The set up

The set up
5.46mm jet delivering 0.68 l/s to the pelton which is rotating at 900 rpm and generating 135 watts into the grid.

Saturday, 21 February 2015

NRW Inspection visit

This week, Natural Resources Wales (NRW), the organisation responsible for regulating water abstraction, paid me a visit to check that I was keeping to the terms of the licence they issued.

 For an organisation which has been deaf to the protestations of the UK Microhydro Association and the British Hydro Power Association that its licensing procedure is inappropriate for hydro installations, I was pleasantly surprised that the two NRW people who came were willing to listen to the arguments I wanted to put forward.

I had prepared for them coming.  I wanted to get across three things:
1. calculating abstraction volumes using the efficiency of the system at maximum power is wrong headed.
2. stipulating an annual maximum volume of abstraction is meaningless if the licence specifies the maximum instantaneous flow which can be taken.
3. the wording of their licence is internally inconsistent by stipulating in one section the maximum volumes to be extracted, yet in another section giving these same volumes as being minimum volumes.

To make the point about efficiency I gave them this graph which shows how efficiency falls off toward the upper end of power output.  It is the same plot as I've posted before but in a different format and with additional data points added:

To make the point about having to adhere to an annual maximum volume, I pointed out that with the volume I've abstracted up to the end of January being 39,727 m³ and with two months still to go before the end of their "abstraction year" on March 31st, I was almost certainly going to breach the annual limit set at 49,982 m³, despite having kept within the limit of instantaneous flow set at 3 litres per sec.

Will anything come of it all ? - I'm not holding my breath, but on the day of the visit at least, it was nice to be reminded that there are, working within this bureaucratic quango, intelligent, approachable, rational, human beings.


regen said...

Hello Bill,

Another interesting post. I am surprised that they can find the time or the money to cover these micro sites. Still after been grilled by you they may not come back for about 10 years! Perhaps this is the justification for raising the licence fee by 1000% - it will stop people from applying!

I found the people on the ground very helpful as well - An email to remind me the fee was going up 0n 01/04/15 and a suggestion that i should ensure I applied for a high enough abstraction limit to cover all eventualities. Consequently I got 70,000m3 for a single turbine at 3.3 lps where as I would have applied for around 55,000 based on my actual figures.


Bill said...

I should've done as you did, - apply for more than the annual flow figures indicate would ever be possible. Oh well, ... next time !!