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Cybernetics & Sustainability:

Comparative LCA TEAM TAMAGOTCHI: CH ARLOTTE BELLIARD – JAMIL JOUNDI – ARNO PENDERS

2 0 1 5 – 2 01 6

INTRODUCTION

CONTEXT

Rabot is one of the poorest districts of Ghent. In the heart of Rabot lies the Tondelier Site. Here, people from

Rabot (the community) can come to work on the fields where vegetables for Café Toreke are grown. Every

helping hand is rewarded with ‘Torekes’, a new implemented currency. With these Torekes, the community

is able to pay for their own city garden at the site, where they can grow their own vegetables.

A container can be found on the site. People that are willing to work on the fields, have to come in this

container to enrol for that day and to receive payment afterwards. Also, a ten-minute break is allowed, during

which coffee is given in the container.

INTRODUCED SYSTEM

In the container, a system has been installed by Team Tamagotchi. Fourteen little pots of dirt are being

illuminated by three LED-lights. The lights emit pink light (red and blue) to stimulate growth.

People from the community can use a pot to plant some seeds. The plant can be fully grown with this system,

but it’s also possible to replant it in the gardens outside when it’s strong enough.

COMPARATIVE LCA

HYPOTHESIS

In this LCA the comparison is made between the sustainability of growing lettuce assisted by LED-lights (the

introduced system), and growing that same lettuce outside in a city garden (the competitive system). The

functional unit in this case is 1 kg of lettuce for the end-user. We expect to conclude that the introduced

system is more sustainable than the current system and predict that some elements of the introduced system

will have to be replaced in order to become a more sustainable system.

REPRESENTATION

We are taking Yusuf as ‘the average’ representation of the community, and study his situation for this LCA.

Yusuf is a 92-year-old man, originated from Turkey where he has been a farmer his whole life. He doesn’t

understand Dutch or English. Every Wednesday, Yusuf comes to the Tondelier Site to work on the fields in

exchange for Torekes. Every work session counts three hours. After these hours, Yusuf stays about one

hour longer to take care of his city garden.

He comes into the container to enrol for that day, to take a ten-minute coffee break and to receive his

payment in Torekes.

For both systems, Yusuf goes the same distance between his home and the site, so we’ll eliminate this

energy flow from the comparison. However, the energy he uses to work at the site won’t be the same in

both systems, so we will have to take this into consideration.

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The community is guided by vzw VELT, telling them what and when to sow and delivering the seeds. In

this specific case, we consider ‘pluksla’ (loose-leaved lettuce). It sprouts within 2-14 days at a temperature

between 5 and 18 °C, but doesn’t like too much sun. The first leaves can be eaten after three weeks, but the

lettuce is full-grown (30 cm diameter and 30 cm high) after eight weeks. Lettuce of this size weighs about

0,2 kg1, in other words: there are five full-grown plants of pluksla needed to become 1 kg of lettuce for the

end-user.

Pluksla needs a lot of water during the sprouting, but an average amount during the growth.

VELT recommends to grow pluksla in a greenhouse to be able to grow it all year long.

MODEL OF REALITY

In Figure 1 the Model of Reality for the competitive system is shown. The Model of Reality for the introduced

system is shown in Figure 2. The percentages of waste and recycling will be calculated later on.

Since we are making a comparative LCA, equal elements can be eliminated. These are marked red in the

figures below. The parts marked grey are left out of the Models of Reality, since these aren’t needed for the

systems to work.

Figure 1: The Model of Reality of the competitive system

1 Personal observation

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Figure 2: The Model of Reality of the introduced system

COMPETITIVE SYSTEM

According to vzw VELT pluksla can be sown from March until September. Nevertheless, pluksla has

limitations which are better not exceeded if you want maximal result. Even during the period March-

September, some days are too hot/cold or have excessive/inferior rainfall. The days during these seven

months that exceed the limiting boundaries are converted to a percentage of wasted lettuce caused by the

weather. We found that 39 % of the sown lettuce goes to waste during March-September due to the weather,

but that .65 %. 2 of it is wasted on yearly basis.

Since we are talking about a city garden, there has to be put energy into taking care of the plants. On one side

we have Dimitry. Dimitry is the supervisor of the Tondelier Site. He guides the volunteers and the

community as they work on the field and in their city gardens. Since Dimitry mainly walks and talks to

support the community, and this energy should be allocated over all the gardens and fields, the effect of

Dimitry on the lettuce will be negligible.

On the other side, we have the owner of the city garden: Yusuf, in this case. As explained earlier, the energy

to come to the site isn’t taken into calculations, since the same distance has to be covered for both systems.

Yusuf uses the large watering can (13 l) to bring water from the faucet to his city garden and to water his

vegetables. To do so, the body has kinetic and potential energy. Yusuf’s total energy put into the system, (1

cycle = 1 batch of full-grown plants) is .2456,4kJ. 3.

2 For calculations, see annex [A.Figure.1-4] 3 For calculations, see annex [A.Figure5-7][1-8]

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Pluksla is full-grown after eight weeks. In his lot, Yusuf grows twenty pieces of pluksla at once. This means

that, in ideal situations, after eight weeks he’ll end up with twenty full-grown plants (waste not taken into

account). If Yusuf sows smartly he can run three cycles of sowing and growing during the period March-

September, which means that in one year Yusuf can grow .60 plants. of pluksla.

Running three cycles means that Yusuf’s total yearly energy input to grow lettuce is .7 369,2 kJ.

The large watering can weighs about 0,5 kg and is made out of HDPE. The can in this case originates from

Jagtenberg Plastics (NL) and has a life span of twenty years. The total amount of energy to produce, transport

and dispose this large watering can is .51 500 kJ. 4, but .10 400 kJ. is recovered by the end-of-life potential.

Since the watering can has to be shared with forty city gardens, the amounts have to be divided by forty.

This makes that .1 287,5 kJ is needed, of which .260kJ. can be recovered. The CO2-footprint of the can is .0,06

kg. due to the production and .0,001 kg. for the end-of-life.

The city garden of Yusuf is supported by six cement bricks of 30x30x5 cm that weigh about 10 kg each. The

bricks originate from pavement of Ghent. The total amount of energy to produce, transport and dispose these

bricks is .181 000 kJ. 5, but .168 000 kJ. is recovered by the end-of-life potential. Since these bricks have a

previous life, we decided to divide the amount of kJ by two, so that .90 500 kJ. is needed and .84 000 kJ. is

recovered. The CO2-footprint of the bricks is .27,2 kg. for the production and .26,2 kg. for the end-of-life.

MODIFICATION

Year in year out, Yusuf will invest the same amount of energy per cycle of sowing and growing lettuce. But,

not every year new bricks or a new watering can are needed. Therefore, a modification is in place.

The city gardens were founded in 20066. Simultaneously the project ‘Oude Dokken’ was founded, with the

vision to renew the Rabot. A new apartment block will be built on the Tondelier Site and is planned to be

done in 20207 approximately. Thus, the city gardens last fourteen years.

In fourteen years, fourteen times the yearly energy of Yusuf will be needed. Taking a margin of error into

account, we decide that not one but two watering cans will be needed in this context in these fourteen years.

We also assume that the cement bricks will not be renewed.

Modifications are shown in Table 1.

Table 1: The Modifications of the values of the Competitive System

What Input (Energy) Output (Energy) Input (CO2) Output (CO2)

Yusuf 7369,2 kJ 0 0 0

X 14 103 168,8 kJ 0 0 0

Watering can 1287,5 kJ - 260 kJ 0,06 kg 0 kg

X 2 2575 kJ - 520 kJ 0,12 kg 0 kg

Cement bricks 90 500 kJ - 84 000 kJ 27,2 kg - 26,2 kg

X 1 90 500 kJ - 84 000 kJ 27,2 kg - 26,2 kg

RESULTS

The amounts of the analysis of the competitive system are given in Figure 3. The comparison between input

and output is given in Table 2. The resulting equation for the competitive system is shown in Figure 4.

4 For calculations, see annex [A.Figure.8-10] 5 For calculations, see annex [A.Figure.11-12] 6 https://stad.gent/samenleven-welzijn-gezondheid/samenleven/samen-doen/tijdelijk-gebruik-van-publieke-ruimte-en-

leegstaande-gebouwen/de-site 7 http://www.oudedokken.be/mijlpalen

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Figure 3: Summary of the analysis of the Competitive system

Table 2: The comparison between the input and output levels of the Competitive system

Figure 4: Energy of the competitive system during the years

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CONCLUSION

Looking at the results of the Competitive system, following conclusions can be made:

The large watering cans

o The amount of energy needed to produce and transport the watering cans, is almost as high

as the most impactful amount of energy (Yusuf’s work) in this system. Besides, only one fifth

can be recovered. But since the cans are shared between forty gardens, the impact of the cans

is very low and almost negligible in comparison to the other values. The impact of the cans

can be lowered even further, by using a different material such as galvanized steel8, which

will also lower the CO2 footprint9. Another possibility is to make sure that the can is always

brought to the recycling centre when it’s no longer needed.

The cemented bricks

o The bricks need a relatively high amount of energy to be produced and disposed.

o The CO2 footprint of the bricks is by far the highest. The main cause isn’t the dact that a small

amount of bricks is transported in a small truck, but is the material itself.

o Luckily the energy and CO2 impact can almost be fully recovered because of the long product

life and high reusability of the bricks.

Yusuf

o The amount of energy needed from Yusuf is the highest of all the elements. A possible way to

decrease Yusuf’s impact could be to make him work harder. This means that more work can

be done in less time, but would also mean that the level of discomfort would rise which can’t

be the goal.

The weather

o The weather has the biggest impact on this system, causing 65 % of the sown lettuce to go to

waste. The only solution for this problem is to introduce a new system. In the next chapter,

the comparison will be made with the system introduced by Team Tamagotchi.

In general, during the full fourteen years of project Site Tondelier 196 243 kJ (of which 84 520 kJ can be

recovered) and 27,3 kg CO2 (of which 26,2 kg can be recovered) is needed to have 58,8kg of pluksla for the

end-user. This means that for 1 kg of pluksla for the end-user 0,5 kg of CO2 is emitted of which 0,4 kg

can be recovered, and 3 337,5 kJ is needed of which 1 437,4 kJ can be recovered.

INTRODUCED SYSTEM

The introduced system is implemented in the container at the site. Indoors, the weather will no longer have

such an impact on the growth of the plants. Yet, the container has its own ‘climate’. The container is heated,

but only during the day. At night, especially during the winter, the container can be too cold for the plants

to grow. The days that exceed the limiting boundaries are converted to a percentage of wasted lettuce. With

the watering taken in account, we found that on yearly basis .10 %.10 of the sown lettuce goes to waste.

Yusuf uses the small watering can (1,5 l) to water his vegetables. He only has to walk 5 m to fill his can with

water from the vat, so this kinetic energy will be negligible. The energy he needs to water his one pot during

one cycle of three weeks is .460,5 kJ11. If Yusuf sows smartly he can run seventeen cycles of sowing and

growing, which means that in one year (ideally) Yusuf can grow .17 plants. of pluksla in his one pot. Running

seventeen cycles means that Yusuf’s total yearly energy input to grow lettuce is .7 828,5 kJ.

All elements from this context of the LCA are calculated with CES Eco Audit, therefore ell the conclusions

and references are summarized in Table 3.

8 According to CES Eco Audit, the same watering can made from galvanized steel requires 20 MJ instead of 39,3 MJ 9 According to CES Eco Audit, the same watering can made from galvanized steel requires 1,58 kg instead of 2,3 kg 10 For calculations, see annex [A.Figure.1-4] 11 For calculations, see annex p.19

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Table 3: The Modifications of the values of the Introduced System

RESULTS

The amounts of the analysis of the competitive system are given in Figure 5. The comparison between input

and output is given in Table 4. The found equation for the competitive system is shown in Figure 6.

Figure 5: Summary of the analysis of the Introduced system

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Table 4: The comparison between the input and output levels of the introduced system

Figure 6: Energy of the introduced system during the years

CONCLUSION

Looking at the results of the Competitive system, following conclusions can be made:

The lamps

o Clearly, the lamps have the largest impact as well on energy levels as on CO2 levels. Their

values are even a factor ten higher than those of the second largest values, namely the impact

of Yusuf. The main reason for these large numbers is the energy consumption. Luckily for the

community, they don’t have to pay for the electricity, but this doesn’t change the fact that the

consumption is relatively high (in comparison to the other values).

o The value can only be drastically lowered by changing the lamps (<20 W), but this will cause

a drop in effectiveness of the system, which can’t be the goal of this system.

o The lamps are reason the percentage of waste is this low.

Lowest impact

o The watering can has the lowest impact on energy level. This, mainly because of the fact that

the can has to be shared between sixteen pots.

o The tensioning cables have the lowest impact on CO2 level.

Yusuf

o The amount of energy needed from Yusuf is the second highest of all the elements. A possible

way to decrease Yusuf’s impact could be to make him work harder. This means that more

work can be done in less time, but would also mean that the level of discomfort would rise

which can’t be the goal.

In general, during the full project of Site Tondelier (14 years) 1 214 195 kJ, of which 19 353 kJ can be recovered,

and 54 kg CO2 is needed to have 42,8 kg of pluksla for the end-user. . This means that for 1 kg of pluksla

for the end-user 1,3 kg of CO2 is emitted and 28 369 kJ is needed of which 452 kJ can be recovered.

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COMPARISON OF BOTH SYSTEMS

The comparison of the energy and CO2 levels of both systems is showed in Table 5 and visualised in Figures

7 and 8.

Table 5: The comparison between the input and output levels of the introduced and comparative system

Figure 7: Comparison of the total energy level per system Figure.8: Comparison of the total CO2 level per system

In this context not only the energy and CO2 levels are important, but for the community the focus lies mainly

on the effectiveness of the systems. The comparison is visualized in Figures 9, 10 and 11.

Figure 9: Comparison of the effectiveness of the comparative and the introduced system

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Figure 10: Total of full-grown plants of lettuce per system in one year Figure.11: Number of full-grown plants of lettuce per month

CONCLUSION

This comparative LCA brought several aspects to light:

In this context, the comparative system requires less energy to produce 1 kg of lettuce for the end-

user than the introduced system, namely 3337,5 kJ to 28 368 kJ. The main reason is the used electricity

for the LED lights, which consumes an amount of kJ a factor ten higher than the largest values of both

systems.

In this context, the comparative system is able to recover more energy in end-of-life scenarios than

the introduces system, namely 1437,4 kJ to 452 kJ per kilogram lettuce for the end-user. This is due to

the fact that the comparative system uses elements that are shared between more units than the

introduced system. Apart from that, the elements of the comparative system are more durable and

need fewer/no replacement. A well-considered choice of materials for the introduced system can

heighten the amount of recovered kJ in end-of-life scenarios. As an example: not using wooden crates

and aluminium pots, but planting directly in a large bin.

In this context, the comparative system emits fewer CO2 than the introduced system, namely 27,5 kg

to 55 kg per kilogram of lettuce for the end-user. You would think that the main reason for this is that

the introduced system uses second life or local materials, where the introduced system mainly has

products delivered from China, but this is wrong. In fact, if the emission of the LED lights wouldn’t

be taken into consideration the CO2 emission of the introduced system would be the lowest, namely

6 kg to 27,5 kg per kilogram of lettuce for the end-user.

In this context, almost all of the CO2 emissions in the comparative system can be recovered. This due

to the fact that the materials used can be reused or need less renewing. In the introduced system only

three percent of the CO2 emissions can be recovered.

After considering the aspects above, one would think that the comparative system is more sustainable than

the introduced system. However, one very important aspect can’t be ignored: time.

Where the comparative system needs eight weeks to produce a full-grown plant, the introduced system

needs only three. Besides, the comparative system can only be used during the period March-September,

while the introduced system can be used year-round. Last but not least, the comparative system is dependent

on the unpredictable aspect ‘the weather’ and therefore has to cope with large numbers of waste (65% to

10%). Of course, we are talking about different scales since the city gardens cover more area, which is why

therefore the comparative system still delivers more plants. But, the sustainability of the introduced system

lies in the fact that the amount of waste can be reduced drastically. Considering Yusuf’s cycles ( twenty plants

in eight weeks in the comparative system and one plant in three weeks in the introduced system), the

comparative system will waste 109 kg of lettuce per year to deliver 58,8 kg, while the introduced system will

waste only 4,8 kg to produce 48,8 kg.

In conclusion, when considering every aspect from this LCA, we advise to use the introduced system as an

addition. Not only to be able to grow vegetables during winter time, but also to strengthen sprouting plants

before putting them ‘out there in the big world’.

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Cybernetics & Sustainability:

Comparative LCA - ANNEX COMPARATIVE LCA

THE COMPETITIVE SYSTEM

THE WEATHER

For this competitive system, the period March-September is taken into consideration.

SUNSHINE/TEMPERATURE

A.Figure.1 shows the normal temperature in Belgium for the years 1981-2010, the average monthly

temperatures and the boundary temperatures for pluksla (5°C and 18°C). This figure confirms that March-

September are the ideal months to grow pluksla. But, some days of these months exceed the boundaries.

Based upon these days, the total waste of pluksla is calculated [A.Figure.2].

A Figure 1: Graphic of the normal temperatures in Belgium – Source: KMI

A.Figure.2: Calculation of the monthly and average percentage waste of lettuce, due to temperature

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From A.Figure.2 can be concluded that the input of the sun in Belgium causes 25 % of the lettuce sown in

this period to be wasted due to temperature.

The energy-input of sunlight isn’t put into the calculation, since the sun can be allocated. The sun was already

there before the city gardens were introduced.

WATERFALL

A.Figure.3 shows the normal rainfall in Belgium for years 1981-2010 and the average monthly rainfall based

upon the years 2013-2015. To calculate the waste of lettuce caused by excessive or inferior rainfall we’ve taken

a reach of 20 % of the monthly normal.

A.Figure.3: Graphic of the normal rainfall in Belgium – Source: KMI

A.Figure.4 illustrates the calculations made.

A.Figure.4: Calculation of the monthly and average percentage waste of lettuce; due to rainfall

From A.Figure.4 can be concluded that 14 % of the total lettuce grown is wasted due to excessive or inferior

rainfall during March-September.

The energy-input of rain isn’t put into the calculation, since this can be allocated.

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CONCLUSION

In total 25 % + 14 % = 39 % of the sown lettuce is wasted due to temperature or rainfall during March-

September.

To compare this result with other findings, e.g. the LCA of the introduced system, the whole year has to be

considered and not just the months March-September. The other five months, during which 100% of the

sown lettuce is wasted, can’t be ignored. Therefore:

% 𝑙𝑒𝑡𝑡𝑢𝑐𝑒 𝑤𝑎𝑠𝑡𝑒𝑑 𝑑𝑢𝑟𝑖𝑛𝑔 𝑎 𝑦𝑒𝑎𝑟 =7 𝑚𝑜𝑛𝑡ℎ𝑠 ∗ 0,39 + 5 𝑚𝑜𝑛𝑡ℎ𝑠 ∗ 1

12 𝑚𝑜𝑛𝑡ℎ𝑠= 0,644

The input of the wind isn’t taken into calculations, since there are too many ‘averages’ to take into account.

Therefore, we decided to round up the total percentage of wasted sown lettuce due to the weather to 65 %.

ENERGY FLOWS

CARRYING THE WATERIN G CAN

About one third of his vegetables are lettuce.

The watering can has a volume of 13 l. Assumed that Yusuf only fills half the can (considering his age), the

can will weigh 7,5 kg + the weight of the can (0,5 kg in average). So Yusuf will have to carry 0,5 kg for about

30 m and 8 kg for about 30 m. The average speed for elderly people is about 1,25 m/s1213, but taking in

consideration that everything at the Tondelier Site is done at ease, we decided to round this number down

to 1 m/s. Assumed that Yusuf is about 1m60, he’ll carry the can about 0,6 m above ground level to bring it to

the city garden and he’ll lift it up to 0,8 m above ground level to water his lot [A.Figure.5-6].

During the process of watering the vegetables, the watering can will lose mass because of the loss of water.

Calculations for watering the vegetables are made with the average amount of water in the watering can.

Yusuf needs to fill his can two times to water his whole lot.

A.Figure.5: Yusuf standing over his city garden A.Figure.6: Visualization of the proportions of Yusuf watering his city garden

Carrying the empty can to the faucet

12 Aspelin, Karen - "Establishing Pedestrian Walking Speeds" (PDF). Portland State University. Retrieved 2009-08-24. 13 "Study Compares Older and Younger Pedestrian Walking Speeds". TranSafety, Inc. 1997-10-01. Retrieved 2009-08-24.

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E 𝑘𝑖𝑛 = 1

2 𝑚𝑣2 =

1

2 0,5𝑘𝑔 ∗ (1 𝑚

𝑠⁄ )2 = 0,25𝐽 [1]

E 𝑝𝑜𝑡 = m. g. h = 0,5𝑘𝑔 ∗ 9,81 𝑚𝑠2⁄ ∗ 0,6m = 2,9J [2]

Carrying the filled can to the lot

E 𝑘𝑖𝑛 = 1

2 𝑚𝑣2 =

1

2 8𝑘𝑔 ∗ (1 𝑚

𝑠⁄ )2 = 4𝐽 [3]

E 𝑝𝑜𝑡 = m. g. h = 8𝑘𝑔 ∗ 9,81 𝑚𝑠2⁄ ∗ 0,6m = 47J [4]

Carrying the filled can to water the plants

E 𝑝𝑜𝑡 = m. g. h =8,00 𝑘𝑔−0,50 𝑘𝑔

2 ∗ 9,81 𝑚

𝑠2⁄ ∗ 0,8m = 29,43 J [5]

Legend

Ekin: Kinetic Energy in J Epot: Potential Energy in J

m: Mass in kg v: Velocity in m/s

g:Gravity in m/s² h: Height in m

Taken into account that only one third of the lot consist of lettuce and that Yusuf does the above actions two

times, the weekly amount of energy needed to water the lettuce is given in [6]

E =2∗(0,25𝐽+2,9𝐽+4𝐽+47𝐽 +29,43𝐽)

3 = 0,05 kJ [6]

Legend - E: Energy in kJ

In conclusion, Yusuf uses 0,05kJ per week to water his lettuce.

GARDENING

Apart from watering, Yusuf does some general gardening too. Weekly, he works about one hour in his city

garden. We assumed Yusuf to weigh 55 kg and took the average of three different calculators [A.Figure.7]

that gave the required energy to perform 1 hour of gardening [7].

A.Figure.7: The energy needed for a person of 55kg to do 60min of gardening

E = 1150 kJ + 924 kJ +690kJ

3= 921 kJ [7]

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Legend - E: Energy in kJ

Taken into account that only one third of Yusuf’s garden consists of lettuce, this amount has to be divided

by three, so that Yusuf uses 307 kJ per week to do some general gardening.

CONCLUSION

As explained higher, pluksla takes about eight weeks to fully grow. Therefore, Yusuf’s total energy input

will be eight times higher [8], namely 2456,4 kJ.

E = 8 ∗ (0,05𝑘𝐽 + 307𝑘𝐽) = 2456,4 kJ [8]

Legend - E: Energy in kJ

WATERING CAN

The specs for the watering can are given in A.Figure.8.

A.Figure.8: Basic specifications for 13l watering can – Source: Jagtenberg Plastics

Choices made to fill in the CES Eco Audit are shown in A.Figure.9,10.

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It is safe to assume that the can is bought in Ghent, since the Tondelier site is located in Ghent. In this

context, the watering cans ship from Heerewaarden in the Netherlands to Ghent(190 km) with a

120m³-truck 14.

HDPE pieces larger than 15cm can be brought to the recycling centre. When a container is full, it’s

shipped to a sorting company in Ghent15 where the plastics are sorted, grinded and melted to new

products. This means that the cans can be recycled for 100 %. There will always be impurities, so we

decide to assume that not 100 % but 80 % of the can can be recycled.

There is a possibility that the can will be thrown away or neglected. This means that it will end

upon a landfill and will not at all be recycled. 80% recycling in the first scenario and 0% in the second, make that the watering can can be recycled

for 40%.

To know the lifespan of the watering can, we took some references. A HDPE liner (membrane) can

last up to 7 years16, but HDPE at 4N/mm² lasts longer than 50 years17. Because of this very diverse

data, we decided to choose the happy medium and go for 20 years.

A.Figure.9: CES Eco Audit for the large watering can

A.Figure.10: CES Eco Audit Report for the large watering can

14 http://www.jagtenberg.nl/nl/service/logistiek 15 https://www.ivago.be/thuisafval/afvalgids/diversen#harde_plastic 16 http://www.ampaplastics.co.za/HDPE-liners.html 17 Dr. Werner W. Müller - "HDPE Geomembranes in Geotechnics" (Book). Springer. Retrieved 2007-05-19.

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CEMENT BRICKS

Choices made to fill in the CES Eco Audit are shown in A.Figure.11,12.

The city gardens are made of cement bricks of 30x30 cm. These weigh about 10 kg a piece.18

The bricks originate from pavement of Ghent. The average brick lifespan is 500 years19, so it’s safe to

assume that after doing their function at the Tondelier site the bricks will be reused again.

A.Figure.11: CES Eco Audit for the cement bricks

A.Figure.12: CES Eco Audit Report for the cement bricks

THE INTRODUCED SYSTEM

THE ‘WEATHER’

According to A.Figure.1, during November-March the average minimum temperature lies below the limiting

boundary of 5°C. Based upon these days, the total waste of pluksla is calculated [A.Figure.13].

A.Figure.13: Calculation of the monthly and average percentage waste of lettuce, due to temperature in the container

18 http://vandeveldebeton.be/upload/files/betondallen_nl.pdf 19 http://www.claybrick.org/news/500-years-average-brick-lifespan

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From A.Figure.3 can be concluded that the input of the temperature in the container (not putting on the heat)

causes 63 % of the lettuce sown in this period to be wasted. Since the heat is put on during the day, the low

temperatures will only have an impact on the plants at night. Dimitry and his team leave the container

around 17h and come back around 8 ‘o clock in the morning. This means that the heating is turned off for

fifteen hours a day. Assumed that only half of these hours (seven) are perceived as ‘too cold’, seven hours

per 24 are affecting the growth of the plants. Because of this, we decided to divide this percentage by 3,5 (18

%).

To compare this result with other findings, e.g. the LCA of the competitive system, the whole year has to be

considered and not just the months November-February. The other seven months, during which 0% of the

sown lettuce is wasted, can’t be ignored. Therefore:

% 𝑙𝑒𝑡𝑡𝑢𝑐𝑒 𝑤𝑎𝑠𝑡𝑒𝑑 𝑑𝑢𝑟𝑖𝑛𝑔 𝑎 𝑦𝑒𝑎𝑟 =7𝑚𝑜𝑛𝑡ℎ𝑠 ∗ 0 + 5𝑚𝑜𝑛𝑡ℎ𝑠 ∗ 0,18

12𝑚𝑜𝑛𝑡ℎ𝑠= 0,075

The input of the water isn’t taken into calculations, since there are too many ‘averages’ to take into account.

Water is given every Wednesday. The plants get enough water, but could use a bit more than once a week.

Therefore, we decided to round up the total percentage of wasted sown lettuce due to the ‘weather’ to 10 %.

ENERGY FLOWS

We learned from the competitive system that carrying the watering can has little effect on the total amount

of energy that Yusuf needs to maintain his plants. Moreover, the mass of the can is a lot less (1,5kg + 0,16kg)

and the distance to fill his can is much shorter – thanks to the vat with water in the container. Therefore, the

potential and kinetic energy to carry the watering can will be negligible.

Apart from watering, Yusuf does some general gardening too. Since nothing has changed, only that he now

works approximately 10 min20 on his one pot, we decided to take the same amount of energy Yusuf needs to

do one hour of gardening [7] and divide this by six. Therefore, Yusuf uses .153,5 kJ per week to do some

general gardening. Thanks to the lamps, the lettuce is full-grown21 after three weeks22 instead of eight. Thus,

Yusuf’s total energy needed to grow one pluksla is three times higher, namely: .460,5 kJ.

WATERING CAN

A watering can is used, similar to the watering can of the competitive system. The only changing factors are

the volume since it’s now 1,5 l instead of 13 l, and the fact that the can is shared between sixteen pots instead

of forty gardens.. Therefore, we decided to take the same amounts as the competitive system, but in

proportion. The small can is 8,7 times smaller and sharing it between sixteen pots, makes that we have to

divide by 139,2.

Originally, the total amount of energy to produce, transport and dispose this large watering can is 51 500 kJ

23, but 10 400 kJ is recovered by the end-of-life potential. 2,3 kg of C02 is emitted, of which 0,37 kg can be

recovered. Now: .367 kJ. is needed of which .74,7 kJ. can be recovered, and .0,02 kg. of CO2 is emitted of

which a negligible amount can be recovered.

LED LIGHTS

Choices made to fill in the CES Eco Audit are shown in A.Figure.14,15.

The lamps are made in China, and shipped to Belgium (18 000 km). Afterwards, they are brought to

Urban Crops by truck (70 km), from where they are brought to the site (by train, 40 km)

20 Personal observation 21 30cm diameter, 30cm height 22 Personal observation 23 For calculations, see annex [A.Figure.8-10]

20

One lamp is 1,2 m and weighs about 0,5 kg24. The frames are made of aluminium, the cover of PC2526

One lamp has a 25000 h27 lifetime. The 20 W lamps burn 18 hours per day, year round, so the product

life is 3,8 years. Since this value is based upon the reseller’s brochure, we decided to round it down

to 3 years.

TL and LED lights can be brought to the recycling centre. There, mercury, aluminium and glass

(assumed to be about 30 % of the lamp) are being recovered and recycled. Polycarbonate is marked

code seven28, which means it is difficult to recycle. That’s why most of PC components end up on

landfill, which is a complete ecological nightmare (not biodegradable). 30 % recycling in the first

scenario and 0% in the second, make that the lamps can be recycled for 15 %.

Since the lamps are used for sixteen pots, the end result has to be divided by 16.

A.Figure.14: CES Eco Audit for the LED lights

A.Figure.15: CES Eco Audit Report for the LED lights

ALUMINUM POTS

Choices made to fill in the CES Eco Audit are shown in A.Figure.16,17.

The pot is made of galvanized steel and weighs 0,13 kg29

24 Personal observation 25 http://www.eslightbulbs.com/products/t8-led-tubes 26 http://www.lanruilighting.com/product/18w-t8-led-tube-light-with-aluminiumpc-material/ 27 http://images.philips.com/is/content/PhilipsConsumer/PDFDownloads/Global/ODLI20150714_001-UPD-en-AA-leaflet_tled_Philips_Horticulture.pdf

28 http://www.azom.com/article.aspx?ArticleID=7963 29 http://www.ikea.com/be/nl/catalog/products/90155672/

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The pot is fabricated in Hultsfred (Sweden)30 and shipped by boat to the distribution centre in The

Netherlands (1200 km), from where it is being transported by truck31 to Ikea Ghent (137 km)

Metal pots can be brought to the recycling centre where the scrap iron is used to make steel32. The

pots are clean and consist of only one material, but can have impurities, therefore we assume that 80

% of the pot can be recycled. Since it’s possible that the pot ends up on landfill, the average is 40 %

recyclability.

Galvanized steel, with a coating thickness of 1mm, has a product life of 40-80 years33 depending on

the pH-value of the used chlorides. We decided to take the average, namely 60 years.

A.Figure.16: CES Eco Audit for the pots

A.Figure.17: CES Eco Audit Report for the pots

INSULATION TAPE

Choices made to fill in the CES Eco Audit are shown in A.Figure.18,19.

The tape is bought at GAMMA Ghent. It came from the distribution centre in Antwerp (61 km) by

truck34 where it was shipped by boat before (18 000 km). We assume that the tape is made in China

(Ningbo Port35)

The small size of a piece of insulation tape makes it ‘easy’ to throw away. Plus the adhesive strip will

be less effective. Therefore we assume that the tape won’t be recycled.

The tape is made out of vinyl36

The life expectancy of sealers, silicones and waxes is 1-5 years37, so we decided to take 2,5 years.

30 http://documentarylovers.com/film/ikea-ultimate-factories/ 31 http://www.ikea.com/ms/nl_BE/this-is-ikea/about-the-ikea-group/index.html 32 https://www.ivago.be/sites/default/files/u3/bestanden/brochures/IVAGO_GIDS_recyclagepark.pdf 33 http://www.galvanizeit.org/uploads/publications/Performance_of_Galvanized_Steel_Products.pdf 34 https://www.intergamma.nl/over-ons/historie.html 35 http://bit.ly/1R1LcYg and http://bit.ly/1X9wupe 36 https://en.wikipedia.org/wiki/Electrical_tape 37 http://www.inspectmyhousenow.com/general-info/life-expectancy-of-components

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A.Figure.18: CES Eco Audit for the insulation tape

A.Figure.19: CES Eco Audit Report for the insulation tape

TRIPLEX

Choices made to fill in the CES Eco Audit are shown in A.Figure.20,21.

The triplex is bought at the IDC shop (52 km). This material is reused from ‘scraps’ of Lagae Wood

(<1km, negligible), which originated from Weida Germany38 (750 km)

Since the material comes from scraps (second life), the result will be divided by two.

Plywood can last between 10-50 years, but since this sheet isn’t exposed to weather, acids, etc. we

decided that 30 years39 is a well-advised value.

The density of birch is 720 kg/m³ 40. The sheet has a volume of 0,005 x 1,3 x 0,50 m (0,003m³) and

therefore weighs 2,34 kg.

Multiplex can have different end-of-life scenarios. It is possible that the sheet will be combusted (100%

recovered). If still in good state, the sheet can also be downcycled or even reused (assumed to be

recovered for 80%). It is even possible that the sheet will end up on landfill (0% recovered). Since

neither of these scenarios can be predicted, we decided that each has an equal chance. The percentage

of recovery is calculated:

𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑜𝑓 𝑟𝑒𝑐𝑜𝑣𝑒𝑟𝑒𝑑 𝑚𝑢𝑙𝑡𝑖𝑝𝑙𝑒𝑥 = 0,25 (1) + 0,25 (0,8) + 0,25 (0,8) + 0,25 (0)

4= 0,16

38 http://www.lagae.be/platen/panzerholz and https://de.wikipedia.org/wiki/Panzerholz 39 http://www.atdhomeinspection.com/advice/average-product-life/ 40 http://www.soortelijkgewicht.com/vaste-stoffen

23

A.Figure.20: CES Eco Audit for the triplex

A.Figure.21: CES Eco Audit Report for the triplex

CABLE TIES

Choices made to fill in the CES Eco Audit are shown in A.Figure.22,23.

We assume that the ties are made in China (Ningbo Port41) and shipped by boat to the distribution

centre in Antwerp (180 000 km), from where they are being transported by truck42 to GAMMA Ghent

(61km)

The cable ties are made from Nylon43 and have a long product life. But, it is recommended to change

the ties after 5 years, since they’ll lose their capabilities44.

The small size of the cable ties make it ‘easy’ to throw away. Plus, to renew the tie, the original tie has

to broken. Therefore we assume that the ties won’t be recycled.

A bag of 100 ties weighs 0,028 kg45, therefore every tie weighs 0,003 kg

41 http://bit.ly/1ZR7Zwr and http://bit.ly/1NuiG7e 42 https://www.intergamma.nl/over-ons/historie.html 43 http://www.lhdottie.com/pdf/Literature/LCABLETIES.pdf 44 http://arbo-online.nl/de-levensduur-van-een-veiligheidshelm/ 45 http://www.hellermanntyton.com/site/products/cable-ties-inside-serrated/t18r/111-01919

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A.Figure.22: CES Eco Audit for the cable ties

A.Figure.23: CES Eco Audit Report for the cable ties

SCREWS

Since the difference between the screws and the eye screws are negligible, both will be taken into

consideration as ‘screws’.

Choices made to fill in the CES Eco Audit are shown in A.Figure.24,25.

We assume that the screws are made in Guangzhou46 and are shipped to the distribution centre in

Antwerp (180 000 km), from where they are being transported by truck47 to GAMMA Ghent (61 km)

The screws are made from stainless steel48 and can last 20 years until a lifetime when in protective

places. In this system, the screw isn’t exposed to e.g. acids or extreme rainfall etc., therefore we

decided to set the lifespan of the screws to 50 years.

Due to the long lifespan and little quality loss, we assume that the screws will be reused.

Every screw weighs about 0,005 kg49

A.Figure.24: CES Eco Audit for the screws

A.Figure.25: CES Eco Audit Report for the screws

CHORD JUTE

Choices made to fill in the CES Eco Audit are shown in A.Figure.26,27.

46 http://bit.ly/1Otwytj 47 https://www.intergamma.nl/over-ons/historie.html 48 Personal observation 49 Personal observation

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The chord was bought at Dille&Kamille Ghent. They stand for natural and authentic products50. Therefore, we

assume that the chord originated from a factory near the distribution centre and that this distance is negligible.

From the distribution centre in Zoetermeer NL a truck drives to Ghent (207 km).

The chord is from jute and weighs approximately 0,02 kg51. It has a life expectancy of 152 – 353 years.

We decided to take the average, namely two years.

Because of the small size and relatively low quality, we assume that the chord will either be burned

(100% recovery) or thrown away (0 % recovery). Therefore, we decided that the chord can be recycled

for 50%.

A.Figure.26: CES Eco Audit for chord (jute)

A.Figure.27: CES Eco Audit for the chord (jute)

CHORD POLYESTER

Choices made to fill in the CES Eco Audit are shown in A.Figure.28,29.

We assume that the chord is made in Guangzhou54 and shipped by boat to the distribution centre in

Antwerp (180 000 km), from where they are being transported by truck55 to GAMMA Ghent (61 km)

The chord is from polyester (acryl) and has a life expectancy of 1056 years.

The mass of the chord is approximately 0,005 kg57

Because of the small size and relatively low quality, we assume that the chord will either be burned

(100 % recovery) or thrown away (0 % recovery). Therefore, we decided that the chord can be recycled

for 50 %.

50 http://www.dille-kamille.be/nl/content/1739/over-dille-kamille 51 Personal observation 52 http://d6cbwp89cp4qo.cloudfront.net/documents/Jute-Mesh-Flyer-11-14.pdf 53 https://www.jutexpo.co.uk/beyond-the-bag/ 54 http://bit.ly/1R281Lq 55 https://www.intergamma.nl/over-ons/historie.html 56 http://www.lehighgroup.com/fiber.htm 57 Personal observation

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A.Figure.28: CES Eco Audit for chord (polyester)

A.Figure.29: CES Eco Audit for the chord (polyester)

WOODEN CRATES

Choices made to fill in the CES Eco Audit are shown in A.Figure.30,31.

The crates are fabricated in Zbazynek (Poland)58 and shipped by boat to the distribution centre in The

Netherlands (870 km), from where it is being transported by truck59 to Ikea Ghent (137 km)

The crate is made from acacia wood, which has a lifespan of 10-15 years60 (average: 12,5 year)

The crates weigh 1,74 kg each61

The crates can have different end-of-life scenarios. It is possible that the wood will be combusted (100

% recovered). If still in good state, the crate can also be downcycled or even reused (assumed to be

recovered for 80 %). It is even possible that the crate will end up on landfill (0 % recovered). Since

neither of these scenarios can be predicted, we decided that each has an equal chance. The percentage

of recovery is calculated:

𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑜𝑓 𝑟𝑒𝑐𝑜𝑣𝑒𝑟𝑒𝑑 𝑚𝑢𝑙𝑡𝑖𝑝𝑙𝑒𝑥 = 0,25 (1) + 0,25 (0,8) + 0,25 (0,8) + 0,25 (0)

4= 0,16

58 http://documentarylovers.com/film/ikea-ultimate-factories/ 59 http://www.ikea.com/ms/nl_BE/this-is-ikea/about-the-ikea-group/index.html 60 https://en.wikipedia.org/wiki/Acacia_salicina 61 http://www.ikea.com/be/nl/catalog/products/40297952/

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A.Figure.30: CES Eco Audit for the crates

A.Figure.31: CES Eco Audit for the crates