Geothermal Generator

See Also: Power Grid

The Geothermal Engine is the main source of power on Oshan Laboratory. It generates power by tapping into the natural heat of tectonic hotspots on the ocean floor.

Parts of the Geothermal Engine

Hotspots

Locating and pinning hotspots and connecting vents from them to the power grid is the primary objective of the engineers running the engine on Oshan. At the beginning of the round, 43 hotspots are spread about the map, and their starting locations are visible by using the "Trench Map" button on all PDAs. All hotspots are a 10-tile radius square, giving them a total area of 21x21 or 441 tiles. Each hotspot starts with a "heat score" of 1000, which can be increased by mining rock out from under them in the trench. These hotspots periodically move, which causes an earthquake originating on a random tile within their volume. When hotspots move, they will step 1 tile in a predetermined direction (generated on round start, or the last influenced direction from a Stomper Unit). These earthquakes will move dowsing rods along with the hotspot, allowing you to keep track of them as they move.

Dowsing Rod

Dowsing rods are used to locate the center of a hotspot for the purpose of pinning it down and building a capture vent on it. When you deploy a dowsing rod on the ground, it will beep and state a number if it is within a 10 tile radius of a hotspot. That number is an estimated distance to the center of the hotspot: if you deploy it somewhere else, the number will probably be bigger or smaller. However, it is not entirely accurate. The motion of a hotspot will bias the readings (referred to in-game as "doppler shift", though much simpler than the real-life phenomenon). The dowsing rod will display lower numbers on tiles the hotspot is headed towards, and higher numbers on tiles the hotspot is headed away from. Luckily, there's an easy way to tell where the real center is: the dowsing rod will emit a cheerful beep when you've placed it exactly on the right spot, and this is not biased by doppler shift. Once a hotspot is pinned, readings will be unaffected by doppler shift.

The image below shows an example of how doppler shift affects the dowsing rod readings.

While doppler shift can make getting an accurate distance reading difficult, the heat on each tile (indicated by the color of the dowsing rod's light) still radiates out from a hotspot's true center. This fact can be exploited to simplify the process of finding the center: First, attempt to locate a corner of the hotspot. From there, proceed 11 tiles diagonally in the direction of the hotspot and you'll end up exactly on the true center.

Stomper Unit

Stomper units can be used to pin down a hotspot by stomping within a tile of its center. Pinned hotspots will no longer move or cause earthquakes. If you stomp outside of that range, the hotspot will quake and move away from the stomper, which can be used to slowly but deliberately move hotspots. When the stomper pins a hotspot, it will emit a beep and say that it pinned a hotspot.

Right clicking a stomper and selecting from the context menu will allow you to toggle it between single and automatic modes. In single mode it will only stomp once per activation, whereas in automatic mode it will continue stomping until activated again.

Engineering also has access to stomper boots, which can be worn and activated to stomp a hotspot. They slow you down immensely when worn, so if you plan on using them it is best to keep them in your bag until they are needed.

Geothermal Capture Vent

After pinning a hotspot in place, vents can be deployed to harvest electrical power from it. To deploy a vent, first use a Power Shovel to dig a hole where the hotspot was pinned. Then, simply click the hole with a vent capture unit in-hand (or drop the vent unit and click-and-drag its sprite onto the hole) to deploy it. Once deployed, it will need to be wired into the SMES units to get its power to the station grid.

The power output of a geothermal vent is dependent on the total heat of the tile, which is determined by number of hotspots stacked on the same tile, the number of rocks that have been mined out from the trench under the hotspot, the number of vents on the hotspot, and the distance of the vent from the center of the hotspot.

Common Hazards

Earthquakes

As hotspots move, they cause earthquakes in their wake. The more powerful the hotspot is and the more of them that are in the same place, the more powerful the earthquake. With just one or two hotspots stacked on top of each other the threat is relatively minimal, but as the hotspot stack becomes more powerful the quakes can start to tear pits into the trench, deal heavy BRUTE damage, amputate limbs, and even outright gib people.

Trench Pits

Whether naturally occurring or caused by an earthquake, holes onto the trench may pose a hazard. Falling into one will cause medium BRUTE damage, but the real danger is being stuck with no good way out. Hostile creatures and syndicate drones make it a dangerous area, and if you don't have a dive suit you will take rapid BURN damage as well. Your power shovel can dig through basic rocks, meaning you may be able to make it to the sea elevator and catch a ride back to the station. Carrying a Sea Ladder will also allow you to climb back out of the trench in the event that you fall in a hole.

Oxygen

Obviously, you cannot breathe the ocean. Carrying an oxygen tank will be necessary for ocean excursions, and you will need to monitor its pressure in order to not be caught in a bad spot with no air left. It may be worth carrying a spare tank in your backpack for emergencies.

Basic Startup Procedure

1. Grab any necessary equipment. Make sure to have a dowsing rod, stomper, power shovel, capture vent, and a box of wire. You will also need an oxygen supply and will greatly appreciate having flippers.
2. Check the trench map on your PDA or sitting on the nearby tables to see where the hotspots spawned. The map will show the trench and not the station, so you will need to use some intuition to know where these spots correspond to on the station level. If all else fails, wandering about the ocean randomly placing dowsing rods will find a hotspot eventually.
3. Scout the ocean for hotspots using dowsing rods. If you don't already know where a hotspot may be, this could take a little while. The dowsing rods will find any hotspots in a 10x10 radius, so if you don't get a hit then walk a bit aways and try again.
4. Once you've located a hotspot and further located its center, use a stomper on it to pin it in place.
5. Use a power shovel on the center of the hotspot to dig a hole there, and then use a capture vent on the hole to deploy it.
6. Use a wire on the vent to lay a wire under it. Continue this wire to connect to the SMES units on-station.
7. Set the SMES units to reasonable charge/discharge rates. Make sure not to set the SMESs to charge with more power then you actually generate, or they will not charge at all.

Raising Output

Hotspot Stacking

Having multiple hotspots pinned on the same tile will multiply all of their power outputs by (1 + number of hotspots / 2.3). Each hotspot causing a multiplication of all hotspot strengths causes output to scale exponentially with hotspot stack size.

Pinning multiple hotspots on one tile will require careful manipulation of the stomper ranges to move the new hotspot onto an existing tile without disturbing the existing pile. Stompers have the same range as dowsing rods detect from, so you will want to space the stomper so that you can move the new hotspot onto the stack without moving the stack itself.

Engineers may also consider producing multiple stomper units to create a 'cage' around a hotspot stack, effectively allowing them to move freely in a small area instead of pinning the stack in place.

Vent Stacking

Building multiple vents around a hotspot will reduce the output of any one vent, but will collectively yield more power than before in most cases. Since vents give less power the farther they are from the center, it is optimal to build any new vents in a square formation around the center of the hotspot. All vents need to be on top of a wire for them to add power to, but they do not need to be on a wire terminal.

Undermining

The area of the trench underneath a hotspot has a lot of latent thermal energy stored in the rocks. By mining out the trench area under the hotspot, you can increase how hot the hotspot is. More specifically, every rock broken adds 95 "heat points" to any hotspots in range of the corresponding tile on the station. This means that mining even a few rocks will cause a significant improvement in the power output of the corresponding hotspots, and that mining under a stack of hotspots can multiply the heat yield to great effect. Be warned, however, that the heat of a hotspot also affects how dangerous and destructive its quakes are, so its usually best to have it pinned down before you start mining it out.

Reaching the area that needs mined out will be much easier by using a controlled demolition pipe to blast a hole in the ocean floor and then using a sea ladder or submarine to descend through the hole into the trench. You can tell if you're mining in the right place because any rocks you break will send off hot sparks. Engineers can mine out rocks using their Power Shovel or the cutter mode on the industrial utility arms of their engineering minisub. It may be worth bothering mining to lend you some tools or mine out the hotspot for you, since they generally have better equipment than your average engineer for this purpose. If you plan on descending into the trench yourself, beware its freezing temperature (wear a dive suit) and lethal wildlife and drones.

After you've mined out all the rock underneath a hotspot, you can increase power output even higher by repositioning the hotspots over fresh rocks and mining more.

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