Rooftop Solar Generation: Ready for Prime Time?

California’s ambitious goal of obtaining a third of its electricity from renewable sources by 2020 has spawned a green energy boom with thousands of megawatts of solar, wind, and biomass power plants planned for ... the middle of nowhere.

And therein lies the elephant in the green room: transmission. Connecting solar farms and geothermal plants in the Mojave Desert and wind farms in the Tehachapis to coastal metropolises means building a massive new transmission system. The cost for 13 major new power lines would top $15.7 billion, according to a report released in August by the state’s Renewable Energy Transmission Initiative.

The initiative, called RETI, is an attempt to build a statewide green grid in an environmentally sensitive way that will avoid the years-long legal battles that have short-circuited past transmission projects.

But the rapidly evolving solar photovoltaic market may moot the need for some of those expensive and contentious transmission lines, requiring transmission planners to rethink their long-term plans, according to Black & Veatch, the giant consulting and engineering firm that does economic analysis for RETI.

In short, solar panel prices have plummeted so much as to make viable the prospect of generating gigawatts of electricity from rooftops and photovoltaic farms built near cities.

“This has pretty significant implications in terms of transmission planning,” Ryan Pletka, Black & Veatch’s renewable energy project manager, told me last week. “What we thought would happen in a five-year time frame has happened in one year.”

That’s prompted Pletka to radically revise the potential for so-called distributed generation—solar systems that can plug into the existing grid without the construction of new transmission lines—to contribute to California’s need for 60,000 gigawatt hours of renewable electricity by 2020.

When Black & Veatch did its initial analysis last year, it predicted that photovoltaic solar could contribute 2,000 gigawatt hours, given the high cost of conventional solar modules and the fact that a next-generation technology, thin-film solar, had yet to make a big commercial breakthrough.

Pletka’s new number is a bit of a shocker: Distributed generation could potentially provide up to 40,000 gigawatt hours of electricity, or two-thirds of projected demand.

“Certainly some of the new transmission lines will be needed but not as many as before,” he says.

That analysis also calls into question the need for as many large-scale solar power plants. Currently there are about 35 Big Solar projects planned for California that would generate more than 12,000 megawatts of electricity.

A game-changer has been the rapid rise of thin-film solar. Thin-film solar modules are essentially printed on glass or other materials. Although such solar panels are less efficient at converting sunlight into electricity than traditional crystalline modules—which are made from silicon wafers—they can be produced more cheaply.

In the past year, utilities like Southern California Edison have signed deals with First Solar, the thin-film powerhouse, to buy electricity from four massive megawatt thin-film solar farms. And in September, China inked an agreement with the Tempe, Ariz., company to build a 2,000-megawatt power plant, the world’s largest.

The next day, Nanosolar, a Silicon Valley startup, announced it had secured $4.1 billion in orders for its thin-film modules, which it claims will be even more efficient and cost less to produce than those made by First Solar (FSLR).

Meanwhile, California’s two biggest utilities, PG&E and Southern California Edison, this year each unveiled initiatives to collectively install 1,000 megawatts of distributed solar generation. SoCal Edison will put solar arrays on warehouse roofs throughout the Southland - First Solar snagged the first big contracts - while PG&E is focusing on ground-mounted solar systems near its existing substations.

So what’s behind this rooftop revolution in solar?

Partly it’s due to a glut in the solar panel market. The global economy collapsed last year just as solar module makers ramped up production. But it’s also a result of technological innovation and economies of scale that have made thin-film solar, for instance, competitive. Strides have also been made in cutting installation costs, which typically account for half the price of photovoltaic systems. And finally, a giant key in gaining traction towards critical mass in rooftop solar systems is financing.

California-based SolarCity has emerged as an industry leader in providing financing that makes fiscal sense for homeowners and commercial building owners through their SolarLease program.

The solar market, of course, is heavily dependent on government incentives—in the United States and overseas—and thus vulnerable to disruption. But the trajectory remains one of falling prices and thus Black & Veatch’s projections pose a conundrum for transmission planners.

Given that transmission projects can take a decade to complete, power bureaucrats make their plans based on 10-year projections of energy costs according to Pletka. That wasn’t much of a problem when planning transmission for, say, a grid supplied by natural gas-fired power plants as the technology or the market was not likely to change radically.

Not so for solar, where technological advances and fast-changing market conditions are shaking long-held views that photovoltaic power, or PV, is not ready for prime time.

“I’ve worked in renewables since the ‘90s and I myself had written off solar PV for years and years and years,” Pletka says. “That’s a firmly rooted mindset among everyone who works from a traditional utility planning perspective.”

“We present this new information on photovoltaics to people and it’s still not sinking in,” he adds. “It would cause a major shift in how we plan.”

While fewer massive transmission projects would be needed if California generates gigawatts of electricity from rooftops, the distribution network will need to be upgraded and a smart grid created to manage tens of thousands of pint-sized solar power plants.

Cities, Pletka notes, could become generators of electricity rather than consumers of power.

“It brings up questions people haven’t had to talk about before,” says Pletka.

Comments

[Davewmart]

The area where I would like to see this introduced is in small towns first.
A lot of the talk of renewables focusses on doing things the hard way - providing all the base load power etc.
What makes sense to me is to play to each technology's strengths.
So you build the solar where the main problem is the heat of summer, not the cold of winter, and where land is cheap and transmission of power would be difficult.
If you build on big warehouse roofs or on flat ground it is much more economic than putting the panels on individual houses.
As well as not having to transport the power and saving on the transmission lines, you don't have to step the power up and down.
So if you are not going to go to the espense of storing the power either, how do you power the littel town when the sun is not shining?
Again, the geographic location is important. In the countryside there are a lot of locations which have good wind resources.
Check out Texas, where wind blows strongly but is weak in the height of the summer, just when solar kicks in.
So what about at night when it is not windy?
The resource I would favour which attracts surprisingly little attention in the US is biogas, which is way more efficient than ethanol production, and could also be used to power agricultural machinery.
Would this system work?
Well, it has already been demonstrated, in Germany:
commentisfree.guardian...

So I would favour doing things the easiest way, and introducing these technologies where circumstances are most favourable and costs likely to be lowest.
I would suggest that is in small towns, with solar installations of 2-10MW at the edge of town, and integrating wind resources and biogas from agriculture a pig farm, for instance, would be ideal.
In that way you could get a major contribution to energy use without ever pushing any of the technologies or attempting to run before you can walk.

2009 Nov 29 12:36 PM

[rooferguy]

Good article, but here are a few clarifying points.

The biggest recent change is NOT the rapid rise of thin film modules (which have always been cheap), but the tremendous decline in price for crystalline modules — which are also much more efficient and suitable for rooftops.

With cheap crystalline modules you can put solar on every sunny rooftop. As Troy Jensen and Black & Veatch consultants accurately point out, Distributed Generation solar is cheaper than central solar since you don’t need all that expensive (and time consuming) transmission and distribution infrastructure.

But what’s more interesting is that the COSTS for rooftop solar are likely to be much lower than what I call “close-in” solar — 1MW or so plants in public areas around towns. Homeowner’s will be able to install their own rooftop systems (using plug and play AC panels and local electrical or HVAC contractors) for MUCH LESS MONEY than a town or utility will spend on a “public” system. Construction costs for public or utility works are always much higher than for residential or commercial projects.

Commercial and residential owners will do their own math and decide that it’s much cheaper to install their own rooftop generating system than to buy power from their utility.

Inexpensive rooftop solar is a disruptive technology for power generation — just like the PC was for the computer industry.

2009 Nov 29 02:34 PM

[Jigar Shah]

Great article. As the Founder of SunEdison, I have been paying $1MM a year nationwide (regulatory affairs budget) to remove the barriers to this vision. We are clearly farther along in California than in other states.

Some thoughts:
1) Net Metering is a big problem. We actually don't need 2-way electricity movement -- what we need is a guarantee that utilities can't change tariffs for customers that install solar and thereby change the economics of their investment
2) We have to deal with a "run on the bank". Today the utilities in PG&E and SCE will go out of business over the next 10 years until we move them to becoming a platform for self generation and they get paid to provide this platform. Today every person that switches to solar, is one more person not paying for the fixed costs of the platform which means that electricity gets more expensive for those that are left on the grid, which means solar gets more cost effective and so on. This will eventually leave the utilities in an awful financial position
3) We need to streamline self-generation. Many communities make it such a pain in a** to switch to solar that some good rooftops go un-harvested. We have to figure out a common sense way of harmonizing these rules in a way that does not unfairly burden anyone but still promotes self-generation
4) This trend really is being led by low cost crystalline, thin-film has very little to do with self-generation -- even at prices below $1/Wdc. Crystalline systems above 280kWdc can be installed for $2.50/Wdc by 2011. Once this occurs solar PV will not have to get any cheaper. In fact solar PV will have to get more expensive as sales and marketing costs increase
5) The tax laws that were passed in the 80's around passive/active loss rules have to changed to allow "doctors/lawyers" to invest in solar PV. Starting in 2010 project finance will be the #1 gap to growth in the Solar PV markets and the banks/insurance companies can't keep up.

Transmission delays will be the #1 reason self-generation wins. It will be led by solar. It all comes down to "respect" for the solution from policy makers.

2009 Nov 29 02:45 PM

[dondon]

The public utilities don't want you to produce power from your rooftop. They cannot profit off of you if you don't buy power from them. That is why the original idea of each home as its own power source has somehow shifted to building big solar farms in deserts and selling the electricity to the consumers.

2009 Nov 30 01:19 AM

[vpratt51]

Good article and outstanding responses. Thanks to all of you.

Regarding competing technologies, I do have to side with the more efficient ones, even with the higher cost, for residential. When the energy production per sq. ft. is at it's highest, it makes the rest of the installation more cost effective. Once it catches on, I find it hard to believe that the same guy that HAD to have a Ram or a Hummer will now consider LESS power as an option.

2009 Nov 30 01:46 AM

[Troy Jensen]

dondon, you are not far off. Utilities are starting to push-back on rooftop solar energy generation, because of a very simple fact - they aren't making as much revenue-per-household right now. But rooftop solar generation is in its infancy - as it advances beyond a nascent component of the Alternative Energy mix utilities have to subscribe to, and when rooftop systems reach critical mass, the low cost-per-kWh the utilities have to pay for the feed-in energy that becomes more substantial as more rooftop systems join the grid make it a net-positive for both the consumer and the utility companies. With the proper financing and system performance, the residential or commercial building end-user has a cash-flow positive investment from the date of energization. The utilities will receive more and more electricity via feed-in solar energy generation as critical mass of rooftop systems is obtained, giving the utilities (via the Smart Grid, a CRITICAL factor in making Alternative Energy successful) access to energy during peak daytime hours in hot Southwest markets (AC's cranking), and the ability as our national grid expands, becomes intelligent and interconnected, to trade that energy to other geographic areas in need of the energy at a substantial profit. The opportunities are absolutely fantastic - and indeed, with an efficient rooftop system and the right financing (it MUST be ROI-positive from day one for the residential user, financing is a huge key to this market - SolarCity is a firm I absolutely think has the drop on this with their SolarLease program), it will evolve as a net-net positive for both homeowners and the utilities. One final note - remember, Cap and Trade isn't dead, and even putting that aside, the Green movement is here to stay, like it or not - and states are setting their own aggressive Alternative Energy goals. Utilities are under pressure to embrace residential solar generation systems as a quicker, more efficient way to generate solar energy short-term - as opposed to financing those giant solar fields, the homeowner takes on the fiscal burden.

Interesting times, and evolving fast!


On Nov 30 01:19 AM dondon wrote:

> The public utilities don't want you to produce power from your rooftop.
> They cannot profit off of you if you don't buy power from them.
> That is why the original idea of each home as its own power source
> has somehow shifted to building big solar farms in deserts and selling
> the electricity to the consumers.

2009 Nov 30 02:43 AM

[Troy Jensen]

Excellent points! Very interested in your thoughts on Net Metering - we should have an exchange of thoughts and ideas offline.


On Nov 29 02:45 PM Jigar Shah wrote:

> Great article. As the Founder of SunEdison, I have been paying $1MM
> a year nationwide (regulatory affairs budget) to remove the barriers
> to this vision. We are clearly farther along in California than
> in other states.
>
> Some thoughts:
> 1) Net Metering is a big problem. We actually don't need 2-way electricity
> movement -- what we need is a guarantee that utilities can't change
> tariffs for customers that install solar and thereby change the economics
> of their investment
> 2) We have to deal with a "run on the bank". Today the utilities
> in PG&E and SCE will go out of business over the next 10 years
> until we move them to becoming a platform for self generation and
> they get paid to provide this platform. Today every person that
> switches to solar, is one more person not paying for the fixed costs
> of the platform which means that electricity gets more expensive
> for those that are left on the grid, which means solar gets more
> cost effective and so on. This will eventually leave the utilities
> in an awful financial position
> 3) We need to streamline self-generation. Many communities make
> it such a pain in a** to switch to solar that some good rooftops
> go un-harvested. We have to figure out a common sense way of harmonizing
> these rules in a way that does not unfairly burden anyone but still
> promotes self-generation
> 4) This trend really is being led by low cost crystalline, thin-film
> has very little to do with self-generation -- even at prices below
> $1/Wdc. Crystalline systems above 280kWdc can be installed for $2.50/Wdc
> by 2011. Once this occurs solar PV will not have to get any cheaper.
> In fact solar PV will have to get more expensive as sales and marketing
> costs increase
> 5) The tax laws that were passed in the 80's around passive/active
> loss rules have to changed to allow "doctors/lawyers" to invest in
> solar PV. Starting in 2010 project finance will be the #1 gap to
> growth in the Solar PV markets and the banks/insurance companies
> can't keep up.
>
> Transmission delays will be the #1 reason self-generation wins.
> It will be led by solar. It all comes down to "respect" for the
> solution from policy makers.

2009 Nov 30 02:46 AM

[mbkelly75]

Thanks for the information update. I have been interested in Solar and Wind since the Mother Earth News did their research and reporting on the actual working installations of individuals in the late 60's or very early 70's. I agree that the Smart Grid is the key. Here in the Midwest - Utility companies are already getting a start on the project by showing homeowners how it can help them even now by installing a new home circuit breaker to replace the older ones already on the home to bring power into the home in a Smart Grid compatible way and lower power costs at the same time by several hundred dollars a year.
For several years now, power companies in rural areas have had alternative energy projects that have saved them from having to buy new power plants and allowed them to hire new workers with the money saved by such projects. Odd as it might sound at first, biogas from large Dairy farms have actually done this in a couple of areas in states here in the Midwest. Around the world, it has been used much more often than here in the US and has been shown to be practical for large farms/ranches as well as the power companies that are involved with them. Thank you for the links for more information - well done and please keep up the good work for both the writer AND the comments on this story.

2009 Nov 30 08:23 AM

[Douglas Hvistendahl]

<i>The utilities will receive more and more electricity via feed-in solar energy generation as critical mass of rooftop systems is obtained</i>

Two points: 1) Look at Conserval's Solarwall/PVT design. Wherever the thermal component can be used also, efficiency jumps to over 70%!!! Personally I'm looking to "Annualized Geo Solar" heat storage to allow me to store summer heat for winter heating loads. Modifying the house is taking work, but much of it is on the DIY level, which keeps costs down.

2) If in net metering, the cost for connecting to the grid is broken off from the electricity cost, utilities are likely to be much more interested. Also, in storage, a solution that allowed safe and economical backup storage in a building to additionally provide utility arbitrage storage, it could be VERY interesting to utilities. If I could get something in my house to keep my electricity (thus furnace, computer, some lighting, etc.) on when an ice storm or tornado breaks the local grid, I'd be interested!!! And if in addition, this could be paid for in the long run by a return from the utility at times when the grid is working! :-)))))

There are going to be changes. As a small town resident, I'm very interested in the possibilities. The best investment possibilities may be more in making use of these things instead of in stocks. I make it a point to compare ROI from stocks to "reality" investments when choosing where to invest.

2009 Nov 30 08:46 AM

[Rick Krementz]

Well, a few more clarifying points...

You can't put solar on every roof. Many do not face south, have trees or other structures causing shade, have gables, or projections, etc. One study I did had only 10% of the roofs in a neighborhood suitable for solar.

No solar technology is even close to "building breakeven". In other words, the energy that can be produced by a roof almost never exceeds the energy consumed by the occupied structure. Almost every structure in the Southland needs air conditioning and there is no way a roof-top solar system can meet that demand.

The real cost of solar rooftops has little to do with the panels, despite all the hype. US labor costs and balance of system (wiring, controls, batteries) outweigh the panel costs. Labor costs are not going down.

For off-grid and other specialized applications rooftop solar makes sense - my house is 100% solar (and off-grid). For mainstream use, it is just an uneconomic fantasy supported by massive subsidies.


On Nov 29 02:34 PM rooferguy wrote:

> Good article, but here are a few clarifying points.
>
> The biggest recent change is NOT the rapid rise of thin film modules
> (which have always been cheap), but the tremendous decline in price
> for crystalline modules — which are also much more efficient and
> suitable for rooftops.
>
> With cheap crystalline modules you can put solar on every sunny rooftop.
> As Troy Jensen and Black &amp; Veatch consultants accurately point
> out, Distributed Generation solar is cheaper than central solar since
> you don’t need all that expensive (and time consuming) transmission
> and distribution infrastructure.
>
> But what’s more interesting is that the COSTS for rooftop solar are
> likely to be much lower than what I call “close-in” solar — 1MW or
> so plants in public areas around towns. Homeowner’s will be able
> to install their own rooftop systems (using plug and play AC panels
> and local electrical or HVAC contractors) for MUCH LESS MONEY than
> a town or utility will spend on a “public” system. Construction
> costs for public or utility works are always much higher than for
> residential or commercial projects.
>
> Commercial and residential owners will do their own math and decide
> that it’s much cheaper to install their own rooftop generating system
> than to buy power from their utility.
>
> Inexpensive rooftop solar is a disruptive technology for power generation
> — just like the PC was for the computer industry.

2009 Nov 30 10:02 AM

[Jigar Shah]

Rick,

I appreciate your support for solar with your actions, many others do not do at least this (I have solar PV as well). Your comments on rooftop spots are simply wrong. Navigant has done studies across the US. In Phoenix alone they can produce 200% of the electricity they need off rootops (because they have low-rise buildings and large parking lots). On average throughout the country the numbers are more like 30% just using rooftops, then another 30% using parking lots and brownfields, and then the last 30% through central station technologies. never mind that all we have to reach is 5% by 2020 and then 15% by 2030 to meet the goal of meeting 100% of incremental electricity (after aggressive plant retirements) from zero emission electricity sources.

Also, with advanced financing methods for energy efficiency I think you will see electricity growth in the US reduce from 1.3% per annum to almost zero % per year by 2015 and thereafter.

Jan 03 02:31 PM

[La Marque]

Everything you say makes sense...but: multi-unit residential and commercial real estate are going to need the central grid. It may work as you say; but, then again, I don't see the 'smart grid' as really smart, just expensive.


On Nov 30 02:43 AM Troy Jensen wrote:

> dondon, you are not far off. Utilities are starting to push-back
> on rooftop solar energy generation, because of a very simple fact
> - they aren't making as much revenue-per-household right now. But
> rooftop solar generation is in its infancy - as it advances beyond
> a nascent component of the Alternative Energy mix utilities have
> to subscribe to, and when rooftop systems reach critical mass, the
> low cost-per-kWh the utilities have to pay for the feed-in energy
> that becomes more substantial as more rooftop systems join the grid
> make it a net-positive for both the consumer and the utility companies.
> With the proper financing and system performance, the residential
> or commercial building end-user has a cash-flow positive investment
> from the date of energization. The utilities will receive more and
> more electricity via feed-in solar energy generation as critical
> mass of rooftop systems is obtained, giving the utilities (via the
> Smart Grid, a CRITICAL factor in making Alternative Energy successful)
> access to energy during peak daytime hours in hot Southwest markets
> (AC's cranking), and the ability as our national grid expands, becomes
> intelligent and interconnected, to trade that energy to other geographic
> areas in need of the energy at a substantial profit. The opportunities
> are absolutely fantastic - and indeed, with an efficient rooftop
> system and the right financing (it MUST be ROI-positive from day
> one for the residential user, financing is a huge key to this market
> - SolarCity is a firm I absolutely think has the drop on this with
> their SolarLease program), it will evolve as a net-net positive for
> both homeowners and the utilities. One final note - remember, Cap
> and Trade isn't dead, and even putting that aside, the Green movement
> is here to stay, like it or not - and states are setting their own
> aggressive Alternative Energy goals. Utilities are under pressure
> to embrace residential solar generation systems as a quicker, more
> efficient way to generate solar energy short-term - as opposed to
> financing those giant solar fields, the homeowner takes on the fiscal
> burden.
>
> Interesting times, and evolving fast!

2009 Nov 30 10:29 AM

[mbkelly75]

Thanks for the Conserval idea. A very neat website that is worth the time to check out. I watched a show over the weekend that spoke of the extra expense that drying crops here in the Midwest is costing because of the wet weather that we have had here. That expense is so high (and causing a propane shortage) that it is changing a profit to a loss for many grain farms for the entire year. This company has products that could solve that problem. That could be very important in the future.


On Nov 30 08:46 AM Douglas Hvistendahl wrote:

> <i>The utilities will receive more and more electricity via feed-in
> solar energy generation as critical mass of rooftop systems is obtained
> </i>
>
> Two points: 1) Look at Conserval's Solarwall/PVT design. Wherever
> the thermal component can be used also, efficiency jumps to over
> 70%!!! Personally I'm looking to "Annualized Geo Solar" heat storage
> to allow me to store summer heat for winter heating loads. Modifying
> the house is taking work, but much of it is on the DIY level, which
> keeps costs down.
>
> 2) If in net metering, the cost for connecting to the grid is broken
> off from the electricity cost, utilities are likely to be much more
> interested. Also, in storage, a solution that allowed safe and economical
> backup storage in a building to additionally provide utility arbitrage
> storage, it could be VERY interesting to utilities. If I could get
> something in my house to keep my electricity (thus furnace, computer,
> some lighting, etc.) on when an ice storm or tornado breaks the local
> grid, I'd be interested!!! And if in addition, this could be paid
> for in the long run by a return from the utility at times when the
> grid is working! :-)))))
>
> There are going to be changes. As a small town resident, I'm very
> interested in the possibilities. The best investment possibilities
> may be more in making use of these things instead of in stocks. I
> make it a point to compare ROI from stocks to "reality" investments
> when choosing where to invest.

2009 Nov 30 10:41 AM

[biomedlives]

I would be interested in the basis for your assertion about "building breakeven." I have room for at least 24 Suntech panels on my southeast-facing roof, but I could put in only 22 on account of the ridiculous New Jersey rule against installing a residential system that is likely to generate more than 100% of the home's annual electricity use.


On Nov 30 10:02 AM Rick Krementz wrote:

> Well, a few more clarifying points...
>
> You can't put solar on every roof. Many do not face south, have trees
> or other structures causing shade, have gables, or projections, etc.
> One study I did had only 10% of the roofs in a neighborhood suitable
> for solar.
>
> No solar technology is even close to "building breakeven". In other
> words, the energy that can be produced by a roof almost never exceeds
> the energy consumed by the occupied structure. Almost every structure
> in the Southland needs air conditioning and there is no way a roof-top
> solar system can meet that demand.
>
> The real cost of solar rooftops has little to do with the panels,
> despite all the hype. US labor costs and balance of system (wiring,
> controls, batteries) outweigh the panel costs. Labor costs are not
> going down.
>
> For off-grid and other specialized applications rooftop solar makes
> sense - my house is 100% solar (and off-grid). For mainstream use,
> it is just an uneconomic fantasy supported by massive subsidies.
>

2009 Nov 30 11:20 AM

[DLSCustomhomes]

All very interesting and compelling views on where our next generation is heading for Electricity Production, Cost, and Sustainability. Has anyone done any research on the Fuel Cell technology being offered in our market here in So. California? I am a builder of large custom homes and my clients all want renewable power and self reliance.

2009 Nov 30 11:22 AM

[a. palmer jr.]

I, for one don't see anything wrong with the power companies making less money from homeowners. Every industry has to evolve, and some industries are not even needed anymore. How many blacksmith shops are around anymore? Some evolution comes with pain, we all suffer from it. Our jobs have become obsolete because of robotics, etc. I would love to have a solar panel on my large south facing roof but don't know of an inexpensive way to get one. Most of us would love to lower or do away with our electric bill especially if we ever intend to purchase an electric powered car.

2009 Nov 30 12:43 PM

[Will Deliver]

My reply to Rick Krementz; A rooftop PV solar system doesn't need to supply 100% of the power to run the summer air conditioning demand to be cost effective. That same PV solar system will reduce demand, which multiplied by hundreds or thousands of systems will save a huge amount of 'peak' electricity. Thus reducing the need to add utility costs & transmission/distribution upgrades.
Also, the PV solar system generates power all year long, thereby reducing the annual costs to the owner.
I agree with Douglas Hvistendahl... In addition to investing in stocks of renewable energy companies, we should all be buying our own piece of the energy mix. Be it in the area of energy efficiency, storage, or generation. These great companies that are taking a risk to develop the products can not be profitable unless they sell their products. They sell, we buy. That's what makes an economy!

2009 Nov 30 01:11 PM

[Jigar Shah]

Buying local solar project as low risk investments vs. CDs in the bank are critical to moving solar and other renewables forward.

Jan 03 02:25 PM

[friar tuck]

all postings were very interesting and informative. the ROI can be calculated as it is based on simple mathematical cost to savings ratios. there is one consideration that has yet to be mentioned and that is the amount of equity a PV roofed house would gather in a resale or a built new with a PV ROOF. i think having a PV roof would be very attractive to a potential buyer. any thoughts on that aspect?

2009 Nov 30 01:11 PM

[Fred W]

Costs are very dependent on the type of roof, its orientation, and the surrounding site conditions. On average, a 1 MW rooftop system will be more expensive that 1 MW ground mount. However, there are some cases where a rooftop system is significantly cheaper (the ideal solar roof: strong, big, low, accessible and free of shade and obstructions.


On Nov 29 02:34 PM rooferguy wrote:

> Good article, but here are a few clarifying points.
>
> The biggest recent change is NOT the rapid rise of thin film modules
> (which have always been cheap), but the tremendous decline in price
> for crystalline modules — which are also much more efficient and
> suitable for rooftops.
>
> With cheap crystalline modules you can put solar on every sunny rooftop.
> As Troy Jensen and Black &amp; Veatch consultants accurately point
> out, Distributed Generation solar is cheaper than central solar since
> you don’t need all that expensive (and time consuming) transmission
> and distribution infrastructure.
>
> But what’s more interesting is that the COSTS for rooftop solar are
> likely to be much lower than what I call “close-in” solar — 1MW or
> so plants in public areas around towns. Homeowner’s will be able
> to install their own rooftop systems (using plug and play AC panels
> and local electrical or HVAC contractors) for MUCH LESS MONEY than
> a town or utility will spend on a “public” system. Construction
> costs for public or utility works are always much higher than for
> residential or commercial projects.
>
> Commercial and residential owners will do their own math and decide
> that it’s much cheaper to install their own rooftop generating system
> than to buy power from their utility.
>
> Inexpensive rooftop solar is a disruptive technology for power generation
> — just like the PC was for the computer industry.

2009 Nov 30 01:25 PM