Floating Solar Panels

Debate between Lincoln Jopp and John Cooper

Thursday 26th June 2025 Commons Chamber

[Lincoln Jopp (Spelthorne) (Con)]

I am delighted to see the House so full for this Adjournment debate. I want hon. Members who are staying to remember who was here. Indeed, people in the Public Gallery might wish to make a note in their diary, too, because I hope that I will in some way blow the House’s mind with what I am about to say and sow a seed that will grow into something fantastic. What we are here to discuss is floating solar.

Members will know that I am the Member of Parliament for Spelthorne. I feel obliged to remind the House on regular occasions that Spelthorne is not in Lancashire or in Lincolnshire. It is everything south of Heathrow until one gets to the River Thames. Hon. Members from around the House know my constituency well, because it is what they see when they take off from or land at Heathrow airport.

I was selected as the candidate for Spelthorne four days into the general election campaign. Having spent 25 years in the Army, obviously I love a map. There is a very good saying, “If you don’t understand what is going on, get a bigger map.” When I looked at a map of Spelthorne, I was struck by these four massive blocks of blue, so I looked into them. They are four raised reservoirs, which hold half of London’s drinking water. Being a practical person, I first thought to myself, “Well, there are not many votes there!” Secondly, I thought, “I cannot really build any houses there.” Spelthorne is 67% green belt and water, and a large chunk of the rest of it is floodplain, so it is difficult to know what we might do to meet our housing targets; people get crammed into the small islands where development can happen.

I was determined, though, to find some way to utilise the 2,000 acres of raised reservoir in my Spelthorne constituency. I looked into it a little further, and came upon the concept of floating solar. This is a terribly simple concept: simply take solar panels, attach them to plastic floats, anchor those floats to the bottom of the reservoir, and string some wires to take an alternating current from the floating solar panels. The clever bits, in terms of intellectual property, are the anchors—because, as I am sure hon. Members know, the depth of reservoirs tends to vary by about 1 metre from time to time. Equally, reservoirs are drained and reassessed on a rolling cycle of about 20 years.

[John Cooper (Dumfries and Galloway) (Con)]

I thank my hon. and gallant Friend for allowing me to intervene. We are told that there is nothing new under the sun, but he is describing something that ticks both boxes—it is quite remarkable. I learned much about reservoirs from playing by the side of the scenic Penwhirn reservoir, outside by home town of Stranraer. I also learned about them in geography classes at Stranraer academy, and it strikes me that one of the reasons that reservoir levels rise and fall is to do with evaporation, and water is obviously a precious resource. Does covering reservoirs help to combat evaporation?

[Lincoln Jopp]

My hon. Friend pre-empts one of the many benefits of floating solar that I will highlight to the House. He remembers his physics highers well, because the placing of floating solar reduces evaporation from the body that is covered by 70%. Given that the vast majority of the water in our reservoirs is lost through evaporation every year, we will save a great deal more water if the Government decide to pursue this technology at a grand scale.

Part of my coming here today is to speak to two large constituencies within this House. There are 543 constituencies that contain reservoirs or man-made water sources. Similarly, countless Members from across the House have very difficult decisions to make about putting solar farms on good agricultural land. Essentially, what has happened is that the whole discussion in this area has become a zero-sum game. It is a battle between food security and energy security, and there has seemed to be no way of unpicking that—until now.

Globally, floating solar has been put to practical application at large scale in China, India and Vietnam. The UK was formerly a leader in this space, because on the Queen Elizabeth II reservoir in 2016, a grand technology demonstrator was put on and plugged in, and it has been banging out 6.3 MW into Thames Water’s water treatment facility ever since. That is enough to power 2,000 homes. Given that floating solar covers less than 10% of that reservoir, I am sure that hon. Members can see the vast potential.

I want to talk about some of the benefits of floating solar, because they are legion. First, as hon. Members will have worked out already, there is the removal of the opportunity cost of putting floating solar panels on grade A agricultural land. If we do not have to put them all over Lincolnshire and we can put them on reservoirs, that land can be used for growing food.

--- Later in debate ---

[Lincoln Jopp]

We have gone from Cooper to Hooper! I am delighted to follow my right hon. and gallant Friend’s endorsement, and wish everyone there the opportunity to get to the polls today to exercise their democratic right.

[John Cooper]

I am very grateful to my hon. and gallant Friend for giving way a second time. I do wonder if I may have stumbled across another advantage to floating solar, which may not have occurred to him. If water quality is improved, will that not help the fish? Clatteringshaws loch reservoir in my constituency has some of the best pike fishing in the country. I wonder if the fish might benefit from having a roof over their heads.