Lots of sun and roofs: Why can't we go solar?

as mentioned in the new newsweek.

http://www.nabble.com/A123-to-sell-plug-in-packs-t4802445s25542.html

As a retired electrician and a certified solar installer and consultant, I can give you the answer. There is not the political will to shift the nations priorities from big oil and coal< aka, those that donate> to solar and other renewables. Renewables on everyone's property is the nightmare of all the big money people, as there is no way for them to get their hands on the money if that happened. The cost of this insane war, if applied to individuals for renewable pv or thermal would put exxon out of business.

from the 70s to assist with heat and hot water. If any area is prime for rooftop solar, this is it. We're high desert and our annual rainfall is a whopping 11 inches.

I'm just waiting for that thin film solar to become widely available and you better believe my flat roof is going to be covered in it.

There are already solar and wind farms being developed in this state. Adding it to rooftops will make us self sufficient, not having to use the power from dirty coal plants up in Utah.

Now is the time, go for solar-thermal, and at least your hot water will be done. It's much cheaper then solar pv and pay back is about 4 years. By then solar pv will be available at a better rate.

and that's why I'm not considering it.

You are talking to an energy miser here with a tiny gas fired water tank turned all the way down.

the summer months.

that`s a lot of retrofitting older houses with window,doors, and insulation, new efficient furnaces and air conditioning,solar heating,etc,etc... ya the war has sucked the life out of our ability to convert to energy efficiency

Collectively, we are more interested in throwing monkey poop, be it flaming monkey poop, jellied monkey poop, white phosphorous monkey poop, or radioactive monkey poop, our favoirite monkey poop of all.

We NEED that money to kill innocents and insure our access to the last bits of draining oil.

Solar power or flaming, radioactive monkey poop? Now I ask you, which is more exciting and FUN?

Setting aside the fact that there is no technology capable of storing the kind of electricity we need for demand outside the 6 hours of peak solar flux per day, to buy enough solar panels to power the country would cost us $2.2 trillion dollars. That's not even figuring for the massive strip-mining and industrial expansion that we'd need to produce all those panels.

Cool! Bush has run up the national debt about 50% more than that during his term in office.

http://www.treasurydirect.gov/NP/BPDLogin?application=np
Now, some might argue he needed to do that as a matter of "national security."

Okay, so how does Global Warming sound as a threat to "national security?"

That's just the manufacturing cost of the panels themselves. That says nothing about the cost of expanding manufacturing by an order of about 1,000 fold, the cost of inventing an energy storage solution which can cope with the kind of demands that would be put on it, the the ecological impact of paving over enough space for around 750,000 square miles of solar panels and support infrastructure.

Got some others?

Cost of building/operating coal and NG power plants?

The acreage of land NOT taken up because they can be installed on existing rooftops?

The expense in terms of health and economic damage done burning fossil fuels for power, which we could in part offset with solar?

I'm not saying solar is a total answer.

But I do ask this: Why does we hesitate to use solar as part of the solution?

That won't do the job, but it'll get us started.

Actually, coal and LNG plants are extremely cheap to build and operate, which is why they're so popular. The byproducts are the problem, not the cost (though LNG is practically blameless compared to coal).

I'm happy to talk about parts of the solution, but it gets me annoyed when people buy into the hype of solar power being the perfect solution, when they clearly haven't thought at all about the drawbacks.

Here's the problem: what is the rest of the solution? Wind? Better than solar, but on an energy density scale, still not enough. Tidal and geothermal? Not yet well implemented, and not easy, respectively. Hydroelectric is by far the closest thing to a truly reliable power source among what's described as "renewable" energy, but it's limited by the number of dams that we're willing and able to build.

Our civilization demands considerable energy to sustain itself, and to have that we need to have what's called base-load power: 24/7, plentiful, and reliable. Solar doesn't do that, and neither does wind. The only technologies which do are hydro, coal/fossil fuels, and nuclear. Fossil fuels are obviously out. That leaves us hydro and nuclear, with the smaller "renewable" techs contributing whatever they can. You know what it would cost us up front to have clean energy using hydro and nuclear? Under $300 billion, less than a tenth the cost of even getting started with solar power.

The Keystone report estimates construction cost about $4,000/kW
for $300B you'd only get about 75GW.
If U.S. demand is around 750GW, you'd need ten times that amount.
http://www.keystone.org/spp/energy07_nuclear.html

I sure hope you're not talking about me!

Your first assumption is that manufacturers don't factor in the cost of their facilities when charging for their products. (No wonder they can never stay in business.)

Your next assumption is that you cannot store the energy (see other thread.)

Your final assumption is that solar cells must stand by themselves, and cannot be installed on rooftops (which is part of the title of this thread, i.e. "Lots of sun and roofs: Why can't we go solar?")

"Your first assumption is that manufacturers don't factor in the cost of their facilities when charging for their products. (No wonder they can never stay in business.)"

It's not about the cost of the facilities relative to production, it's building them in the first place. That's a front-heavy cost, and amortizing it over the life of the factory doesn't help, because you have to pay for it right away. Buying an electric car may be profitable for you in the long term, with no more gas bills, but that doesn't change the fact that it's expensive up front.

"Your next assumption is that you cannot store the energy (see other thread.)"

You cannot store the energy. Period. That's not an assumption--it's a fact. No existing technology has anywhere near the kind of mass storage capability we'd need. Even that press release you quoted, assuming that such panels could be produced in quantity and have them work as advertised--which is far from guaranteed--you'd still only be storing a small fraction of the energy that would be needed just to get from solar peak to solar peak.

"Your final assumption is that solar cells must stand by themselves, and cannot be installed on rooftops (which is part of the title of this thread, i.e. "Lots of sun and roofs: Why can't we go solar?")"

There aren't enough roofs. For starters, in most areas, covering a home's roof with solar cells will NOT eliminate the average home's power bill. It will reduce it, perhaps even significantly, but almost all homes will still be a net drain.

That's just homes, which only eat 1/3rd of our power, but account for a disproportionately large amount of roofspace. If they can't break even, there's no chance in hell that your average office building can, with hundreds of times greater power requirements, but only a few times the roof space. Not to mention heavy industry, which tends to be extremely energy-demanding.

Covering every roof in America with solar panels would help, but it would not end our reliance on other energy sources. I would guess--and this is just a rough guess, mind you--that it would probably cover 1/3 to 3/8ths of our total power requirements. Again, assuming that you found a way to store all that energy--otherwise that number drops precipitously.

Fortunately, we don't need to "store all that energy." We only need to store some of it.

It's a funny thing about "Solar Power" it tends to generate the most, when we need the most (i.e. during the day.) Its supply curve nicely matches our demand curve.


My brother is "off the grid" in upstate NY, and his roof is nowhere near covered with solar panels. How can that be? Well, the house has batteries, and a small wind turbine which is primarily used during the colder/darker months. Finally, they conserve electricity. (You know... they turn off lights when they aren't using them... stuff like that.)


I'm always amused when people say something like, "In most areas, covering a home's roof with solar cells will NOT eliminate the average home's power bill."

If you can do it in upstate NY, where can't you do it?

Anywhere you need air conditioning for an appreciable part of the year.

I was born and raised in Upstate New York. I can tell you that you need much less electrical energy there than I do now in Central Texas where my air conditioning still runs daily (and has been on since March). I can't put anywhere near enough PV panels on my roof to power the A/C that makes living here tolerable most of the year.

And I'll also opine that MOST families in the US would not conserve enough to make their homes capable of being powered by sun and wind. It just ain't gonna happen until things get a LOT more expense.

I just came back from two weeks in Germany. Had a Mercedes diesel rental car. Diesel sells for 1.35 Euro/ltr or $7.50 a gal. There were still way too many cars on the road.

The beauty is, the reason it's so danged hot in Central Texas is that you get so much more sun than we do!

However, as solar cells become more efficient, you'll be able to fit more on your roof.

And press releases mean little if they're not implemented in the real world.

Average electrical demand in the United States is about 760 gigawatts. That means that to store one day's worth of power--a bare, razor thin minimum for a solar-based system--you'd need to store 18,000 gigawatt-hours. Have you ever seen a forklift battery? It's one of the denser types of battery we can mass produce. To give you an idea, to store that much energy, you'd need 1.14 billion forklift batteries.

A single panel will (obviously) not hold a charge of gigawatt-hours. Then again, it won't generate gigawatts either. It will however hold a charge comparable to what it generates. The result is a solar panel that generates power during light periods and stores it for dark periods, with no batteries.

What they're talking about is not intended as a mass energy storage system on that scale. Even assuming it can be brought out of the lab: "Miyasaka says that the next goal is to increase the charging voltage and the charge-discharge capacity to a practically and industrially useful level for applications."

I repeat--there is no known technology that can hold that much power in a practical and controlled manner. Even those ridiculously powerful new sodium-based batteries that they're building are only capable of a few megawatt-hours.

Not really a useful press release to our current problem.



I read that as impractical and industrially useless for current applications. But that could just be me.

If it did work very well, it would be an exajoule scale form of energy, given that we've now endured decades of big talk about solar PV electricity.

Another problem with solar is that they, um, can't seem to manufacture enough solar cells on the entire planet to make up for a single small gas plant in say, the wonderland of Maine.

In fact, mostly the entire solar energy conceit is increasingly a consumerist fig leaf for a set of people who couldn't care less about the environment but still want to lie to the external world and probably themselves as well.

The "solar will save us" meme, which I have been personally hearing for more than 3 decades - and in which I once believed myself, albeit when I was young and stupid - will continue right up to the end, I bet. Never underestimate the power of denial.

My house uses approx 1200 KW per month. Divide that by 30 days gives me a requirement of 40 KW per day. Assume 8 hours of daylight on average give me a requirement of 5 KW system.

5 KW * 8 hrs / day * 30 days / month = 1200 KW / month.

Approx cost about $40-45K. Add more for batteries.

Add it to my mortgage @ $6 / $1000 and it works out to about $250 / month. Current electric bill is just about that. Furthermore, assuming economies of scale along with government incentives / rebates and the cost gets even lower. Even more, by distributing production to all those rooftops you lower the chances of widespread power outages.

Add on top of that the Net Metering laws which allow me to sell my excess power back at market rates and if I stay on the grid, then I won't need to add batteries and I can still offset my costs.

...... but otherwise you're on the right track. There's nowhere in the US where you are going to get 8 hours of equivalent peak sun on your 5 KW array. Your 8 hours of sunlight contains some morning and afternoon periods where you will be getting much less than your rated power from the PV array. About 4 to 5 hours of equivalent peak sun is more realistic. That is going to increase the size of the PV array significantly.

http://www.solarseller.com/solar_insolation_maps_and_chart_.htm

Also, your PV array and inverters are not 100% efficient, so you want to add another 20% or so for that.

I love PV. I have used a PV system to power my ham radio gear for the last 15 years or so. I've upgraded the system several times to keep up with new technology. But it is still too expensive and not practical for 95% of people. It may work OK on your house, or a house that was custom designed for a PV energy system. But most homes will use far more electricity than their roof square footage can produce (especially in the places requiring air conditioning.) How many roofs face due south? How many have an unobstructed view of the solar arc? How many have roof structures that can accommodate the weight, wind, and snow loads that PV panels would place on them? What do you do when your PV covered roof starts to leak and needs to be replaced? How much extra expense involved in the labor to remove and re-install all those panels? What about apartment buildings and hi-rise condo towers? They have no where near enough unobstructed south facing square footage to power all the people in the building and it's systems. Any ideas how much power elevators require?

There's just too many impracticalities involved for there to be "solar on every roof." Perhaps in the future when homes and buildings are specifically designed with an integrated PV system in mind it could become practical. But it's going to be a LONG time before any significant portion of the US housing infrastructure is converted or re-built to be PV practical. (And that's ignoring the whole issue of energy intensive industries.)

But keep dreaming. Someday ............... :-)

A homeowner, who is already hooked up to the grid, sees no reason to spend thousands of dollars on a new system when his current electric bill is affordable.

A developer sees no reason to install a system that will add thousands of dollars to the price of the home he is selling when the other developers are not doing it.

Utility companies see no percentage in setting their customers free and watching their profits plummet.

Politicians get more campaign bucks from the energy companies than they do from the environmentalists, and they haven't seen any reason to believe that the voters give a shit......

I think you're exactly right. It's hard to shift people off bottom dead center when things seem to be going fine...

...to reach that conclusion. Not many, I expect.