Energy storage

How can battery storage support the use of renewables, how financially viable is it, and are there any alternative storage options?  

The drawback with renewables, such as solar PV and wind, is that their power may be generated at a time when it is not required, resulting in export to the grid and lower income (or cost avoidance). Charging electrical storage batteries as a short-term measure to soak up additional generation for consumption later or to export when the price is better is a good solution. Similarly, where producers employ an energy purchasing strategy, attempting to avoid expensive periods or to benefit from cheap or negative energy prices, batteries could provide a short-term load or supply.

How financially viable is battery storage?

There are limited ‘behind the meter’ installations which are the preserve of domestic users and enthusiasts. Having said this, the cost of batteries is reducing, and the market dynamics are changing quickly. Therefore, battery storage may soon become viable for price arbitrage (when the mismatch between supply and demand is clear, repeatable, and reliable), or where consumption cannot be avoided at peak tariff periods.

A 2019 article published on Forbes includes a graph taken from a market report by Bloomberg into the cost of batteries and shows the fall in manufacturing cost. It is expected that by 2023 this will fall to under $100/kWh, a point where electric vehicles will start to become comparable in costs to internal combustion engine models. The development in electric vehicle (EV) batteries will have a knock-on effect into static applications.

Other challenges

The dominance of Lithium-Ion technology brings several challenges as well as benefits. The clearest benefit is cost reduction of batteries resulting from the automotive industry’s developments. However, many of the materials required for battery manufacture are scarce and have an environmental footprint of their own, causing concern for many.

Further developments, especially around flow battery systems where storage capacity is easier to manipulate, mean that static applications of batteries where large quantities of electricity may be stored for longer periods, reducing the temporal mismatch, will likely be more viable.

Large grid support batteries, such as the recently announced 50 MW/250 MWh liquid air battery that is to receive £10 million of government development funding, have very little day-to-day impact on dairy farms. However, it highlights the interest in developing other forms of energy storage.

Are there alternative storage options?

To capitalise from energy storage, it may be necessary to be more creative in our thinking, additional energy storage forms can sometimes be called secondary storage.

Other forms of secondary storage include:

• Daily hot water requirements
• Ice building or other cool storage
• Inter-seasonal heat storage for space heating (ground recharging)
• Overcooling for limited times
• Glycol cool storage

These secondary energy stores have the benefit of being tailored to individual energy requirements and in many cases reduce the energy transfer process (by avoiding placing energy into electricity and back again) and may well be the best solution in the short term.