regeneration

Regenerative braking in electric cars

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My Nissan Leaf dashboard showing that it has regenerated enough energy through regenerative braking to add three miles to the range

One of the benefits of most electric cars (and many hybrid cars) is regenerative braking – recovering the energy created from braking to charge the battery. It’s something that most petrol and diesel cars can’t do, and it allows electric cars to extend their range slightly.

Regenerative braking is something that electric trains have done for many years (indeed most electric passenger trains in the UK have regenerative braking), but it’s something that is probably new to car owners.

The first law of thermodynamics

If you’ve studied physics, you may be familiar with the first law of thermodynamics. This law dictates that energy can’t be destroyed and it can only be changed from one form to another. When you press the brake pedal to slow your car down, the energy from the brake force has to go somewhere.

On a internal combustion engine (ICE) car powered by petrol or diesel, your car will slow down by the friction created when your brake pads are pressed against your brake discs. The energy is therefore wasted as heat, and braking gradually wears your brake pads down over time.

Electric cars brake slightly differently. They still have brake discs and brake pads, but when you want to brake, the electric motor can work in reverse. The resultant kinetic energy can then be converted into electrical energy that is fed back into the battery, rather than being wasted as heat. From what I understand, this is done using magnets; if you think back to GCSE Science, you’ll remember that a magnet, combined with motion, produces electricity.

Additional range

That additional energy flowing back into the battery can therefore extend the range that your car can achieve on a full charge. We’ve actually noticed the charge level go up whilst driving downhill. An example is when we’re heading home from Manchester; to reach Sowerby Bridge, we exit the M62 at its summit point which is 372 metres above sea level, and descend around 300 metres. Typically, the charge goes up around 2% over the 8 miles from the M62 to Sowerby Bridge.

One thing to note is that your battery needs some capacity to accept the extra charge from regenerative braking. Therefore, if your car is 100% charged, there won’t be any regenerative charge. On our car, regenerative braking is limited above 80% charge.

Overall, depending on the types of roads, regenerative braking tends to add between 5 and 10% more range, which equates to between 7 and 14 miles. As well as allowing you to drive further on a full charge, it also saves a bit of money.

Reduced brake wear

Because you’re using the car’s electric motor to slow down, you should also find that your car’s brake pads and brake discs suffer less wear and tear. Again, this will save you money, as the discs and pads won’t need replacing as often as they would in an ICE car. It also reduces your car’s emissions; not only do electric cars not have any tailpipe emissions, but the particulate emissions from your brakes is also reduced compared to an equivalent ICE car.

How much regenerative braking your car will do, will depend on its mode. On our Nissan Leaf, in standard and eco driving modes, it will do a moderate amount of regenerative braking. But if we pop it into e-pedal mode, which is its one-pedal driving feature, the motor brakes more aggressively to regenerate more energy. We tend to keep it in e-pedal mode almost all of the time, although it’s of less use on motorways, for example.

Regenerative braking is a nice bonus feature of electric cars, and helps them be more efficient. It also adds to their lower maintenance costs, through lower brake wear. It’s certainly something to consider when weighing up whether to buy an electric or hybrid car.

Making Victoria Posh

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Manchester Victoria Concourse

Manchester Victoria station has had a rather large makeover. It’s not the dark, dreary place that it once was, and now sports a new roof that lets in far more light. And not before time, too.

One of the worst

Back in 2009, Victoria was named as one of the worst railway stations in Britain. The roof over platforms 1 and 2 and the Metrolink platforms was in a poor state of repair, following damage sustained in the 1996 IRA bomb attack that was never fixed. It leaked, and was partially covered in tarpaulins which made the station seem dark. To prevent fare evasion, ticket inspectors had erected temporary barriers around the platforms with confusing one way systems. Platforms 3-6 were now underneath the Manchester Arena, and were poorly-lit with a confusing layout for the footbridge.

It wasn’t a very inviting station to spend any time in, especially at night.

Management

To understand why the situation at Victoria got so bad, it may be worth looking at the management of the station over the years.

When the railways were privatised in the 1990s, the running of most smaller and medium sized stations was taken over by the largest train operating company (TOC) that called there. Control of major stations was passed to Railtrack, and then Network Rail when Railtrack went bust in 2002. Many of these major stations underwent major regeneration work, which usually involved massive expansion of retail space to bring in more rental income.

Manchester Piccadilly is the biggest station in Manchester and so Railtrack managed it, but management of Victoria has always been with a train operating company: since 2004, this has been Northern Rail. Northern Rail’s franchise was let on a ‘no growth’ basis and so very little investment has been made in either trains or infrastructure, despite Victoria being a major hub for Northern Rail.

Manchester Victoria

Capacity

Victoria was once a much bigger station than Piccadilly, with 17 platforms at its peak. But in the early 1990s, the decision was made to re-route most trans-pennine services away from Victoria to Piccadilly, which is on the West Coast Main Line. Previously, passengers travelling from, say, Leeds to Stoke would have to take a short shuttle service between Stalybridge and Stockport – now they could simply make one change at Manchester Piccadilly. This shuttle still runs, albeit only once a week.

Victoria was subsequently downsized to 6 rail platforms, and 2 platforms for the then new Manchester Metrolink tram system. The now disused platforms on the north side of the station were demolished and the land sold off to build the Manchester Arena which sits above part of the station.

At the time, re-routing services to Piccadilly made sense, as the railways were in a period of managed decline. But following privatisation, passenger numbers have rocketed to record levels, and now capacity at Piccadilly is becoming an issue. Those trans-pennine services have to cross the paths of mainline trains from London on flat junctions, which limits the number of trains that can depart and arrive from Piccadilly station. And of Piccadilly’s 14 platforms, 12 of them are bay, or terminating platforms. Any train that needs to pass through Manchester has to use the two through platforms, numbered 13 and 14, which are now full to capacity. Work is planned to add an additional two through platforms, but in the meantime there can’t be any additional services that cross Manchester city centre via Piccadilly.

1st Class Refreshment Room

The Northern Hub

The Northern Hub project is a Network Rail initiative to improve rail capacity in the north of England, and it’s focussed on Manchester. Part of this will involve a new section of track, called the Ordsall Chord, which will allow trains to leave Victoria going west, and then loop around to Piccadilly. At the moment, most trains that call at Victoria terminate there, even though 4 of its 6 rail platforms are through platforms, which is a poor use of capacity. Upgrades at stations such as Rochdale and Stalybridge will allow trains that currently terminate at Victoria to continue, in turn allowing more trains to stop there. Last year, a new direct Liverpool to Newcastle service started calling at Victoria, and this is likely to be the first of several new long-distance services that will call at Victoria, rather than Piccadilly.

Making Victoria Posh

Eventually, money was found to refurbish Victoria and bring it up to the same sort of standard of other major stations. The old roof is gone, and has been replaced with a new ETFE roof. New flooring has been lain on the concourse, automatic ticket barriers have been installed, and a new footbridge has been erected to improve access to the Manchester Arena. New shop units have been opened and the existing ones refurbished – the old first class refreshment room is now a Starbucks, but retains its original tiled interior.

Meanwhile the Metrolink platforms have also been rebuilt, and expanded from two to four, albeit with only three tracks. Some trams will call at both platforms B and C – they’re lettered to avoid confusion with the rail platforms.

Together, these projects have been branded as ‘Making Victoria Posh’ a pun presumably inspired by Victoria “Posh Spice” Beckham.

A separate project has seen the lines coming into Victoria from the west electrified for the first time. This means that electric trains can run from Victoria to Liverpool Lime Street – these services started earlier this year. Eventually electrification will extended eastwards towards Stalybridge.

The works still aren’t quite complete – there’s a little bit left to do, and only a couple of the retail units are occupied (both of which are coffee shops). But the station already looks so much better than before. No longer will it be an embarrassment to the city.