Energy flexibility from Heavy-Duty Vehicles
Greening our energy system
The story is this: we can decarbonize our economy by greening our energy systems with renewable energies generation and by electrifying major energy demand, starting with transport, heat and heavy industry. On the next level, we can align supply from renewable energy generation with electricity demand, for example, by using batteries (creating ‘energy flexibility’).
Many batteries are actually used in electrified transport. Thus, electric vehicles can support the balancing of a renewables-dominated electricity system whose energy supply varies with the sun and the wind. With an integrated approach to flexibility from heating, transport and industry, net zero will be affordable and achievable.
Flexibility is the key
If we do not pay attention to flexibility, electrification of transport will be less effective in terms of both emissions and cost. In the electricity system, timing and location are key: we will need to charge vehicles when there is an abundance of renewable energy and reduce charging (or even inject back into the grid) at times of low renewable production and high demand. We also need to operate within the limits of the power networks; there is plenty of spare grid capacity outside peak periods, and flexible charging should not require significant grid build. Flexible charging can use cheap and green electricity within the grid limits. Conversely, badly coordinated charging that uses more expensive and higher carbon electricity would require lots of new grid capacity and would not have the same beneficial impact on cost-effective decarbonization.
Flexibility is multi-layered, and monetizing its value is complex even for seasoned electricity companies. A combination of value streams can be captured from flexible charging (or discharging):
- optimizing the time to charge when energy is cheap (and perhaps discharge when it is expensive);
- committing firm reliable capacity at times of peak demand to help keep the lights on for other grid users;
- providing frequency support services to maintain power quality for other grid users; and
- minimizing grid investment costs and allowing faster connections.
Some of this value can be achieved through automation and without advance commitment, on a ‘pay-as-you-go' basis. Other types of revenue can come through selling committed services and capacity to a grid operator. Maximizing the commercial opportunity means dancing between these revenue streams.
Answering some strategic questions
The quest for economic flexibility raises some questions:
- What does this need for flexibility mean in practice as we decarbonize transport?
- How can the owners and operators of HDVs profit from flexible charging?
- What types of flexibility are needed and what impact would it have on the life of the battery?
- Where is the most value, and what components make up a strong business case?
The electrification story has so far focused on passenger cars, which spend 95% of their time stationary, and which can use smart charging and vehicle-to-grid to support the flexibility needs of the power system. Cars are important – they make up 60% of road emissions – but influencing the charging behaviour of the drivers of 300 million cars in Europe will be challenging.
Heavy-Duty Vehicles have a role to play
Heavy-Duty Vehicles (HDV) have a key role in the decarbonization of transport. Trucks and buses make up only 4.5% of Europe’s vehicle fleet, but due to their high utilization emit around 28% of the emissions in transport sector. Although maturity is lower than for cars and there are far fewer electric vehicles on the road today; the scale, commercial motivation and scope for professional management of charging presents a real opportunity for HDV fleet operators to profit from cheap and low carbon energy. Bus and truck depots will deal with tens of MWh in storage and several MW of charging capacity. This is the equivalent of a grid scale battery which would cost several million pounds to build. The cost (and carbon) savings from flexible charging (and potentially discharging) at each site could be very significant; especially as investment cost to release this flexibility from the vehicles could be relatively low.
There are some valuable opportunities and potentially early-mover advantages for HDV operators who embrace flexible charging (and potentially bidirectional charging) as they electrify their fleet. There are design choices to be made, and certain types of operation and depot location are much better suited than others.
As always, deep understanding of technical and commercial risks and opportunities is the key to success.
