Is Solar Really Too Expensive?

Larry Mapes | Sep 29, 2011


A friend of mine called and was very agitated because she had heard a commentator/professor from MIT say on a national news cast "solar is too expensive." The newscast had been centered on the nuclear plant meltdown in Fukushima, Japan and had apparently asked if there was a better way to power the region.

"Too expensive?" I was at a loss for words. With more than three decades of experience in the solar energy industry, I hear this all too often from the folks who are more familiar with traditional energy sources. For some reason, people in the US have a hard time understanding that solar energy is cost effective; this is especially true if you are talking about solar heating. Indeed, solar energy is not really understood by the general public, much less a professor from a respected institution.

I then decided to compare the costs of solar heating to nuclear power by measuring the energy produced for initial cost of construction or installation -- apples for apples, real numbers.

The solar heating numbers come from a nationally certified BTU (KWH) energy meter. The meter is installed on the solar heating system that heats Valverde Energy's headquarters. It is about 321 square feet of solar hot water collector area. This square footage would be a little more than we install on an average home. The electrical equivalent production of this solar system was about 18.9 Megawatt hours, or enough electrical equivalents to run 4 homes in the Taos, New Mexico area for this test period (note: I am measuring the heat output of a solar hot water system, not a solar electric system).

Solar hot water systems produce heat only. Solar heat systems like this are 4-8 times more efficient at half the cost of solar electric systems for the same amount of roof space. Now, the take away here is that I am producing energy that heats water the same as electricity would, and right where it's needed. The neat thing about solar heating is that storage of the energy is easy. No batteries! The water tank or the home is the storage system (this makes a well insulated house much more important!). I call this "point of use" storage.

Nuclear Comparison 

Fukushima Daiichi reactor #3 output is 760 Megawatts. If I measure the output of the reactor (when it was running) for the same time frame as my solar system measurement, the reactor produces 6,876,480 Megawatt hours of energy. This is taking into account that "nuclear does it all night" and my solar system takes a break when there is no sun.

If we were to rebuild the Fukushima reactor #3 today it would cost about $3.5 billion dollars. To decommission it would cost about the same as it does to build - the total cost: $7 billion. This does not include fuel for the reactor or any issues such as core meltdown or property damage resulting from a catastrophic plant failure.

To produce the same amount of energy with solar hot water systems that Fukushima Daiichi reactor #3 produces, we would need about 363,653 solar systems similar to the one I have at Valverde Energy headquarters. At this quantity of solar systems I am figuring the cost to be about $8 billion. This does not include maintenance costs, which are the only recurring costs with solar systems.

The lifespan of solar systems is similar to that of a nuclear power plant.
Some other points to note: solar heating systems will provide long term local jobs; a nuclear power plant has to be refueled about every 2-3 years; a solar heating system needs to be maintained about every 3-5 years.

Locally installed solar systems do not need a huge infrastructure to deliver energy (the grid); the energy is essentially free after the solar system is installed. I also don't have a bunch of fuel rods to store or worry about as I would with a nuclear power plant, if all of the worst-imaginable catastrophic events were to happen to the solar system, my neighbor does not have to evacuate his or her home.

All of the information here is real measured numbers. The information in this article is to create food for thought and not meant to endorse one energy source over another, as most energy sources have good and bad points. I did not account for any subsidies or loan guarantees that both the solar and nuclear industries presently receive. I also did not take into account the environmental impacts of mining the raw materials and manufacturing processes for either the nuclear or solar industries.

Perhaps the MIT professor would consider this information in his overall analysis.

Related Topics


Solar Cost

Larry: Based on worldwide costs, solar costs from $0.40 - $0.50 per kwh (based on the latest FIT figures received within the last 2-3 months),. If you are comparing the cost of solar to nuclear you may have a point, the constructed cost of a nuclear facility in the United States is beyond estimate. Comparing the cost of solar to natural gas fired energy it costs at least several times as much per kwh. What happens when we will no longer be subsidizing solar (or wind)?

Joseph Langenberg

solar technology

Indian govt is not at all suppotive of any such efforts.They should provide funds for development and manufacturing.And the process must be handled by Engineers and not administrators all along.

Solar will become competitive soon

As things stand Solar is expensive. There are two ways to reduce cost,one is higher efficiency of solar cells and the other bulk production. Every day in the press some advance in the efficiency of solar cells appears.

The researchers in Switzerland are changing the top glass structure of the solar cell, by depositing a layer of nanosized crystals from a transparent conductive oxide (TCO) onto the glass. This layer gives a high scattering effect and the light beam generates more electrons when it travels a longer distance though the cell, which enhances the cell’s light absorption. The researchers have managed to achieve a 30 percent increase in efficiency in comparison with standard thin film solar cells.

Another process that could increase the efficiency of thin film silicon solar cells, through changing the surface structures, includes ultrafast pulsed laser irradiation. Researchers at Singapore Institute of Manufacturing Technology have shown that this irradiation makes a nanospike pattern on the silicon surface which reduces reflection of the light from the surface. More light will therefore be absorbed.


New processes which create nanostructured surfaces are improving solar cell efficiency substantially.

Excellent research is reported by Argonne National Laboratory scientists on luminescent solar concentrators, thin film plastics treated with phosphorescent dyes that capture light rays, change them to a different wavelength, and then concentrate them along the outer edges of the film will improve the efficiency of solar cells, which when commercialised will increase the efficiency leading to reduction in the cost.

 Dr.A.Jagadeesh Nellore(AP),India




Solar Hot Water

This article is pretty disappointing.  As others have pointed out, it makes a comparison with nuclear power that is inappropriate - under the case most favorable to solar heating, solar should be compared to some blend of the incremental cost of nuclear, coal and gas-fired generation (not necessarily the prevailing cost of grid power, which is based on average costs). 

Moreover, while it is possible to store heat in the form of hot water, you'd need a pretty big tank.  Our home uses around 300,000 BTUs of gas per day in the coldest months.  assume 2/3rds of that thermal load has to be captured and stored during daylight hours and that the maximum temperature differential is around 120 degrees (210 degree hot water in storage, 90 degree water in the radiant heating loop).  The storage requirement would be around 1600 pounds of water, or 200 gallons. Most homes have 40 or 50 gallon tanks for domestic hot water, and of course all of the above assumptions area bit on the optimistic side.

It's something I've thought about since we already have radiant heating loops in our floor, but gas would have to be a lot more expensive than it is today and prices would have to stay at those levels for a long time before a solar heating system would be cost-effective.  Gas-fired radiant heating is a much better alternative in my opinion.  Our average annual cooling load is nearly 8,000 heating degree days, and we spend about $1,000 per year for gas to cook, heat a 3,700 square foot house and make hot water, which the neighbors find truly amazing.

Jack Ellis, Tahoe City, CA

By your numbers

By the numbers you provided:

Solar thermal is 1/7 (or 15%) more expensive than conventional fission thermal, capital cost, by gross energy.

You said, "Solar heat systems like this are 4-8 times more efficient at half the cost of solar electric systems for the same amount of roof space."  So, solar electric will be several times more expensive (28%, then increased by the lower efficiency modifier), than the fission power you compare to.  By your numbers.

Solar thermal heating is great, but I want lights, TV, a freezer and an air conditioner.  Your solar thermal doesn't provide the electricity for my home. And your Solar electric won't provide it at night, even after I pay at least a third more for it (your numbers).

 Now I did recently replace my home hot water heater, an affordable several hundred dollars from my local plumber.  Apples to apples solar thermal for home heating.

$8,000,000,000 / 363,653 Solar units = about $22,000 per solar unit?

"a little more than we install on an average home."

For my home heating, I can put in a new natural gas furnace, natural gas water heater, and buy natural gas at a residential cost of $16 per thousand cubic feet (EIA number) for many years at half that cost.

I'm not talking national energy policy.  But as a husband and father, considering median US household income is less than $50,000 a year (BLS number) - a little less than $22,000 of capital cost doesn't look feasible for most households, not when options that cost an order of magnitude less are being sold at Home Depot and Lowes.  Your numbers for solar, not mine.

I am a huge fan of renewables and solar thermal in particular.  The Mojave has like over a terrawatt of solar thermal potential - enough to power the US (I recommend you do the calc, it's impressive).  But solar isn't there yet.  Solar won't give us super critical steam for competitive heat rates. (Thermodynamics 101 –  temperature difference matters as much as BTU for power generation).  We don't have gigawatt hours of electrical storage to get us through the night (even more cost). Yet.  Solar is a great niche with potential that deserves to be developed until it becomes cost effective for more applications.  But those investments are measured in millions, not billions of dollars.

“Too expensive” is a matter of opinion.  But by your own numbers, solar is more expensive, even simply for heat.  And even in a good economy people have limited resources, and will tend towards the most affordable option. 


Compare the apples with apple pie

The problem with intermittant energy resources, like Solar and Wind, is that they need to be adjusted somewhat to be compared with grid power.  If you want to do an economic analysis of solar PV, you either can include the cost of storage, like batteries and associated support, or compare it to the generation costs of grid power without the transmission, distribution, and support costs. 

If you want to consider off grid (battery based), remember to size the system based on what you are expecting from it.  This needs to include starting the larger anticipated loads, like compressors, running the larger intermittant loads, like dryers or ovens, or converting them to other fuels than electric (which might not be very clean).  At the end of the day don't assume you can get 200 amp service with your off grid system, at least not very cost effectively.  If a larger system, like the multi-megawatt systems being installed, include some type of demand limiting to avoid overload.  Remember that once you touch the grid your generation value has changed.

if you are comparing to grid connected, the cost of base electritiy, without the transmission and other support costs, is only $.02 to $.03 per kWh.  Not too many solar systems want to be compared to this, but go ahead and run the numbers.  Coal and gas generation are relatively cheap, and the capacity needs to be built anyway because the wind and solar they are backing up are intermittant.  So really only the fuel costs can be considered as the avoided cost, maybe with some small diversity factor included.  But there will be a day when the wind doesn't blow and the sun doesn't shine, so don't discount it too much.

I believe in the long run we will need to get ourselves off of the fossil fuels, as we have more valuable ways to use them, but let's not underestimate the costs or effects of doing this.  We may be more willing to put on the sweater, or sweat a little in the summer, than to pay the true cost of living our present life style with renewables.


Is solar really expensive?

I will not disagree with you, but we cannot define what is too expensive. That is a perspective of the user and owner and changes with each individual and from region to region. The key to the comparison is what are you currently paying for power and energy and what is the comparible cost using solar or renewable technologies. I am an Energy Engineer and promote all the technologies but do it in a pragmatic way showing our clients this comparison.

The cost of PV solar ranges from $0.12/kwh to $0.20/kwh depending on the life of the system, the range and other factors. This may be less than utility power in the east and west coasts but not in the middle of the US. Solar thermal is another issue and is usually less costly but most of the time is used to heat and not provide electricity although it can offset electric use and may range from $8-$16/mmbh.

So you do the comparison and if solar is more than your utility power, is that expense worth it to you to save the environment?

J. Christopher Larry "Captain Energy"



Holy Cow I can't believe this was printed

Solar Heating is not what people think when you say solar is "too expensive", I don't  care what was on tv at the time.  And you compared solar heating to nuclear  Here in the unidos estados we generate using slightly lower cost generating resources, we call them coal and gas plants.  Although you might not have heard of these crazy technologies, they actually have been around for a while and make up over 50% of the generation in the area between Canada and Mexico 

Do me a favor and change your article title to "Does Nuclear Still Cost Gagilians and Is Solar Less?"  Part II of the article can address the important decision of whether  installing your own residential nuclear driven water heater is in fact  more expensive in the long run than a residential solar water heater.  I know you will think a micro nuclear plant at your home may be more expensive, but consider power density.  Before I read this article through, I must admit, that I had the inclination to believe that MIT professors may be educated. 

Not apples to apples

Comparing solar heating to a nuclear power facility is not an apples to apples comparison because of the differing "quality" of energy produced.  It is actually pretty dumb to heat water with an electric water heater except for the fact it is so easy to transport electricity.

Anyway, solar water heating works at temperature levels that are adequate only to generate hot water or maybe low temperature steam--too low to reasonably produce electricity.  This makes solar water heating only good for that although it could be usefule for building heating and for absorption chilling for building cooling if one has a large enough heat sink.  Electricity from a nuclear facility--or any other electrical generation facility--can be used for lighting, computer power, appliances, induction heating of metals in industry, driving electric motors....a myriad of things low level heat cannot do.

Solar as an electricity producer is too expensive.