A new report underlines the benefits of hydrogen for energy storage. The UK’s Institution of Mechanical Engineers (IMechE) suggests that hydrogen stored in Britain’s gas grid could be more effective for making use of excess renewable power than batteries.
The IMechE report says that surplus electricity generated by wind power and solar photovoltaic farms could be used in an electrolysis process to create hydrogen, which could be stored in the natural gas grid until needed by generators. It would also provide a solution to one of the biggest challenges facing the renewable energy sector.
The growing penetration of wind power and solar photovoltaic farms is a positive consequence of government incentives and industries working together in a worldwide context. This has succeeded in bringing down the cost of the technologies and greatly increased their deployment.
However, the implication of large volumes of power emanating from variable and intermittent renewable sources being fed into conventional grid structures is often the reason why the use of these forms of energy is curtailed in favour of grid stability. Smart grid solutions can only partially adapt electricity demand to these unpredictable patterns. In order to avoid installed capacity and clean primary energy going to waste, it is crucial to be able to store the electricity produced from these renewable sources.
Using water electrolysis to produce hydrogen is a weight-efficient (compared to batteries) and location-flexible (compared to pumped hydro) method to convert and store surplus electricity.
Hydrogen can be converted back to power effectively in commercial, low-temperature FCs. It is particularly suited to mobile applications in fuel cell electric vehicles (FCEV), where the electricity that has been stored as hydrogen can add value by supplying energy for transportation.
Similarly, hydrogen is a highly valuable primary substance for the chemical industry, when used in conjunction with industrial processes to produce substances such as ammonia, chlorine and steel. It is also used in the refining of fossil fuels as well as in the food industry.
The electrochemical production of hydrogen has enormous potential for the profitable matching of large-scale renewable energy generation and economic development. Although it requires the hydrogen handling infrastructure to be set up, the use of fuel cell systems in reversing mode for alternating power storage and power generation within a unique system boundary is a readily available engineering solution to the issues currently connected with distributed energy management.
Furthermore, the interesting prospect of using high-temperature, solid oxide cells which are capable of being operated directly as both power generators and power storing devices simply by inverting polarity, has prompted IEC Technical Committee (TC) 105: Fuel cell technologies, to look into the need for standardizing developments in this direction.