This breakdown uses estimate inputs and assumptions to calculate its outcomes. Assumptions and inputs are described through the evaluation and workings. Another assumption is that the site energy consumption has stayed the same as when the site was running on HVO. If the site energy consumption has changed, then the case study does not show this.
We would also be able to give a clearer calculation if we knew the exact capacity of the solar racks shown in the case study. This capacity has been estimated using what we expect to be seen as optimistic numbers.
An ultimate evaluation and comparison between diesel could be given if the site energy consumption and power requirements were known.
Main issue observed
An initial read of the case study indicated either a discrepancy in energy requirements, appropriate sizing of equipment, or an unrealistic view on hydrogen costs.
On this basis a number of things could be happening behind this case study:
Diesel consumption has been overstated (pushing the diesel cost up)
Hydrogen has been understated or seasonality not accounted for (pushing the hydrogen cost down)
There is an unrealistic view on the amount of energy solar can provide (and more hydrogen will be needed, increasing cost)
The cost of hydrogen is impossibly low (keeping the cost down)
Diesel generator is still far too large and running extremely inefficiently (driving up fuel use, and fuel costs).
From a deeper review of this study it seems this is the perfect example the inadequacies of diesel generators vs a modern hydrogen fuel cell hybrid setup. Namely that diesel generators will always have to sized in order to meet the peak power requirements. But that peak load will be infrequent, short and many times the size of the normal operating power requirement. Often the generator will be running at 10% it’s rated power, leading to drastically lower energy efficiencies*. In turn commonly leading to 3x the fuel consumption than the estimated consumption at project initiation. In other words, the costs presented up-front for diesel generators are often just theoretical, based on impossible assumptions around operating a generator at the most efficient load.
In this case most likely the equipment used, both the diesel generator and they hybrid setup, were correctly sized for the power and energy needs according to what each technology can provide. In this case it meant that a 60kVA generator was needed to cover peaks, but under the majority of normal conditions it would have been running very inefficiently. For the energy from diesel consumption to match the energy from on site solar+hydrogen the generator would have been running at around
This is a great case study in showing how we need to move to modern setups, and that doing so can deliver better site power while achieving cost savings against the real costs of the typical diesel generator setup.
Analysis methods summary
There are a few ways that this case study and the numbers can be evaluated:
Quoted prices for a much higher scale of hydrogen deployment are at circa £
/kg. Usually, for the type of deployment pictured in the case study, costs per kg hydrogen would be closer to £70/kg in 2022.
Even if we take £26/kg as an optimistic cost for the case study’s hydrogen, and we assume that the stated diesel requirement was correct with respect to the energy needed on site, this would put the total cost for the hydrogen deployment at:
New annual cost for hydrogen fuel if energy of diesel is needed:
Total deployment annual cost with increased hydrogen fuel use at optimistic market prices:
This just shows that if all of that diesel were turned into energy and was needed by site - then the real cost of hydrogen would be much higher. So either there is too much diesel being burnt, or not enough hydrogen.
Method 2 - reviewing the stated hydrogen volumes
Amount of hydrogen consumed as indicated by case study
Hydrogen volumes hard to say. If they were having bi weekly deliveries as stated for 2x MCP packs every 2 weeks, or 1 pack per week. This would have meant consuming
However, the stated costs for the implied hydrogen use in the case study is inline with BOC market rates. Based on the cost and the hydrogen volumes stated in the case study, hydrogen will be costing around
/kg. Which is inline with the BOC costing Hydrologiq receives.
Using hydrogen fuel pricing for fuel Hydrologiq was supplied by BOC during summer 2022, the total cost of this hydrogen would be around
for the year with no additional servicing cost added.
Method 3 - evaluation of the potential from the equipment
Loads capable of being served by the deployed hydrogen + battery setup
Assuming that the load on average had a 8kW baseload for 8hrs, with an aggregate of 10 minutes of peak draw at 18kW, a 44kWh battery and a 4kW hydrogen generator would be needed to cope with the demand when the sun wasn’t shining. This was approximately the size of the system that was installed. To go beyond these loads, the required setup wouldn’t cope.
Energy output from the setup
This loading would give a total daily energy provided to the site of 68kW, or 338kWh assuming 5 days running, or 473kWh assuming 7 days running.
Energy output from the diesel setup
However, the diesel consumption numbers would indicate that the 60kVA would have provided the site with
There is a large difference in what energy output the battery + hydrogen setup can provide and the energy being provided by the diesel fuel (even after efficiency conversions).
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