whole series of parts to be organised and work together efficiently to provide a service that is economically viable. All the parts need to reach a sufficiently advanced stage of development and the capture part involving solar is just the front end of that and our electricity grids need to be adapted. However, a lot of the world has no electricity grid or it is in pretty poor shape.

Monitor the price of an off grid solar panel/battery combo because much of the system is self-contained and is not dependent on other developments in utility grids. At the moment these are very expensive items unaffordable to much of the world, somewhat like Elon Musks cars.:dubious: