Renewables and Energy Density
Here’s a video featuring a scientist who’s bearish on renewable energy because of energy density. “The trajectory of humankind’s use of energy has always been toward greater density. We gave up biomass in favor of coal. Nuclear is millions of times even more energy dense.”
It’s painful to listen to people claim “that’s the way we’ve always done it” as proof that it’s a good idea. If it were that good an idea, we wouldn’t be baking our planet right now. Einstein was even more emphatic (see meme).
In any case, there is no doubt that solar and wind take lots of surface area, insofar as the sun is 93 million miles from here, and its incident radiation is approximately 1KW/square meter. There is nothing we can do about that. And, if energy density were the only criterion, e.g., if our planet were so small that we had no room for renewable energy devices, he’d have an unassailable point. The fact is, however, that we could power the entire Earth with a solar farm of one one-thousandths of its land mass. Living on the other 99.9% is not going to make us uncomfortably crowded.
Now, are there other issues that make 100% renewables unfeasible in the short-term? Yes, as discussed here and elsewhere.
Craig,
Of course it’s easy to say that: “The world needs ~20 PWh of electricity, and a single m2 of Earth at the equator at noon on a sunny day receives ~1 kW of radiant power. If we assume 20% efficiency, and 20% cf, that would only require 57,000 km2 of solar panels, which is NOTHING!”
🙂
But the real world isn’t that simple, and space is a consideration… as is transmission.
The very low energy density of solar panels means that in some cases they will never be suitable for a large percentage of the population needs without extremely long transmission routes.
It’s easy to imagine solar being the solution for all if one lived in the American Southwest in the suburbs, because the non-North square footage of most unshaded rooftops in the suburbs would be sufficient to provide for all of the home’s needs. It’s a no-brainer. Of course you should have solar panels on your roof, and provide your own energy.
Of course, if you lived in Seattle, you’d need ~2.5 times the area of solar panels to provide the same energy as a home in Southern California, so that doesn’t fit anymore… now not only rooftop solar but also ground mounts in and around the yard are needed, and it’s still not enough..
But what about multi-story buildings. If you lived in a condo in a 20-story building? You wouldn’t come close to providing enough energy for yourself. If you were discussing a factory, and all of it’s energy needs? Likely not… etc…
So in order to make up the energy shortfall for cities and locales with less optimal insolation, you’d have to build large industrial solar farms..
This can certainly happen, and it does… But now you’re taking up land that would otherwise be used for farming, or you’re clearing land that would otherwise be forested… etc..
I’m not saying this to be belittling of renewables at large. You know that. I think we should build as much and as quickly as we can… but we need to acknowledge that there will be shortfalls. There will be balance problems… there must be some consideration and planning for those events before they arise and crush the growing industry…
And there must be contingencies planned for the areas that solar and wind will not work… such as Bangladesh. Bangladeshi are poor, and they are incredibly densely populated.
It would be far easier for them to find a couple of km2 for a nuclear power plant than it would be for them to find a few hundred km2 for only solar panels.
Acknowledging the challenges that make renewables a poor panacea can still be done in a mindset of solid support for renewables. Their low energy density will be a factor in how quickly they can penetrate and deeply disrupt fossil power. It’s a problem, and we need to face it.
Craig,
Glenn’s comment makes a lot of sense. Advocates for any particular type of energy generation tend to become very partisan and unrealistically passionate about the technology of their choice.
Solar, Wind, Geo-thermal, hydro, waste to energy technologies all can prove useful, economic and practical in appropriate locations and applications.
Nuclear energy, (especially thorium) natural gas, (LPG etc) along with clean(er) coal technologies also have an important role, especially for heavy “power on demand” industrial requirements.
I have long advocated the focus should be on lowering harmful emissions economically and effectively, not forming “cheer squads” for any individual technology.
The need for clean(er) energy will continue to grow as more nations industrialize and living standards increase.
Only Thorium based mini-reactors can overcome the problem of energy waste due to transmission logistics economically.
Each energy generating technology will possess advantages and disadvantages. While at the moment, natural gas is proving a popular and economic rival to Clean(er) coal, the investment is a gamble on the current low cost and plentiful supply of domestic natural always being available.
IMO, this is an error. Demand for LPG and natural gas in Asia is growing and this will be reflected in the pricing for electricity generation. China has proved to have a voracious appetite for LPG and natural gas, which will accelerate demand in Europe placing greater reliance on Russian natural gas resources.
Russia, with vast reserves of both natural gas, and irreplaceable forest bio-pellets, while be able to exert greater political pressure on a Western Europe unable to survive without Russian energy.
Nuclear power generation is the only base-load resource able to replace coal and fossil fuels in some conditions.
Once all the political/ideological/ philosophical agenda is set aside, an objective, dispassionate, non-partisan analysis can take place. The focus should be on guaranteeing supply and reducing emissions without a disruptive, and realistic reorganization of society.
Craig, btw, do you know how Frank Eggers is faring, I miss his comments on nuclear Energy ?