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Hydro Power Generation in a Refugee Camp in Mekhmur Iraq

We have recently received an email from Pablo on behalf of the Economic Committee of a refugee camp S.Rstem Cudi near Mekhmur Iraq. Pablo wants to the technical advice for generating 1 and 3 MW energy for the camp through Hydro Power. And for it, he is looking for advice and information about it, or ideas for alternative methods.

On request for further information on the project, the enquirer replied with the following.

"The camp is next to a hill. The idea is to dig a well on top of the hill and run the water downhill through a pipe and run a Pelton turbine at the end. The estimated depth of the well is about 250 m.

I am aware that this plan seems to defy the laws of physics, but for some reason according to my rough calculations, it can work. So I must be doing something wrong, I guess..

We have 2000 houses, most of them badly isolated. In summer they need cooling 24h a day. In a rough estimate I would say each house needs at least 5 A. We also have about 800 wells, about 50 m deep, but if the big well on the hill works, we wouldn't need them anymore.

We also need to figure out how to potabilize the water from the well.. but that is another issue.

In any case, this will not be enough for the camp, so we need to think of alternative or complementary ways of producing electricity. There is not enough wind, and since this is a desert, the obvious thought is photovoltaic panels, however, there are some problems to that: 1. They are very expensive 2. It is alien technology: nobody here knows how to install them or maintain them (but they are experts in digging wells!) 3. There are frequent dust storms in summer, so they would require constant cleaning

I have seen this, which seems great https://cleantechnica.com/2013/01/17/..., but how realistic is it? How can we get it?

We don't have a specific budget. At the moment we are spending almost $500K a year in diesel for the emergency generators, so every million spent would pay off in 2 years.

The good news is that we already have the complete grid installed with cables and transformers, so distribution is not a problem."

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there's a useful guide to figure out how much energy you can get here: https://wind.appstate.edu/sites/defau...

Recall that energy will be required to pump the water up the well so that it can run down the hill and generate electricity.

Reading the post it would be useful to know: - what is the rating of the diesel generators? - what are the priority loads? For example, are there medicines to be chilled, food to be stored? What's the relative priority of 'phone charging, light and cooking over air-conditioning?

The stirling engine will have the same issues as PV panels, and since it also has moving parts it'll have maintenance needs too. PV panels need not be expensive, they're easy to install and they need less maintenance than a diesel generator. Installing them in a pole or on a roof is not that difficult and then you have fewer issues with distribution of the energy and voltage drop from your generating point. A 100W system is about US100 so with 2,000 customers the cost of the solar panels is less than the annual cost of the diesel. Then perhaps you can balance when the diesel runs versus when you rely on the solar

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Hi, Unfortunately your plan will not work. the energy consumed lifting the water will exceed the amount you could generate, and the flow rate for such an enterprise is very high, requiring a large scale investment, even if you had a water source at the height required.

Best suggestion: Do an energy usage survey and find what the power goes on. Many instances of power usage will be very inefficient and can be curtailed significantly though you will need to gain cooperation from the camp inhabitants to make this work, though what ever incentive you can figure out. This is a key first step to alternatively sourcing your future power.

In Iraq you have a lot of sun light, there are obvious opportunities for solar power. You may want to think in terms of small scale and very small scale, so small localities or individual dwelling level systems. These in conjunction with insulation (from both heat and cold) will work well in Iraq. Solar thermal will heat water very easily, in Iraq very low tech local fabricated systems can be produced, though you need to ensure that over heating to dangerous water temps is protected against, standard for purchased systems, not so in local fabrications. Solar electric is easier to manage and install.Doing micro systems you remove the need for central supply lines, and if at a dwelling level or small set of dwellings level, the users will protect the system from damage or theft.

There a re a lot of options with solar, the above is likely good ina refugee scenario. Good Luck

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From a very quick look at current pricing, a 1MW solar array may cost 1M USD to install. See this link: https://news.energysage.com/solar-far... as the first one I tried.

If you have an existent installed electricity grid as you state, the panel field installation would then be the majority of the costs, however a distributive generating system would probably work better in a refuggee camp environment.

You should be thinking in terms of panels laid out at ground level on mounts set at the correct angle for your location rather than the considering expensive the dish structures you have provided a link to.

Solar panels and their control gear is all solid state, you may need to dust them sometimes and protect the inverters form excess dust and heat, but that is the majority of their maintenance requirement.

Cost and technical complexity to install a 1 - 3 MW hydro system supposing the water volume and water 'head' were to be available, would likely have a significantly higher upfront cost and also maintenance requirement.

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My interest is with small scale hydros of up to about 125kW. So comment below are based on that knowledge. Others with knowledge of high power hydro schemes may wish to add to comments below.

My gut feeling is as follows. Good that you have distribution system. This suggests that a central power generation is way to go. It is technically possible with hydro. However it would be too complicated and too expensive for hydro compared to better insulated houses (to keep heat out and cool in) and big PV array (as long as you have the space) with battery storage (buffer and night time) with existing generators as back up. You should note that I am not a PV expert so it would be good for a PV expert to also respond to your question. Maybe you should ask the same question but focussed on PV as a solution to attract responses from PV experts.

On the 'hydro power from borehole/well source of water' question there is no technical reason why you could not produce a balance of electricity as long as the turbine was located at a level that was well below the drawdown level of water in the borehole/well. In your case you would need to pump water up (before allowing it to gravity feed down). You would probably need some sort of buffer holding tank on the top of the hill. Due to efficiency losses you would need more power to pump water to the top of the hill than you would gain from hydro power to get water down to the same level of the drawn down water in the borehole/well. If you were able to tunnel in horizontally to the water table then you would not have these same losses.

So, stating the obvious) your power balance would be total hydro power produced minus the power to get the water to the top of the hill/hydro pipe.

The rule of thumb for 'normal' hydros is about US$10k to 5K per kW of power. This probably holds true in you case. Maybe much higher than the US$10k mark because of the borehole/well/pumps. So if you are looking at a 1,000kW output then expect it to cost at least US$10 million, probably more.

You also need to consider the quantity of water that you would need (to give idea of borehole and pump sizes) Basic calculation is: kW = [residual head (m) x flow (lts/sec) x 9.81 (gravity) x 0.75 (efficiency guestimate)] / 1000

If borehole/well is expected to be 250m deep then i suspect that the drawdown would also be quite a long way down. In brought terms what is the height difference between the position of the turbine and the drawdown level of water in the well?

Let's assume the height difference between draw down level in borehole/well compared to position of the turbine is 100m. The pipe you choose ... (more)

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Hi Nischal. I'm a hydropower professional who has been pointed to your question. I hope I can help. I think the problem with your idea of using wells on top of hills to supply water to a hydropower scheme at the bottom of a hill is: 1) the fact that you will need to pump the water out of the well using significant energy before you can then generate energy using that water - with a likely net demand in energy. 2) the water table on top of a hill is likely to be at a much deeper depth than in the valley floor - requiring significant energy for pumping, 3) the yield from a well (even a very good well) will typically be very small compared to the flow of water needed for 1-3MW of hydropower. Assuming you have a gross head of 250m between the top of the hill and the bottom of the hill where your hydropower station would be situated, then you would need approximately 0.5 to 1.5 m3/s of flow - much greater than your likely well yield. My guess would be that the PV solar panel solution would be your best option to offset your diesel use, but I'm no solar power engineer - so explore this with the right person. Regards.Brian

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Install Solar - it is reliable, cheap and maintenance free. The idea of a perpetual motion machine with water from a well creating more electricity than it requires to lift it out of a well is really not a practical solution - if it was every city in the world would be powered by wells generating power and fresh water...

Solar panels are cheap, and except for occasional dusting they need no maintenance. Batteries are relatively cheap and LiIon batteries are now becoming mainstream together with sophisticated control units. If you are primarily using the power to run A/C units for cooling you don't even need much battery capacity since all the current draw is during the sunny day.

The site is described as being in a desert - so the idea of using ground-water simply to generate electricity is completely unacceptable even if it was not also impractical.

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I clicked through and read the brief and I found it rather unrealistic. A first glaring issue is a proposal to build large permanent infrastructure (3 MW hydro dam) at a "camp" which is a non permanent entity by its' inherent nature.

Is it needed to providing "cooling" to 2000 houses? Aircon is hardly an essential of life. As a basic principle of providing assistance - do not create a demand where none existed previously, and which will be expensive and next to impossible to fulfill in the long term.

Solar panels (Photovoltaic) are not an alien technology and they are not that expensive. You should be planning a combination of solar panels (photovoltaic) per each household, and diesel generators (say, 350kVa self-contained units, multiple units) that can be a flexible solution which can also be moved /repurposed as future demand requires. Hydro well might not be such a good idea. The hydro cost would be many times the price of generators / solar, and could take years to get finished.

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Hi Pablo,

My name is Nick. I am a chartered civil engineer with a Master in Renewable Energy. Most of my renewable energy field experience has been in small scale solar pumping. My knowledge of hydroelectricity is theoretical rather than practical. I do have some experience in developing ground water schemes, plus a number of missions to Iraq. Introductions over, here goes....

If I understand correctly you plan to 'dig' a 250m well on top of a hill, presumably then raise this ground water to a header tank at the top of the hill, releasing it to drive a Pelton wheel. You are correct in your notion that you will defy the laws of physics if you are successful in this. The energy required to lift the water to the top of the hill, will be much more than the energy generated from releasing it, due to common sense compounded by the efficiency losses in an albeit high efficiency system. Furthermore - digging a 250m well is no small feat, a drilling rig will be required, plus a well lining installation and an expensive submersible pump.

Pelton wheels are suitable for situations where there is either a natural large head of water, such as a river in in its youth. Or on a large hydro-scheme, with a high impoundment dam.

Based on the information that you have given me, I would recommend pursuing solar PV as an option. Modern PV systems are easier to operate than small hydroschemes. When I was in Southern Iraq about 8 years ago, I saw some solar PV arrays in remote rural areas, being used by villagers to operate borehole pumps. I am pretty sure there would be a good local solar contractor available who could do a design and build. You could build into the contract a clause to train a local engineer on operation and maintenance, as well as periodic maintenance. If not - get a specialist solar NGO to do it.

A few other things:

  • You could consider decentralised PV systems - e.g. mount panels on individual houses, so householders can keep panels clean
  • Is there a prevailing wind direction - can you use the wind shadow of the hill to mount the panels to reduce dust cover?
  • Consider using evaporative cooling systems rather than conventional chillers. They use much less power than pressurised refrigerant systems. Very common in shops when I was working in Kurdistan a few years back.

Good luck, would love to hear how it goes,

best wishes

Nick

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Hi Nischal,

This is no doubt quite a task, requiring many pre-analysis of hydrogeological and geological nature. Do you have enough water yield for a sustainable installation? Never the less as for cost you can get some guidance from http://www.engineering.lancs.ac.uk/lu...

We have a few similar power stations in Sweden with very large heads, tunneling water from a lake, and I was (long time ago) involved in one of them in Jämtland (near a place called Frankrike).

In order to help you we would need to see your Feasibility Study, and overall design.

Best wishes

Per

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I would definitely think about how you can improve the houses insulation and reduce solar gains. Anything you can do to reduce or eliminate the air conditioning load will have a very quick payback given the cost you are paying for the diesel. Only when certain that you have minimised the electrical loads would I then look at more efficient ways of generating power - PV looks like the obvious candidate as a robust and proven technology...

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Asked:
2019-02-19 08:03:34 +0100
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Last updated:
Mar 06