Solar Power isn't Feasible!

Solar Power isn't Feasible!
This cartoon was on the cover of the book "SolarGas" by David Hoye. It echoes the Sharp Solar slogan "Last time I checked nobody owned the sun!"

Saturday, February 16, 2008

Preliminary Results of Hot Water Usage and Demand Survey

The graph shows the differences between the Zabaleen Community of Zurayib and the Historic Cairo Community of Darb El Ahmar in terms of hot water usage. As is evident from the graph, the largest percentage of hhouseholds interviewed in Zurayib (N=225) use their kitchen stoves to heat water for bathing (46.7%) while the largest percentage of households in Darb El Ahmar (N=231) use small electric heaters (54.5%). There is still an appreciable number of people using kitchen stoves in Darb El Ahmar (20.8%) but a much greater number of people in Darb El Ahmar use wall mounted gas heaters (fueled by a butagas bottle since there are no gas pipelines in Darb El Ahmar) -- 19.5% versus 7.1 % for the Zabaleen.

Technically, the data show that only 35.6% of the Zabaleen in Zurayib posess "hot water appliances" per se (Electric or Gas hot water heaters sold specifically for heating bathing water) , while 64.5% make multiple use of simple technologies normally used for cooking in order to heat their bathing water.

This is contrasted with 74% of the households in the Darb El Ahmar area, with 26% using cooking apparatus for heating bath water. Thus the Zabaleen case is almost the inverse of the Historic Cairo case (nearly 65 % without heating appliances in the former versus nearly 75% posessing heating appliances in the latter.)

The figure for the Zabaleen Zurayib area is consistent with data from an old GTZ study that showed the residents of what they dubbed MN4 (the Manshiyat Nasser area that consists of Zurayib) having up to 3/4 of households having "no hot water". Our study, of course, contradicts their description of the situation (we find that 100% of all households have hot water from somewhere, but that approximately 65% don't have hot water appliances per se. Economic studies, unlike studies in physics, look at what are ostensibly moving targets -- more people could have purchased hot water appliances since the GTZ study (approximately 10% more) as hot water appliances and advertising become more and more ubiquitous throughout the city. What is most interesting are those families that have purchased hot water heaters, gas or electric, but have ceased using them and gone back to heating water on a stove.

(Photo: Aba Nob's mother in the Zabaleen community heats water for her family on a "Hamil" or "portable" ground stove with rubber gas tube and large bottle)

Another interesting finding was that there was a much greater reliance on the "Hamil" as a water heating source among the Zabaleen (11.6% versus a mere 0.4%). The "Hamil" is a floor mounted grill that is connected by a rubber gas pipe to a large bottle of gas. It can have from one to 4 "eyes" (flames). It has an advantage over smaller "one-eye portable stoves" in that one can connect it to any size bottle, and one can put larger buckets of water on it. It's greater use in the Zabaleen homes may be due to culture and availability, but it also probably reflects the larger bare open spaces in the cement and brick Zabaleen homes, usually on the ground floor of the family owned building where people collect to cook and bathe. Darb El Ahmar has small multi-family apartments with tiny bathrooms that would not accomodate the "hamil". So Darb El Ahmar bathrooms would be better suited to a small one-eyed portable butagas stove, or to use of the existing kitchen stove.

(Photo: The author, T.H. Culhane, preparing a 20 liter bath on a "one-eye butagas stove" in his apartment in Darb Al-Ahmar after the heating element in his 50 Liter electric heating appliance burned out due to use when the water supply was cut. From a January 28 start temperature of 14 degrees, The one-eye butagas stove has heated the 20 liters to 31 degrees after 12 minutes. In another minute the water was at 32 degrees C, warm enough to take a comfortable bath, but not ideal. After 16 minutes the water had reached 36 degrees, the temperature of the water in the German public bath. The author waited 19 minutes, however, to get the water to 40 degrees because the air was cold and he wanted the bath to feel hot. Several independent tests with stopwatch and temp gauge revealed that the average time for heating 20 liters of water to bath temperature was 20 minutes).

The data show that the Zabaleen use the one-eye butagas stove more than the Darb Al-Ahmar community (4.4 % of the sample versus 0.4%) but the 0.4 % figure could be misleadingly low since many respondents in Darb El Ahmar have both kinds of stoves - a kitchen stove and a portable one-eye -- in their apartments. Cairenes use the word "butagas" to refer to both the kitchen stove and to these small portable one-eyed stoves (and sometimes even to refer to the "hamil", since all three use the same fuel (Butagas bottles). To correct for this we asked respondents how many "eyes" their butagas stove has, and asked them to identify the type of stove they use for bathing from a set of pictures. However, many families who had both a kitchen stove and a portable one-eye stove actually use both at different times (for example, using the one eye portable when the kitchen stove is being used for cooking, but eschewing the use of the portable stove when their are children around because of the fear that they will trip on it or kick it over). The surveyors often failed to capture when this was the case, noting on the survey sheet people who had kitchen stoves and used them for bathing as "butagas stove users" and people who did not have kitchen stoves but heated on one-eye stoves as "one-eye stove users." This reflects a flaw in the methodology -- future surveys should specifically find out when families who have stoves also invested in a portable stove and why, and when they use it. The purchase of a one-eye butagas stove is non-trivial: the author paid 60 LE (12 dollars) for his, plus 5 LE for the first fill, and 3 LE for each additional fill.

The most outstanding use of water heating devices for bathing in Zurayib was one family in the Zabaleen community who still uses a Kanoun (Campfire, shown above), since they live in a shanty on the edge of the city by a rock quarry with plenty of open space.

Since this family is on the edge of urban density, they also took advantage of their quasi-rural situation to build a traditional mud-brick oven for baking bread and to cultivate sugar cane, grapes, guava trees and vegetables.

(Photo: The "Mina House", i.e. Mina's shanty (far right) at the edge of the garbage dump next to the quarry. Note the guava trees and date palms to the left of the house. Behind Mina's house the concrete and brick towers of the Zabaleen informal community begin. Mina's father has been offered large sums of money for this location but refuses to abandon it saying "it offers the most beautiful view in the area, and we have all the sunshine. Here we can live in the city as though we were still in the countryside!" We call it "The Mina house" with some irony, because one of the most luxurious hotels in Cairo is the famous "Mena House" next to the Giza pyramids. Mina's house shown here is next to the quarry which looks like an inverted pyramid.)

In Darb El Ahmar the most outstanding use was by a family that uses water heated by the electric element in a washing machine!

Here are the actual numbers:

Virtually NOBODY in our sample of 456 households used solar energy, but that does not mean that nobody in these communities does -- Solar CITIES has already built and installed 8 solar hot water systems (4 in each community) and is on the way, thanks to a US AID grant of $25,000, toward building 11 more in each community (for a total of 30 this year). We chose not to include these households in our survey since the Solar CITIES initiative is new and the systems are fully subsidized. Thus they would not reflect the choice or preference patterns of the communities.

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