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Old 08-11-2016, 05:42 PM
 
5,090 posts, read 9,834,071 times
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Quote:
Originally Posted by Submariner View Post
Solar Power [Photo Voltaic] is completely different from Solar Thermal.
Agreed.

And we are WAY off from Tesla, at this point.

But looking at Building Energy Use (not Transportation) it looks like we dump A LOT of the Energy Demand on Solar Thermal -- heating and cooling -- as heating and cooling are the largest users of Energy for buildings.
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Old 08-13-2016, 08:04 PM
 
Location: "Silicon Valley" (part of San Francisco Bay Area, California, USA)
4,099 posts, read 2,902,547 times
Reputation: 1965
Actually, solar used for heating water in a house is known as "solar heating", not "solar thermal".

The latter is a technology used in central power plants. There are three main types of solar thermal power. With the central tower type, what happens is that the sun's energy is focused onto a small point using mirrors. That point has a large volume of molten salt. The heat from the Sun heats the salt. The heat turns water into steam and turns a turbine.

After the Sun goes down, the salt retains the heat, and continues to radiate heat for 12 hours until the Sun comes up again.

Molten Salt Tower Receiver

Another type of solar thermal is known as "solar trough." Here, mirrors are still used to focus the heat of the Sun. But instead of all the mirrors pointing to one place, you have a series of mirrors. Each mirror is built around a pipe, and the pipe is located at focal point of the mirror. The mirrors heat the fluid, and the pipes transfer the heated fluid to a unit that stores the heat (such as with molten salt, similar to the other system). The heat is used to make steam, and the steam turns a turbine. The salt again retains the heat for 12 hours until the Sun returns.

Our Technology - Why Parabolic Trough?

The third type of solar thermal is the Dish type. These resemble a satellite television dish, only the dish reflects visible light. At the focal point of the dish, there is either a Sterling engine or an electronic device that converts heat directly into electricity (usually a "peltier element"). In the case of the Sterling engine, it uses heat to expand and contract a fluid, and that expansion and contraction drives a piston, generating electric power.

Most efficient solar energy dish in the world uses engine developed in 1816 | Science! | Geek.com

Solar thermal is typically a lot more efficient than PV -- one of the solar dish systems is 34% efficient -- but it has the disadvantage that it can't be placed on just any flat surface that is exposed to the sun; there are pipes and moving parts.
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Old 08-18-2016, 06:39 AM
 
Location: Whereever we have our RV parked
8,692 posts, read 7,652,489 times
Reputation: 14850
To ever expect renewables to be a significant supplier of power in the USA is a pipe dream. For example. We were driving home today, just at dinner time. Temp at 90 and about that time of day, power usage spikes because people are getting home and making dinner, which takes a lot of power. As we drove past a bank of windmills, they all stopped just as we were driving by. The wind was slowing to a point that it wouldn't drive the windmills.

This just goes to show, wind and solar are not reliable sources of power. They have to continue to run the other power plants anyhow, just to cover the windmills, should the wind die down. So, in fact, you haven't saved anything. IN fact, in a few cases, the windmills have almost crashed the system in Texas.
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Old 08-20-2016, 07:16 AM
 
16,571 posts, read 14,026,756 times
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People keep talking about solar subsidies without realizing fossil fuels, despite an over hundred year head start still get billions in subsidies every year across the globe.

https://en.m.wikipedia.org/wiki/Energy_subsidies
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Old 08-20-2016, 07:25 AM
 
16,571 posts, read 14,026,756 times
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Quote:
Originally Posted by augiedogie View Post
To ever expect renewables to be a significant supplier of power in the USA is a pipe dream. For example. We were driving home today, just at dinner time. Temp at 90 and about that time of day, power usage spikes because people are getting home and making dinner, which takes a lot of power. As we drove past a bank of windmills, they all stopped just as we were driving by. The wind was slowing to a point that it wouldn't drive the windmills.

This just goes to show, wind and solar are not reliable sources of power. They have to continue to run the other power plants anyhow, just to cover the windmills, should the wind die down. So, in fact, you haven't saved anything. IN fact, in a few cases, the windmills have almost crashed the system in Texas.
You think pointing at a single bank of windmills shows anything? People have been reliably getting tidal power out of plants in France and the bay of funds for 50 years. Niigata falls, for over a hundred. No single renewable will work everywhere at all times, but they are absolutely reliable, it's just takes more than a one size fits all approach. Texas for example, large areas would be prime for solar. I live in the NE, offshore wind is a good choice for us.

And your issues with peak power are a strawman. Power grids in the continental US, are interconnected and energy is no long generated in one spot for one locale. And, we have the capability to store electricity in reserve against peak usages built right into the grid. Those technologies are only improving over time.
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Old 08-22-2016, 10:43 AM
 
Location: Londonderry, NH
41,505 posts, read 51,274,872 times
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The gasoline fueled car for longer trips combined with a electric car for errands and such makes a very good combination for us. When our Subaru finally rusts out we may buy an electric or hybrid. We will also need a long distance winter car as my 2004 Corvette would be difficult to drive on snow or ice but it does make a very good touring car.


If I really take a hard look at what we really need/want we will continue to use gasoline powered cars and, primarily because of the cost of propane gas and associated heaters, electric power from a local nuclear power plant for winter. When it come right down to it the only green I really care about is the color of money.
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Old 08-22-2016, 11:04 AM
 
Location: Forests of Maine
30,650 posts, read 49,325,799 times
Reputation: 19075
Quote:
Originally Posted by augiedogie View Post
To ever expect renewables to be a significant supplier of power in the USA is a pipe dream. For example. We were driving home today, just at dinner time. Temp at 90 and about that time of day, power usage spikes because people are getting home and making dinner, which takes a lot of power. As we drove past a bank of windmills, they all stopped just as we were driving by. The wind was slowing to a point that it wouldn't drive the windmills.

This just goes to show, wind and solar are not reliable sources of power. They have to continue to run the other power plants anyhow, just to cover the windmills, should the wind die down. So, in fact, you haven't saved anything. IN fact, in a few cases, the windmills have almost crashed the system in Texas.
Nobody has stated that wind or solar systems provide power 24hrs a day. You are making a strawman argument, or at worst stuffing your words into other people's mouths which is rude.

Many homeowners have been shifted to solar power and to wind power. Because they can support reliable home power, they can have fairly quick ROI, and they can make a lot of economic sense.

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Old 08-22-2016, 11:06 AM
 
Location: Forests of Maine
30,650 posts, read 49,325,799 times
Reputation: 19075
Quote:
Originally Posted by GregW View Post
The gasoline fueled car for longer trips combined with a electric car for errands and such makes a very good combination for us. When our Subaru finally rusts out we may buy an electric or hybrid. We will also need a long distance winter car as my 2004 Corvette would be difficult to drive on snow or ice but it does make a very good touring car.


If I really take a hard look at what we really need/want we will continue to use gasoline powered cars and, primarily because of the cost of propane gas and associated heaters, electric power from a local nuclear power plant for winter. When it come right down to it the only green I really care about is the color of money.
We have been driving a Prius hybrid since 2011, it turns out to be an ideal vehicle for Maine driving. We only wish it was a plug-in model.
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Old 04-11-2017, 05:57 PM
 
9,821 posts, read 10,065,705 times
Reputation: 5256
[quote=Mack Knife;44998089]Tesla's battery factory, a joke. Nothing is going on over there. Literally nothing. There are the PR shots but not much else./QUOTE]

Tesla has released the PowerWall II.

The PowerWall I was 7kWh and cost $3000 or $3500 and had no inverter. The PowerWall II has 14 kWh and cost $5500, but it includes the inverter. So on the face of it it looks like a much better deal.

But the warranty seems to be much worse. While it is guaranteed to last 10 years, it is only under warranty for 37 MWh of aggregate throughput.

https://www.tesla.com/sites/default/...ty_USA_1-3.pdf

Somebody please correct me if I am wrong, but that sounds like a terrible deal!

For 37,000kWh at $5500 that means it costs $0.149 per kWh to run power through this battery. Even if you get your energy for free (a ridiculous assumption) and you don't consider the installation cost (~$1500) the price of $0.149 per kWh s higher than most people pay an electric company in the USA (except for a few expensive places like Hawaii).

So if you can't even fill it up and empty it for less than you pay an electric utility, how would it save you money in any realistic scenario?

===========================

As a backup for power outage it seems only useful to people with one bedroom apartments in Manhattan that have only (29" x 5.5") floor space weighing 264.4 lb t. At $5500 for 5kWh continuous and 7kWh surge, for only 14 kWh storage, it will probably last less than a day and possibly only a few hours.

A 22kW Generac Guardian Home Standby Generator | (model #7042) Natural Gas or LP Gas Operation weighing 476 lbs sells for $4289 ($1000 less) and it has a much bigger capacity, and can run as long as you have fuel.
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Old 04-11-2017, 06:17 PM
 
Location: Forests of Maine
30,650 posts, read 49,325,799 times
Reputation: 19075
Quote:
Originally Posted by PacoMartin View Post
...
Somebody please correct me if I am wrong, but that sounds like a terrible deal!
I do not see how it would help anyone.



btw, we did a trade-in and got a plug-in hybrid last November. We have been charging it from our solar power system. The first 20-25 miles is on electric before the hybrid system kicks in.

This winter with negative temps we have been only seeing 20 miles of electric, that was because we have been running the defrost and heat. This week without the defrost going we are seeing 25 miles [before the hybrid system takes over].

It has been great on ice too. But this week it looks like the ice on our rivers and lakes is breaking up, so we will not be driving on ice again until next Winter.
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