My attention was drawn recently to the new plans by the Mayor of London, Sadiq Khan, to accelerate the Cleaner Air and Climate Change policies of his predecessor. You can read more about them here.
The plans focus on addressing London’s chronic air quality, which breaches the legal limits for Nitrogen Oxides (NOx) and the WHO limits for Particulate Matter (PM). In almost all areas of London particulate pollution is more than 150% of the legal maximum, and at times this year air pollution in London was worse even than in Beijing. The EU is taking legal action against the UK in this regard.
The Mayor’s plans to cut emissions are extensive and ambitious, and draw upon last year’s report by the Institute for Public Policy Research: “Lethal and Illegal – Solving London’s Air Pollution Crisis”.
Speaking earlier this year when announcing the plans, Sadiq Khan said: “The air in London is lethal and I will not stand by and do nothing.”
Because emissions from vehicles represent the largest part of the problem, vehicle emissions are accordingly the largest part of the Mayor’s proposed solution. An “Ultra Low Emissions Zone” is being introduced in 2019 in central London, with a daily charge raised on all vehicles which do not meet the latest (2014) Euro 6 standards for emissions. The zone is to be extended to encompass greater London by 2021. In the meantime, a new “T-charge” (T=toxicity) is being introduced this month, additional to the existing congestion charge for all vehicles which do not meet the Euro 4 (2005) emissions standards.
Additionally, from January 2018, all newly licensed black hackneys in London must be zero-emission, with the same requirement covering all new private-hire cabs by 2020. Meanwhile, the fleet of over 9000 London buses is being transitioned onto diesel-electric hybrid and all-electric models. To support these initiatives, a programme is currently underway to install hundreds of fixed charging points throughout the city to service the new taxi fleet, while a trial of induction-charging points for electric buses is in progress.
In short: London (in common with other cities in the UK) has a serious problem with air pollution, caused in large part by emissions from road vehicles. The problem is a major public health issue, with NOx and PM pollution exceeding both legal and health authority limits.
The proposed solution, in part, is: To reduce emissions from vehicles by further discouraging drivers from coming into the city; To replace the fleet of diesel taxis with electric cabs; And to replace the bus fleet with zero emission all-electric or low emission hybrid vehicles.
True to his word, the Mayor is not standing back and doing nothing; Fair play Mr Khan. But, there’s a problem with all of this, and it’s not a London problem. It’s a UK problem: Quite where is all the electricity going to come from to power this ‘green revolution’ in the capital?
Let’s take just one small example: Black Hackneys. Under the plans, from January 2018 all newly licensed black hacks must be zero-emission vehicles. There are currently 21,000 black hacks in the capital, and the plan is that all of them will be replaced by zero-emission cabs within 5 years.
The leading zero-emission taxi model is the LEVC TX6. While no official data has been released, figures from the LEVC website indicate that the new all-electric model has a power consumption figure of 26kWh per 100 km.
Allowing for single and double “shifted” cars, the average London cab drives around 40,000 miles each year (64,373km). The new LEVC electric taxi consumes 26kWh per 100km. From these figures we can calculate the required electricity generating demand for each vehicle:
64,373km x 26kWh / 100km = 16,737kWh
16,737kWh/ 365 days / 24 hours = 1.9kW
Thus, for each new electric taxi, we require to increase our electricity generating capacity by 1.9kW.
Every year, and for the next 5 years, around 4,200 old diesel hackneys will be replaced by new all-electric ones, giving a required increase in generating capacity of an additional 8MW every year. Accordingly, the total additional generating capacity required to support the plan to replace the taxi fleet is 39.9MW over the coming 5 years.
To put that in some perspective, and since this is a “green” programme, let’s assume that the new power generating capacity will be from renewable sources, let’s say Wind. How many ‘standard’ onshore wind turbines will it take to power London’s new fleet of Black Hacks?
A typical onshore turbine has a ‘plate capacity’ of 2MW. That is, when working at full tilt, it generates 2MW of power. However, because wind is a variable resource, weather and location dependent, the actual output is considerably less. The most recent figures show that the UK onshore Wind fleet has a ‘capacity factor’ of 26% – that is, the actual output of electric power is 26% of the plate capacity.
In order to power London’s new fleet of 21,000 zero-emission Taxis, we will need to increase the capacity of onshore Wind generation by around 15 new ‘standard’ 2MW turbines each year for the next 5 years. This notional ‘new wind farm’, once complete, will have 77 2MW turbines installed over an area of around 20 square kilometres – or six times the size of Hampstead Heath.
And that’s just for London’s Black Hacks. The Mayor’s plan extends to London’s fleet of 80,000 private hire vehicles. Allowing a reduced mileage of 25,000 (40,233km) per year, and as private hires are generally smaller (lighter) than black hacks, a reduced power consumption of, say, 20kWh/100km, we can estimate the corollary increase in electricity demand:
40,233km per car x 20kWh / 100km x 80,000 cars = 643 million kWh
That’s 73.5MW of new generating capacity, or an additional 141 new ‘standard’ 2MW wind turbines to power the private hire fleet.
And what about the bus fleet? London’s bus fleet comprising over 9,000 single and double decker buses, each driving some 57,000km per year. A new all-electric single decker uses around 120kWh/100km, while new diesel-electric hybrids use about one quarter of that, topped up with diesel. The total demand for electricity to power the bus fleet will clearly be dependent upon the ratio of engine types across the new fleet, but if we allow a mix of 80% hybrid: 20% all-electric, we can estimate the total demand at around 30MW to power the bus fleet. Add another 58 ‘standard’ turbines to our new notional wind farm.
In sum, the plan to transition London’s fleet of Hackney and private hire taxis from diesel to zero-emission electric vehicles, and its bus fleet from diesel to a mix of hybrid and all-electric, will require a lot of new power; around 145MW of new renewable generating capacity. That’s equivalent to a notional new wind farm comprising around 275 ‘standard’ 2MW turbines requiring a rather windy place in an area of land ten times the size of the City of Westminster.
To put that all in some perspective, the UK’s largest onshore wind farm, Whitelee near Glasgow, comprises 215 turbines with a plate capacity of 539MW. With a capacity factor of around 20%, its output is 110MW. Big as it is, and it is the largest in the UK after all, a new Whitelee-scale wind farm is not big enough to generate the electricity required to power London’s new transport plan. We need to go offshore to find the power.
The largest offshore wind farm in the world is the London Array. Located off the Kent coast, the first phase was completed in 2013 and comprises 175 turbines with a plate capacity of 630MW. Accounting for a capacity factor of 35%, its output is around 220MW.
The second phase of the London Array planned to install a further 166 turbines, increasing plate capacity by 370MW, and delivering an additional ‘factored’ output of 130MW by 2020.
Clearly, although large in scale, phase 2 of the London array would not be sufficient to power the transport plan for London. It does though bear noting that the 130MW of additional local generating capacity would have been very timely, had the project not been abandoned due to planning concerns over environmental impacts. Oh!
None of this should detract from the Mayor’s plans. London’s air quality problem is a population health crisis, and demands to be addressed. The Mayor’s ambitious plans are laudable in that light, and call for broad support. But they can’t be delivered in isolation.
And moreover, this is simply London, and public transport in London at that. What of private vehicles? Commercial traffic? What of the other cities in the UK with similar (though lesser) air quality issues?
And what of the Government policy to phase out petrol and diesel vehicles altogether by 2040? (2032 in Scotland).
There are 37 million vehicles on the UK’s roads, almost all of which petrol or diesel, and almost all of which to be phased out over the next 25-30 years. Last year in the UK, we drove in the order of 326 Billion vehicle miles. That’s an average mileage of 8,810 (14,178km) per vehicle per year. And let’s assume traffic volume doesn’t increase in the intervening years (forecasts suggest it will).
Drawing on the UK Government’s traffic data set, we can infer an average power consumption per vehicle of 26.25kWh(e)/100km. If all of these vehicles are to be electrically powered, the resulting figure for electricity generating demand is big. Very big:
14,178km per vehicle x 26.25kWh/100km x 37,000,000 vehicles = 137,720,099,646 kWh
That’s 137.7 Kilo Mega Giga TeraWatt Hours of electricity each year, requiring 15.7GW of new electricity generating capacity. Or 30,000 of our ‘standard’ onshore wind turbines.
We simply don’t have sufficient land mass in the UK with adequate wind characteristics to deliver this. Neither do we have sufficient continental shelf with adequate wind characteristics offshore.
If we’re going to power our vehicles electrically, and we’re committed to generating our electrical power from renewable sources, we’ve got quite the problem.
The problem is, we need to build an additional 16GW of generating capacity in the next 25 years to power transport. Meanwhile, we’re committed to decommissioning the existing 14GW of coal-fired generators. That’s a 30GW sized hole, or 50% of current UK capacity, and renewables simply can’t deliver on that scale, or certainly not on their own.
Short of reverting to fossil fuels (which in effect means imported gas, implying an energy security problem as well as a climate change contradiction), we’re left with Nuclear. And that means the equivalent of five new nuclear plants of similar size to the new Hinkley Point C plant simply to ‘green’ transport, and the same again to replace coal.
Let’s leave aside for the moment the issues of nuclear fuel availability, safety and waste disposal. It took eight years to get Hinkley C through planning and contract negotiation, and it will be a further 10 years before it’s online. We need to build generating capacity equivalent to 10 such, and with an 18 year planning-negotiation-construction timetable, we don’t have the time remaining.
Moreover, at £20 Billion a pop, it remains to be seen whether we even have the money to pay for them. What’s more, there isn’t a queue of contractors able to build them, whether in your back yard or mine. It’s fair to say that we’re as short of able contractors as we are of willing back yard owners.
In announcing his plans for London, Mayor Sadiq Khan said: “‘Now I urge the Government to step up and match my ambition to transform the appalling air we breathe.”
Quite right! More power to you Mr Mayor. But just where are you going to get it all?
Notes
As usual, this is written by a Dummy, and the usual dummy caveats apply.
The discussion above is based upon calculations scribbled on the back of a fag packet. While I have been fairly diligent in cross referencing data and double checking the arithmetic, it remains a series of approximations.
Some rounding up and down is inevitable in the numbers. If you can sharpen the pencil, please do.
Moreover, if you have a practical solution to the problem, please, please let Mr Khan and the rest of us know!
The calculation on total energy demand to establish the electric power generation required to power the UK’s zero-emission road transport policy from 2040 draws upon published 2016 UK traffic data, and uses an approximation of vehicle types and estimated energy demand as follows:
For those interested in further reading, I thoroughly recommend “Sustainable Energy Without the Hot Air” by the much-missed Dave MacKay. His book is available to download for free here: https://www.withouthotair.com/
Some Old Hat 