A unique indoor/outdoor circuit, set in London's ExCeL exhibition centre, brought electric racing back to the UK capital, though a year later than originally planned.
The debut of the Formula E London E-Prix had originally been intended as the finale of the 2019/20 season. However, the coronavirus pandemic saw ExCeL repurposed as an NHS 'Nightingale Hospital', leaving the venue unavailable for racing.
The circuit duly made its debut in July 2021, with a lightly modified course from the original proposals being used for the double header event. The London race is set to feature in successive seasons, with series organisers having signed a multi-year deal.
London had been without a Formula E race since the agreement to end racing at Battersea Park following the threat of court action by environmental groups. After a search for a new location which lasted several years, championship organisers revealed in March 2019 that they had successfully concluded negotiations for the race to make the ExCeL exhibition centre its new home. The multi-year deal would see the venue hosting the London E-Prix from the 2019-20 season onwards, with a double-header race set to round out the season.
Uniquely, the proposed 23-turn course would feature a design which took it inside the main building, before emerging outdoors to loop around the exterior past the Prince Regent Station and then briefly in front of the quay side of the Royal Victoria Docks. Key features included a series of switchback hairpins and ramps to lead the track inside and out of the elevated main exhibition centre.
Coronavirus brings a half to plans
Formula E had scheduled the original dual header races to take place on 25 and 26 July 2020, however the coronavirus pandemic put paid to those plans. On 24 March 2020, the ExCeL was announced as a temporary NHS hospital, containing up to 4000 beds and named NHS Nightingale, boosting the healthcare response to the pandemic for Londoners. The new hospital was opened on 3 April 2020 by the Prince of Wales via video link, equipped with 500 intensive care beds. The first patients were admitted four days later.
In the event, NHS Nightingale London was only ever was required to treat a small number of patients, the last of which were discharged in May, after which the facility was been placed on standby by the NHS, ready to resume operations as and when needed. The hospital reopened for recovering and non-COVID patients in January 2021, when another part of the site was also used as a vaccination centre. By April 2021, the hospital had served its useful purpose, with the vaccination programme running well and hospitalisations from Covid-19 not reaching previous levels. The hospital was finally decommissioned, meaning the ExCeL Centre could be released for conversion into a racing venue, with the E-Prix the first event at the centre since the pandemic began.
The E-Prix is back on, a year late
With the announcement that the race was finally on came the parallel news that the course had undergone some revisions in design from the original proposal. The switchback double hairpin loop had been reversed (in the process mapping out a giant 'e' shape when viewed from above as a happy coincidence) and a tight chicane added immediately afterwards. Further round the section through the car park behind the Prince Regent station was also much altered to make better use of the space. A hairpin within this section included the attack mode activation zone.
An unintended consequence of the changes became apparent when the new layout was released to teams and trial laps were run on simulators. The amount of extra energy that drivers would have to re-generate during the race outside of braking zones was found to be massively reduced by the changes, with estimates putting it at around 5% compared the usual 35%. With little energy regeneration required, the fear was that cars would be able to complete the races at unabated speed, leading to either a processional race or increasing the potential for a crash-fest as drivers made desperate lunges in a bid to overcome the difficulty in overtaking.
With the race just over a week away, there was little that could be done the circuit itself, so championship organisers instead announced that there would be a 4kWh reduction in the energy available to each driver for the two London rounds.
Drivers face unique challenges
The part indoor, part outdoor course provides a number of challenges for the drivers. The course features a wide variety of surface changes around the lap, leading to wildly different grip characteristics. These are only exacerbated in inclement weather, since part of the course is completely dry while the rest is wet, though this is mitigated somewhat by the all-weather tyres used in Formula E.
Starting indoors, the start finish straight and first few corners feature silky-smooth Tarmac, which is specially laid on the exhibition hall's floor and offers maximum grip. However, on the cross over to the outdoor section the cars must navigate a strip of slippery metal, onto further asphalt and then a painted section and finally the highly abrasive Tarmac that surrounds the exhibition centre.
That shift from inside to out also poses a challenge for the drivers as they transition from an almost night-like state indoors to the bright light of the outside. Fortunately the human eye works better than most onboard cameras!
The final challenge comes from the ramps that lead into and out of the main exhibition hall, forming steep declines and an energy-zapping incline to end the lap.