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Solar Just Hit a Record Low Price in the U.S

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Re: Solar Just Hit a Record Low Price in the U.S

#291

Post by aalleavitch »

CyberDildonics wrote: post #198
reaperducer wrote: post #146

Earlier quoted context omitted.

Plus, just because the sun goes down doesn't mean all solar generating stations stop making electricity. I'm not even remotely an expert in this field, but the towers at the solar furnaces I've seen continue to glow well into the night, meaning they're hot enough to still generate steam, and thus electricity, long after it's dark. I don't expect they generate electricity all night, but maybe not as much energy needs…

Not only that, but solar generated in one place can supply electricity to areas where the sun has not hit yet, and likewise after the sun goes down, those same places can draw power from further west.

I like the idea of having essentially a grid “wave”: in the morning your power comes from the East, in the evening it comes from the West.

Re: Solar Just Hit a Record Low Price in the U.S

#292

Post by KVFinn »

greenburger wrote: post #215
CompelTechnic wrote: post #124

Earlier quoted context omitted.

One weird thought I had the other day: high voltage DC transmission lines are getting more popular. I wonder if it would be economical for a high voltage DC line to form a loop around the entire planet, so that the load can follow the sun through a complete cycle.

In the US alone this would greatly aid a transition to wind and solar: http://www.sciencemag.org/news/2016/01/better-power-lines-wo...

>In the US alone this would greatly aid a transition to wind and solar:

http://www.sciencemag.org/news/2016/01/better-power-lines-wo...

For all the talk about inventing new batteries, I wish improving the existing grid would be more prominent in the conversation. High-voltage longer-distance power markets are something that can be built right now.

Re: Solar Just Hit a Record Low Price in the U.S

#293

Post by toomuchtodo »

gibybo wrote: post #254
toomuchtodo wrote: post #238

Earlier quoted context omitted.

ROI for cash invested in your solar install is greater than 4% in almost every state.

I didn't say it wasn't. We're talking about the cost per kWh which depends on the interest rate that you can finance it with, not your ROI.

You should always be paying cash whenever possible for the remaining system cost (after incentives). Failing that, you should be able to get a HELOC, home equity loan, or roll the system cost into a first mortgage at low (~4%) fixed rates (that might also be tax advantaged).

Higher interest rates would change the equation, but I don't know of people who are using high interest loans (like an unsecured loan) to finance residential solar.

Re: Solar Just Hit a Record Low Price in the U.S

#294

Post by mrb »

opo wrote: post #290
mrb wrote: post #246

Earlier quoted context omitted.

Residential-only energy use is irrelevant. What matters is peak grid usage (ie. residential+industrial) and it is actually mid-day—perfect for solar. For example the UK's real time grid monitoring system clearly shows this peak on the weekly chart: https://i.imgur.com/wTIt5tg.png (source: http://www.gridwatch.templar.co.uk/ )

A weekly chart like that isn’t really granular enough to show that. This chart is a few years old, but it shows that the peak demand was in the early evening: https://www.eia.gov/todayinenergy/detail.php?id=830 The peak demand will also vary at different locations and times of year. As the wikipedia article states: >...It depends on the demography, the economy, the weather, the climate, the season, the day of the wee…

Your chart is even less granular than mine (hourly vs half-hourly), and it has a timezone conversion error. The source they use (ISO New England - https://www.iso-ne.com/isoexpress/) shows the peak of a typical October month to be between 3pm-4pm and not 6pm-7pm: https://i.imgur.com/5rWlnVO.png (the 3 hours difference is the timezone offset between east coast and west coast.)

My chart, if you look closely, has a granularity of one half hour. If you want something even more granular, ISO New England data more clearly shows the peak to be between 2pm-3pm for a typical summer month: https://i.imgur.com/rX1JqoJ.png

Re: Solar Just Hit a Record Low Price in the U.S

#295

Post by sunstone »

hueving wrote: post #277
sunstone wrote: post #209

Earlier quoted context omitted.

However the amount of storage (battery or otherwise) for a network of renewable electricity producers depends on the full diversity of the complete network. Which is to say, for example, that a grid supplied by solar and wind will need proportionally less storage per megawatt as the geographical size of the grid increases. A larger grid "averages out" the intermittent sources better as it gets bigger.

Not for solar. There are no grids nearly large enough to have half in the day time and half in the night time on average.

The type of renewable generator, ie solar, wind, hydroelectric, geothermal and tidal, or a combination thereof is another dimension of grid diversity.

Re: Solar Just Hit a Record Low Price in the U.S

#296

Post by [deleted] »

w8rbt wrote: post #227
criddell wrote: post #177

Earlier quoted context omitted.

I've thought about adding solar to my home and can't see any reason why I should even consider a battery for storage. I'm in Texas and so I get plenty of sun and my peak energy demand happens to coincide with that sunlight (due to HVAC). Why should I worry about a complete solution?

Bob Bruninga has written and researched this a great deal. He's pretty well known and respected. He feels grid tie is the way to go for homes (no batteries). Lots of great info here: http://www.aprs.org/off-grid-maybe.html http://www.aprs.org/solar-now.html

[deleted]

Re: Solar Just Hit a Record Low Price in the U.S

#297

Post by stale2002 »

djrogers wrote: post #225
ben_w wrote: post #200

Earlier quoted context omitted.

Dinner is relevant. Lights… take a standard lightbulb form factor fill it with batteries and coat the outside with LEDs, and it can last most of the night.

Now you’re right back where this started - accounting for the cost of batteries. Oh, and my stomach says dinner is most definitely not irrelevant.

It is an irrelevant portion of total electricity usage. It doesnt matter if a very small portion of your electricity usage has high costs.

Re: Solar Just Hit a Record Low Price in the U.S

#298

Post by stale2002 »

hueving wrote: post #279
jartelt wrote: post #140

Earlier quoted context omitted.

This comment gets made in every single solar article put on HN. The true price of solar is what the market is willing to pay for it. If the solar was ruining the grid or was way more expensive than what it seems, we would not keep seeing solar installed at this pace and at these costs. We need to get out of the mindset that all power generators need to produce a steady amount of power 24/7. A flexible grid made of ma…

>If the solar was ruining the grid or was way more expensive than what it seems, we would not keep seeing solar installed at this pace and at these costs. This completely ignores the fact that the people buying solar get subsidies and they aren't the ones paying for the burdened grid. In some states, distribution companies are paying retail prices back to solar producers. That means these people get to freeride on th…

Highly polluting energy sources are not paying to clean up the environmental costs that they produce. Maybe THEY are the free riders.

Re: Solar Just Hit a Record Low Price in the U.S

#299

Post by stale2002 »

coryfklein wrote: post #228
immad wrote: post #78

Earlier quoted context omitted.

Why can't existing energy infrastructure handle the gaps? Does it take too long to boot up a natural gas plant just for the night? Would still make a huge dent to energy needs and the existing infrastructure already in place.

Because total load on the power grid peaks at 8 PM when solar is providing nearly 0% of the power [1]. This means that no matter how many additional solar panels you add to the system, you are not displacing a single fossil fuel plant . Sure it's good that those plants are running nominally fewer hours per day per additional solar panel, but the cost to own, operate, and maintain the panels is roughly constant. This…

Industrial usage makes up a large percentage of total energy usage.

Industrial energy usage can be time shifted.

Who cares about residential power, if it is a small percentage of total energy usage?

Re: Solar Just Hit a Record Low Price in the U.S

#300

Post by aoeusnth1 »

gibybo wrote: post #234
aoeusnth1 wrote: post #171

Earlier quoted context omitted.

Online calculators over-estimate costs for large systems. You can find newer installers who are more willing to negotiate prices, and play them off each other. I negotiated one company down from ~$3.5/W to $2.30/W (before 30% credit) on my large residential system - and these weren't budget panels either (Sunpower E20). If you do the discounted cash flow calculation of solar, at $2.3/W, electricity costs you around 5…

I think your numbers are pretty optimistic. You're neglecting depreciation for one. Panels have a lifetime in the range of 20-30 years, inverters have a lifetime in the range of 10 years. 4% is also an optimistic interest rate for a loan that lasts the lifetime of the system. You may be able to get that for a ~5 year loan, but then you need to include the higher opportunity cost of the money that was used to pay that…

Ok, I've updated the spreadsheet to properly account for discounted energy (discount rate: 4%) and degradation (at the rated 92%/25yr). It comes out to 6c/kWh, which is about 20% larger than my first number. Half of that increase was due to the degradation, the other half from the limited time horizon - and assuming the system will be worthless after 25yr (!!).

http://databin.pudo.org/t/4cb861

This is all just a thought experiment for me, because my electricity costs 22c/kWh :)

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