Solar Thermal is Dead

Bob Gagnon plumbing and heating

Rob

When people "Go by the book" they keep making the same mistakes that people have made in the past. We can greatly increase the amount of energy we harvest from the sun, for space heating, by making a few small changes, like a steep collector tilt, low temperature collection, and using two, large storage tanks with really big heat exchangers. I'm very happy with the way my system has been working, and expect it to payoff in 20 years or less, depending on fossil fuel price increases. My small storage tank is 200 gallons, and the big tank is 1500 gallons, the coils are made out of 5 coils of 1/2" X 60' soft copper. Thats the only specs I have on the tanks. I agree that if someone installs a conventional solar hot water system, by the book, they will not be happy. we have to change things and with these small changes I get 100% of my domestic hot water and about 40% of my heating load, I'm very happy with my system.



Thanks, Bob Gagnon LEED AP

NRT_Rob

that's great

that you're happy with it. but you're an industry professional getting a 20 year payback. retail that's what, 30 years? non starter. No one in their right mind pursues a 30 year payback... there are endless other things you could do with that money with better economics and with better energy savings to consider.



PV is about a ten year payback in the northeast these days just on the federal credit, 15 without... and that's still a stretch for most people. My heat pump is a ten year payback or five if it saves me a boiler, with no credits at all... unless you're in a natural gas situation, of course, since it's so cheap these days.



So you just proved it makes no sense whatsoever to pursue solar thermal for space heat. I know your system is older and PV was more expensive when you did it. but things have changed. Why would you ever do thermal for space heat now, when PV is so much more effective at offsetting your energy use?



I socked away almost 4 million BTUs last month to use later when I need it. My heat pump will double that to 8 million+.

jumper

how do you heat with 75° water ?

how do you heat with 75° water ?



I suspect that if PV was any good businesses would be doing it. Industrial buildings are covered with huge empty roofs.

jumper

here's an idea

Collect warm water with solar thermal; then use PV to drive heat pump to boost temperature of that solar heated warm water. When thermal collectors are working so are the PV.



NRT's arguments depend on somebody else subsidizing PV. In addition to installation subsidies, the electric company uses resources to accept his electricity when he wants and then provide him with electricity also when he wants it. Those resources are paid for by other customers. Clearly not sustainable.

NRT_Rob

you're still

limited by the btu collection of the thermal in that case... all it does is improve the heat pump COP for a portion of its usage related to that number of BTUs. remember heat pumps do not create BTUs, they only move them. so your heat pump in that case isn't helping much.



without any subsidy right now PV has about a 15 year payback by itself here in maine. the net metering is an issue if it went large scale, but there are many, many ways to work with that. also:



1. PV collection is strong during peak electrical usage periods (summer cooling period, even here in maine). if/when the peak shifts to heating periods (winter nights) that may change but for now blunting the peak demand with solar production is a big win for the grid that greatly offsets any additional cost for handling net metering administration.



2. Thermal energy can easily be stored in tanks. there are ETS systems out there as well but I think tanks will be the big winner. right now I run a heat pump time shifted by using my lower level slab as a heat battery to maximize COP but could do it to maximize electrical economy just as easily to take advantage of any time of use metering solution anyone wants to dream up, and those schemes are in the works because the utilities know this is all coming. Smart meters exist right now in every home in Maine even though those TOU plans are still in their infancy here, they are ready to go.





Like it or not the grid is going to have to deal with intermittancy. What is clearly unsustainable is a long term focus on unsustainable energy sources, not the economics of renewable energy long term.

SWEI

Thermal energy storage

has been available for decades and it works.  With all the fuss over next generation batteries, I'm somewhat surprised it isn't getting any press.  We should see a healthy retrofit market as TOU metering becomes more widespread.

michael_34

solar cooling

I have read this post for months now, listening to the bantering back and forth. All valid points.



Solar thermal will only become a mainstay, only if it's functionality is increased. If the function of solar cooling can be added to solar thermal, then the sky is the limit.



There are already many systems of these types throughout the world: http://solarthermalworld.org/solar_cooling?module=browse

or

http://oxfordgardenssolarproject.com/.



I've been to the Oxford Garden install. Very well done.



If solar cooling component can be added to thermal on a grand scale, problem solved. Now the economics change.



It has a way to go, but it is going. Maybe some of you can make it more streamlined and user friendly.

Bob Gagnon plumbing and heating

Jumper

I use radiant heat in my walls, floors and ceilings to heat my house and I use solar as supplemental heat. So any energy over room temperature helps heat my house. If I come home during a cold sunny winter day, my house might be 60 or 65 degrees instead of 50 degrees or so, it''s a lot more comfortable and warmer through out the house. I have a house I built during the 80's and it's leaky with 2X4 construction, if I had a super-insulated house 75 degrees would supply most of my heat, even on the coldest, sunny days.



Thanks, Bob Gagnon

Bob Gagnon plumbing and heating

Rob

Have you taken into consideration the maintenance and replacement costs for the heat pump? When I Goggle it, most sites tell me the life of a heat pump is about 15 years, are you going to have a major repair bill just as your system is paid off? When I Goggle "Solar Space Heating Combo Systems" Wikipedia tells me that many countries in Europe have these combo systems in place to heat domestic hot water, and for space heating and cooling. In many countries 50% of the solar hot water systems are also combo heating/cooling systems, and in Germany, perhaps the world leader in Solar 25% of it's solar hot water systems provide space heating as well. It just makes sense to me that a simple hot water system added to a pv collector would have a much longer life with extremely little maintenance. Every article I read about solar hot water not being worth it, they are talking about solar domestic hot water only, including the article this thread is referring to. We keep doing things the same way as everyone before us, and everyone is afraid to think outside the box. Maybe solar thermal is dead in the town you live in, but here in Lowell, Massachusetts, it's alive and well, and now that I know there are thousands and thousands of these combo systems in Europe, I think I'm in pretty good company.



Thanks, Bob Gagnon LEED AP

NRT_Rob

sure

I have seen a large number of solar thermal systems that didn't make it 15 years so I wouldn't get too snug in your assumptions there. but you misunderstand what I was saying with paybacks. the payback on PV itself is 15 years... it has a lifespan of 25+. That's pretty great.



the HEAT PUMP itself typically has a payback much faster than that (5 to 10 years), but it depends on what you compare it to... if we compare to natural gas in a heat only application, not so great. Compare to electric resistance doing heating and cooling, it's great. so pick your comparison. But if you want to compare it to the solar thermal system of a size you'd have to put in to offset the same amount of energy it does, then the heat pump doesn't need to talk about payback, it's cheaper up front and it will probably a similar level of service as the solar thermal system... i.e., not much. You need to save about 30 million BTUs/year to hang with the heat pump on that basis if you want to pencil out what that system looks like for my shop which is a heat load similar to many single family residences. I suspect you'll find that only the very smallest heat loads would shift that economic analysis.



I don't know what you're reading, but optimal economics for solar has to be for year round loads... that's DHW. Maybe if our energy was three times the cost it is now, like it is in europe, we'd see more space heat systems like that here too, especially in the past when PV was much more expensive than it is now so it would be the only solar option that really made sense. you get maximum production per square foot of panel you buy and per gallon of storage you buy (and thus, optimal return on investment) when you use everything you collect. You cannot do that by buying a lot of extra panel that is utterly useless for half the year.



HERE in america you will never pencil out a payback that makes any sense whatsoever for a solar thermal space heat system unless your labor or components are free, your subsidies are huge, or energy gets a lot more expensive than it is now. Plain, simple, fact. I will happily eat those words when you show me a payback less than 15 years on any solar thermal combo space heat/DHW system without subsidy, but you'll have to pardon me if I don't hold my breath while I wait, because quite simply I've looked at the numbers and I'm pretty sure that beast doesn't exist in the US and isn't going to anytime soon. If it does, it's certainly not the system in your house, which is awesome and great and cool and not going to save america very much energy because a 30 year payback is, one more time, a dead horse in this race. My hat is off to you for being willing to do it, of course. but I don't have many clients who would buy it. and I have a lot of green clients.



If you can do cooling, that would help a lot, but solar cooling is in two flavors, one is solar absorption chilling which is complicated and fantastically expensive here in the US, and one is night sky radiation which is limited in capacity, but might help. no evacuated tubes there, and I would love to see the performance of such systems in greater detail. Maybe that's your in, I don't know.



but right now, at today's pricing, PV is ready for prime time and dead simple to deploy. we hit the tipping point of grid parity a couple years ago and we're beating it now. significantly. moving into heating and cooling is as simple as deploying a heat pump and upsizing the array and pow, there you are.

Bob Gagnon plumbing and heating

Two Things Wrong Here Rob

First, I said I figured my system has about a 20 year payback, so you rounded that up to 30. I don't know where you got that 30 year figure from.

The second thing I see is where you say Solar Thermal won't make any sense unless we see energy costs get a lot more expensive than it is now. Now I've been wrong before, but I'd bet my Evacuated Tubes against your PV Panels that in 20 years when my system is paid off, energy costs will be a lot higher. A good hot water solar panel should last a lot more than 15 years, I've seen only a few systems around, but a couple of my customers have systems over 30 years, and there is no reason to doubt that a good system should last many, many decades, just like a forced hot water system, they  are very much the same. Domestic does have a year  round load and that's great, but as you point out fossil fuels would have to be three times as expensive to make solar worthwhile. I have a domestic AND space heating together, not one or the other. It's interesting too that for our energy dollar here in Massachusetts, 17% is spent on domestic hot water and 52% is spent on heating, that's about three times as much. Wouldn't harvesting 3X the solar energy have the same effect on payback as having energy prices 3X higher?

NRT_Rob

yes

you said YOU have a 20 year payback. Are you going to sell that system to your customers at cost? No one but you, or another professional can install your system at your price. right? All my numbers so far have been installed retail. even IF your number is retail and not your cost every thing I've said still holds true, it's just less dramatically true.



Your analysis on chasing more energy is also not correct. Your price to collect 3x the solar is not 3x the cost. it's significantly more than 3x because you are trying to collect during time periods where the solar just ISN'T THERE. So your payback gets longer and longer because the cost to collect more of your load goes up and up faster than your collection does... because you are wasting more and more of the capability of every panel you add after your baseline DHW load is met at optimal summer tilt.



I agree that solar thermal SHOULD last a long time. Many do. but a lot of systems definitely don't... maine has a lot of abandoned solar systems that the local plumbers couldn't keep in service or didn't save enough to make it worthwhile. it's got moving parts and thermal stressed and maintenance requirements that PV doesn't have at all.



In 20 years energy probably will be more expensive. and I bet your solar thermal system against my PV that PV will be even cheaper then, solar thermal won't be as much cheaper, heat pumps will be significantly cheaper, and that there might even be something new in that time we have no knowledge of. But we're not talking about the system we'd put in, in 20 years. we're talking about today.



TODAY, if you want to do solar space heating, you should be looking at PV and a heat pump. That's all I'm trying to get through here. Solar thermal stops making sense after a DHW load is met... that's the only thing it can do more cost effectively than PV. Unless the very intriguing idea of solar cooling comes into play in a way I don't expect to see happen (but, like you, I've been wrong before.)

jumper

solar energy storage

Well with solar cooling much of the load occurs when sun shines, so that helps. You still want energy storage, and thermal is way cheaper and more durable than electric. You could use solar thermal to provide cooling for heat rejection part of PV powered refrigeration. But don't you think that such complicated schemes make more sense for large installations ? If energy becomes expensive enough solar will prevail. I suspect that a new generation of nuclear will render solar unpractical except for locations off the grid.

Bob Gagnon plumbing and heating

No Nukes!

The waste by product of nuclear makes burning coal look green.

Thanks, Bob Gagnon

michael_34

NO NUKES...

new or old.

Cancer rates are high enough.



Yes I do agree solar cooling is only viable for large installs, but down the road with advancement in technology it may be come more applicable for residential also.

SWEI

I'll believe in Nukes

when they're insurable without government guarantees.



I remain hopeful.

Eastman

MORE NUKES!

Radiation is natural.  I'm vastly more concerned with the combustion byproducts associated with other forms of power generation and the soup of chemicals from a variety of other industries that make life modern.  Granted, the current generation of technology is pathetic and wasteful, but there are superior concepts that have the potential to deliver truly clean energy. 

michael_34

Not in my backyard

Or yours.



plutonium 238 and 239 are spent fuels from producing nuclear energy. When plutonium 238 breaks down over 90 years becomes uranium 238, it's half life of radiation will last 250 million year or so, Natural Uranium by it's self is very low in radiation.



Plutonium on the other hand is very radioactive, but during the fission process with uranium becomes highly dangerous and hazardous to all living creatures.



This from IAEA:



The radioactivity of all nuclear waste diminishes with time. All radioisotopes contained in the waste have a half-life—the time it takes for any radionuclide to lose half of its radioactivity—and eventually all radioactive waste decays into non-radioactive elements (i.e., stable isotopes). Certain radioactive elements (such as plutonium-239) in “spent” fuel will remain hazardous to humans and other creatures for hundreds or thousands of years. Other radioisotopes remain radioactive for millions of years (though most of these products have so little activity as a result of their long half-lives that their radiation is lost in the background level). Thus, these wastes must be shielded for centuries and isolated from the living environment for millennia.[2] Since radioactive decay follows the half-life rule, the rate of decay is inversely proportional to the duration of decay. In other words, the radiation from a long-lived isotope like iodine-129 will be much less intense than that of a short-lived isotope like iodine-131.[3] The two tables show some of the major radioisotopes, their half-lives, and their radiation yield as a proportion of the yield of fission of uranium-235.

The energy and the type of the ionizing radiation emitted by a radioactive substance are also important factors in determining its threat to humans.[4] The chemical properties of the radioactive element will determine how mobile the substance is and how likely it is to spread into the environment and contaminate humans.[5] This is further complicated by the fact that many radioisotopes do not decay immediately to a stable state but rather to radioactive decay products within a decay chain before ultimately reaching a stable state.



Not in my backyard, which is this whole planet. Cancer rates have exponentially grown since the first nuclear tests and directly coincide with the advancement of nuclear anything.

Eastman

I would gladly live

in the backyard of nuclear power plant.



Quoting you:

"Cancer rates have

exponentially grown since the first nuclear tests and directly coincide

with the advancement of nuclear anything."



First of all,

What are you basing this on?

michael_34

Enjoy your backyard then

http://www.americanscientist.org/issues/feature/2006/1/fallout-from-nuclear-weapons-tests-and-cancer-risks/1



http://www.iaea.org/Publications/Magazines/Bulletin/Bull332/33205892027.pdf



http://www.state.nv.us/nucwaste/news2001/nn11105.htm



It depends on the source of course. The corporations provide major funding for most studies through IAEA and Universities.

Eastman

Did you read the articles you linked to?

From http://www.americanscientist.org/issues/feature/2006/1/fallout-from-nuclear-weapons-tests-and-cancer-risks/1



"Cancer investigators who specialize in radiation effects have, over

the intervening decades, looked for another signature of nuclear

testing—an increase in cancer rates. And although it is

difficult to detect such a signal amid the large number of cancers

arising from "natural" or "unknown" causes, we

and others have found both direct and indirect evidence that

radioactive debris dispersed in the atmosphere from testing has

adversely affected public health."



----The issue is not whether radiation can cause cancer.  Is it acceptable to release unnecessary radiation into the environment? Of course not.  Nuclear weapons are bad, but does this mean nuclear power is bad?

****************************************************************************



From http://www.iaea.org/Publications/Magazines/Bulletin/Bull332/33205892027.pdf



---This article is actually on the nuclear power industry and it's relationship to cancer.  The authors' conclusion was negative though; there wasn't sufficient evidence to support a link.  Keep in mind that radiation is very easy to detect.  No one has to stay up at night worrying about the unknown.  If reactors were spewing it out we'd know about it right away.



*****************************************************************************

From http://www.state.nv.us/nucwaste/news2001/nn11105.htm



This is a newspaper article discussing claims made by Dr. Sternglass.  Wikipedia indicates his statistical research and conclusions are hyperbolic and generally not accepted.

NRT_Rob

there are 3 major issues with nuclear

1- pollution from source extraction of uranium. not the hugest problem, but it's an issue.



2- safety. SWEI nailed this... when they can afford to privately insure, maybe it will make sense. with highly qualified and regulated insurers, of course.



3- storage. when we don't have a waste storage issue anymore, great. until then, even the best waste results I'm aware of stretch into timeframes longer than our country has even been a country. Seems unlikely we can ensure the safe storage of such waste. Maybe when we have a safe way to hurl it into the sun or something...



Hey, the sun. that's nuclear. it's in your backyard! Maybe we should stick with that

SWEI

Safer nuclear power

with no fuel shortage could have been widely available by now if had we actually wanted it back in the '50s and '60s http://en.wikipedia.org/wiki/Thorium-based_nuclear_power

hot_rod

also the uranium enrichment

is often done at plants fueled by coal. The Paducah, Ky. enrichment plant recently closed, powered by one of the dirtiest coal power plants. One of the last US owned and operated plants.

Seems the movement is to multi-national ownership of enrichment plants now. One of the newest plant in the US is "essentially a French plant on US territory" according to World Nuclear Association



Now the taxpayer funded cleanup begins for the decommissioned Paducah plant site.

NRT_Rob

woulda coulda shoulda

but didn't.



http://www.guardian.co.uk/environment/2011/jun/23/thorium-nuclear-uranium



"But even were its commercial viability established, given 2010's soaring greenhouse gas levels, thorium is one magic bullet that is years off target. Those who support renewables say they will have come so far in cost and efficiency terms by the time the technology is perfected and upscaled that thorium reactors will already be uneconomic. Indeed, if renewables had a fraction of nuclear's current subsidies they could already be light years ahead."

SWEI

If renewables had a fraction of nuclear's current subsidies

of course, but the 50+ year lead time is an even bigger challenge.  Amazing progress has been and continues to be made on many fronts.



Base load is a tough nut to crack, though... 

jumper

realistically

Nukes produced energy for 3 cents per therm fifty years ago. Were it not for bureaucrats having a good time, price would have gone down like other high tech products. Renewables, coal or gas can't approach 3 cents per therm.



Proliferation and waste problems are more bs from fools who don't understand atomic energy.

SWEI

realistically

The short term dangers of high pressure live steam are staggering regardless of the energy source.  960 PSI is scary stuff, but some designs rely on even higher system pressures.



The real challenge with nuclear is time.  Half lives of tens of thousands of years lie outside of our ability to comprehend, much less manage.

NRT_Rob

incorrect

unless you ignore insurance, cleanup, and storage of waste.



as of now it is impossible to insure a nuclear reactor at any price. hard to think it'll be "3 cents" or whatever after all that is taken care of.



what's the cost for containment for thousands of years? oh right, we have no idea, because there is no such thing as reliable containment for thousands of years.

Bob Gagnon plumbing and heating

Giant Corporations Lie!

To make money, that's all they care about. They told us how cheap our electric bills would be with Nuclear, but ask the people in southern New Hampshire who have some of the highest rates in the country, they lied to get it approved, and they still make a profit anyway, and we pay the price. And like Net Rob says thats not even counting the insurance costs, security costs, or the cost of disposal. Nuclear is the MOST expensive energy we produce, but the Nuclear industry won't tell you that, they just want to make profits. There's a reason another plant hasn't been built in 35 years. The Nuclear industry told us there would be on average one major accident in a thousand years, well we've had three in what, the last 30 years. Nuclear is the dirtiest energy, and the most expensive, stop drinking the Nuclear Kool-Aid!

Thanks. Bob Gagnon

jumper

specific numbers

Instead of railing against corporations or plumbers' valuable evaluations of atomic energy; why not post some specific numbers. And please spare us the we don't discuss prices excuse. I saw some figures on a new apartment building in Venice,California. Solar thermal on roof projected to deliver 5000 therms each year with a budget of $250,000.00.

Fifty year payback in a sunny state with high gas prices. In US solar thermal looks pretty moribund.

NRT_Rob

while I agree

right now in america you cannot cost justify anything against natural gas. what is the value of that comparison?

Bob Gagnon plumbing and heating

Jumpers Right

We don't need a bunch of stupid Plumbers voicing their opinion about Nuclear Energy or Giant Corporations, who do these Plumbers think they are anyway?? I also disagree Jumper, with trusting numbers instead of people. There was at presenter at SolarFest this year, Chris Wetherby from the Consortium for Advanced Residential Buildings, they built two similar homes, side by side, to see how solar thermal stacks up against  mini splits and found out that the solar thermal beat the mini splits by using less energy, under actual heating conditions. Someone can easily make the numbers look however they want, I trust people who have actually done it and I value their feedback, but I am "Only a Plumber".



Thanks, Bob Gagnon Plumbing and Heating LEED AP

jumper

yes building owners like gas cos

The larger the monthly gas bill the happier they are. That's why they're not installing solar water heaters. Otherwise they'd love to pay GBC for a LEED badge. BTW, Bob, most plumbers avoid solar thermal because they have colleagues who have been hurt by its impracticality.

michael_34

smile

: )

Bob Gagnon plumbing and heating

Tools That Don't Understand Nuclear Waste

Jumper is it total BS the the Nuclear Plant in Japan leaked 300 tons of highly radioactive cooling water a couple of days ago?? We don't have to fully understand Atomic Power to understand the risks, keep drinking the Nuclear Kool Aid.



Thanks, Some Plumber

Jean-David Beyer

is it total BS the the Nuclear Plant in Japan leaked 300 tons of highly radioactive cooling water a couple of days ago??

Not only 300 tons of nuclear waste a few days ago, but probably 300 tonnes every day since the accident started.



http://www.bbc.co.uk/news/science-environment-23779561



http://www.irishtimes.com/news/world/asia-pacific/fukushima-nuclear-waste-leak-worse-than-thought-1.1488603



Clean nuclear power: too cheap to meter. If so, why has the Price Anderson Act not been repealed?

michael_34

Jumper

The problem is most solutions in this country (and world) come down to cost effect, not the correct healthy approach. No, solar thermal cannot compete with NG when it comes to dollars, not even close.

Nuclear almost never pays for itself: http://www.ucsusa.org/assets/images/np/np-cost-overruns.jpg. Then you have the costs that are not introduced into any ledger, such as the on going struggles in Japan.

http://www.time.com/time/magazine/article/0,9171,2059603-2,00.html



When our culture values money over health, health of ourselves, loved ones and people unknown, we are in turn killing each other and ourselves. Money is a necessary cog in our society, but it can't be the dominating factor in our decision making about the future of our planet. It does not add up.

kcopp

Maybe not...

Here is a huge  Solar thermal project....

http://www.youtube.com/watch?v=7N3WUSeXJQw

Bob Gagnon plumbing and heating

Dead???

Wow, 15 million investment,with an expected 5 year payback, and panels that may last 30 years or more, solar thermal isn't dead, it's just not real easy to do, so everyone makes excuses to not do it.



Thanks, Bob Gagnon