AWACS - An American With A Chinese System
Copyright© 2025 by PT Brainum
Chapter 55
I was at a bit of an impasse. It was late Friday here in Portland, but rest and sleep had little meaning. In Geneva it was Saturday morning. I had a very nice 5 star hotel in Geneva, and it was only a dozen minutes away. The next part of my plan required talking to someone who wouldn’t be available in Geneva until Monday.
Finally deciding that sticking around all day just on the chance that I’d be able to see Mo sing was foolish, I returned to Hamburg instead of Geneva. I still needed to talk to the guy at the hydro power company, and he was available on Saturdays. The text from Aida arrived only a few minutes after I returned to Hamburg. I only had to look at the person to start it, ending it was easy, even from so far away.
I arrived at the office unannounced, the engineer I had been emailing was there to let me in. He was rather excited about the potential power from the aquifer.
“It’s a high head, low flow operation. Unlike, say the big dams in America, where you have a large flow generating power as well as a significant drop, a high head is when the head waters are at least 300 meters above the tail waters.”
“What is important to me is the low flow. We will be using a horizontal drill to reach the bottom of the aquifer thru the mountain it sits in.”
“Yes, with the generator design we have put together, you wont need more than an eight centimeter bore to carry the water from the aquifer. It’s very exciting, we’ve never tapped a mountain aquifer for hydro-power before.”
I showed him my written authorization and request to find and purchase carbon free energy sources for Pitcairn, signed by Mayor Anthony. It had been done up to look extra pretty and official.
“Yes, serving the small island, using components we already have on hand, and considering the environment, and the small population this generator will be serving, I’ve been able to secure a 90% discount for the generator and engineering design. You said that you would arrange installation on the island, correct?”
“Yes, we have a specialist engineering firm that will be working with us for the install. It’s important that we have the engineering requirements well in advance of the generator arriving.”
“Yes, I have the calculations. It will be very important that the pipe be of plastic or steel. The smooth interior surface will allow the velocity of the water to be higher. It needs to be above 10 meters a second to achieve full power efficiency. If you have to use a rough pipe like concrete, or cast iron, then you will need a larger pipe diameter. The flow rate for the generator we are building for you requires that velocity, considering the flow is only going to be approximately 3 cubic meters per minute.”
“Once we know it works, we can install additional generators?” I asked.
“Yes, the aquifer is large enough to run 19 generators for an entire year without it refilling. With a refill rate of 50 percent per year you could run up to 50 percent more.”
“How much power will one generator produce?”
“Using the Turgo wheel design we are estimating just under 90% efficiency, so about 140 kW.”
“That’s the amount of power it produces in an hour, correct?”
“Yes. That’s about three and a half homes worth of power, at about 1200 kWh per month each home. Now the generator provides constant power, and sometimes the homes will need less, and other times will need more. The Turgo wheel can be throttled down, but you are much better served with a storage system at each home to meet peak demand. With proper peak storage you don’t need to throttle the system at all, and let it produce at peak efficiency.”
“I’m hoping our refill rates are higher than 50%, it’s a newly discovered aquifer and we know it’s size, but because we haven’t tapped it yet, we don’t know it’s refill rate.”
“Yes, that will be a critical measurement. If it fills slower than you use it, then you’ll have to install a shut off valve. As the water level drops your head height lowers, and your produced power will drop as well. It’s too bad you haven’t drilled already, having that done first would tell you your true flow rate, and refill rate.”
“That’s actually expected to be accomplished next week,” I told him.
“That’s great. If you can get those details then you can estimate the refill rate as well.”
“How would you do that, wouldn’t you have to let it run for a year to see how full it was afterwards?”
“How did you determine the size of the aquifer?”
“Something similar to ground penetrating radar.”
His nosed scrunched up as he parsed the feasibility of that sort of thing, but carried on, “If you know what the volume is before a rain, and can measure the volume after a rain, and you know how much it rained, then you can calculate how much rain will bring how much water into the aquifer.”
“I think we can do that. We have a good idea of how much rain the island gets every year, so that would let us calculate the refill rate. We are guessing, since the level has remained the same despite the rains we’ve been having that it’s currently full, and has a relief mechanism of some kind.”
“Yes it probably has a slow seep already. If you find that it doesn’t refill fast enough you could try to locate and block the existing exits. That would increase your refill rate.”
“How much more power could we generate if we used a larger bore size?”
“A pipe diameter of 12 centimeters would give you over 400 kW instead of 140.”
“Is that advantageous?”