15-11-2022 | By Robin Mitchell
The push to reduce CO2 emissions is increasing the pressure on engineers to find suitable energy storage solutions for renewable energy sources while simultaneously trying to find methods to improve grid stability. One company, HiiROC, may have the answer in the form of electrolysis which generates hydrogen, and their hydrogen is now being used to replace methane in some rapid response power stations. What challenges do peak demand generators face, how does HiiROC plan to solve this challenge, and is electrolysed methane a viable option?
What challenges do peak demand generators face?
By far, one of the biggest challenges currently faced by renewable energies is reliability. There is no shortage of renewable energy accessible to man no matter where you are on the globe; the artic has plenty of wind, the Sahara Desert is bright as anything, and Iceland has geological activity in abundance. But with the exception of dams and geothermal plants, renewable energy sources are intermittent in availability, and this means that energy grids cannot rely on renewables for a stable supply.
In contrast, fossil fuels are not only able to provide stable energy outputs, but their output power can also be adjusted on-demand to provide the exact amount of power needed when it is required. To make problems worse, renewable energy sources can produce too much power that the grid cannot use at that moment, and since current energy storage solutions are limited, most of this energy goes to waste.
As such, current energy grids rely on small power stations called Peaking Power Stations that provide small bursts of energy to stabilise the grid. In most cases, these power stations are based on turbines or engines that directly burn gas to drive a generator and produce electricity, and these plants can respond in under 30 seconds (depending on the technology). While these plants may sound like an excellent solution to peak energy challenges, they are expensive to run, which is why peak power costs are very high compared to standard rates.
But with the growing concerns regarding CO2 emissions, peaking plants face environmental challenges. If the entirety of an energy grid in future societies is to be 100% renewable, the use of peaking plants prevents this from becoming a reality. One solution is to burn biogas that would otherwise be released into the environment, while another is to burn hydrogen instead of methane, but where the hydrogen is sourced from will dictate if the process is green technology or not (see blue hydrogen).
HiiROC to use its hydrogen process for peaking plants
Recently, Centrica Business Solutions announced that it will be integrating a new hydrogen generation technology to feed a peaking gas plant owned by British Gas. Initially, the plant will mix natural gas with 2% hydrogen to confirm the stability of the plant, and from there, the plant will slowly increase the hydrogen content to 100%. By doing so, the plant will be able to produce peak power with no carbon emissions and therefore provide a benefit to the environment while also proving the benefits of green hydrogen.
To generate the hydrogen that will fuel the plant, Centrica Business Solutions have teamed up with a small start-up called HiiROC (whose logo is suspiciously similar to Hydra, but it’s unlikely that there is a hidden evil agenda). According to HiiROC, their hydrogen-generation process is more efficient than direct electrolysis of water and doesn’t produce CO2, unlike the steam process that combines steam and methane to produce hydrogen and CO2.
The process developed by HiiROC uses 50KW plasma jets and high pressures to separate methane into its constituent parts, hydrogen and carbon, and then these two parts are separated. The resulting hydrogen is syphoned off and stored for later use while the carbon particulate is captured as carbon black, a compound with numerous industrial applications, including tyres, plastics, and printer toner.
Is electrolysed methane a viable option?
The first factor that needs to be considered in the process developed by HiiROC is that it is dependent on methane sources, which can be derived from either fossil fuels or biomass naturally decaying. While those derived from biomass would indeed be fully renewable, using fossil fuels would make the process non-renewable. However, just as nuclear energy is non-renewable but climate-friendly, separating natural gas into carbon and hydrogen is still an excellent alternative to burning methane outright.
The second factor that needs to be considered is the efficiency and price of creating hydrogen. While the electrolysis of water to generate hydrogen and oxygen is inefficient and power-hungry, the technology needed to manufacture is relatively simple and easy to manufacture. Furthermore, water electrolysis requires highly available water. By contrast, the process from HiiROC would depend on natural gas, whose price has recently skyrocketed. Thus, the cost of using HiiROC gas is likely greater than just burning gas outright.
If the HiiROC process is combined with naturally occurring methane sources and utilises renewable energy to generate hydrogen, then it presents itself as a possible solution for renewable energy storage. However, the balance between CO2 emissions from powering the process and the resulting hydrogen must be kept in check; otherwise, the HiiROC process will just be another unnecessary step in energy production that looks good on paper but, in reality, fails to deliver on its promise of green energy.