Hydrogen based distributed power solutions are now available and they can replace diesel as a fuel with the benefits of zero emissions, similar operational benefits and overall through life cost savings.
Hydrogen for fuel cell systems is an emerging global value stream for gas producers and third party refuelers, through a rapidly expanding delivery infrastructure. The cost of hydrogen can vary depending on where the hydrogen is produced and the cost of the delivery method.
Centrally produced hydrogen from large scale production facilities can be produced at a lower cost, but delivery costs to the point of use have to be considered. Distributed on-site production facilities have lower delivery costs, but production costs are likely to be higher due to lower production volumes.
The total output power and location of a fuel cell site are primary considerations for delivering an optimised hydrogen fuel solution to support our partners' on-site power requirements.
How is hydrogen produced?
Steam methane reforming (SMR)
Most large scale hydrogen production is through steam methane reforming (SMR), in which high temperature steam is used to produce hydrogen from natural gas. Oil refineries are existing high volume SMR hydrogen producers, as hydrogen is a key enabler allowing refinery products to comply with the latest environmental fuel production standards. SMR is a mature and well understood process where the capital cost of distributed on-site hydrogen production continues to reduce, year on year for smaller (100kg/day) facilities.
Electrolysis using renewable energy sources
Electrolysis is the process of using electricity to split water into hydrogen and oxygen. The reaction takes place in a device called an electrolyser. Electrolysers are commercially available and can range in size from low volume distributed hydrogen production units to grid-scale units that can be used directly with renewable energy sources such as wind and solar power arrays.
For a low CO2 society, hydrogen is an energy carrier and grid-scale storage provider that can enable renewable integration into the existing energy infrastructure and can be produced from renewable electricity using proven grid scale electrolysis.
Hydrogen is produced in biomass systems using bacteria to break down organic matter. Research is underway to improve the yield and speed of hydrogen production using this fermentation process. Biomass is an attractive technology as it has the ability to produce hydrogen from resources that are not currently used for fuel production, including waste water.
How is hydrogen supplied for use with distributed fuel cell systems?
Hydrogen supply and storage
Hydrogen for distributed fuel cell systems is supplied in standard storage cylinders containing approximately 260ft3 (7.36m3) of compressed gas. Hydrogen is typically delivered as clusters of 6, 12 or 18 cylinders for direct site deployment. This ensures a long run time for the fuel cell system.
Hydrogen can be transported from centralised production facilities via pipeline or as a compressed or liquefied gas, using tube trailers for road delivery to refill hydrogen tanks and cylinders local to the point of use. High volume road distribution helps to deliver a low cost molecule for use with distributed fuel cell systems.
Hydrogen gas cylinders and cluster packs are widely available from global gas providers.
The need for electrical energy storage is regarded as a global strategic imperative, but unfortunately there are few available options to provide grid-scale electricity storage for days and weeks in duration.
Large scale storage can only be addressed by pumped hydro and compressed air (CAES) – both having limitations in capacity and flexibility, or chemical storage media like hydrogen and methane. Hydrogen is the only option to implement energy capacities over 10GWh. Batteries by comparison can only provide kW to MW grid storage in the seconds to hours energy storage range.
Intermittent renewable energy sources like wind and solar power require energy storage to be efficiently integrated into the existing electricity grid.
Hydrogen produced by electrolysis from renewable energy sources could be co-mingled and stored in existing gas pipelines (up to approx. 15% hydrogen) where it can be transported and used as part of the fuel stream for power plants to generate electricity at peak times. Research in the USA and Europe is currently underway to examine this approach.
Leading gas turbine manufactures for the power industry, such as ALSTOM, GE and Siemens are developing turbines that can operate using a wide variety of hydrogen-rich fuels, delivering high performance and flexible operability.