By George Muthui Song’e
Kenya seeks to be the pioneer country in Africa to embrace battery-powered locomotives. This comes after the government-owned Kenya Railways announced grand plans to migrate to BEMUs that will reduce the parastatal’s carbon footprint. A battery electric multiple unit BEMU comprises an onboard battery pack from which the locomotive draws its energy.
The project is supported by the World Bank and SYSTRA group. It intends to cover the Nairobi commuter network, as well as cover the longest route: the 178 km-long Thika-Nanyuki line.
The use of batteries to power locomotives is not a new phenomenon. In 1842 Scotsman Robert Davidson built a battery-powered locomotive. Since then, technology has advanced, making the battery-powered locomotive a reality. Globally, reducing emissions from the transportation sector is a key priority. This has included electrifying railway systems through overhead cables or onboard battery packs also referred to as Energy Storage Systems ESS. Like in most electric vehicles, lithium-ion is the go-to chemistry for locomotive batteries.
Lithium-ion batteries are cheaper to maintain. They have more charge-discharge cycles that enable the owner to benefit from a higher rate of recurring benefits. This translates to value for money. Their high energy density allows them to provide power for longer periods while maintaining compactness. Fast charging is another advantage. Their unique electrochemical properties allow quick flow of ions translating to a shorter time required to achieve 100% charge.
Besides reducing reliance on fossil fuels and cutting carbon emissions, BEMUS can run on the current railroad infrastructure. Indeed, they do not require any overhead lines that come at an extra cost. The batteries increase the gross weight of the locomotive. Like with electric vehicles, this hurts the range per charge. This is mitigated by using the BEMU for trips within the battery range, hence the natural decision to use them for the Nairobi commuter service.
BEMU’S are silent. They make far less noise than their diesel or coal-powered counterparts. This will relieve the residents living close to the rail tracks. Furthermore, they are cheaper to maintain as they have fewer moveable parts since the engine is removed. Given the high upfront cost of the batteries, it will be necessary for more trips on the routes. This will increase passenger volumes and attract off-peak commuters. A much more reliable schedule will give commuters much more confidence in using the rail network.
As the electric trains will require charging points, Kenya Railways can install solar systems on the canopies of their stations to supplement the power from the grid. Apart from charging the batteries, the power can be used to provide electricity in the stations.