Hydrogen Pipelines Include Energy Storage
Backround: Very few people understand the impact of pipeline packing
Hydrogen is the lowest cost long-term clean energy storage, full stop. When including all upstream components, blue hydrogen and pipeline remains lower cost long-term storage now and going forward. By 2030, cost-downs and performance improvements in electrolyzers and fuel cells will make green H2 and pipelines second only to blue H2 for low-cost clean energy storage. The major take-away is that if someone is building an H2 pipeline, a local utility or the state government should be providing incentive to over-size the pipeline for additional low-cost storage.
This is a surprise to utilities and energy experts right up until I walk them through the numbers. Two months ago I was on a call with a regional utility and their energy consultant who were struggling with the costs of their 2035 net zero mandate. This particular utility was looking at building a $4B power line to a renewable-rich area to handle the power most of the time, but energy storage from the renewables remained a concern: batteries for storage of more than a few hours are too expensive. They were in disbelief when I said “That four billion dollars could buy you 400 miles of pipeline, or 80GWh of storage. That’s enough to power a large city for three days.” Their energy consultancy hadn’t thought about pipeline packing, either, so this was new to all on the call.
This isn’t a rare occurrence in H2. No part of H2 is more misunderstood or glossed over than midstream. This article delves into the cost of H2 pipeline packing compared to any other energy clean energy storage tech. In almost all cases, it’s the lowest cost storage, even including any inefficiencies in the H2 system.
Here we are going to discuss how pipeline packing works, what other long-term energy storage options are, and how H2 compares currently and in the future. Keep in mind that this is commercially theoretical until states or the federal government get their act together on H2 pipeline permitting.
How pipeline packing works
Most pipelines can operate at up to 80 bar pressure, but in reality often operate at lower pressures. Shoving in all the gas that you can is known as pipeline packing, and it represents a residual store of available gas.
Hydrogen pipelines are a low-cost way to store energy. A 42” pipeline packed to 80 bar can hold 10 tons of hydrogen per mile[1]. With 20MWh usable power per ton H2[2], that is 200MWh of storage per mile. Given that a pipeline of this size is $10M/mile to build (less on flat, unpopulated terrain), we’re talking $50/kwh of storage. Current grid-scale batteries are $500/kwh – and while they don’t need extra generation facilities at the end like H2 does, the CapEx is such that it doesn’t make sense to use these batteries for more than a few hours.
Startups are developing technologies to use low-CapEx systems like iron-oxide reactions (literally, rust) or chemical flow batteries to make battery systems. These systems are gigantic in terms of size, very expensive in terms of kW, have poor efficiency (similar to H2), and have massive embodied emissions problems, but they are very inexpensive in terms of kwh of energy storage – just not as inexpensive as H2 for long term storage.
When talking about energy storage, two metrics are important – how much power the storage can put it, and how much energy it can store. A one kw battery system with 100 kwh of storage can provide 1kw of power for 100 hours, and a 10kw battery system with 100kwh of storage can provide 10x the power, but only for 1/10th the time. Generally speaking, high ratios of energy storage to power are useful when we plan on not having access to other sources of power for a most of a day or for several days. Lithium batteries will never be cost effective for multi-day power storage.
This table shows the Levelized Cost of Storage for just the energy storage medium as well as the total CapEx required for a full renewable+storage system using this medium
Some details on how this could work: 15GWh per day example (time-shift from renewables)
A $4B 100 mile right-of-way HVDC power line could co-host a hydrogen pipeline. Sharing right-of-way could reduce cost to build the pipeline. Moreover, if the power line is meant to move renewables, we know for certain that the line will have open capacity when the renewables aren’t in use, so the hydrogen backup power generation could be built on the line to zero out the interconnect cost. Alternatively, hydrogen production plus pipeline could be built to provide backup energy without building an additional HVDC line at a considerably lower cost than building a new HVDC power line.
With blue H2 this is very cost effective. With current electrolyzer costs green H2 plus storage is not as cost effective as grid scale lithium storage for overnight power shift, but green H2 remains much more cost effective for storing more than 10-15 hours of energy compared to batteries now. By 2030 there will be no situation in which lithium battery storage is more cost effective than hydrogen with pipeline packing, and very few situations in which speculative battery models are more cost effective than H2.
Summary and so what: Like in all things, there are regions where each of these technologies excel
H2 looks even better when considering embodied emissions - For the most part, this analysis compared low emission sources of energy and storage. Embodied emissions are not considered - if they were, all battery solutions would come out much worse. Yes, pipelines use steel, but most of pipeline is empty space whereas all batteries use materials that linearly increase the use of materials per kwh
Hydrogen will require H2 pipelines to work for power - without access to salt domes - which are geographically restricted, the amount of hydrogen demanded for power use will require pipelines
Blue H2 for power combined with renewables is the lowest cost zero-emission solution - If there is access to blue H2 on the pipeline, the cost of zero emission power will be lowest with renewables while using H2 as backup power with pipelines as storage for H2
Green H2 will not be cost effective for power storage for the next several years until electrolyzer costs come down - they are coming down rapidly with or without the US, and when they halve from where they are now, no batteries can compete on cost for H2+pipelines for low-cost renewable energy storage
Lithium batteries are too expensive for long term storage - Lithium batteries are fine for shifting 4 hours of solar to evening, but too expensive for longer term storage
In the absence of pipelines and low cost hydrogen production options, iron-oxide batteries will be the most cost effective zero emission solution with renewables - Iron oxide batteries are now in the pilot stage. This and similar solutions would be cost competitive in regions with plenty of space. In other words, it’s won’t work in the Northeast of the US.
All of these are more expensive than fossil power with unmitigated CO2 emissions – In the US we have very low cost natural gas, and there is no way to get the cost of renewables + backup power as low as the cost of a natural gas fired power plant unburdened by CO2 emission controls.
In geographies with high costs of natural gas and low cost of renewables, the cost of renewables + H2 could compete with energy from imported natural gas
Caveats that are barriers or deal breakers:
PHMSA/DOT/FERC don’t have oversight over hydrogen pipelines, so rules revert to state laws. States are quick to block anything new, so in most cases getting these things built will be tough. Until congress gives mandate for H2 pipelines to FERC, we don’t have an option to build these things in most places.
The next problem is the power generation. We’re talking about GW scale power generation, but we don’t yet have combined cycle hydrogen plants. Given that we have H2 turbines, however, engineering the combined cycle plants should be coming soon.
The biggest problem, however, is electrolyzer CapEx. With batteries, there is no need for an electrolyzer. Just oversize the renewable production, store the extra, and then send it down the power line. With hydrogen, electrolyzers are currently $2000/kw. If we assume 8 hours of operating time per day, and 50% round trip efficiency, that comes out to $500/kw for extra CapEx, putting it in the ballpark of lithium batteries. Once electrolyzer cost drops towards 2030, when we really need to start building for netzero 2035 goals, we’re down closer to $250/kw additional cost for electrolyzers.
Finally, the scale to make this work is large. Notice the $1B price tag I mention for the 100 miles of pipeline. That’s the entirety of the federal funding for a Hydrogen Hub.
Caveats that aren’t real:
Diameter is not an issue: The largest hydrogen pipelines today are 12-16” in diameter, but scaling to large diameter pipelines is simple. The largest gas pipelines are 52” in diameter. It’s not hard to make a hydrogen pipeline – just use materials that don’t embrittle from H2. So making a large bore H2 pipeline will be relatively easy.
Length at this scale is not an issue, but longer pipelines will need pumping stations: long pipelines require pumping stations. These stations use massive centrifugal compressors that operate based on the density of the gas they move. Hydrogen has low mass, so current compressors can’t be used for pumping stations. While we have centrifugal H2 compressors for other uses, they haven’t been integrated into a pumping station. This is not really an issue – a large diameter but relatively short pipeline that is meant in part for storage will not need a pumping station – the pressure from the production site will push the H2 to the end, much like current offshore rigs don’t use pumping stations to get natural gas on land
[1] This is basic math.
[2] Assuming one of two things – either a combined cycle plant that captures 60% or more of the HHV energy of
[3] I am the EPC on a project right now for only 60kw and it is getting $1200/kw cost for a fully installed system. Going to 1GW should bring the price down below $1000, so this is very conservative
[4] Levelized Cost of Storage – this means only the storage. IE the pipeline or the battery, not the electricity, H2, or generation that produced the electricity or H2
[5] The cost here includes pipelines, all upstream production including extra needed to address inefficiencies in the system, and power lines if needed.
[6] $1B for pipeline, $2B for the H2 production and CO2 capture equipment. Note that this is the only column with variable OpEx, so ongoing expenses will be considerably higher
