I was reading this article about the (possible) potential of solar energy so I thought I’d start a debate here on the subject and see what 'Dopers think. According to the article something similar to Moore’s Law is at work in the solar energy field, with a doubling of ‘advancement’ every 2 years. By this futurists calculations we should, in theory, be able to scale up to 100% use of solar power within 20 years at the current rate of progression.
I’m…skeptical. I have no doubts that solar energy will play a vital role in the future mix of energy sources as we ween ourselves away from fossil fuels, but I just can’t see how we could scale up to even 50% of our energy needs coming from solar in 20 years (hell, even 10-20% would be an achievement considering how much we currently get from solar)…let alone 100%.
As the value of energy increases, the practicality of energy harvesting technologies becomes greater. As the number of methods increases, engineering refinement makes previously rare methods more efficient.
Algal farming for bio-diesel in marginally useful desert land brings heavier development of infrastructure to remote areas. With that infrastructure available, those areas can implement wind and solar energy harvesting more efficiently. As increased numbers of consumers buy the products for this new economic niche, industry finds it more useful to fund research in small improvements to existing technology.
There is a synergy to the process. Predicting exact outcomes is chancy, but the trend is inevitable.
Yeah, we still need a cheap, efficient, commercial scale solar cell. I see lots of articles about how some group has invented a revolutionary device, but never anything on how they’re actually going into production. Assuming someone does finally come up with the right device, it probably will take 20 years to start to saturate the market.
Ray Kurzweil is somewhat bombastic about his own predictions about future developments. He certain wasn’t the first person to foresee the expansion and application of global communications and computer networks, and his famous prediction regarding the fall of the Soviet Union (based upon expanded communication capability “disempowering” authoritarian govenments) is simplistic, failing to acknowledge that the USSR had long been economically insolvent and that the political issues which resulted in the collapse of the Warsaw Pact (upon which the Soviet Union was economically dependent) predated the earliest personal computers by about a decade.
With that being said, whether there is an exponential advance in the collection and storage capability of solar power or not (and while I don’t work in the field, in my cursory reading I haven’t see anything indicating this) the increased global energy demand of emerging industrial nations and continuing depletion of known fossil fuel reserves may demand a transition to solar-based or solar-renewed energy, i.e. PV and thermal solar, wind and wave power, renewable biofuels, et cetera. (Virtually all energy, save for nuclear and geothermal, originally comes from the Sun anyway.) Whether this happens in twenty years or fifty largely depends not on advances in technology or government regulation, but market pressures; when oil is $200 a barrel and China is demanding 10kW-h/person/day, the impetus to develop the necessary technology and apply what is currently feasible will be much higher despite the costs.
And Kurzweil is right about the supply of solar energy vastly exceeding foreseeable need. I’m just not seeing this vast explosion of the capability of applicable storage and collection technology driving this.
The big problem with solar energy is transporting the energy from where it’s generated to where it’s needed. And then there’s storing it until it’s needed.
Solar power is good, but it’s not going to be the sole solution.
Welcome to the American West, where the sun always shines and the wind blows! The future of the American energy industry lies in Colorado, Wyoming, Texas, New Mexico, Utah, etc.
Large scale solar plants use mirrors to focus sunlight and store the heat in molten salt. This heat is then used for more conventional turbines to generate electricity. The heat will last into the night so they can generate power when the sun is down.
There are a few of the plants running in the southwest US currently.
I, too am skeptical of solar’s potential. But I got a little less skeptical after reading this Scientific American article which outlines a “grand plan” for using solar to make the US energy independent.
Problem is the need to develop a stable, economically viable efficient solar panel.
The most efficient panels operate at what, 16% efficiency now? The conversion rate is insufficient. As I recall, and it’s been a while since I studied solar tech, that’s about the theoretical maximum for the materials currently used, and developing new, more efficient panels requires developing materials with a higher maximum.
Now, that’s for direct conversion of sunlight into energy through illumination of a band gap. For solar panels reliant on converting sunlight by other means, most of those are some form of heat engine, and there we’re limited by the absolute maximum efficiency of 40% for heat engines.
40% is good. Is it good enough, vs. the amount of space and sunlight needed to create sufficient heat?
So what this guy is saying is that even with 100% perfectly (flying pink unicorn) efficient solar panels, we’d need to cover 1/10,000 of the planet’s surface (including the oceans and ice caps and mountains and other completely impractical places) to meet the energy needs of TODAY, let alone the likely higher energy needs of 20 years from now.
The idea that we’ll ever get anything close to 100% of our energy requirements from land based solar panels is certainly logistically impossible. And, the more sun energy we harvest with solar panels, the less is used to stimulate photosynthesis in plants. We can’t just smother the planet’s surface with solar cells. Solar energy isn’t, and wont ever, be even close to adequate to meet our energy needs, especially compared to the much cheaper, smaller, and more practical alternative of nuclear energy.
#1, there is no Moore’s law with solar energy production. There is only X amount of energy available per square foot. Period. You can’t double your efficiency every 2 years when there’s a hard cap.
#2, Increasing the percentage of our energy created through solar means covering more and more stuff with solar panels. Not only does that mean that we’d be perpetually looking at solar panels, but someone has to manufacture and maintain all of these solar panels. You’d need to be able to lay solar panels like shingles, or asphalt to get enough area covered without busting everyone’s bank.
#3 Storage. You can’t transport an entire continent’s worth of power across the globe. Not with anything remotely resembling current technology. Battery storage sucks.
The former isn’t a problem in the sense of it being technically infeasible; high voltage DC transmission is a well-developed technology that scales up very well. Of course, there would be the need to create a distribution infrastructure with much more capacity than is currently extant, but the present system (at least in the continental United States) is a cobbled together patchwork of different systems that are all past designed capacity, so the expenditure is well overdue anyway.
As for storage, storage on large scales in a static system isn’t difficult, and can be done as gravitational potential energy (water or sand reservoirs), lightly compressed gas (air or nitrogen at low pressure), rotational energy (massive banks of flywheels), thermal storage, et cetera. There are mechanical and thermodynamic losses to these, but then tend to get smaller in overall proportion as the amount of storage capacity scales up. The problem is mobile energy storage; rechargeable electrochemical (NiMH) batteries are, despite decades of evolutionary development, still about two orders of magnitude or more distant in mass energy density from petrofuels, and well over an order of magnitude versus alcohols. Technologies for fuel cell storage and synthesized fuels are still in their infancy in terms of viability for transportation, with no realistic projection as to when those will be competitive with existing fuels on a cost or performance basis.
The real problem with replacing existing fossil fuel plants with solar or solar-derived energy is implied by the cited Scientific American article: “But $420 billion in subsidies from 2011 to 2050 would be required to fund the infrastructure and make it cost-competitive.” This is $420B in today’s dollars, never mind inflation, competition for fiscal resources, the difficulty of getting consistent funding for far-future rewards, et cetera. In short, solar power may be feasible, but even if the ongoing production and maintenance costs are lower than digging and processing fossil fuels the initial capital cost of building a new infrastructure to collect and store energy isn’t currently competitive with coal and oil, for which the infrastructure already exists. Hopefully, by the time the cost of the latter rises we’ll still have the capability to build the former, and we don’t suffer a precipitous decline in energy availability.
It would be wise now to start investing in renewable energy production despite moderate efficiencies, if only to start making the mistakes to learn from and build up a legacy of research knowledge and technical talent to apply to the next generation of energy research. But wisdom has rarely been part of any nation’s long term fiscal strategy.
I’m not an engineer but I haven’t heard of any technologies in development that are going to bring solar energy in mainstream production. So I think we still need some revolutionary advances before we can switch over.
These arguments are nonsensical; there is no “Moore’s law with” petroleum or coal production, either; indeed, while the availability of solar energy is essentially limitless on any time scale we’re likely to be concerned about in the next few millenia, coal and oil are very finite resources, and fissile fuels, while more extensive, are still ultimately limited, even assuming fuel breeding and activation methods. (Nuclear fission, of course, also has political and radioactive waste ramifications as well.) Barring the advent of nuclear fission (which perpetually seems to be “20-30 years away”) or something more exotic we’re going to have to transition to solar or solar-derived energy sources anyway.
The PV solar cells of today will resemble solar collection technology fifty years from now in the same way that a Model T resembles an Audi S8. No doubt they will be laid like shingles and be essentially just as robust (and readily replaced and recycled when they wear) rather than the delicate and complex PV systems today. But the efficiency of photovoltaics, while suitable for small installations, will probably never be suited to wide scale energy production. Thermal solar and solar-derived energy production systems are likely to be more effective on large scales.
In order to get hydrogen to anything like a reasonable energy density you have to liquify it, which requires extremely high pressure or cyrogenic storage, both of which have obvious problems. And even in the liquid state, hydrogen has very low volumetric energy density, so it takes up a lot more room per joule than gasoline or alcohol. Handling pure hydrogen also has other hazards (explosion, containment, hydrogen embrittlement) which make it an undesirable fuel for long term storage. We use it in space launch rockets because of how energetic it is for its mass, and because it combusts almost completely with liquid oxygen or peroxide, but even then it has significant drawbacks that resulted it hydrogen being abandoned as a fuel for missile and quick response use. Hydrogen might be usable in fuel cells where it is stored in a solid matrix or catalyzed into and out of a bound state, but this technology isn’t going to give us a replacement comparable to the performance of gasoline-powered engines any time soon.
We aren’t likely to have the high density nano-engineered solar cells any time soon either. So, as a convergent technology along with fuel cell development I would have to think it’s at least viable. I can’t believe that major manufacturers are pouring billions into hydrogen technology if it’s not viable on a large scale…they have to be able to look at the same things you have brought up, no?