I'm sooooo glad we gave tax money to Solyndra, et al.

[RevDisk]

Gizmo isn't very impressive - a ball of even "cheap" optical glass like BK7 or B270 as large as his invention appears to be would be rather heavy and quite expensive. Plastic would have its own problems, so casting PMMA or some other polymer doesn't look like a very attractive alternative.

And the concentration ratio would be less than what you'd get with something like a CPC (Compound Parabolic Concentrator) array.

I was going to say, how well does this compare to an old clucker satellite dish that someone mirrored while intoxicated, and put a PV cell over the feedhorn?

[Headless Thompson Gunner]

I was going to say, how well does this compare to an old clucker satellite dish that someone mirrored while intoxicated, and put a PV cell over the feedhorn?

Well, the glass sphere at least has the advantage of not needing to be pointed at the sun all day long like a giant dish reflector would.  Spherical optics are cool that way.

I've seen some old installations that used satellite-dish-like parabolic mirrors to focus sun onto a stirling engine.  Neat stuff, but not very practical.  Too complicated, too many moving parts.

[Firethorn]

Okay, so I broke out the electric bills and crunched the number.   I use 7,112 kwh last year.  I pay .05990 per kwh (Not including all the additional charges and taxes).

My bill splits my electricity charge into a basic charge, fuel surcharge, and a regulatory charge per kWh, and I pay between 15 and 21 cents per kWh depending on time of year and how well the power company manages things, the fuel charge can swing wildly.  It's not being entirely honest if you don't include fuel charge.  Then again, you could be in the NW and getting 99% of your power from hydroelectric dams, which is the only place I remember still having power that cheap.  National average is on the order of 12 cents per kWh, so congratulations.

That still a long ROI, but somewhat more economically feasible before you add in repairs, maintenance and upgrades.  If there was someway to produce more electricity to sell, then it becomes even more feasible.

*Shrug*,  Like in most cases with new technology, you have early adopters and late adopters, even non-adopters because the economic cases vary.  Somebody already getting cheap electricity is less in need of solar than those who have expensive electricity.  See Hawaii - they're actually within a hair of busting power grid stability they have so many installs, so some of the new installs are going 'off grid'.  Of course, Hawaii is one of the two states to get most of their electricity from oil, so that explains some of the expense.

I can accept if you prefer gas stoves, but at the price you're at an electric furnace might save you money, even direct resistance, though a heat pump would save more, but again with more up-front cost.

[MechAg94]

Okay, so I broke out the electric bills and crunched the number.   I use 7,112 kwh last year.  I pay .05990 per kwh (Not including all the additional charges and taxes).  So amusing I'd generate 50Mwh, I'd have just short of 43 Mwh to sell to Comed.  Assuming that I'd get the same price to sell as I'm paying to buy, then I'd make $210 per month, a net swing of $260 per month.

Divide that $28k (net difference between regular roof and solar roof) and that becomes 108 months or 9 years.

That still a long ROI, but somewhat more economically feasible before you add in repairs, maintenance and upgrades.  If there was someway to produce more electricity to sell, then it becomes even more feasible.

And no, I will not convert my stove nor furnace to electric.  Cooking on electric is what heathens do and is an affront to G-d and all his creations.


Especially the tasty ones.  

Aren't you sort of assuming all that power generated is useable power on demand?  Likely you will need power when it isn't available and will have more power available when you don't need it.  The savings will degrade quite bit accounting for that.You might be taking advantage of peak power price versus off hour price if that is available.

[Brad Johnson]

My bill splits my electricity charge into a basic charge, fuel surcharge, and a regulatory charge per kWh, and I pay between 15 and 21 cents per kWh depending on time of year and how well the power company manages things, the fuel charge can swing wildly.  It's not being entirely honest if you don't include fuel charge.  Then again, you could be in the NW and getting 99% of your power from hydroelectric dams, which is the only place I remember still having power that cheap.  National average is on the order of 12 cents per kWh, so congratulations.

Last year we almost had a lynching when the local power company announce a rate hike... to 11 cents/KwH (including fuel surcharge).  People were going absolutely apoplectic.  No sense of just how good they have it.

Brad

[Scout26]

As stated my electricity runs $.05990 per kwh.  However, if you are to add in all the delivery fees, surcharges and taxes, it averages out to about $.14 per kwh as a total charge.    I did use my total monthly bill of ~$50 (It's actually closer to $44) to calculate the savings.   Again that's making several assumptions.  1) That I generate 50Mwh and only use 7.1Mwh and that I would never have to buy any from the grid. 2) That I could sell at the same rate I buy. 3) Continue with same appliances.  3) ComEd has flat rate pricing, however they also offer "Real-Time Pricing", which does not sound like a winner for customers.

I *might* consider changing to an electric furnace after a couple of years, if the cost savings are there (and chances are they may be) with the gas furnace as a back-up/supplement.  However, that would throw a new wrinkle in the calcs and a question of would there be enough electricity being generated during the winter/snow months to run it, and everything else, reliably.   I'm too far north (Western Suburbs of Chicago) for a heat pump to be effective in winter.

[MechAg94]

Last year we almost had a lynching when the local power company announce a rate hike... to 11 cents/KwH (including fuel surcharge).  People were going absolutely apoplectic.  No sense of just how good they have it.

Brad

The traditional monopoly power company charges more than 11 cents, but the rates for shopping around can be found a bit less at least in the Houston area.  Not sure how it all tallies up.

[Firethorn]

As stated my electricity runs $.05990 per kwh.  However, if you are to add in all the delivery fees, surcharges and taxes, it averages out to about $.14 per kwh as a total charge.    I did use my total monthly bill of ~$50 (It's actually closer to $44) to calculate the savings.   Again that's making several assumptions.  1) That I generate 50Mwh and only use 7.1Mwh and that I would never have to buy any from the grid. 2) That I could sell at the same rate I buy. 3) Continue with same appliances.  3) ComEd has flat rate pricing, however they also offer "Real-Time Pricing", which does not sound like a winner for customers.

~.14 cents a kwh makes much more sense.  Still, #2 generally means that you only install enough to cover your needs, often a little less.  Depending on location, a 'little' more will work as well, but when you enter that territory getting off the grid may actually be more economical.  It's all very complicated.

To bring it back to the op - fancy ball type solar cell is less useful(if apparently easier to make) than solar panels that can BE the roof as opposed to simply laying on top of it.  Saving the cost of shingles and such may be a minor saving, but you're on such a razor's edge anyways for whether it makes sense that it could be a make/break point.

BTW, install costs are currently the single largest remaining expense for roof mount solar power - the panels themselves are no longer the greatest cost.  So the greatest return would be figuring out ways to make the install cheaper, with cheaper inverters and such being a distant 3rd.

[Tallpine]

To make home solar work well, you need lots of expensive batteries which need to be replaced.   

I do know some folks in the neighborhood who built a solar only house from scratch.  They have a roof water collection system so they don't have to run a deep well pump.  Seems to work pretty well for them.

[Firethorn]

To make home solar work well, you need lots of expensive batteries which need to be replaced.

Why?  The only reason you'd need batteries is if you don't have a grid-tie system.  If you have that you either only have to 'suffer' that any power outages will leave you without power as well, or get a combination inverter system that only 'needs' a much smaller set of batteries to stabilize your power in case of an outage.

[Tallpine]

Why?  The only reason you'd need batteries is if you don't have a grid-tie system.  If you have that you either only have to 'suffer' that any power outages will leave you without power as well, or get a combination inverter system that only 'needs' a much smaller set of batteries to stabilize your power in case of an outage.

So you're sucking off the grid when you need it, and selling it back to them when they don't need it 

[MechAg94]

To make home solar work well, you need lots of expensive batteries which need to be replaced.   

I do know some folks in the neighborhood who built a solar only house from scratch.  They have a roof water collection system so they don't have to run a deep well pump.  Seems to work pretty well for them.

What do they do in a drought?

[Tallpine]

What do they do in a drought?

Use water very carefully 

Actually, there are water delivery vendors in this area that bring out hundreds of gallons in a truck just like bulk fuel delivery.  We know another couple that for many years did not have a well and they either bought water delivered or hauled it themselves in a several hundred gallon tank in the back of their pickup.  Of course they had a cistern and shallow pump.

The pickup tanks are readily available at TSC and Big R, etc.

We also have a rain collection system at our fire station for the kitchen/bathroom since at that location there probably isn't water at any reasonable depth.

[Scout26]

So you're sucking off the grid when you need it, and selling it back to them when they don't need it 

Not necessarily.  On a bright summer's day,  you could be using only a portion of what your produce to power your appliances, if you are willing to forgo air conditioning*.  Then you will be selling your excess at a time when they need it most.



*-as I often am, it's got to be above 100F for me to turn it on.  It only ran three times last year, and those were at night, simply to reduce the humidity.  Otherwise, I'm down in the basement where it's 68F all year round.

[Firethorn]

So you're sucking off the grid when you need it, and selling it back to them when they don't need it 

Since power demand is approximately 50% higher during the day, you have to get a pretty big group installing enough to cover their net needs in order to be producing power 'when they don't need it'.  

If Elan Musk ends up building his huge LiIon battery factory that doubles the world's LiIon battery capacity and cuts the cost almost in half, we might see some things like serious home level UPS systems that sell power to the utility when electricity is it's most expensive, while buying it to charge said batteries when power is at the cheapest.  Or if you have a huge solar install, charges the batteries when power is too cheap to sell to the utility(and the batteries aren't full), while buying only when cheap/necessary.

I'm not going to say that it isn't a potential issue, especially when solar energy starts hitting 20%, but until then it can actually help even out electricity needs.  I've lost tract of some of the conversations, so I don't remember what I've proposed here, but to keep it simple there are all sorts of tricks you can do, especially with a new build home.  For example, instead of using an HVAC system to heat/cool your house on demand, you install some sort of thermal bunker system such as a BIG tank of water. When power is cheap, you heat/cool that, then cycle the water to heat/cool your house when power is expensive.  A properly designed house will maintain a good temperature through many hours, allowing you to help even out the power company's load so it doesn't have to fire up expensive peakers.

[Tallpine]

Since power demand is approximately 50% higher during the day, you have to get a pretty big group installing enough to cover their net needs in order to be producing power 'when they don't need it'. 

Not sure that is true when everyone is trying to heat their house with electric on a minus thirty night ...   

Our co-op is a distributor only - they have to buy all their power.  Last I heard they weren't too happy with home solar, which doesn't seem like a conflict of interest since they have to buy all their power from somewhere anyway.

[RevDisk]

Since power demand is approximately 50% higher during the day, you have to get a pretty big group installing enough to cover their net needs in order to be producing power 'when they don't need it'.  

If Elan Musk ends up building his huge LiIon battery factory that doubles the world's LiIon battery capacity and cuts the cost almost in half, we might see some things like serious home level UPS systems that sell power to the utility when electricity is it's most expensive, while buying it to charge said batteries when power is at the cheapest.  Or if you have a huge solar install, charges the batteries when power is too cheap to sell to the utility(and the batteries aren't full), while buying only when cheap/necessary.

I'm not going to say that it isn't a potential issue, especially when solar energy starts hitting 20%, but until then it can actually help even out electricity needs.  I've lost tract of some of the conversations, so I don't remember what I've proposed here, but to keep it simple there are all sorts of tricks you can do, especially with a new build home.  For example, instead of using an HVAC system to heat/cool your house on demand, you install some sort of thermal bunker system such as a BIG tank of water. When power is cheap, you heat/cool that, then cycle the water to heat/cool your house when power is expensive.  A properly designed house will maintain a good temperature through many hours, allowing you to help even out the power company's load so it doesn't have to fire up expensive peakers.

Ehhh, nyet.

One of my responsibilities is running the power meter hardware for a manufacturing plant. We use up a lot of power. Our fans alone can suck up several hundred kilowatts. We are tied into a system that asks us to reduce power, which they will pay us for every watt we don't consume. You're generally correct that with neutral weather, power load is higher during the day. Heat or cold distorts that. By a lot. I've seen plenty of warm weather circumstances where power "dips" (or rather doesn't increase beyond the average baseline) and shoots up when people get home to fire up A/C. And I've REALLY seen power demand spike in the evening from a cold snap. While these may seem like niche or edge cases, it happens enough that a grid has to take such behavior into consideration.

Solar panels do make the grid more wonky. They're great for manufacturing plants, as they tend to make power when the big machines are in use. For grid-tied systems, they can make things really interesting. Solar can spike or cease very abruptly, depending on weather. It sucks for planning things out. More solar means more gas turbine peakers.

I'd love me some dirt cheap household battery banks. I doubt it will happen as energy storage is hugely expensive and wasteful. I should know, unfortunately, I'm trying to build one.

I love PV cells and have all kinds of PV cells around the house. But I'm far from blind from their limitations. Without subsidies, tax credits, etc they would be hugely more expensive (ie closer to their real cost). They're awesome for niche circumstances. But it doesn't hide their many many negative points.

[Firethorn]

For both of you - I was speaking of NET AVERAGE. 

Also Rev - keep in mind that I specified 20% as a maximum, and proceeded into various ways to massage power usage to help alleviate many of the peaks.