I don’t think Power by itself reduces Spark costs. That’s definitely something to try on the test server though. You can just spawn machines and power coils and all that.
I do know there’s skills you can pick up that reduce spark costs for certain things. That might be where you’re seeing the spark cost reduction if you’re getting one at all.
I haven’t crafted anything with power coils since the Beta.
@Jirodyne @crypticworlds Yup, power reduces the amount of spark you need for a recipe, no skill point needed 
Which adds motivation for power progression, which in my opinion is a great addition - slow and steady 
Machines with power coils do show less spark needed the more power you have. I’m not pro enough to know it’s a specific amount of spark reduced but my thoughts are that amount of spark needed is tied to the crafting time of the item being crafted. So when you add more power it reduces the crafting time which then lowers the spark cost.
power coils definitly reduce spark cost.
the game does tell exactly that.
Not sure, there was a thread around showing that but I believe is out dated with the new skills the reduce cost.
With overpowered extractor I was able to reduce the cost of mass craft of oort shards from 10k+ pre 7200 power down to around 2675(I have to confirm those number) after I repaired my coils. Give me an afternoon and I’ll get you exact number. As I was repairing my coils though I hit that 2675 before I fixed all of them so you don’t need 24 coils or 7200 to get max efficiency or cost reduction of spark.
I think this is the thread…which would be outdated but gives an idea of the relationship
Power definitely reduces spark cost. And with the correct setup, even completely eliminates spark cost from some recipes. I havent plotted the trends but could get it done tomorrow after court.
In my case with a crafter spec, i gain a speed increase and spark reduction on my “lesser coiled” mixer, but the same recipe has zero spark cost on my more powered machine
Edit- I think that link is indeed outdated, the speed effect is now much smaller but spark reduction is new.
my mixer is fully powered ( doesnt allow any more advanced power coils) and stuff that cost 10k spark, now cost 4675 spark
Shades, do you have a cook? If so, i bet you can mix raw persisting loaves spark free 
Any tests should probably be done with and without skills that reduce fuel/spark cost?
loaf costs 10k spark, too (mass crafted)
I have alts at all stages of skills with access to most recipes, just dont have all machines fully coiled. Will do mixer specific stats, then anyone with other machines can chip in any discrepancies.
@Shadesmar that’s weird, mine is free…
i dont have efficient crafting epic on my cook ( but that would be 30%?)
wait… why dont i have efficient crafting on this skill set? forgot to transfer it >.<
k loaf cost is now mass crafted 1675… with food crafting epic it would drop down to 0
Just like speeding up crafting time, the spark reduction depends on the power cost of recipes.
For recipes that require no power at all, you’ll get the best bang for your buck with up to 14 advanced coils (I often split the coils from a fully powered machine to a second machine, 12 12, when doing large batches of unpowered crafting), then you get into heavy diminishing returns (in some cases to the point of not even showing in the crafting menu). After 16 advanced coils you’ve hit the cap of reduction for recipes that don’t require power.
The reduction is not a flat rate, its non-linear, and has diminishing returns.
Thus the first coil will offer the greatest benefit.
Let’s say we’re using mass crafts of Refined Titanium Alloy with Advanced Refinery Power Coils as an example:
| Adv. Coils | Time | Spark |
|---|---|---|
| 0 | 50m | 20000 |
| 1 | 38m18s | 15323 |
| 2 | 34m50s | 13938 |
| 3 | 32m1s | 12809 |
| 4 | 29m45s | 11902 |
| 5 | 27m58s | 11187 |
| 6 | 26m35s | 10633 |
| 7 | 25m32s | 10216 |
| 8 | 24m46s | 9909 |
| 9 | 24m13s | 9693 |
| 10 | 23m51s | 9546 |
| 11 | 23m37s | 9452 |
| 12 | 23m29s | 9397 |
| 13 | 23m25s | 9368 |
| 14 | 23m23s | 9355 |
| 15 | 23m22s | 9351 |
| 16 | 23m22s | 9350 |
| 17 | 23m22s | 9350 |
| 18 | 23m22s | 9350 |
| 24 | 23m22s | 9350 |
Edit: And of course, you can only have a maximum of 24 coils hooked up to a single machine.
The first coil offers a reduction to both crafting time and spark of about 23.4%. Second one is a reduction of 9.05% and it goes down from there.
Ovis, I guess that gives even more motivation to max out the power on all your machines, which is 24 Advanced Power Coils for 7200 power.
mmmmm
Anyone calculated this as a % per 100 power before? Would be awesome to use this in my spreadsheet…
I only own advanced coils, so I can’t confirm how much per 100 power, only per 300 power.
I have a table (percentage in relation to the 0 coil cost) for the refined titanium mass craft example:
| Adv. Coils | % of Total | Time (seconds) | Spark |
|---|---|---|---|
| 0 | 100.00% | 3000 | 20000 |
| 1 | 76.62% | 2298 | 15323 |
| 2 | 69.69% | 2090 | 13938 |
| 3 | 64.05% | 1921 | 12809 |
| 4 | 59.51% | 1785 | 11902 |
| 5 | 55.94% | 1678 | 11187 |
| 6 | 53.17% | 1595 | 10633 |
| 7 | 51.08% | 1532 | 10216 |
| 8 | 49.55% | 1486 | 9909 |
| 9 | 48.47% | 1453 | 9693 |
| 10 | 47.73% | 1431 | 9546 |
| 11 | 47.26% | 1417 | 9452 |
| 12 | 46.99% | 1409 | 9397 |
| 13 | 46.84% | 1405 | 9368 |
| 14 | 46.78% | 1403 | 9355 |
| 15 | 46.76% | 1402 | 9351 |
| 16 | 46.75% | 1402 | 9350 |
| 17 | 46.75% | 1402 | 9350 |
| 18 | 46.75% | 1402 | 9350 |
| 24 | 46.75% | 1402 | 9350 |
Edit: As you can see, after you hit the 50% mark the diminishing returns kick in pretty heavily. Still worth to go up to 12-14, particularly for recipes with large spark costs / long crafting times (like shop stands for example).
Ya know, it would be great if you people could add this to the official wiki instead of random undiscoverable posts in the forum or mysterious unsearchable spreadsheets out in the cloud.
This is an awesome Spreadsheet, thanks a lot for doing this!