A UK politician has been vocalising his support for the development of floating solar power, saying it offers a game changing solution to the UK’s energy dilemma.
Lincoln Jopp, Conservative MP for Spelthorne in Surrey, England, claims that putting solar panels on just 15% of the UK’s reservoirs would double the country’s solar energy production and avoid, what he calls, “the visual vandalism” of putting panels across the countryside.
Jopp is a keen advocate for FPV, especially as his constituency is home to four raised reservoirs that contain half of London’s drinking water.
“Unlike traditional land-based solar farms, which consume valuable agricultural land, floating solar installations sit atop reservoirs, spaces that are already in use and largely invisible to the public,” he says. “Spelthorne is uniquely positioned with four prime reservoirs, offering the perfect opportunity to harness solar power without harming biodiversity or disrupting water sports. It also improves water quality and reduces water loss from evaporation by 70%. It’s a win-win for our environment and our community.”
Jopp also gives the example of FPV technology sited on the Queen Elizabeth II reservoir near Walton-on-Thames which, when built in 2016, was the largest floating farm in Europe and generated 6.3MW of power for Thames Water. If water companies “were smart”, he claims, they could lease the surface area of their reservoirs and “make a few bob”.
Jopp says he was disappointed by the Labour government’s recent solar roadmap which only made a passing one-page reference to FPV. He urges them to invest in this forward-thinking solution which could generate 16GW of power, generating 80,000 jobs in the construction phase and 8000 more in operation and maintenance – when using just 15% of the UK’s existing manmade water bodies.
Jopp says floating solar is good for food, energy, and water security, and with the right support, the UK can lead the way in cutting-edge renewable energy. In response, the government has said although keen to encourage growth of this technology, more needs to be done to make it cost-effective.
Floating solar under review
Due to its superior flexibility and affordability, solar power is predicted to be the most popular energy source in the future, according to new research published in Renewable and Sustainable Energy reviews. And whilst the energy output of a PV system is proportional to its surface coverage area, finding available space for future deployment ‘points the finger’ towards water bodies.
This is why an interdisciplinary literature review of floating solar plants has been undertaken by researchers from the UK, Australia, and Germany. In their study, Wei et al say that the extrapolation of solar power plants from land-based to water-based requires interdisciplinary expertise from a variety of specialist fields such as energy, hydrodynamics, structures, environmental, and electrical engineering.
To undertake what they call is a unique analysis of technical engineering challenges and environmental considerations, the authors say they scanned over 900 existing floating solar related publications comprehensively, selectively leading to the inclusion of approximately 400 papers. They claim the ‘key innovation’ of their review lies in its comprehensive, inter disciplinary approach to examining FPV systems and is one of the first to synthesise knowledge across multiple domains, including hydrodynamics, structural analysis, power prediction, and environmental impacts.
Some of the key findings from this study suggest:
- The potential for enhancing energy efficiency through water-based cooling techniques.
- Innovative modularised designs to support upscaling.
- Positive environmental impacts including artificial habitats.
Although the design, modelling and environmental effects of existing FPV research are discussed in detail, research gaps remain. This review highlights an urgent need to simulate the dynamics of numerous floating bodies in waves, i.e. modular FPV systems. There is also a significant gap to designing and optimising the mooring system and although FPV systems have somewhat shown positive impacts on the environment, the environment can also induce biofouling and corrosion on FPV which, the authors claim, is barely studied nor mitigated.
Swiss studies
To help address the question of how hybridisation of existing hydropower plants could affect water resources management, new research has focused on a project in Switzerland. And although the joint operation of solar and hydro power can certainly improve the performance of a power system, on the other hand, Miocci et al say in Renewable Energy, complementing an existing reservoir-based hydropower plant with a PV plant may affect the way the reservoir was previously operated, with possible consequences on storage conditions and water availability.
‘To our knowledge, these effects have been rarely investigated in the literature, despite their relevance,’ the authors claim.
In their work they proposed a modelling framework for an existing pumped storage hydropower plant located in the Swiss pre-alpine region, complemented by a fictional floating solar photovoltaic plant with a nominal capacity equal to about 50 % of the hydropower plant.
Lake Sihl is an important artificial reservoir, located in the foothills of the Swiss Alps and was created in the 1930s to regulate the streamflow regime of the torrential river Sihl. The lake drains a 155.5 km2 large catchment, spanning from 889 to 2282 masl.
Water collected in Lake Sihl is mostly used by the Swiss Federal Railways for hydropower production in the Etzelwerk plant, which is an open-loop pumped storage plant that exploits a difference in elevation of about 480m between Lake Sihl (upper reservoir) and Lake Zurich (lower reservoir). Seven Pelton turbines are installed in the powerhouse providing a nominal installed capacity of 120MW.
Although Lake Sihl mainly has a hydropower purpose, its management is still dictated by a set of flood protection rules and environmental mitigation measures. Indeed, the Sihl river poses the largest flood threat for the city of Zurich, while from 1 June to 31 October, Lake Sihl must undergo a strict constraint to prevent mosquito proliferation which means active storage capacity is reduced to about 20×106 m3.
The modelling framework for this study considers reservoir management constraints and environmental flow requirements. Long-term simulations covering 38 years were carried out at a relatively high temporal resolution (one-hour). The authors explain that such long-term simulation allows for better characterisation of hydro-climatic conditions, which drive both hydro and solar power generation.
The hourly simulations over 38 years show:
- A 20% increase in overall annual energy production.
- An improvement in the system reliability through mutual complementarity.
- A potential for enhancing downstream environmental flow up to 50% during the hot summer season, thereby enabling more streamflow for ecological purposes.
The results confirmed some benefits of hybridisation already pointed out in previous studies, such as an increase in the overall annual energy production and an improvement of system reliability. In addition, the authors noted a potential for enhancing downstream environmental flow conditions, without strongly invalidating the benefits of energy production and reliability of supply.
Micocci et al say this hybridisation real-word case study is particularly significant due to:
- The presence of a pumped storage facility, which also allows for storage of PV energy exceeding the demand.
- Detailed representation of the mechanical and hydraulic components of the plant.
- Reproduction of strict management rules which guide reservoir operations, particularly during summer.
As a further development of this work, the authors say they are planning to repeat the numerical experiment under future climate scenarios, to analyse possible vulnerabilities and opportunities of solar-hydro hybridisation in a changing climate.
