Maybe fifty percent cheaper.

I'd seriously consider a rooftop system here in south Florida if that happened. Those kinds of prices would seriously reduce payback time.

Way cool. Can't wait to get my hands on some of them.

Way cool. Can't wait to get my hands on some of them.

Eh, then they tell us that th solar cells have 10% efficiency.

Cheaper production does not imply much cheaper installation until they stop building manufacturing plants for other technologies. Before that, it's a sellers' market and demand eats up all available supply below the average cost of the expensive technology. That is, almost all the benefit accrues to the seller until they can flood the market sufficient to drive competitors to stop growing, and ultimately, out of business.

I'd imagine those kind of miniconcentrator cells had temperature problems. They could also be more direction sensitive.

Low efficiency per area is usually not a problem if the panels are still cheaper per watt. You just put a bigger area of them.

with reel-to-reel thin film cell production, they are promising sub dollar per watt next year ( cell price, not installed system )
Miasole, HelioVolt, First Solar and a few others are reportedly ramping up production

I expect most of you are already aware of this, but a great site for generating maps of available solar energy (in the US) is U.S. Solar Radiation Resource Maps.

Sorry, I got the impression that the cost was per unit area not per kW.

You're going to see solar power at a dollar a watt or less (including installation and without government subsidy) commercially available within the next six to nine months. Unfortunately I can't disclose more information at this time.

One of the options I am looking at is solar thermal -- in Rosendale, Wisconsin (famous for the police officer who will give you a ticket for doing 1 MPH over the 30 MPH limit, and no speeding up until you are past the 55 MPH sign), a homeowner has a glass wall covering the south side of the house along with fans to circulate the warm air when the sun is shining.

This solar heat system is different than passive solar which has the problem of the amount of heat you lose when the sun isn't shining. This has the collector on the outside of the house wall insulation, and it circulates air through the collector with fans only when the sun is shining, either with a thermostatic or photocell control. As far as storage, one could size the system as a supplement to your primary heat so you wouldn't need to store heat apart from the thermal capacity of the house.

I figured I could do OK to build one of these systems for 30 dollars per square foot. This is a thermal system where there is no silicon, unless you want to use a small PV panel to run the fans in response to sunshine. I would cover 300 square feet of the south wall of my house if I could do it for 10K.

If you figure 150 peak watts for PV per square meter, 15 peak watts per square foot of PV, I am talking a solar thermal system priced the equivalent of 2 dollars per "peak watt." Now I know current PV systems are more than 2 dollars per peak watt installed, but if you could get 2 dollar per peak watt PV, that is one of those "tipping points" people are talking about.

My point is that if you could build a solar thermal collector for 30 dollars/sq ft, the area equivalent of 2 dollars per peak watt PV, solar thermal starts to look really attractive. But that is the rub. Do you really think a person could get someone to install 300 sq feet of glass panelling over an insulated wall for about 10 K? Given the cost of windows, forget that, given the cost of insulated window coverings for passive solar as a comparison, I am thinking that cost/price is optimistic.

Installing any kind of major structure on a house that doesn't harm the house and stands up to the elements is a major cost, and for the solar thermal application I am thinking about, there is only glass, black paint, maybe an added layer of wall insulation and some fans -- I am not talking about a large scale semiconductor electronic device (the PV collector). Anything you do to a house costs money. I suppose if I could figure out how to do this as a DIY project, it might pay, but it may be hard to afford to pay someone to do this.

While the price of solar electric is being driven down to 30 cents/KW, comprable with oil, production limitations will keep the street-price high and availability low for the next 5-7 years at least. There are a numbef of commercial solar plants being built around the world and they've spoken for most if not all the production of the new generation of solar electric for at least that length of time.

I can see it now: The courts will soon be getting cases on new construction and add-ons blocking someone's constitutional right to sunlight.

I even wonder if it will escalate to the point where someone sues to remove existing construction that blocks their sunlight.

Pop Sci has an article that talks about making solar panels for one tenth the cost. Efficiency about as good as today. 30 cents/watt.

By the way, did anyone here buy First Solar (FSLR) when they had their IPO ?
There will be other solar companies following. There are lots of different technologies tested CIGS cells, anything that doesnt use silicon, new thin-film manufacturing, concentrators etc.
Is suppose Ed was mentioning something like this.

There's a sense in which residential PV customers are often subsidized by the utility, even if not explicitly. The utility provides free backup power for when the sun is down or occluded, but this backup is not being fully paid for (since the customer is not buying as much power from the utility at other times). If there are few PV users, the utility can eat this cost, but with growth eventually the utility rates would have to change to fully charge for the service being provided, through some combination of time-of-day rates and capacity (not energy) related charges.

BTW, cheaper PV modules are only part of the solution. Balance of system costs are also important. This includes cost of the mounting hardware, installation, and power conversion/regulation equipment. As the cells/modules become less expensive these all become comparatively more important. IIRC, below about 15% efficiency the first two costs are high enough to render PV uneconomical, even if the modules themselves were free.

I've never thought the installation costs to be that large, especially for residential solar. The main costs are the pannels temselves, the inverter, power monitoring equipment and batteries. Reducing the pannel cost/watt is a key perameter though.

I have a friend who has what I like to call a solar system without the solar panels. He did the cost/benifit analysis, and determined that he was better off to build a system without any panels. He charges the batteries at night, and runs the house on stored power during the day.
The cost ratio of peak to off peak electricity here (AZ)is arround 3:1, depending on who your provider is.

The key metric is the system ROI. Residential solar will take off once the ROI is such that it will pay for itself in 4-5 years. Currently it takes around 20 years for a system to pay for itself. Within the next 5-10 years though, we ought to be able to nickel and dime the cost down by a factor of 4.

> You just put a bigger area of them.

Residential solar in suburban and urban regions typically has to work within a fairly small footprint. For some people, it's the size of the roof. For most, it's the size of the roof with southern exposure.

There's a sense in which residential PV customers are often subsidized by the utility, even if not explicitly. The utility provides free backup power for when the sun is down or occluded, but this backup is not being fully paid for (since the customer is not buying as much power from the utility at other times). If there are few PV users, the utility can eat this cost, but with growth eventually the utility rates would have to change to fully charge for the service being provided, through some combination of time-of-day rates and capacity (not energy) related charges.

I don't buy this at all. Solar is very cost beneficial to utilities in that they don't have to run as much peak power generation plants to provide that power during the middle of the day. Also, when the sun is not shining typically power demand goes down so that is a wash.

BTW, cheaper PV modules are only part of the solution. Balance of system costs are also important. This includes cost of the mounting hardware, installation, and power conversion/regulation equipment. As the cells/modules become less expensive these all become comparatively more important. IIRC, below about 15% efficiency the first two costs are high enough to render PV uneconomical, even if the modules themselves were free.

Nope. If modules were free, installation costs will be around $4 per watt which is half of today's costs which would tip the balance, especially for large commercial power users. Ten year PPA's would then be no brainers, even with no subsidies.

If the goal is for electricity generation capacity for solar to make a greener world and not a kind of knee-jerk personal isolationism to avoid the bad karma of commercial electricity, then one can do the solar without the battery. Further, if the roof is the solar thermal or the roof is the photovoltaics, then new house construction with a solar roof installation will be much cheaper than retrofits net of the savings on the regular roof. And the support structure is integrated with the roof itself making the joint design much more economical than a retrofit. Together, getting materials and installation down to a fraction of the refit/regular roof construction costs, the cost-per-watt tipping point for putting solar on new houses during construction is quite a bit higher than for retrofits.

Paul

Your 300 square feet of heating panels would
seem to be well under $10k to me. You are
talking about an area of less than 10 sheets
of plywood.

For a quick and dirty homebuilt test, you
might try a roll of plastic insted of glass.
10 sheets of cheap plywood, 60 8' 2"x4"s,
a roll of visqueen, and a box of nails should
stay a bit under $500.00.

One of my favorite alternate energy tales
is the windmill air conditioning/heating
scheme. Supposedly the compressor for the ac
is just as happy at 10 rpm as it is at 1,000.
Cut to Rube Golberg.