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Comment by willholloway | Hacker News Reader

I believe this is the development that will let us avoid run away catastrophic warming.

In order to avoid catastrophic warming we have to reduce emissions by something like 80% by 2050. That seemed a pipe dream before cheap solar panels, now it feels inevitable to me.

70% of the power generated by a coal plant is wasted in the transmission line before it reaches your home, distributed generation has this huge efficiency benefit going for it.

The Chinese solar industry has gotten the price down below .50 per watt this year, in a few years it won't make sense to add carbon-sourced marginal capacity. Almost all of new demand can be satisfied with solar pv. We will have to solve the energy storage problem, and I think we will. Superconducting magnetic energy storage gives me hope.

https://en.wikipedia.org/wiki/Superconducting_magnetic_energ...

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>70% of the power generated by a coal plant is wasted in the transmission line before it reaches your home

...that sounds like an order of magnitude too high. Here's couples of sites that claims that the number is 6%-7%.

http://www.eia.gov/tools/faqs/faq.cfm?id=105&t=3

http://en.wikipedia.org/wiki/Electric_power_transmission#Los...

I think the 70% number includes inefficiencies associated with the generation cycle. A coal plant efficiency is around 35-40% subtract off transmission losses and you are close.

70% wasted in the transmission line, eh? Where did you get that number?

http://www.eia.gov/tools/faqs/faq.cfm?id=105&t=3

Probably confusion with the thermal efficiency (which Wikipedia says is ~33% for coal).

Just for context, solar provides <1% of world electricity and nuclear provides >10%, both of which produce very little CO2

I can install solar on my roof in 1-2 days (after permitting/approval). I cannot install a nuclear reactor on my roof.

What's the purpose of stating the obvious here?

My interpretation of the post I responded to was that solar and nuclear are both carbon neutral energy sources, but that somehow nuclear was "better" because it provided 10x as much power globally. My post was to articulate that solar can be deployed anywhere, much more rapidly, and is therefore the better choice.

Thanks for calling me out on it!

Not yet!

They've become smaller and more maintanence-free than you might expect. http://en.wikipedia.org/wiki/Small_modular_reactor

I don't doubt that, and they're probably very valuable in locations that don't get a significant amount of sunlight (near the poles), but I can walk into Costco and pick up enough solar panels to power my house.

that's 1% and growing, 10% and shrinking.

Flywheels are pretty neat too. https://en.wikipedia.org/wiki/Flywheel_energy_storage

You missed an easy pun with some outdated lingo. Lemme correct you.

Ahem

Flywheels are pretty fly yo.

A lot of research has gone into flywheels over the last 40 years or so. The best that came out of that was ride-trough systems for hospitals and other large consumers (datacenters!) which catch the load until the generators can be spun up and power stabilization for wind parks (but these have now been supplanted by more solid state tech using superconductors).

There are all kinds of reasons for that much too involved to go into here but for most practical (and cost efficient) applications fly-wheels are probably not going to happen unless there is a breakthrough in materials that would allow much higher RPM.

Other interesting applications where the gyro bus (http://en.wikipedia.org/wiki/Gyrobus ) and a similar system used to power regular cars (the flywheels were in the 100K+ RPM region and the size of a large dewar flask).

Well, they just don't seem as science fictiony as superconducting batteries. Coal and oil seem like great ways to store energy until you need it. Turning electricity into coal seems pretty tricky though.

If the cost of panels keeps dropping like this, i think a lot more money will go into electricity storage. no idea what that storage system might be though. with home generation, batteries aren't as encumbered by size and weight when compared to a car or a laptop. Maybe some big heavy battery tech will come along and give us a good chemical storage answer.

Maybe in the future, power is generated on rooftops, and large centralized installations store the excess energy till night - replacing some fraction of our current coal/oil/gas/nuke generating capacity.

1. 70% loss is incorrect as others have pointed out. 2. What 'catastrophic runaway warming'? The latest IPCC report says 1.5 degrees by 2100. Neither catastrophic nor runaway. That is business as usual scenario, which doesn't factor in the development of new generation methods in the next 80 years, which is a virtual certainty.

There is a 70% loss in generation and transmission. Standard coal plants convert 30-35% of the energy in coal to electricity, ~7% is lost in the lines.

https://www.nema.org/Products/Documents/TDEnergyEff.pdf

Runaway catastrophic warming is what we will be dealing with if we stay on the business as usual approach: http://rsta.royalsocietypublishing.org/content/371/2001/2012...

I'm basing my argument on the work of Dr. James Hansen from NASA. The IPCC's predictions keep coming back as incorrect, too conservative. The IPCC has had to rewrite their predictions, the situation is proving worse than they thought.

Dr Hansen has had himself arrested for activism so many place little credence in his views, particularly as he likes to contrast his scientific work with exaggeration when talking to the media.

The IPCC predictions have all been revised downward with each report. The only thing that has increased is their 'confidence level' which is not statistical confidence but author confidence.

I don't know what will happen, but I do know that nobody else does, either. Every single simulation so far has been completely off by a factor which makes it worthless.

The only thing we can predict is that better, cheaper forms of energy will be produced, and these are likely to be lower emissions than what we have today. Pricing out lower income people in the present day in the hope of making a difference is morally wrong in thighs is context.

Electricity generation is only a small part of carbon dioxide emissions. If you're worried about global warming, I suggest becoming a vegan.

that's disingenuous - electricity from fossil fuels, along with agriculture and transport are the 3 biggies. it makes more sense to say "yes, but don't forget transport and food". cheap solar and electric transport are pretty closely coupled as well especially if your car(s) can seamlessly act as your battery pack reserve.

Private car transportation is only a small part of transporation.

How would becoming a vegan materially affect carbon dioxide emissions (or more saliently, the ratio of CO2 in the atmosphere).

He's probably referring to methane produced by livestock.

http://epa.gov/climatechange/ghgemissions/gases/ch4.html

Hmm, but there's lots of livestock that doesn't generate methane (and she/he did specify CO2 there).

Making everyone else become a vegan (or, at least, internalizing the externalities associated with livestock so that market forces would make that a much more common choice), but doing so yourself won't. Classic tragedy of the commons.

I do understand the logic of pro-vegan types on this front, but apart from believing it's fundamentally flawed, I was especially curious on the specificity regarding CO2 in this case.

If the planet's population became vegan, we'd have some serious nutrition and soil management challenges to contend with. Cycling (or part-provisioning of) nutrients without using animals or without using methane and other fossil fuels (think Haber Bosch) is a mystery to me absent animals on the farm.

Here's study on carbon footprint of different diets: http://shrinkthatfootprint.com/food-carbon-footprint-diet

"If the planet's population became vegan, we'd have some serious nutrition and soil management challenges to contend with."

Nope. In addition, the whole world is not becoming vegan at once. If you think that's a problem, become a vegan now so that the whole world is not becoming vegan at once.

I carefully avoided the 'at once' bit. Clearly that would be even more infeasible.

That study / blog post is certainly partisan - but it is written by an energetic vegan (hmm, you'd think that'd be an oxymoron).

I've still yet to see a workable solution to the Nitrogen and Phosphorous (as well as all the other micronutrient and mineral) cycles that does not intrinsically require the involvement of animal husbandry or the input of massive amounts of energy.

Let me throw a reference to a properly researched study back at you - Simon Fairlie's 'Meat: A Benign Extravagance'

http://books.google.com.au/books/about/Meat.html?id=iid8mTmX...

Solar is only a piece of the puzzle.

The main issue is that in the US, we use up twice the amount of electricity in the day than we do at night. Spinning up and spinning down the turbines / generators causes enormous amounts of waste.

Green energy can't "spin up" and "spin down" like coal, oil, or nuclear.

http://www.forbes.com/sites/quora/2013/10/07/what-is-the-hol...

Some large percentage of our grid (in particular, the "dynamic" portion) will have to be Coal, Oil, Gas, or Nuclear. The Gigawatts of energy differential between day-usage and night-usage foregoes any hope of storing that energy.

Combined cycle natural gas turbines are extremely easy to throttle compared to baseload like coal or nuclear. Even most diesel/bunker fuel facilities that were used for peaking have been shuttered or switched to natural gas, because of cost as well.

Natural gas turbines are just fine as a peaking stop gap until we have the renewables dispatchability problem solved.

here in NZ (no subsidies in our electricity market) we are about 70% renewable via hydro and geothermal. we run a parallel 'reserves' market (everyone does, it's there to take up the slack of a plant tripping out). typically a hydro plant will run 'tail depressed' which means it's not as efficient as it could be but can scale up within 7 seconds (there's another 7 minute reserve market). prices adjust, people get paid to conserve fuel (water) but it's availalbe when needed. fast start gas turbines are also common but these tend to be at the 10-15 min mark (which is still blistering!). tl;dr 'green' energy _systems_ spin up and spin down just like the regular kind...

Hydro is one of the best "green" energy sources, and we definitely need more of it.

The downside is that rivers of the size that can power a Hydro-dam are relatively rare, and ecological issues (flood zones, and whatnot) need to be taken into account.

So I'll amend my original post with Coal, Oil, Nuclear or Hydro.

Solar and Wind are absolutely terrible at "spin up" and "spin down". So other sources are needed to cover the differential.

My understanding is that it is not practical to turn nuclear on and off to meet demand. Am I just wrong on that? Do you know of a good resource to learn more about this?

It's not practical to turn on and off any steam based power plant.

Coal and nuclear fuel are simply used to boil water. The steam created in both plants is then passed through a steam turbine, which turns a generator. The turbine is finely tuned to a specific set of steam characteristics. These are generally related to temperature and pressure. The process of getting the steam loop up to the right temperature and pressure takes a significant amount of time and energy. Once it is at steady state, it is very efficient.

Natural gas turbines work differently. There is no steam. The natural gas is burnt directly in the turbine, much like a jet engine. Thus you can throttle it just like an airplane. There is some lag, but it is relatively responsive.

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