Here is the correlation of Nat gas and coal price. With coal prices and gas prices largely moving in sync we must take a bird's eye view of the situation. Gas prices are at almost historic lows over the last 20 years. It is clear to see that historically they do not stay there for long. There are some key points that need to be taken into account over that period,
1 - Unaccounted for inflationary pressures on price.
2 - Depletion of finite reserves to add additional pricing pressures.
3 - Continuous demand increase over the period.
4 - Minimal new reserve discovery/investment in supply.
5 - Current adequate NH stockpiles are temporary.
6 - Gas is in fact cheaper today than what it was 20+ years ago when taking into account inflation.
7 - Significant direct market disruption in supply and logistical routes given geopolitical events.
8 - Peak state of global sanctions on Russian fossil fuels yet to be seen. Sanctions intensifying.
9 - Due to sanctions, overall Russian gas/oil/coal production reduced. If sanctions were lifted immediately, supply would be limited.
10 - Considerable logistical shifts over time would also make Russian fossil fuel supply limited to traditional buyers.
Much of this applies to coal also, however gas is the more popular market and has a longer history in terms of the NEWC price index so we will use gas as the face to paint a portrait of coal. We can see that after the dotcom crash in the 2001-2003 the gas price fell and recovered in a short time. Prior to this, there was relative price stability over the preceding 15 years.
From the chart, gas price rallied for the next 5 years and peaked even higher at the 2008 financial crisis. Following this crash there was prolonged price weakness for 13 years all the way up to 2021. We can see that these 13 years are reminiscent of the 15 years preceding the 2001 dot com bubble, where price was low and stable.
The geopolitical and economic pressures of today are in fact very similar if not more profound of those in the early 2000's. Iraq, Afghanistan, terrorism and economic turmoil were at the forefront. Today however, the risks are far greater with global insecurity gradually intensifying with each passing day. The fossil fuel markets are indeed more directly displaced today than they were 20 years ago, with obvious reasons.
If we simply compare the price levels circled in red below, we can see what gas and coal prices may do in the coming 12-24 months. It really does beg the question as to how much lower gas prices can realistically be expected to fall given all of the above. With continuing global uncertainty (as with the early 2000s) I would not be surprised if coal/gas prices in the next 5 years follow the trend of 2003 - 2008.
The one difference now is that interest rates can no longer be lowered. They must continue to rise in our high inflationary environment. This however does not guarantee permanent weakness in fossil fuel prices, even though temporary declines can seem permanent. The reality is that the interest rates are nowhere near the current inflation rate, meaning that unless interest rates exceed inflation rates, we will not see significant contraction in energy use. For example, from 1980-1985, oil (the most interest rate sensitive fossil fuel) maintained its strong price (compared to pre 1980s) despite a 17% interest rate. This led to a boom in drilling and exploration which eventually led to the 1985 bust.
If one purely relies on these charts, it suggests that coal prices will follow gas prices closely and revert below $80 per ton. This does not take into account significant market manipulation form sanctions. I believe this is the main reason why coal price outpaced gas price on a trend basis in the last 2 years. If we look at the graph, gas prices were usually elevated or side by side in relation to coal prices since 2010, rarely did coal move above gas. If not for sanctions on Russia the coal price may have peaked at $200 per ton, which would have made $80 per ton realistic today.
There is a lot to consider, and in short, I do not see how such low coal/gas prices can be sustainable for any meaningful amount of time.
Although the above graph shows coal prices outpacing gas price significantly in the last 2 years, on a shorter time frame (see graph below) the difference is not as profound. Showing strong correlation between gas and coal prices given their interchangeable use. 
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