Sort of off topic a little but along the same lines. Well batteries anyway, I work in the powered access industry. They have been looking into the different types of batteries to power machines, we are still heavily using lead acid batteries. But some companies have been looking into the use of lithium or li-ion batteries. But they are so expensive they wont use them. as it is a 19 foot scissor lift may be hired out for lets say £100 per week. if they used li-ion batteries that hire would cost at least £400 per week. The companies know people would not want to pay this price...