Are there two types of Minimum Ignition Energy (MIE) for powders?

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Yes, there are two types of MIE, where one type is carried out without inductance and the other is carried out with inductance.

Minimum Ignition Energy is the minimum energy that is required for ignition of fuel. In other words, the minimum energy an ignition source must provide to the fire triangle for the fuel to burn in presence of an oxidant.
The test to establish MIE is carried out in an apparatus called MIKE3 (refer image below). It is performed using ASTM E2019, “Standard Test Method for Minimum Ignition Energy of a Dust Cloud in Air” or EN13821 “Potentially explosive atmospheres — Explosion prevention and protection — Determination of minimum ignition energy of dust/air mixtures”

MIE (Without inductance) corresponds to the energy required by electrostatic discharge to ignite a dispersed cloud. The circuit of MIKE3 for this test is purely capacitative and the spark energy can be related straight to 1/2*C*V^2 based on the capacitance selected.

MIE (With inductance) simulates the longer duration discharges from electronic circuitry that can occur from machines or control equipment (essentially a spark from short in a wire or electronic equipment) or mechanical sparks, by adding an inductance in the existing circuit.

Now one thing to remember is that MIE (With Inductance) is more conservative as compared to MIE (Without inductance). 

Next question that comes is which one to choose?

Depending on the unit operations the powder is subjected to, tests might change. If your process involves milling, I would definitely go for MIE (With inductance). However, if your process only requires manual charging of powder to a hopper, I would definitely go for MIE (Without Inductance). 

If, after a review of your facility, you are only concerned about electrostatic discharges, then the MIE test without inductance should be performed. If however, you are worried about sparks from electronic circuitry, other ignition sources or if you wish to publish the MIE value on a Safety Data Sheet, then the more conservative MIE method using inductance in the circuit is more appropriate. 

The data provided by MIE testing can be even more useful when combined with a process hazard analysis or PHA which is a systematic evaluation of the hazards involved in the process.

Yes, you can also go for a lower value every time. But then yes you could have also made your plant with GOLD.

Hope that clarifies the subject. Will get back later with another concept.

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