The sun does not always shine, the wind does not always blow
Germany, on its green endavor toward renewable energy, faces an urgent need for effective energy storage solutions as it furthers its reliance on wind and solar power. As these renewable energy sources are inherently intermittent - the sun doesn't always shine, and the wind doesn't always blow - efficient and large-scale storage systems become essential. Enter hydrogen, a versatile energy carrier, which can meet the requirements of the energy transition.
Germany's commitment to "Energiewende" - or energy transition - is remarkable, but the challenges are substantial. While wind and solar power generate substantial energy, their availability doesn't always coincide with the demand. On sunny and windy days, they may generate more power than required, leading to a surplus. Conversely, on cloudy, windless days or at night, they may not produce enough to meet demand. Traditional batteries can bridge short gaps, but they are unsuitable for long-term storage or large amounts of energy.
Hydrogen could provide the missing link in Germany's renewable energy strategy. When there's surplus power from wind or solar farms, this can be used to produce hydrogen through electrolysis - a process that splits water into hydrogen and oxygen. The hydrogen can then be stored for use when needed, either to generate electricity or as a fuel for transport or heating.
To put this into perspective, let's consider a calculatory example. If a solar farm produces 100 megawatt-hours (MWh) of excess electricity on a particularly sunny day, it could use this to generate about 2,400 kilograms of hydrogen via electrolysis. This hydrogen, when later used in a fuel cell, could produce approximately 60 MWh of electricity. While some energy is lost in the process, this is a relatively small price to pay for being able to store large amounts of renewable energy for weeks or even months.
Moreover, hydrogen storage has the potential to smooth out not only daily but also seasonal fluctuations in energy production. For instance, Germany has less sunlight in winter, reducing solar power output precisely when demand is high due to heating needs. Excess solar energy from the summer months could be stored as hydrogen and then used to meet this increased winter demand.
Hydrogen can also be transported relatively easily, allowing for geographical flexibility. For instance, northern Germany, where much of the country's wind power is produced, could generate hydrogen that could then be transported to industrial hubs in the south and west of the country.
Looking beyond national boundaries, hydrogen could even pave the way for an international energy market. Countries with abundant renewable energy resources, such as solar power in North Africa or wind power in Scotland, could export their surplus power as hydrogen.
The potential for hydrogen as a key element in our renewable energy future is huge. Yet, as we stand on the brink of a new era in energy storage, it's crucial that we invest not just in the technologies that can produce and utilise hydrogen, but also in the infrastructure needed to store and transport it. Only then can we fully harness the power of the most abundant element in the universe to keep the lights on when the wind doesn't blow, and the sun doesn't shine.