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Comment: Re:Drop solar heat for direct conversion (Score 1) 485

by Smidge204 (#47711961) Attached to: Solar Plant Sets Birds On Fire As They Fly Overhead

Except you can not exceed the solar power that hits the surface of the planet from the sun.

...which is a hell of a lot of energy. Collectively it's several orders of magnitude more than we as a species could ever reasonably harness, let alone use.

You could, for example, generate more kWh of electricity by putting 15% nominal efficiency PV systems on the roofs of ONLY single-family homes in the US, based on 2010 census data (67% of 130 million residences being single-family homes, with an average size of 2,400 sq.ft.).

In other words, we could hypothetically generate more than 100% of the electricity we need in 7800 square miles - about 5 Rhode Islands. That's at 15% nominal efficiency, assuming only 4 hours per day of operation. In other words, an extremely conservative value.

Just putting things into perspective.
=Smidge=

Comment: Re:Some can be done - and is. Most is bull. (Score 1) 435

by Smidge204 (#47711197) Attached to: Is Storage Necessary For Renewable Energy?

What resources did you use to model these inputs? PVWatts I can understand for solar, but I'm not aware of any similar tools for wind and micro-hydro. Genuinely interested in what your data sources were.

Not that I'm yet convinced your model is applicable to a regional or national scale grid. Did you account for geographical diversity? Availability of these resources spread out over maybe 200-300 mile radius?

Also, peak demand of 5kW for 3 hours? My home has all electric appliances and I rarely, if ever, hit that... including the 3kW clothes dryer. This observation is neither here nor there, but that just strikes me as a high value.

To put things into perspective, I've been collecting minute-by-minute data for my own home's electrical usage (Got one of these things) and based on incomplete-at-the-time data it was looking like I could get away completely off-grid with a 6-7kW PV system and about 6kWH of storage. Less if I was smarter about how and when I used that power. Maybe your data doesn't have good enough resolution to really optimize the system.
=Smidge=

Comment: Re:Estimates (Score 2) 485

by Smidge204 (#47711105) Attached to: Solar Plant Sets Birds On Fire As They Fly Overhead

1. Solar Thermal plants are built in the desert because that's where they have the most ideal operating conditions. The fact that there are more birds in forests than deserts is completely irrelevant because they don't build concentrating solar plants in forests.

2. We would expect the casualties to scale roughly with the number of plants, so is you had 1,000 such plants, that would be 1,000x the casualties. Still a drop in the bucket compared to the billions of birds killed by feral cats every year in North America.

3. You are right, of course, however you have to consider a cost-benefit as well. The cost of preventing bird deaths from not building concentrating solar plants (both monetarily and environmentally) versus, say, the cost of preventing bird deaths by doing something about the cat population. If saving the birds is the priority, then perhaps your dollar would be better spent on programs to reduce feral cat populations than preventing solar thermal plants from being built.

=Smidge=

User Journal

Journal: Mars, Ho! Chapter Forty Two

Journal by mcgrew

Boarded!
Me and Bill hauled ass out of there towards Mars as fast as his crippled boat would take him. I did another inspection because first, I hadn't done a full inspection yet that day, second because I'd pushed her pretty hard, and third because I sure didn’t need any new surprises. We were at a third gravity because of Bill, and he was having a hard time keeping up. A third gravity? On batteries? I need to have him teach me some of that nerd

Comment: Re:Some can be done - and is. Most is bull. (Score 1) 435

by Smidge204 (#47696889) Attached to: Is Storage Necessary For Renewable Energy?

A single home isn't a very good proxy for a regional or even national scale grid.

With your house example, the only options are solar and generator. In reality you would have more than these two options. For example, add wind to the mix. You can argue that it's not 100% but it will cover a lot of run time at night, saving you battery capacity and reducing the required over-sizing of your PV system. Perhaps instead of 400% oversizing on PV, you only need 200% PV+Wind oversize.

Now add in something else... biogas perhaps. That covers you a little bit more and you can again reduce your oversizing.

Now add geothermal, hydro, solar-thermal (which works at night), and you start to easily fill in the gaps.

The US had 1,153 billion watts of generating capacity as of 2011 (Nameplate ratings, spreadsheet) and used ~3,797 billion kilowatthours that year. Naively we can say that if all our powerplants ran at 100% nameplate capacity, we could generate an entire year's worth of electrical energy in just about 3300 hours, or about 4 months... giving us a roughly 300% oversize on our electrical generating capacity *now*.

The key, of course, is that none of those plants are operating 24/7/365, and rarely are any of them operating at peak capacity.
=Smidge=

Comment: Re:There is a big construction boom in Germany... (Score 1) 435

by Smidge204 (#47696309) Attached to: Is Storage Necessary For Renewable Energy?

I'd also point out that Germany's accelerated decommissioning of nuclear power plants (all shutdown in 8 years) has a lot more to do with the coal plants than the increase in renewables.

Doesn't make sense: Coal power has actually decreased since 2000 when it was first decided that Germany should ween themselves off of Nuclear power, and the slight increase in coal power in the past two years is only a fraction of retired nuclear capacity, both in total and as a percent of total generation.

Germany's renewable energy push is what's filling that gap. If it wasn't for the nuclear phase-out, they'd probably have lost a third of their coal plants instead.
=Smidge=

Comment: Re:There is a big construction boom in Germany... (Score 1) 435

by Smidge204 (#47694875) Attached to: Is Storage Necessary For Renewable Energy?

Germany is actually a net exporter - Their total gross production (Bruttoerzeugung insgesamt) for 2013 was 629.0 TWh, while their total consumption (Brutto-Inlandsstromverbrauch) was 596.0 TWh for that same year... resulting in a net import of -33 TWh, aka an export. Of course, these are year averages and they almost certainly import during some times of the year, and when they do most of it comes from France, Denmark, Sweden and Czech Republic.

I also do think it's somewhat unfair to use numbers all the way back to 1990. If we are interested in the impact of renewables, then it would be more appropriate to go back to 2001 at the earliest, when the Renewables Energy Act went into effect. That's when they started getting serious about it.

We can instead consider 1990-2000 as a baseline decade to compare the 2001-2013 decade to, in terms of growth by fuel type.

In the 1990-2000 decade, coal decreased and was supplanted by nuclear and natural gas. In the 2001-2013 numbers, total coal decreases slightly overall but nuclear drops considerably post-Fukushima. Natural gas ramped up to nearly double mid-decade but dropped back down to about 20% higher than it was in 2001. The resulting gaps between these decreased outputs and increased demand is filled entirely by renewables which nearly quadrupled in capacity to become the second largest energy source in the country, just a hair's width (15 TWh) behind soft coal.
=Smidge=

Comment: Re:Expert?? (Score 1) 435

by Smidge204 (#47693343) Attached to: Is Storage Necessary For Renewable Energy?

Actually, from what he presented, that is pretty much what would be required.

I don't get that impression at all. He makes a point about being able to predict loads and generation, which strongly suggests that the strategy is to plan well in advance where the power comes from and where it goes to.

Also, large power stations are located along strategically designed/placed transmission corridors and still generally only serve a regional load based on years of growth and demand. And don't confuse the marketing of power with the actual transmission.

Rather, transmission corridors are strategically located to link power plants to the grid. Power plants are built where they have the resources and infrastructure to support them - near waterways, for example, or close to their source of fuel.

Market is a total sum game and the buyers and sellers don't really control where the power comes from or goes, they just ensure enough is available regionally. The power generated closest to the user is what is used, even if it is credited for sale in a different area.

Not entirely true. Utilities (who are resellers) prioritize the lowest cost power sources first, and only buy more expensive power if necessary.

Here's a quick example, which I chose because it's germane to the overall topic of renewable integration.

https://www.youtube.com/watch?...

The power generated closest to the user is what is used, even if it is credited for sale in a different area.

Nope. A good portion of my electricity comes from a coal plant upstate, but there are gas turbine power stations just a few miles from here... they only turn on those turbines for peak shaving, because they cost more per KWh to run. You can tell if they're running or not because you can see the cooling towers steaming up from the highway.

Power comes from the cheapest available source, not the closest. Not all power plants operate equally, or even all the time.
=Smidge=

Comment: Re:There is a big construction boom in Germany... (Score 1) 435

by Smidge204 (#47693311) Attached to: Is Storage Necessary For Renewable Energy?

http://www.ag-energiebilanzen....

It's in German, of course. The key things you're looking for are the second and third rows (Braunkohle and Steinkohle) which are Lignite and Anthracite, respectively. Upport portion of the table is in TWh (Billion KWh) and lower table is percent of total generation by fuel type.
=Smidge=

Comment: Re:Expert?? (Score 1) 435

by Smidge204 (#47690615) Attached to: Is Storage Necessary For Renewable Energy?

First, please realize that right now we as a country are in the process of rebuilding the entire power transmission system. That's happening no matter what, and it needs to happen no matter what.

In terms of the HVAC thing, which was just an example but one that seems to have stuck with you disproportionally so whatever... you would need to reduce the duty cycle to reduce power consumption, agreed? You would not have to turn it off for hours at a time - the entire concept here is that you could spread that reduction across a large population so that no single group bears the entire burden. We could, in theory, reduce electrical loads from AC units by 33% by disabling one in three units each for twenty minutes per hour.

As for "getting that power to flow the way he describes" - what is it you're imagining is happening NOW? You have power plants dotted all over the place, each with varying output, and power flows in any particular direction at any time. Nobody is proposing we instantaneously divert megawatts halfway across the country on a moment's notice - such a thing would be entirely unnecessary. However, diverting megawatts - even gigawatts - between substations and across counties and states is something that happens routinely right now, planned and unplanned. Nothing that can't be handled.
=Smidge=

Comment: Re:There is a big construction boom in Germany... (Score 1) 435

by Smidge204 (#47690537) Attached to: Is Storage Necessary For Renewable Energy?

Yes, a boom in coal plant construction... I guess that explains why Germany's coal generating capacity (hard coal + lignite) is down nearly 5% over the past ten years... all those new plants they've been building.

Any new plants they have been building - mostly to replace older, decommissioned ones - have been having problems because the cost of power has dropped significantly since construction began thanks to the glut of wind and solar. All that, despite reducing their nuclear generating capacity by nearly 44 TWh/yr after the Fukushima meltdown.

As for subsidies... have you accounted for the subsidies that current fossil generation gets? Land rights, construction cost subsidies, operational cost subsidies, environmental remediation subsidies... to make an indirect comparison, there's a reason the rest of the world pays three or four times more for their energy than the US does - subsidies.
=Smidge=

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