Nope your right.

I looked at a whole house backup genset with auto switch over and all that and then in to solar. I figured for about twice the money for solar I actually use the solar almost every day and still have a great backup power setup. I couldn't calculate the payback on a backup genset, but I can on a solar setup

fallguy-

I have a 3.15 kW PV system in a sunny part of Colorado with an annual average solar insolation of 5.9 kWh/m2/day. Using PVWatts v2.0 for my area with an efficiency factor of 83.5% as given by my manufacturer, the predicted power for one year is 5152 kWh. For the 7 months that they have been installed, they are making 16% more than the PVWatts v2.0 predictions to date, but let us assume that the performance is as predicted by the model. Taking the 5152 kWh at an estimated average price of $0.098/kWh, this equals $505 worth of electricity for the first year, assuming that I displaced that much electrical use (my actual use is less than this).

The cost for my system was $5451 after the rebate by the utility of $2.45 per DC watt, and the 30% of the hardware cost credit against my income tax . Assuming an inflation rate for energy of 6% per year, excluding any interest that I might have received by investing the $5451, and excluding any maintenance costs, then the system will be paid off in a little less than 8 years. I could claim that after that time, I am receiving free electricity for the rest of the 25-year lifetime of the system. This analysis does not take any credit for an increase value for the house at resale. That is an acceptable payback for me, and is better than most of the things that I waste money on. It provides entertainment for me to see my meter run backwards, and to realize that I am not sending money to Iran's Ahmadinejad when I turn on the lights around here.

Lee

Lee,

Would love some details on your system, it sounds like you have a $5,000 system that is providing 20-50% of your power needs, that sounds nice

I did a ton of research into residential wind, and found it just didn't make sense....... a decent wind turbine that in reality might provide 20-30% of my power would cost about 12 grand installed after rebates, ok, that comes up to about a $30 per month savings in electric bills, so my payback would be about 30 years, assuming it never broke down.

Also, with wind, they all say, oooo, watch your meter roll backwards, etc.etc... but in reality if you do some heavy digging you'll find most people get about half of whatever its actually rated for.

IN the end, wind at the current prices doesn't make sense from a money perspective

However lees system with a 10 year payback isn't all too bad....

Wind and solar will make sense, when you can get the payback down to 5 years

The other thing to consider is peace of mind, if the power goes out for a long period of time, the ability to make some of your own power form wind or soalr could be something that helps you feel more self sufficient.

I also live in Colorado, I know of no grid tied system that is economic without subsidies. Where I am there are none, elsewhere they are being reduced making the numbers less attractive.

A grid tied system will not make you self sufficient.

There are systems available now that allow grid-tied alternative energy sources to be utilized when the power grid is unavailable.

JPM1730-

The PV system that I have is a high-quality, professionally installed, 3.15 kW-DC rated system.  The installed price in April, 2010 was $18,337.28. The rebate from the U.S. government was 30%, or $5501.18, reducing the price of the system to $12836.10. The rebate from the local utility supplier, Xcel, was $2.35 (or $2.45) per watt, or $7402.50, reducing my cost to $5433.60.  Xcel is trying to do away with the rebate, and that issue is up for review by the PUC.  (Como, when you say you live in Colorado but do not qualify for rebates, the federal rebate of 30% applies for you unless you do not live under the U.S. tax system.)

The performance of my system and the electrical use at my house are publically available at http://www.ResidentialEnergyLaborat...se_pv.html. Between June 1, 2010 and Feb. 28, 2011, the PV system generated 4495 kWh.  Using DOE’s PVWatts 2.0 to extrapolate energy produced through the end of May, the yearly output will be 5697 kWh.  (As can be seen from the web site above, the actual power produced has been higher than PVWatt predictions every month, so it is conservative to use that model to extrapolate for the last 3 months of the first year of use.)

My electrical usage for the seven months that I have been in the house full time has averaged 253 kWh per month. Extrapolating this for the 12 months in a year gives 3038 kWh per year.  Thus, I am generating 187.5% of what I use (or 1.875 times what I use if you don’t like percentages). This electrical usage is lower than average, and the background for that can be found at http://www.residentialenergylaborat...on_am.html.  The fact that I generate more electricity than I use allows me to offset the natural gas that I use for space heating and supplemental water heating and cooking, and meet my net-zero source energy goal.  However, a better economic trade-off is provided by NOT over-sizing the PV system relative to electrical needs (at least at my location).

So the “hard facts” are available above for costs and energy generation and usage (with documentation on the web site), and how one treats these facts becomes the subject of some debate.  Let us assume that my system was not oversized relative to my needs, and that I was using all the electricity that I generated.  This is more typical of most households.  Current residential electric rates in my area are $0.9974 per kWh (roughly 10 cents/kWh) for small users.  Further assume that the electric rates scale with natural gas prices that have increased in Colorado at an annual rate of 4.7% since 1990.  Then keeping that same inflation rate, after seven years I would have paid $5540 for electricity without a PV system, but, as shown above, I paid $5433.60 for the PV system.  Therefore, I could say that for seven years, I pay the same price for electricity with or without the PV system, but after year seven, I get electricity for free for the life of the system (perhaps 25 years total).  Without the Xcel rebate (Como’s case), the payoff would be a little more than 14 years, at which time regular electricity bills would have cost me $12,373 versus the PV system cost of $12,836.  This analysis ignores the 0.5% interest I could get if I deposited the money in a bank savings account instead of the PV system.

My system is grid-tied, and it would cost another $8,000 to modify the inverter system to allow it to operate when the grid goes down.  I have another small PV system in Texas that is not grid-tied, and dealing with the batteries is a nuisance.

Lee Dodge
http://www.ResidentialEnergyLaboratory.com
in a net-zero source energy modified production house

My supplier is IREA and unfortunately my business is not making any money so the tax credit is currently useless. Now if they sent me a cheque...

But lets say that was not an issue.

My rate is 11c, so lets say that is $700. So $13,000 investment gives me a 5% rate of return. Hopefully increasing over time, without the tax credit it is 3%. but then the system has a finite life span and requires some maintenance.

So without subsidies it is nonsensical. Hopefully prices will continue to fall so it becomes a more practical proposition.

I am putting in a Biomass system, the numbers there are much more attractive, wood being 1/10th the price of propane per btu.

Wind is worse than PV, unless maybe if you are on the Easter Plains. Much more maintenance.

Without the distortion of subsidies for most people Solar DHW is a much better bet than PV.

Agreed, alternative energy subsidies are a distortion attempting to make up for another distortion - artificially low energy prices. Charge for all the environmental damage, depletion for future generations, wars, etc. Then things will take care of themselves.

Como-

Last year’s defense budget, including overseas contingency funding, was $663.8 billion. If I assume that 20% of this was to invade and occupy the country with the world’s second largest oil reserves, and to maintain a huge presence in the Persian Gulf region to safeguard the 4.1 billion barrels of imported oil per year, then I compute a subsidy of $0.06 per kWh for electricity generated from imported oil. (This includes no value for the 4,439 American lives lost in the Iraq area, the 32987 Americans wounded, and maybe 100,000 citizens of Iraq killed.) This would increase electrical costs in my area from $0.10 per kWh to $0.16 per kWh if generated from imported oil. Now electricity here is mostly generated from natural gas and coal, but the U.S. shares a pool of available fuel supplies, and increases one place impact the rest of the country.

Further, oil companies claim the enhanced oil recovery credit, and intangible drilling cost deductions, increasing my tax burden, although I use no oil or gas for production of my electricity. So we are directly and indirectly subsidizing the production of oil from both domestic and foreign sources. This oil production has also provided the recent Gulf of Mexico oil spill, as well as CO2 when it is burned. "Energy indepedence" for Republican Mitch McConnell is to drill faster so that we can more quickly use up the other half of the petroleum that we have not already burned up. I would prefer that my tax dollars subsidize a renewable energy source that will be here long after the petroleum is gone.

So why would you comment about the subsidy for solar energy, and not acknowledge that there are significant subsidies for other non-renewable energy sources?

Lee Dodge
http://www.ResidentialEnergyLaboratory.com
in a net-zero energy modified production house

In Colorado I do not believe any electricity is generated from oil, mainly from coal and more coming from Natural Gas. I would rather they kept Natural Gas for other uses, seems a waste for a high quality fuel. Mind you if we had NG, I am not sure if I would have gone biomass.

We actually sit on a coal seam, but not economic to operate. Coal is something that generates local jobs whilst PV panels seem to come from China.

The moralistic issue I have is that your kick back came from Xcel, Xcel funded it from a general levy on rates so you have the poor subsidising the wealthy, just does not feel right. A bit like the lottery.

Each coal plant kills at least 10 people a year from the pollution it creates. Makes nuclear plants look quite safe.

How many deaths is each McDonald's responsible for?

If that is going to be the determining factor, Nuclear would be the best option.

http://nextbigfuture.com/2011/03/deaths-per-twh-by-energy-source.html

Fig. 1.  Suggested long-term energy approach by jonr and Como.




Fig. 2a.  Suggested long-term energy approach by Lee.



Fig. 2b.  Suggested long-term energy approach by Lee. 

Lee Dodge
http://www.ResidentialEnergyLaboratory.com
in a net-zero energy modified production house

so you have the poor subsidising the wealthy,

I can understand your objection there, but let me also point out that the poor have at least an equivalent stake in the big picture which is achieving some sort of sustainable energy plan sooner rather than later. If things go poorly in the long run, even if it is just spikes in energy prices, not to mention significant shortages, they will be the ones suffering the most.
Does Excel Energy have some sort of Green Energy program in which customers (who, presumably can afford it) voluntarily pay a premium on their electrical rates in order to subsidize investment in Solar?

ICFHybrid-

I am not aware of Xcel in Colorado having such a program. City Public Service in San Antonio, Texas had a program that like for wind energy, so customers could pay a premium on their electric rate, and the sum of all those customers times their fraction of wind energy selected determined the amount of wind energy that the utility was obligated to obtain. When they first introduced it, they still charged me a fuel adjustment charge in addition to the wind premium, and I told them they were inconsistent and dropped it. When they finally dropped the fuel adjustment charge, I signed up again. I don't know how successful the program was, but there are a lot a wind generators in west Texas and in the Panhandle.

Interestingly, the first requirements for renewable energy in the utility mix in Texas were put in place when George W. Bush was governor, or at least there were significant increases in the requirements at that time.

Lee Dodge
http://ResidentialEnergyLaboratory.com
in a net-zero energy modified production house

New Belgium brewing used to advertise that they were wind powered, they were not, coal, but paid the surcharge so they could say they were. Just looked at is seems that they have stopped.

Have you checked out the Sierra Nevada brewery? They have some PV panels. And a fuel cell. And a methane gizmo...

Posted By Como on 15 Mar 2011 09:26 AM
How many deaths is each McDonald's responsible for?

If that is going to be the determining factor, Nuclear would be the best option.

http://nextbigfuture.com/2011/03/deaths-per-twh-by-energy-source.html

The whole model of large central generators separated from the loads by large distances of grid is less secure, less stable than the same generating capacity generated more locally to the loads.

Solar, while predictable in output by the weather, requires substantial "hardening" to be a reliable base-load generation source.  (With smart grids and smart-batteries in an electrified automotive fleet it can provide something less ephemeral though.)  If the backup for distributed PV is the grid, it imposes a higher capital cost for generation capacity on the backup-end that doesn't appear in the capitalization cost of the grid-attached PV array itself.  Not saying it isn't worth doing, but smart grids & smart appliances might be a cheaper/better way to manage the grid as a whole.  Idle grid generators are expensive and un-green, as is power-dumping by oversized base generators that can't track loads over 24 hour periods, such as nukes, which can be throttled back quickly but take days to come back to full capacity. (You can't thermally cycle coal plants very quickly or efficiently either.)

Distributed natural gas fired mini and micro cogenerators can be quite flexible for grid hardening of solar/wind, since daily thermal loads are predictable, and thermal storage in tanks can be easily managed over the course of hours/days.  By not simply dumping the thermal output, cogens are significantly more efficient than even combined-cycle gas generators, and far more flexible, achieving source-fuel efficiencies comparable to mod-con boilers or condensing gas furnaces, but with a mixed power/heat output.  This approach is currently being developed on a large scale by the utility LichtBlick in Germany, for grid-hardening their substantial wind power investment.  They're using VW powered cogens & 1000+ gallon tanks with small building or house-sized thermal output, all under the remote control of the utility, who guarantees the building owner that their thermal loads are met. The building owner pays the fuel, but gets essentially free electricity, and all maintenance is performed by the utility.  They're on track to installing a couple-nuke's worth of highly flexible peak capacity before 2015. There are many parts of the US (most of it, in fact) where a similar model could be used to good effect. Gas-fired chillers' peak loads coincide with peak electricity loads, space heating loads have similar profiles, and the thermal output is storable for days.

With distributed generation, the grid is less susceptible to the types of interruptions being suffered this past week in Japan (even when you take the meltdown out of the equation.)  Whole chunks of the distribution grid can be taken down in such a scenario without having to resort to rolling blackouts, and if local generation capacity is reasonably sized to local loads, the generating capacity that's taken out in a disaster is only what was feeding the likely-damaged end-use load infrastructure.  With remote large central generators broken transmission lines or generators going down cripple the entire system.

By any factor, there is no one "best option".  But large-scale generation is expensive, slow to build/deploy and not very flexible at all.

Pretty interesting, Dana1, thanks for putting it up.

Do you happen to have any links to full English versions? GOOGLE translations are leaving me hanging a bit on the technical details.

When electricity hits 0.33 / kWh, couldn't we do this, too?

Assuming you're referring to the LichtBlick website PR descriptions, the only thing they have is:

http://www.lichtblick.de/h/english_information_395.php

The German descriptions are more complete, but still not very technical. VW has more English language descriptions of their part:

http://www.volkswagenag.com/vwag/nb09bis10/content/en/Ambitionen/Klima_und_Energie/Blau-Power.html

Searches on [vw cogeneration] come up with other English language descriptions eg:

http://www.german-info.com/press_shownews.php?pos=Economy&pid=1600

The US company Marathon has a somewhat smaller unit with ~40K of thermal output available in the US, but no big distributor or utility-scale buyer such as the the VW/LichtBlick arrangement. Installed pricing is on the order of $30KUSD at their current rate of production, but if they were cranking out 10,000/annum with a simplified standardized system setup (LichtBlick style) that could probably be cut to ~$20KUSD, maybe less.

http://www.marathonengine.com/cogeneration.html

The only other micro-cogens available in the US is a ~12KBTU/hr Honda, and their sole distributor only sells them bundled with condensing boilers & furnaces- independent designers can't just buy 'em to integrate into their own systems:

http://www.freewatt.com/

The bundled hydronic systems are WAY oversized for a superinsulated house, or even a modestly insulated non-McMansion house such as mine, (an 80-200K boiler + 10K cogen for a min-burn rate is WAY more than most US homes could ever use), but I have backchannel information that they expect to be selling a bundled system with a much-downsized hydronic boiler late this year- hopefully thats more than an insider-generated rumor. http://www.freewatt.com/hydronic.pdf

The smallest of their condensing furnace bundled versions can probably work for many existing homes though: http://www.freewatt.com/warmair.pdf

The Freewatt/Honda system is cost effective if net metered & at current MA natural gas electricity as prices (15-20cent electricity, $1.25-1.75/therm gas). Gas rates could double and there would still be a long-term NPV argument for it, but at current Boston area utility pricing it's a VERY good deal, if you have the thermal load for the ridiculously oversized hydronic boiler. (My biz partner has a ~6000K' leaky creaky 1840s antique of home in Newton, MA heated by a Freewatt Hydronic system. My house is less than half the size, and has ~1/3 the design-condition heat load despite a ~10F lower design temp where I live.)

Installed cost on the hot-air versions (not including ducts) is typically under $15K. The bigger hydronic system under $25K. (My partners' installed cost 4 years ago was about $20K.)

With micro cogens not under utility control running heating systems their peak output tracks perfectly with electricity peaks related to heating systems (heat pumps & air handlers, etc), but it takes a Lichblick approach and larger sizing on both the cogen and the thermal storage to use them for wind/solar power hardening. But even without smart grid control still a worthwhile approach though, since there isn't the additional capitalization costs- it IS the self-regulating peak generator for space heating related loads to the grid, not a backup, and doesn't introduce an intermittent wild-card into the grid control.

A substantial portion of the total grid power in Denmark, Finland, Russia, and the Netherlands is currently being source from gas fired mini & micro cogenerators. Team USA is WAY behind on the approach, with many nay-sayers despite the European existence proofs of how it's done:

http://www.climate.org/publications/Climate%20Alerts/Winter2009/EU.html

http://large.stanford.edu/courses/2010/ph240/askarov1/

Cogeneration in the US is about 8-10% of the total, but mostly at larger scale industrial & commercial installations. The micro-stuff could make a HUGE difference going forward though. State of the art combined cycle gas-fired power plants run at sub-60% thermal efficiency, traditional versions are sub-35%. With mini & micro-cogens running space heating or chillers, net thermal efficiencies north of 90% aren't hard to hit.

The economics of various approaches to mini-& micro cogens, wind, etc are spelled out reasonably in this document from 3 years ago that was primarily intended as pushback on the revived interest in nuclear power in the US:

http://www.rmi.org/cms/Download.aspx?id=2585&file=E08-01_NuclearIllusion+(1).pdf&title=The+Nuclear+Illusion

While it's biases are clear, the numbers are well-supported, and not particularly cherry-picked. It's a lot of reading, but if you want the synopsis, look at the charts & figures carefully. Micro-cogeneration is quite competitive on the total lifecycle cost on a per-kwh basis with coal (even without carbon tax) or large scale wind, and a fraction of the per-kwh lifecycle cost of nukes.

PV was of the charts at the time that was written, but panel pricing has crashed in the past 3-4 years with the growing production capacity of decent-efficiency CIGS technology PV in the US, and massive investment in silicon technology PV in China. To make PV cost-competitive without subsidy took ~35 cent/kw retail a handful of years back when Germany was setting subsidies, but it would be sub 25 cents now, and if the cost of the inverters/meters/installation came down by half, at current panel pricing on single-home scales it could compete straight-out in higher-priced electricity markets like CT or MA. (On 200kw+ installations it's cost competitive now.)

You can pick what ever alarmist photos you want, but nuclear kills 1/10 the people that solar does (see above link). Even so, I'm a solar fan - if they can just get the price and storage issues solved. Co gen (preferably turning geo thermal compressors) is OK when one needs the heat - but equipment price and maintenance is an issue.

The price issue with PV is now primarily an "all the rest" situtation- lifecyle cost/kwh the panels themselves are pretty cheap. The storage issue may (eventually, in some locations) be somewhat solved by an electrified auto fleet & smart grid, but longer term storage of PV output is still a pretty tough nut to crack.

Micro-cogens are cost-competitive with other sources NOW, (and will be more so when in higher production), even when maintenance is included. (Curiously, the engine used in the Marathon cogen was originally design as a direct-drive for a heat pump compressor, not a generator, but it get's higher net thermal efficiency as a generator unless the compressor end can run with an average COP of ~4.0 or better.) The Marathon micro cogen can be controlled as a modulating system (but with only a 1:2 turn-down), which can be used to lower the minimum thermal storage size or track electric loads directly. Thermal storage over periods days is quite cheap, and allows micro cogens serve the electrical peak loads asychronously with the peak thermal. The contrast of the capital required for storing the output of PV for a few days at similar efficiency is pretty stark. But if the PV storage costs become bounded, in heating dominated climates there's a pretty good complement to the seasonal outputs of space-heating microcogens and PV. In cooling dominated climates the daily/hourly output of PV falls significantly with cooling loads (PV runs at lower efficiency when hot- even worse when it's both hot and hazy), but a cogen's thermal output applied to chillers tracks both the thermal and electrical (from AC compressor) loads nicely. They're extremely flexible.

Nuclear may kill fewer people but...

...they take forever to build (making it a big financial risk)...

...are remote from loads (increasing the grid infrastructure requirements)...

... require backup power from other sources to cover refueling days/weeks down-time...

..do not modulate well to track grid load (primarily due to limited startup ramp slope- they turn down just fine)...

... and have a lifecycle cost/kwh 3-5x the alternatives.

As base-load generators to extensive & large grids they're OK, but at France's current share they're a serious pain to manage. Without a Spain and Italy to dump off peak power onto (at below the cost of producing that power) France would be in serious trouble with them, and they would be forced to build a huge amount of other, more flexible generation to manage the 24 hours grid loading cycles. When power can't be sold, the output of nukes is dumped, converted to heat rather than turning them down to suffer the power shortfall during the morning peak. (An electrified auto fleet could be used to advantage there as well.) During peak grid loads for air-conditioning nukes have to be throttled back due to their own increased cooling needs at max power during periods when cooling towers are less effective, making them an even worse choice for cooling dominated climates. (France has had to seek EU permission to increase the temperatures of rivers used for cooling to be able to supply sufficient power during heat waves.)

They may be safe enough, but they've gone from "too cheap to meter" to "too expensive to matter" at least for new nukes, in the intermediate term. (Keep the existing fleet going as long as they're still economic.) It's far easier & cheaper (even for the end customer) to regulate into existence a nukes-worth of higher efficiency at the load than to build the nuke to supply the same juice.

, not a generator, but it get's higher net thermal efficiency as a generator unless the compressor end can run with an average COP of ~4.0 or better.)

Not true. Either way, all the heat is used except for what goes out via exhaust. Plus any geo system with a COP > 1 will also bring in heat from outside - so it always wins over straight use of electricity. York's idea in their NG driven compressor was for cooling which makes far less sense.