The Beeb offers a data point on the efficiency of biofuels:
Cold snap stops green bus service
A bus company’s efforts to cut global warming emissions have led to services being disrupted by cold weather.
First Eastern Counties Buses, which runs services in Norfolk, Suffolk and Cambridgeshire, said bio-diesel had turned waxy in sub-zero temperatures.
The thicker consistency of the diesel meant fuel lines became blocked.
The company said it had suspended use of the bio-diesel, and was refuelling buses with ultra low-sulphur diesel which is not temperature sensitive.
Managing director Peter Iddon said the company was working with bio fuel suppliers to develop a fuel that does not freeze in temperatures below -15C.
He added: “I would like to apologize to all our customers who today experienced delays because of this cold weather.
“With the introduction of bio-fuel our intentions were to utilize a product that offered a green and environmentally-friendly alternative to diesel.
“However, our priority must be offering a safe and reliable bus service and until the problems of using bio-fuel in cold weather are overcome we must return to the use of low-sulphur diesel.”