Renewable energy production currently accounts for roughly 29% of global power generation. The International Renewable Energy Agency estimates that by 2050, 90% of the world’s electricity can and should come from renewables. Whilst governments, businesses and individuals are increasingly recognising the benefits of renewable energy sources, it’s vital that focus is retained not only on the production of the energy itself, but its effective transmission and integration into the grid.
The task of integrating renewable energy into the grid is not always as simple as creating more transmission lines. Typically, renewable energy generation occurs in locations remote from already established transmission networks. Offshore wind energy farms, in particular, require advanced and expensive infrastructure to enable the transportation of their power. The UK is the world leader in offshore wind farms, but its future generation of energy will be severely hampered if not accompanied by an appropriate expansion of transmission services.
Indeed, in the case of offshore wind, effective transmission requires the development of underwater cables and offshore, onshore and national grid substations before it even reaches traditional transmission lines. In addition to the huge costs incurred through this infrastructural development, environmental concerns and regulations must also be adhered to, resulting in further costs and delays in establishing the transmission route.
Infrastructure aside, the unpredictable nature of variable renewable energy (VRE) production increases the difficulty of matching power supply to demand. Despite peak demand for electricity only occurring over a few hours of the year, the grid’s transmission system must be sized to cope with this higher-than-usual level of demand. If existing transmission lines face brief periods of overload, they require a subsequent scale-up in transmission capacity, despite the fact that this will likely be underutilised for large portions of the year.
Power system planners have a huge role to play in effectively managing and understanding grid integration considerations. To aid this, recent advancements have emerged in the form of grid integration studies, whereby power systems with a high level of VRE resources can be evaluated under a framework of various potential scenarios in order to better plan and maximise generation, whilst still considering grid integration.
To further counter the unpredictable nature of VRE, energy storage technologies can be used alongside renewable energy production to enable heightened flexibility in the transmission of energy from its source to the grid. Battery Energy Storage Systems (BESS), have the potential to store renewable power during peak production and low demand, ready for transmission to the grid during periods of low production and high demand. This can remove the aforementioned need to upgrade existing transmission lines, as BESS can meet the incremental increases in demand independently.
Aside from pure storage, BESS can also offer a range of additional functions through value stacking. Not only can storage help improve renewable grid integration through transmission, but they can also earn revenue through the operating of reserve provisions to transmission system operators. The Energy Storage Grand Challenge Market Report 2020 highlights the fundamental role BESS could play here, and explains how the annual global deployments of stationary storage are expected to exceed 300Gwh by 2030, representing a 27% compound annual growth rate for grid-related storage. Clearly, there is growing awareness regarding the value of storage solutions in maximising the efficiency of renewable energy production and transmission.
But to fully facilitate changes in transmission and storage, domestic policy frameworks must be updated to accommodate the rapidly expanding market. Currently, even the simple definition of ‘energy storage projects’ is causing a hindrance to investment. In many markets, storage is considered a ‘generation asset’ and as system operators are prohibited from using generation assets, transmission and distribution deferrals are being blocked.
In general, public acceptance of renewable energy is high, meaning pressure is increasingly being placed on governments to encourage the provision and implementation of renewable energy. Through policy change, investment into large-scale transmission expansion is likely to increase, ensuring the long-term reliability and flexibility of grid transmission and integration.
