Sun Rises on Toyota UK Solar Project

Tuesday 7th June, 2011
Naturally, when Toyota made a press release regarding them achieving a "UK Car Industry First" with a massive solar array, I thought I would take a closer look. I thought the press release might give some very interesting numbers relating to the CO2 of car manufacture and I wasn't wrong.
You may have seen solar panels popping up on the roofs of homes all over the UK and they usually consist of a few square meters of shiny PV cells on a suitable south facing roof. Such installations cost around £10,000 and are rated with values like 2kW peak. Which means that, in optimum conditions, they will generate around 2kWh of electricity every hour - saving you around twenty pence on your electricity bill for each hour the sun is shining.

Enter Toyota Manufacturing UK who have decided to scale this up to industrial level by deploying a PV array that's big enough to cover four and a half average football pitches - 17,000 panels on 90,000m2 of land. The peak output of this is expected to be 4.1MW - some 2000 times larger than your normal domestic install and naturally there are many savings to be had.

Obviously conditions aren't always perfect for solar panels. Sometimes it's too hot, sometime it's too cold and, for many hours of the day, it's just dark! The end result is that, instead of the theoretical maximum of around 36,000MWh of electricity if it were sunny twenty-four hours a day, the array in Derbyshire is expected to generate 4.6 million kWh of electricity each year. This equates to an efficiency of around 12.8% which is pretty fair given the claimed 20% from modern Solar PV panels.

Of course, there is still a long way to go - these savings represent just a 5% reduction of the total consumption of the plant, which can build around 140,000 cars each year at full output, but it's a massive start towards reducing the total emissions footprint of owning a car. The driving phase of a typical car with a conventional engine accounts for 75% of all the emissions in its lifetime, switching to a hybrid can save around a third of this. Now the cars can be built with a further 5% reduction in energy use and the saving is across the board on other standard petrol/diesel models too.

The savings from the solar install have been expressed in a number of different ways by Toyota, such as the equivalent of brewing 150 million cups of tea, but in real-terms that's enough electricity to supply my home around 600 times over! More importantly, however, Toyota explain that this is enough electricity to build around 7000 cars each year. It doesn't take Carol Vorderman to then conclude that the electrical footprint of car assembly is actually 4,600,000/7000 = 657kWh per car - enough to fully charge the forthcoming Plug-in Prius vehicle over 130 times and power it over 1600 miles.

This figure is even a little pessimistic as it's actually based upon the whole consumption of the Burnaston plant. So not only does it include the assembly of Auris and Avensis cars, it also includes all the lights and air conditioning in the offices, the ovens in the works canteen and even the coffee machines. So whilst the actual footprint of building a car may be a little lower, we have a more useful real-life consumption including all of the overhead of the workers, premises etc.
Dropping these numbers into my favourite NEF Carbon Calculator, we can see a carbon footprint of approximately 358kgCO2 per car which, if expressed in terms of the 89g/km Auris Hybrid that is built there, is a saving of 2500 miles worth of CO2 emissions or cover the entire CO2 footprint of 1750 Auris Hybrids doing an average 10,000 miles a year.

To top it all, these cars are built in the UK, removing the need for them to come to Europe on a car carrier from Japan; which can itself produce more that double the emissions released from building the car in the first place.

Altogether, this is a great environmental success story and shows that Toyota are still making continuous improvement 15 years after being the first UK car manufacturer to be awarded the international ISO 14001 standard for environmental management in 1996.

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