Frontiers of Sustainable Energy Integration

Callum Peverell explores breakthrough projects within sustainable energy.

Global perception of the energy industry is changing. Oil prices and UK vehicle emissions have decreased throughout the COVID-19 pandemic and appetite for a sustainable energy network is growing. The United Kingdom faces an ambitious target of achieving net zero emissions by 2050, a feat which will require the widespread integration of multiple sustainable energy sources. Here we will explore some of the current focal points and breakthrough projects within the sustainable energy community.

Vanadium Flow Batteries

A boom in lithium ion cell demand for grid energy storage, vehicular use, and use in appliances from smartphones to drones, has led to scepticism of the longevity of widespread battery cell integration. Monopolies on mining operations, specifically that of cobalt (a typical lithium ion cell cathode component) in the Democratic Republic of the Congo, and their links to poor conditioning and human rights violations, has caused this scepticism to grow, bringing forth the question of whether continued operation in this way is ‘sustainable’.

One option to keep up with the rising focus on energy storage for renewable sources is the Vanadium Flow Battery (VFB). Some investors and startup companies are calling for the integration of VFBs into more residential and commercial applications. VFBs typically operate through two separate tanks containing a vanadium-based electrolyte, one at a positive charge state and one at a negative, fed by closed circuits into a battery stack. If the electrical energy is being stored, the electrolyte, which is used as an energy storage carrier, is reduced at the anode (negative half-cell) and oxidised at the cathode (positive half-cell), driving a transfer of electrical energy to chemical energy.

A startup company has secured $7 million in funding for their VFB technology advancements. VoltStorage, a Germany-based company, is proposing to use these VFBs at scale in residential homes, offering an energy storage mechanism to a local photovoltaic solar system. These batteries can offer a constant power output of 1.5 kW, attaining more than 10,000 charge cycles without any capacity loss, with an average reduction of 80 kg CO2 equivalent per year when combined with unsustainable technologies.

Will VFBs ultimately be doomed to the same fate as lithium ion batteries? Will an increase in mining lead to dwindling levels of precious metals which are economically viable materials for electrodes and cells? Can the construction and continued operation of these batteries be maintained in a sustainable way? Only time and industry investment will shed light on these doubts.

Wind Energy

In October 2020, UK Prime Minister Boris Johnson pledged that offshore wind farms would be able to supply enough electricity to power every home in the United Kingdom by 2030, but just how realistic is this target?

Wind power generates electricity causing the blades of a turbine to rotate, thereby converting kinetic energy to mechanical energy. This rotation further turns an internal shaft to increase the speed of rotation before spinning a generator and producing electricity, which can then be supplied to the grid.

But what if there is no wind? Fortunately, wind power does not require constant operation to supply electricity. At times when supply is greater than demand, energy can be stored in large batteries (another potential use of VFBs), and during peak energy times these batteries can be used to supply energy to the grid. This means, in principle, if enough energy could be stored during off-peak hours to meet peak electricity demand, wind energy could then meet the target. The difficulty arises in the creation of the infrastructure to supply this energy and in the integration into the UK electric grid. In 2017, around 15% of the UK’s electricity came from wind power generation, approximately 29 million tonnes of oil equivalent (toe), whilst the residential demand for electricity in the UK was approximately 41 million toe, representing a 12 million toe discrepancy between the demand and the wind energy supply.

So, can we close this gap? Aurora Energy Research has calculated that a £50 billion investment will be required to meet Boris Johnson’s target with the equivalent of one wind turbine installed every weekday for the next decade. Chief Executive of Scottish Power Keith Anderson has stated he is “absolutely confident that the industry can achieve this”. If successful, completion of this project will be a key step in meeting the net zero UK emission target by 2050, and will also create a vast array of employment opportunities in the sector.

Nuclear

Nuclear energy is seen as one of the main intermediates between the current fossil fuel industry and reaching a sustainable energy utopia. Whilst nuclear reactors do not directly produce carbon dioxide emissions, mining and refining of reactor feedstock can require copious amounts of energy and a large requirement for metal and concrete in their construction. So, whilst it may currently be considered a cleaner energy source than fossil fuels, the combination of large energy requirements and nuclear waste production means nuclear energy is far from being this utopic sustainable energy source. That being said, nuclear energy could act as a key transition catalyst between the current fossil fuel market and full sustainable energy integration. France carries this mindset, with around 75% of its electricity being generated from nuclear sources.

Currently, Électricité de France (EDF) is constructing two new nuclear reactors at Hinkley Point in Somerset, capable of providing 3,200 MWe of the UK’s energy requirement (approximately 6%). This will be the first nuclear power station to be installed in the UK in over 20 years and is causing quite the buzz amongst nuclear enthusiasts. These reactors, expected to be completed in 2025, are estimated to use 17% less uranium than preceding technologies with an expected carbon dioxide offset of 9 million tonnes of CO2 equivalent per year.

Will this bring us closer to widespread sustainable energy? Protest group ‘Stop Hinkley’ think not, with a fear of risks such as leaks and radiation levels from nuclear waste storage. This is despite a UK government plan to construct a geological storage facility for this waste. Whilst perhaps not an ideal solution, if integrated successfully, these nuclear reactors will offer more sustainable energy sources for the UK grid and contribute to destabilising the oil monopoly held by the Organisation of the Petroleum Exporting Countries (OPEC).

The world still continues in its search for large-scale sustainable energy integration with some steps forward presented within this article. With this momentous task, one thing is clear, a successful sustainable network of energy will rely on a global effort and the incorporation of many different technology sources.

From Issue 21