The UK Committee on Climate Change recommends a global reduction in CO2 emissions of 50% for developing countries and 80% for the developed world by 2050. In the UK, that 80% target would mean bringing down emissions from ca 12.5t CO2/person/year in 1990 to just 2.5t CO2.
A significant part of the solution lies in road transport, according to Julia King, a government adviser on transport emissions, speaking at an SCI public meeting in October.
Road transport accounts for 17% of global carbon emissions, second only to electricity power generation (26%). In the UK and US, the numbers are higher at 20% and 33%, respectively. The 1bn vehicles on the road today use more than half of the oil produced.
By 2050, the UN predicts that 70% of the 9bn population will be middle-class city dwellers. About the same number of people on the planet today will live in cities, explained King. And, with the number of cars expected to reach 3bn globally by 2050, the UK’s response to the transport challenge will have important ramifications for the rest of the world, she added.
The latest figures from the UK’s Department of Energy and Climate Change point to 73% of greenhouse gas emissions coming from light duty vehicles (cars and vans); 20% from HGVs; and 4% from buses. However, with the average car in the UK car emitting ca 160g CO2/km, even if people drive less than the average 15000km/year, they are already using 2.4t, almost their entire 2050 personal carbon budget.
Increased car usage, as well as car ownership, leads to another serious problem in cities – congestion. A 2009 study by Massachusetts Institute of Technology (MIT) researchers showed that of the fuel used in urban areas, about 40% is consumed looking for parking, and concluded that urban transport is twice as energy dense as transport between cities.
Changes in behaviour, such as choice of car, eco-driving, and reduced speed limits could reduce emissions by around 50%, King said. Traditionally, however, this has been difficult to achieve – so only around 6% of the emissions target is expected to come from government initiatives aimed at influencing behaviour. Moreover, according to a study by the Indian Institute of Technology in Delhi, the quickest way of making journeys up to 12km, even in this very congested city, is by car. ‘It is really difficult to get us out of our cars with evidence like that,’ said King.
While individuals are not yet contributing much to lower emissions, car manufacturers have nevertheless made huge strides in this area, said King – driven mainly by European targets. Improvements in engine and fuel design, bodywork and tyres have seen CO2 emissions in new cars drop from 160g/km in 2007 to 140g/km in 2011. And with the introduction of hybridised technology, the internal car combustion engine can now emit as little as 80–90g/km CO2. Since 2000, the average new car’s fuel consumption has improved from under 40mpg to around 55mpg. ‘This is one area where we are achieving even faster [emission reductions] than we predicted,’ said King.
Good public transport systems and city design can also make a big difference. In Calgary, US, where the population density is not enough to sustain affordable public transport, around 90% of journeys are made by car. Compare this with London, Tokyo and Hong Kong, where 40%, 20–25%, and 10% of journeys are made by car, respectively. Hong Kong not only has a very good public transport but it is growing within a limited compacted space.
However, the challenge of bringing down CO2 emissions goes beyond internal combustion technology, King said, adding that biofuels, hydrogen and significantly electric vehicles will all have a part to play. While biofuels and hydrogen technology both have drawbacks when it comes to road transport, electric vehicles will be crucial to any solution, she said.
Decarbonising electricity generation by nuclear and renewable sources is another priority. If CO2 emissions from power generation reach the targeted 50g/kWh by 2050 – down from 490g/kWh currently – the benefits of the electric vehicle become apparent, she said. Today, the electric car is just slightly better in terms of CO2 emissions than the hybrid Toyota Prius, King explained; by 2020 if CO2 targets from power generation are met it will produce about half the emissions of the hybrid and by 2030 less than 10%.
The argument for electric cars in the UK is strengthened, said King, if you consider the distances people drive. The vast majority of UK trips are less than 50 miles/day, and likely to be less than 35 miles/day – well within the range of an electric car. Charging electric vehicles at night, when electricity consumption is low, would have the added advantage that it would place a more constant load on the electricity generating system, making it more efficient.
Over the past 10 years alternative fuel vehicles have seen their market share grow from almost zero to 1.3%. To realise the government targets, this figure needs to be 17% by 2020, King commented, adding that incentives and lower running costs will make them competitive – if not cheaper – than conventional cars by 2020.