A question of energy

by Philip Selwyn, Founder and Director of Water Powered Technologies Ltd

I recently visited a lady customer who was in the process of installing a Papa Pump – but had unfortunately taken bad advice from some well-meaning male friends regarding the location of the pump.

Basically, instead of placing the pump further down the valley she had installed it close to the water source because they had assumed that because our literature indicates a minimum supply head of 1-2 metres – this is all that is required!  Moving the pump down the hill gave her a 7 metre supply head instead of the current 2 metre head providing her with over three times the water delivery.

Anyway, the conversation with her led me to explaining how supply head related to the energy of the water flow and how this impacted on the performance of the pump and the water delivery.

As part of this explanation I also made reference to the fact that most people now had very little awareness of energy or its true value and then proceeded to demonstrate this by comparing the energy input of her Papa Pump compared to a gallon of petrol and how this could be related to human effort – to which most people can relate.

In this particular case the power input available from her water source was 17 Watts and from this the pump is delivering 3,000 litres/day of water over a distance of 150 metres to a height of 28 metres with a supply head of 7 metres.  I then postulated that if a human could carry two 15 litre buckets of water up the 150 metre climb and back down every 10 minutes then this would equate to 180 litres/hour and therefore would take 16.66 hours to carry the days 3,000 litres. At U.K minimum wage of £7.83/hr this would cost £130.50/day!

In contrast – a gallon of petrol currently costs £5.60 but has enough energy to transport 255,000 litres of water to the top of the hill (less engine and pump losses) and equates to a human effort of 1,416 hours or £11,087!

Although the customer claimed that she found this hard to follow – I believe she understood the message which is a message that governments and the world in general need to start learning quickly – because what it indicates is that the current price of fossil fuel energy bears no relationship to the energy value – and whilst there is a lot of talk about how renewable energy will/should become economically viable – without some price escalator on fossil fuels – it is difficult for people like me to see how this will occur?

My next blog will follow on from this theme shortly – but I remember a quote from the great Carl Sagan saying,

‘we live in a society exquisitely dependent on science and technology,
in which hardly anyone knows anything about science and technology’. 

This is particularly true about modern politics and a quick check on the backgrounds of politicians will only endorse the above quotation – God help us!