Building wind turbines to dry laundry…?

Do we really want a CO2-neutral society, or even a society with closed cycles? If yes, a lot will have to change and we will need to become extremely creative. And not directly with the input of a lot of ’technology’, in the sense of high tech, but back to methods that demand very little energy and material input, and let the sun or its derivatives do its work. I wrote earlier about de-electrification, where I replaced my electric transformer door bell with a XL bicycle bell. And it works fine, I can tell you. Only you can not hear the bell in the back of the garden, but whether that is the main criterion ….

There are many studies that indicate in which direction we have to develop, if we are to become CO2 neutral, or as indicated in German studies: a society of 1 ton CO2 / year per capita. That is not possible without some modifications in the lifestyle. Now for a doorbell is not such a big thing, (why does not that happen to everyone?) , but more compelling is ‘living smaller’ , less m2 house per person. A more appealing example might be : drying the laundry outside again. Let the sun and wind do its work. That’s how we did it 30 years ago. To reintroduce that again, of course, will meet some resistance (also with my wife!), because someone has to hang up the laundry. But if we compare that system-technically, an electric dryer versus hanging the laundry to dry outside, it turns out to be advantageous in many respects.
Remember: We construct millions of wind turbines to generate the electricity to drive our clothes dryer, but to hang up the laundry and let the wind do its work directly, we ignore… Its a strange attitude: “ The government should catch the wind, so that we can have our drying machine ..”

Drying the laundry outside, skips all system conversion steps, and is from cost point of view a no-brainer” the most simple way to do something about CO2 emissions, and without cost, even saving yourself and society a lot of money. But Hey, whats money ? Raising children does not cost anything either, still we bring them to a child care center paying a lot of money. A kind of robot training centre ‘avant la lettre’. Which will be also the problem later, with real and learning robots: They do not have real parents anymore, to which they are loyal, or parents that are responsible and can correct the robots/children. Nor will robots have children for which they will feel responsible. Anyway, I am deviating from the subject. We want to know if it works physically, laundry drying , that is.

So lets do some math: the space-time of laundry drying.

With space-time calculations, its only about system value: calculated from solar energy input, the real driver of the earth ( closed) system, the only source that does not deplete our system. And to capture and intercept solar energy requires land, to convert it in a useful form: , which gives a certain flux over time to be captured from a standard land unit. To convert it into food, energy or mass resources.

For laundry drying we take the example of 1 drying cycle, out of 200 a year, with around 4 hours of drying outside for one cycle.

The clothesline alternative

We need 4 meter of clothesline, to hang up the laundry, possibly with coat hangers, and reserve 40 cm width. Which gives a ground projection of 1,6 m2 .

The laundry hangs for 4 hours ( so claims 4 hours of sunshine/wind potentials as energy source). Related to a year ( of 365 days and 12 hours of potential), thats 0,00092 year.

Together: thats 1,6 m2 times 0,00092 year is 0,00147 m2-year/ Thats the space time needed for delivering solar related energy potential to dry 1 laundry cycle.

It will not happen by gnomes, so someone will have to invest labor (-energy) : 10 minutes to hang up the clothes, 5 minutes to take hem down, total 15 minutes per cycle. Thats part of say 8 hours of energy input per day by a human being, so the 15 minutes is the 1/32 part of food/energy intake . Assuming a affluent diet, that takes 3000m2 yearly to produce, it requires 0,26 m2-year for labor-food-energy to dry the laundry.

Together thats 0,26147 m2 year.

Which is without impact from clothespins and drying line, which however can be neglected, its a very little contribution, since being made from (very little amount of) renewable material, and per year they account only for 1/200 part).

But its also exclusive from double use of the space: above the drying line there could have been solar panels installed. Sharing and halving the drying space need.

The drying machine alternative

One cycle of drying in a machine consumes around 1,35 kWh ( for a A++ machine, 200 cycles a year, 10 year lifespan) If one m2 of solar panel produces 120 kWh a year , then 0,0112 m2-year is needed for that drying cycle.

We have to add the Embodied energy of the drying machine: its estimated as 800 kWh * . With 200 cycles a year and 10 years of lifespan thats 0,4 kWh per cycle, which requires 0,0033 m2year of a solar panel.

We have to add the space time taken by the machine itself: which is 0,8×0,6 = ~ 0,5 m5-year. ( in fact it requires some working space around, say 1 m2, but since the drying machine can be stacked upon the laundry machine, we give it this shared benefit) Mind that this indoor m2 could have been avoided constructed, and then act as outdoor space to collect energy)

Together for the machine alternative thats 0,5145 m2-year

Which is double that of the drying line alternative ! And even only accounting the primary direct impact. The difference is in fact much bigger since some 2nd and 3rd order impacts have been neglected so far, like:

The actual production of solar panels has impact as well. So fare we just took the actual installed fraction. But we have to compensate the the production energy and regeneration of used resources. **

Even then we are not complete: For the drying machine we only took the embodied energy , but not the circular energy: required for regenerating the machines resources ( the circular part of a resource cycle) . [1] Unfortunately data are not yet available for that, but have a serious extra impact since its nearly all metals involved. And then we still need to add the impacts from the materials to construct that extra m2 in your house.

While on the side of the clothesline , things can be easily reduced: if the inhabitant is a vegetarian eater, the space time, land needed to produce food reduces significantly: to 1/3 , and the impact from the drying machine eve becomes 5 times as big.

However, the message is clear even without all those detailed calculations: System-analytically spoken its much more interesting to hang up the laundry to dry outside by the sun and wind: energetically and resource wise . Its also very effective to put in some labor by yourself. Yes, you might find it a boring task, and prefer to work a extra 15 minutes a day in your job, to earn enough money to pay for that drying machine processing. But hey, money is schizophrenic, it values office meetings more then labor, even when including the burden to the government of constructing wind turbines….

By the way. Here it is assumed the laundry is dried outside . To do that inside is not wise, since it raises the heating energy ( at least in the heating season) . Unless you have a unheated ventilated area like a garage. ( In summer it can provide some cooling when drying inside) .

In frost period its a bit different: if you have the laundry inside it still will cost extra heating but can increase humidity in a usually too dry indoor environment. However, the amount of frost days in the Netherlands during daylight is very low, in 2015 that was in total 1 day. Just wait a day with doing the laundry then. [2]

The beautiful thing about this calculation is that it shows that a detailed and complex LCA or other environmental impact calculation might be commercially interesting for a drying machine producer, but socially is superfluous: Socially and environmentally seen the solution is not in optimizing the drying machine, but by analyzing the function of “ drying laundry” , leading to a scale step, or another system choice. Which is analytically much easier made and effective. A LCA of a clothesline solution is then reduced to the line and pins ….




* probably much too low: another research shows 1000 kWh [3] Both calculations are based on process analyses, for which its scientifically known to be too low. Input output methods to calculate embodied energy show much higher figures, but are not known for drying machines . At least not publicly available, or anyway, not found so far.

** A first exploring study shows that some 130 m2 of solar production space should be reserved per m2 installed solar panel, during the lifespan of the panel, required to close the resource cycle of the panel ( to compensate for energy input and restoring resources stocks) . Embodied land is around 3200 m2-year total, divided by 25 years of lifespan ). The share in this case comes down to 0,0112 x130 = 1,456 m2 per year extra. [4]





[3]zie oa:

– Resource efficiency indicators for EU product policy, embedded energy in washing amchines – using EcoReport tool , Alma Garcia , thesis Aalborg University , June 2013

– Boustani, A. et al. “Appliance Remanufacturing and Life Cycle Energy and Economic Savings.” in Proceedings of the 2010 IEEE International Symposium on Sustainable Systems & Technology, IEEE, 2010. 1–6. Web..

– LCA study laundry drying systems,

[4] zie [1] en berekening met Maxergy: (onderaan xls file voor PV)

Author: ronald rovers