Background
In a world in transition towards a new model of decarbonized and sustainable power energy systems, renewable energies -both solar (photovoltaics and solar thermal power) and wind energy- will play a relevant role. However, they have a major inconvenient: their source (sun, wind) is very variable. Because of this, it is certainly difficult to plan and to produce in a stable way the electricity (causing peak and voltage instabilities in the grid). Furthermore, these energies have periods without power production (night, absence of wind). The solution is, accordingly, to store the energy surplus during the production period, and releasing it during the deficit periods.
In addition to this, development of sustainable mobility it is another game changer. This mobility, to the full transport electrification, requires advances batteries having very high energy density and easy charging capabilities. In figures, “classic” ion-Lithium batteries typically reach about 200 W/kg and 400 Wh/L, being the objective to double these values.
In parallel, battery cost must be below a certain threshold value. Currently the battery pack cost lies around 200 and 300$/kWh. Different studies indicate that the threshold of full competitivity is about 150$/kWh and that it can be reached as soon as 2020-2025.
Therefore, this is promoting an enormous technology effort to develop the chemistry and components of these devices, that it is also being transferred to the power generation sector.
Challenge description
Energy storage is very complex, and it can be found at very different scales, since the domestic range (home, vehicle) to very large power plants with tens of MW. In broad strokes, storage is the key for:
- Dispatchability of the future electricity grid: Control and dispatch of solar and wind energy will be the key for the large-scale integration of renewable and sustainable electricity in a more and more decarbonized power system.
- Distributed energy: in order that the user, even a domestic one, can be a small energy producer, thus minimizing the energy distribution losses and diminishing the electricity costs.
- Towards a sustainable mobility: Transport electrification is strongly needed to achieve the full decarbonization of this sector, until now based in fossil fuels. Advances in battery technology must solve the inconvenient of the current electric vehicles (range, recharging time, safety).
However, it must be said that today, even though the great advances in the technology and the big R&D efforts that have been made, the storage technology it far from being fully solved, both in the technology level and, especially, in the question of cost reduction and commercialization of the systems.
What is looking for?
In general terms, it is intended that the commercial systems costs to be competitive with the current grid electricity costs. Thus, things like these are welcome:
- Advances in materials technology, especially in the anode design in the case of Li-ion batteries
- New ideas for battery chemistry, going beyond Li-ion for stationary batteries, new electrolytes and, as well, for flow batteries development.
- Advances in the scaling of the production processes since lab scale to pilot and industrial scale, improving bottlenecks of the current processes.
- Improvements in the industrial manufacturing processes leading to a cost reduction of the battery.
- New business models for commercializing energy storage devices in different scales: in the order or kW for home appliances and in the order of MW in large power plants.
- New developments and business ideas based in the “smart grid” concept as well as “virtual power plant” concept, for achieving a real time integrated energy management of several small power plants with storage.
- Illustratively, the performance objectives for the new batteries lies around:
- Mobile systems: cost < 150 $/kWh and storage density > 400 Wh/kg, 800 Wh/L
- Stationary systems: cost 100 $/kWh, storage density > 150 Wh/kg and life cycle by 10-15 years (5,000 – 10,000 cycles)
- Specifically, for electric vehicles, the challenges would be the following ones:
- Passenger cars range: more than 300 km (NEDC cycle)
- Development of new charging systems:
- Super-charger net to fast charging time < 15 min.
- New Wireless charging (mainly for public transport)
