Sat, 18 Apr 2026 13:52:44 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12125&Focus=202561#Comment_202561 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12125&Focus=202561#Comment_202561 Sun, 25 May 2014 11:27:30 +0100 Doubting_Thomas Interesting take on the storage problem with variable output from renewables.

http://www.economist.com/blogs/babbage/2014/03/electricity-storage?fsrc=rss&utm_source=dlvr.it&utm_medium=twitter]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12125&Focus=202566#Comment_202566 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12125&Focus=202566#Comment_202566 Sun, 25 May 2014 13:23:36 +0100 tony https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12125&Focus=202571#Comment_202571 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12125&Focus=202571#Comment_202571 Sun, 25 May 2014 14:20:51 +0100 Ed Davies http://www.iprplc-gdfsuez.com/~/media/Files/I/IPR-Plc/Attachments/presentations-pdfs/2005/hydrosite05.pdf

Linked from Wikipedia. Page 7 (about Dinorwig) says “Cycle Efficiency 74-75%” and page 16 (about Ffestiniog) says 72-73%.

By the way, “proper” gliders (as opposed to hang gliders) already do use a form of pumped storage in that they often carry water ballast to increase their weight so that they store more potential energy in thermals in order to be able to glide faster to the next thermal.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12125&Focus=202603#Comment_202603 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12125&Focus=202603#Comment_202603 Mon, 26 May 2014 13:09:43 +0100 Paul in Montreal Posted By: tonyI thought pumped hydro was a lot more than the 74% efficient that the article mentions.

That's the efficiency of the turbines - the generators are close to 100% when used as motors. It's impossible to get all the potential energy out of the water as it still must contain some in order to flow out of the turbines.

Paul in Montreal.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12125&Focus=202647#Comment_202647 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12125&Focus=202647#Comment_202647 Tue, 27 May 2014 11:40:20 +0100 SteamyTea https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12125&Focus=202649#Comment_202649 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12125&Focus=202649#Comment_202649 Tue, 27 May 2014 13:06:59 +0100 Paul in Montreal Posted By: SteamyTeaWould the efficiency be higher in some PS's if the reservoir is also supplied by land run off, small amounts of rainfall and river inputs?

Maybe a tiny bit - but the limiting factor is the efficiency of the turbine itself. Ben Cruachan is supplied by land run off, for example. The reservoir has a capacity of about 18 hours of run-time - there's no way that can be re-filled by rain and river inputs when it's most of the way up a mountain.

(I just visited there a couple of weeks ago).

Paul in Montreal.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12125&Focus=202650#Comment_202650 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12125&Focus=202650#Comment_202650 Tue, 27 May 2014 13:22:17 +0100 Ed Davies