Floating Solar Basics

1 Floating a hot idea

Utility-scale solar power is now commonplace worldwide, but there are places where a lack of suitable land for space-hungry solar farms has led to the development and installation of floating solar photovoltaics (FPV) on a range of water bodies It’s an ingenious solution that’s enjoyed widespread adoption in Asia in particular. Will Africa follow suit?

Solar panels are a key element in sustainable renewable energy plans, especially in sunny African countries with inadequate generation capacity and weak grids. They provide low-cost energy, last a long time and (once manufactured) are environmentally friendly – but substantial solar arrays do require a lot of space. This can be an issue in urban environments, where land is scarce and expensive.

Typically solar panels are mounted on land in solar farms or parks, or buildings. But they don’t have to be – they can float on water. That makes them useful in areas where land is at a premium but water bodies are numerous, such as cities, which generally have many artificial bodies of water, ranging from dams to tanks and ponds at wastewater treatment works. Here ’floating solar’ can use scarce space close to infrastructure and customers effectively.

Floating solar photovoltaics (FPV) – sometimes called ‘floatovoltaics’ – simply refers to solar panels mounted on a structure that floats on a body of water, such as a reservoir or a lake. Floating solar is a fairly recent development in solar photovoltaics, which has been around for almost seven decades.

2 A brief history

Solar power dawned (dimly) 140 years ago, in 1883, when New York inventor Charles Fritts created the first solar cell by coating selenium with a thin layer of gold to create a current that was “continuous, constant, and of considerable force,” though the energy conversion rate was just 1 per cent.

The first demonstration of practical PV was seventy years later, on 25 April 1954, when Bell Laboratories researchers Daryl Chapin, Calvin Fuller, and Gerald Pearson presented a silicon solar photovoltaic cell at Bell’s New Jersey labs, using it to power a small toy Ferris wheel and a radio transmitter. That pioneering cell’s efficiency was about 6%. However, the base material was cheap and plentiful – silicon is the second most abundant element in the Earth’s crust (about 28% by mass), after oxygen.

The silicon cell was just one of many important developments from the prolifically-inventive Bell labs, which also produced the charge-coupled device (CCD), information theory, programming languages C, C++ and others, the laser, radio astronomy, the transistor, and the Unix operating system. Nine Nobel Prizes have been awarded for work completed there.

Photovoltaics (PV) were initially extremely expensive to manufacture, and fittingly the first significant application was in space when the United States Navy Naval Research Laboratory’s solar-powered Vanguard 1 research satellite was launched in March 1958. Vanguard 1 stopped transmitting in 1964, but in its short life showed that the Earth is not quite a perfect sphere. Vanguard 1 is the oldest human-made satellite in orbit and is still being tracked. The first commercial satellite, the 14-watt solar-powered Telstar 1 communications satellite – built by Bell Labs – was launched on 10 July, 1962.

Eventually, solar power came back to earth, and domestic solar power can be said to have been shown to be viable in July 1973 when the University of Delaware completed the ‘Solar One’ PV- powered residence. The roof-integrated arrays fed surplus power to the Delmarva Power and Light Co during the day and bought power from the utility at night.

On a utility level, the first multi-dwelling system lit up on 16 December 1978, when NASA’s Lewis Research Center activated a 3,5-kilowatt PV system in Schuchuli village, in the Papago Indian reservation in southern Arizona. The system provided energy for water pumping and residential electricity in 16 homes until 1983, when grid power reached the village.

The oil crisis of 1973 – 1980 fuelled interest in solar power, but panels remained expensive, and softer oil and energy prices in the last two decades of the 20th century dampened enthusiasm. But the dawn of the new millennium saw several developments that made the industry shine: improving panel efficiency, growing awareness of climate change, tax credits, and economies of scale.

In the 1980s, PV conversion efficiencies of 8-10% were thought good, but today 25-30% is the norm for consumer-level panels, while more expensive and experimental panels are at 45% or better. Improved efficiency has gone hand-in-hand with vastly increased production, which was initially fuelled by government policy – and in some surprising places.

3 Unintended consequences

Policy in two countries not primarily known for their sunshine, Germany and Japan, set the tone. In 1991, the German parliament passed the Erneuerbare Energien Gesetz (renewable energy law), or EEG. The law was drafted to guarantee small-scale hydroelectric generators, mostly in southern Lande (states) like Bavaria, with a subsidised net-metering mechanism or feed-in tariff (FiT) from grid operators that justified investment. It was a little-noticed piece of legislation at the time but was to have unintended, and impressive, consequences. Solar, wind and other renewable operators liked the implicit guarantees and piled in. Other European countries, particularly those in the sunny South, followed suit.

In Japan, perpetually worried about energy security (they went to war with the United States in 1941 partly over this), the oil shock of the 1970s led to intense research and development into PV and other sustainable technologies. Japan Inc’s close ties between government ministries, industry and academia helped drive some impressive technological advances, and the introduction of a FiT in 1992 made a market. The upshot was that by 2004, Germany and Japan were the first countries to have 1 gigawatt (GW) of cumulative installed PV capacity each.

The United States, which had dominated PV research and development (with generous public funding) and manufacturing between the 1960s and the 1990s, was somewhat slow out of the solar starting blocks for a country synonymous with ‘market’. FiTs were a bit harder to tailor and near-impossible to impose in a deregulated energy market addicted to fossil fuels, until the federal government introduced the Energy Policy Act in August 2005, in effect providing a government subsidy for PV.

Naturally, rapidly-industrialising China sought to supply these now fast-growing Northern Hemisphere markets, and solar PV prices plummeted. Since 2010 module prices have fallen by 85% at a utility-scale level, and by 64% for residential rooftop installations. In 2011, China’s PV products accounted for more than two-thirds of global production .

Subsequently, the USA and the European Union imposed anti-dumping duties on Chinese PV products, and the Chinese government devised market incentives that, coupled with a national embrace of renewable energy, led to rapid growth in domestic solar installations. In 2011, China had a PV capacity of 3,3GW, but by the end of 2011, China’s installed PV capacity was 253 GW, almost a third of the world’s total installed photovoltaic capacity (760,4 GW).

At the end of 2021 cumulative installed global capacity for PV stood at 942 GW. China retained a third share, with 308,5 GW, the European Union collectively was next biggest at 178,7 GW, and the United States third with 123 GW of installed capacity. The European Union is comprised of 27 countries, out of which Germany, Spain, France, the Netherlands and Italy are individually amongst the top ten markets for installed capacity. The remaining top ten markets are Japan (78,2 GW), India (60,4 GW), Australia (25,4 GW), Korea (21,5 GW) and Vietnam (17,4 GW).

That installed capacity is in two forms, generally – domestic-scale rooftop solar, and utility-scale solar ‘farms’ or ‘parks’. ‘Rooftop’ is a loose term to describe PV panels mounted on buildings, either as building-applied photovoltaics (BAPV) – retrofitted rooftop panels or cladding – or, increasingly as building-integrated photovoltaics (BIPV) where PV panels, tiles or films are incorporated into the construction. This can be done compactly, effectively, and even elegantly.

Utility-scale solar farms, by contrast, require space. Lots of it: the world’s largest solar farm, the 2,7GW Bhadla Solar Park in Rajasthan, India occupies 5 700 hectares (14 000 acres). Unsurprisingly, the bulk of the world’s big solar farms (with a capacity of 250 MW or more) is in a handful of countries with space and cheap land: India, China, and the United States. It’s also obvious that countries or cities with limited space should look for alternative space – and find it in bodies of water. Enter the Japanese, with 125 million people in the eleventh most populous country jammed into the narrow coastal plains that make up just one-quarter of their mountainous island state’s area.

4 Floating an idea

Long leaders in developing and making PV technology, they floated a novel idea, and the first floating photovoltaic (FPV) system, a 20-kilowatt-peak (kWp) research prototype, was commissioned in August 2007 on a balancing reservoir in Aichi, Japan. The pilot, funded by the National Institute of Advanced Industrial Science and Technology, had a two-fold aim: firstly to show that floating solar was feasible, and secondly to see if cooling the panels with water could improve efficiency (as it happened, the lower ambient temperature above the water was more cost-effective than mechanical water cooling).

The first notable commercial installation was a 175 kWp ‘Floatovoltaic’ system commissioned at the Far Niente Winery in California in May 2008, which enabled power generation without sacrificing valuable vineyard land. It was a combination of Japanese technology – solar panels from Sharp – and American ingenuity – the pontoons were made of foam-filled drainage pipe.
Floating solar as a concept was no longer a novelty, and the race was on to design and produce cost-effective, durable and effective flotation and mounting systems. A flurry of patent applications in several countries – Canada, Denmark, France, Japan and the USA – followed, one of the first being awarded in Italy in February 2008.

5 Wind and water

Typically, large-scale FPV plants use pontoon-type floats, either so-called ‘pure’ floats, which are moulded to accommodate the solar panels, or floats that have metal trusses supporting the panels. Systems generally have ‘primary’ floats supporting the panels and one or more styles of ‘secondary’ floats that provide additional support and stability, and walkways and conduiting. The pontoons are coupled together, and the resulting platform is anchored to the banks or bed of the water body, or attached to piles sunk into the bed.

As with land-based systems, the direct current (DC) electricity generated by PV modules is converted to alternating current (AC) by inverters. For small-scale floating plants, it is feasible to place the inverters on land (if the floating array is close to shore). For large systems, inverters are housed on specially designed floats.

There is another technique – “PV over water” – which involves mounting PV panels on piles above the water surface. This is used quite widely in China in installations that combine PV and aquaculture, where access to fish ponds must be maintained and the fish can be protected from the sun. In terms of this report, this small segment is not considered to be FPV.

Managing tilt angles is an important pontoon design consideration. The tilt angle – the angle at which the panel faces the sun – corresponds to the latitude of the installation. The further from the equator, the greater the angle. In Aichi Prefecture, Japan, that would be 35ºN, in Rajasthan, India 27ºN, and in Cape Town, South Africa, that would be around 33ºS. The greater the tilt angle, the greater the wind resistance, a factor of some concern when linking, securing and anchoring floating objects.

In the trade-off between wind resistance and optimal tilt angles, floating solar installations do not always provide the optimal tilt angle, particularly in higher latitudes where the angle is larger. This is offset, however, by the cooling effect of the water body, which improves the efficiency of the panels. A Singaporean study of an FPV testbed showed that the ambient air temperature above the water is about 5 to 10ºC lower than on the adjacent land, depending on the ventilation underneath the panels.

In 2010 French solar system manufacturers Ciel and Terre developed their ‘Hydrelio’ technology, consisting of modular ‘Lego-type’ floaters, and after testing a 64-panel, 15 kW on a flooded quarry in February 2011 industrialised the pontoon manufacturing process. This system was used to build the first gigawatt-scale FPV system, a, 4 530-panel 1,18 GW array installed on a rainwater retention reservoir in Okegawa, in Saitama Prefecture, Japan. The system, commissioned in July 2013, supplies power to Tokyo Electric Power Co. in terms of a 20-year FiT contract. Utility-scale floating solar had come of age.

6 The great flotation

The global FPV market, estimated at 1,6 GW in 2021, is projected to reach 4,8 GW by 2026, an annual growth rate of 33%. Most of that market is on one continent – densely-populated, energy-intensive Asian countries. As with land-based PV, China is the world’s largest market for FPV. Interestingly, many installations are on the man-made lakes caused by coal mine subsidence, of which China has dozens. The Chinese government’s much-emulated ‘Top Runner’ FiT programme has spurred investment, and research firm IHS Markit estimates China’s installed floating PV base to be double the size of the next largest 11 countries combined. China is home to the world’s three largest floating PV installations, the biggest being a 320 MW facility near Huaneng Power’s 2,65 GW Dezhou thermal power station in Shandong province.

India’s market is one of the most competitive, as state-level energy utilities seek to add capacity and reduce reliance on coal. Japan remains a technology leader and implementer – Hyogo Prefecture in southern Honshu has almost 40 000 lakes and already hosts nearly half the floating solar capacity of the world’s 100 largest plants. South Korea, Taiwan, Thailand, and Vietnam are also substantial markets. Indeed, South Korea will in 2025 have the world’s largest FPV project, a 5-million panel, 2,1GW project developed inside the world’s longest dyke, the 33 km long Saemangeum seawall on the southwest coast of the Korean Peninsula.

The city-state of Singapore, with an area of just 733 km2 and home to more than 5,5 million people, is a committed investor in FPV, with a goal of quadrupling its solar energy capacity by 2025. The world’s fourth-largest FPV installation, the 60MW Sembcorp floating solar farm, comprises 22 000 solar panels across 45 hectares of the municipal Tengeh Reservoir.

In Europe, sunny southern countries are obvious sites, and the European Union’s largest FPV installation, a 12 000 panel, 5MW plant on Alqueva dam in southern Portugal will be commissioned in July 2022. But Europe’s two largest FPV sites are in not-so-sunny Britain, where the 6,3 GW 23 000 panel Queen Elizabeth II Reservoir installation near Heathrow airport helps Thames Water offset its water treatment and pumping energy costs, as does the 2,9GW Godley plant in Greater Manchester.

In the United States, California is home to the country’s biggest FPV installation, a 4,8 MW project at Healdsburg in Sonoma county. It was developed partly, like the pioneering 2008 Niente Winery project, to avoid using scarce land. Additionally, in the Golden State’s water-stressed wine country, reducing evaporation losses from the municipal wastewater treatment plant’s shallow retention ponds is also helpful. Here efficiencies are boosted through the use of double-sided panels, which generate power both from direct sunlight above and from light reflected from the water below.

Australia is an energetic installer of solar generation, which accounts for almost 10% of total electrical energy production and represents the highest per capita solar capacity worldwide, but with its vast land area has little by way of FPV. The countries with outsized FPV footprints tend to be smaller, with land and water at a premium, or are deeply committed to renewables. Canada, the Netherlands and Norway are substantial users, and all three have vigorous policies to reduce dependence on fossil fuels.

7 Pros and cons

As this report has shown, floating solar uptake has been rapid in densely populated Asian countries where there is limited flat land. FPV is generally more expensive to install and maintain than land land-based PV. How much more is difficult to say, though, as there are so many variables at play.

Start with site acquisition and permitting costs. In densely populated places, land prices are generally exorbitant. In those same places, population pressure has led to complex, restrictive, land-use frameworks, and lengthy permitting processes. This is an obstacle to space-hungry ground systems. By contrast, water bodies seldom have these restrictions, if they have any at all – FPV being a relatively new development with which legislation may not have kept pace.

Space requirements are not negligible – one MW of FPV generation requires between 17 to 25 acres of surface area. Still, it is no coincidence that many utility-scale developments are on government-owned or -managed water bodies, such as reservoirs or retention ponds, where site costs are low and permitting procedures are largely in-house. Overall, deployment times are shorter, and costs lower, than for land-mounted PV.

One particularly attractive FPV application is the augmentation of hydroelectric schemes, as they comprise large water bodies and existing grid infrastructure. The first large-scale project combining floating solar and hydropower was commissioned in November 2017 at Alto Rabagão Dam in Montalegre, Portugal, where solar panel installation increased Energias de Portugal’s power plant’s peak capacity by 220 KW.

FPV-augmented hydropower plants can also help to manage times of low water levels by allowing the plant to operate in ‘peaking’ rather than ‘baseload’ mode. This could be helpful in mitigating against increasingly frequent droughts in the Indian subcontinent, many Mediterranean countries and those of Southern Africa, for instance.

Capital expenditure and Installation costs are not that easy to compare, either. Land systems can require significant civil engineering and grid transmission infrastructure, particularly if they are in remote cheap-land areas distant from consumers. FPV systems cost more in terms of pontoons, mooring systems and cabling, but can be assembled on shore and floated out quickly and efficiently, and are usually close to existing transmission networks. One factor that is a concern at the time of writing is the cost of crude oil. Pontoons are generally made of rugged high-density polyethylene (HDPE), derived from petroleum, and rising crude oil costs naturally impact construction budgets.

An exhaustive 2019 study by World Bank Group’s Energy Sector Management Assistance Programme (ESMAP) and the Solar Energy Research Institute of Singapore (SERIS) found that on average, capital costs for FPV were around 18% higher than for land-based systems, but FPV installations were 5-10% more efficient. On balance, the levelized cost of electricity (LCOE) for a generic 50 MW FPV system did not differ significantly from that of a ground-mounted system, the study found, if appropriate tariff structures and other considerations such as water conservation were taken into account.

All PV systems require weatherproofing and maintenance, including cleaning of panels (panels on or near the sea can suffer from the corrosive effect of fish-eating marine birds’ excrement), and bio-fouling can be an additional challenge. Aquatic environments are somewhat harsher than land ones. Factors to be accommodated include winds and storms, changing water levels, and the constant movement of pontoons. Some of the biggest FPV markets are in fact in typhoon-prone areas, and there have been lessons learned.

In September 2019 the 13,7 MW installation at Yamakura Dam, near the Japanese city of Chiba (that country’s largest FPV installation when it was commissioned in March 2018) was badly damaged by typhoon Faxai. In fairness, that typhoon was one of the five strongest typhoons recorded in the past 60 years, with wind speeds of more than 200 km/h. Just seven of the installation’s 420 anchors failed, but the floating ‘island’ broke up, panels piled up, and fire broke out. The installation was rebuilt in smaller ‘islands’ less prone to wholesale damage.

8 Novel ideas

Most FPV installations are pontoon-and-panel and fixed in orientation, but there have been developments in the azimuth tracking and solar concentration techniques some land-based systems already employ. With FPV, azimuth tracking is generally achieved by rotating a circular array around a central pylon. While this improves efficiency, it comes with the costs of the motors and controls required to move the array and the challenges of mooring a platform expressly designed to rotate. A 100 kW tracking plant, consisting of four rotating structures, has been installed at Hapcheon Dam in the Republic of Korea, primarily as a research bed.

In theory, concentrated solar power should be an attractive form of FPV, since ambient temperatures are lower and water, as a coolant, is readily to hand. This couples naturally with tracking systems, and a pilot 4 MW floating-tracking-cooling-concentrator system, where mirrors are placed in front of each PV panel, and the entire platform rotates, was commissioned at a wastewater treatment facility in Jamestown, Australia. Again, the cost and mechanical complexity of such systems limit their application at present. The now-mature pontoon-and-panel systems remain the norm

9 All at sea

There are more than 404 000 km2 of man-made reservoirs worldwide, but for a variety of reasons these may not be suitable – or even available – for FPV. Such a problem faced the Maldives, composed of 1 196 islands, with few of these larger than one km2, and heavily reliant on diesel generation – in 2014, the Maldives spent one-fifth of their gross domestic product on fuel. These considerations, and a reluctance to clear aesthetically-important scarce land, led to the development of the first marine offshore system in August 2014, initially to supplement existing rooftop PV. The system, developed by Austrian PV specialist Swimsol, can withstand 2,5 m waves and winds of 120 km/h and has a design life of 30 years.

Marine systems must deal with more stresses than reservoir, dam and lake systems. While installed systems and locations vary widely, from shallow tropical lagoons in the Maldives, through the rough North Sea off The Netherlands to the deep, protected fjords of Norway, the common enemy is building against a harsh environment, and in particular, managing corrosion.

The marine system in the Maldives has the advantage of relatively sheltered seas, as such systems were, and generally still are, positioned in lagoons behind protective reefs, which also helps mitigate against monsoon and typhoon conditions.

The first open seas offshore FPV project was the 8,5 kW ‘Zon op Zee’ pilot installed in the Dutch North Sea at Scheveningen, just north of The Hague, in November 2019. Having weathered winter storms with winds gusting at 62 knots (115 km/h) and waves over five metres high, the scheme was expanded to a 1 MW plant the following year, and a 3 MW plant of the Belgian coast was built in 2021.

These early marine installations followed the established FPV principles – glass panels mounted on pontoons anchored to the sea bed – but there could be other approaches. One is self-contained floating membrane flexible modules, currently being tested in Canada. Potentially, these offer several advantages. The cooling effects of direct contact with water improve electrical efficiency, and reduced mechanical loads from wind or currents simplify mooring.

Even under benign conditions, FPV’s many moving parts present challenges, including ingress of moisture and water to electrical components, and potential damage to cabling caused by the movement of the water – even if this is only slight, as in reservoirs. Cable chafing led to a small fire at one of the largest floating photovoltaic installations in Europe, the 17MW O’Mega 1 power plant in southeastern France, in January 2022. Damaged cable insulation caused a short circuit on a three-panel floater, and while the affected inverters automatically shut off, the three floats ignited.

The additional costs involved in making FPV suitably durable are in part offset by other benefits. One of the most useful is the conservation effects FPV can have on their host water bodies. In hot, dry countries evaporation losses can be considerable – Australian studies have put it as high as 40% for a large reservoir in Queensland. Large FPV installations reduce evaporative losses, a factor that makes the technology doubly attractive to municipalities such as Healdsburg. Floating panels also limit the effects of wind on the water surface, reducing evaporation. Reducing the amount of light that falls on water bodies also helps to reduce algae growth, which has positive implications for aquatic life and, where sited on reservoirs, potable water treatment.

10 In Africa

In most African countries, there is generally ample cheap space for land-based solar, but there are exceptions. The continent’s first private scheme was commissioned at Marlenique Estate, a fruit and wine farm near Franschhoek, South Africa, in March 2019. The reasoning behind the 60 kW scheme was the same as the first notable commercial installation at the Far Niente Winery in California in May 2008 – to avoid having to sacrifice valuable arable land.

This was followed by a 2,33 GW, 48-panel array on a dam at Alzanne farm, near Vredendal in the Western Cape, a hot and dry drought-prone area where water conservation is a priority. In fact, the design had to make allowance for continued operation when the dam was empty. Interestingly for an area where land is plentiful, here an added issue was concern over theft of land-based solar panels, and a FPV system was considered simpler to secure.

The first African utility-scale FPV tender was announced in April 2018 for a 4 MW system on Mahé Island, in the Seychelles. The project, one of the first in the world to be installed on a shallow saltwater lagoon, has subsequently been delayed by Covid-19-related supply constraints.

The primary application on the African continent so far has been FPV installations to augment hydroelectric schemes. At the end of 2019 Africa had an installed hydropower capacity of 37 GW at 108 hydropower plants, with another 15 GW under development or construction, and researchers at the Joint Research Centre (JRC) – the European Commission’s science and knowledge service – estimate that at these hydropower plants utility scale FPV may reach a capacity of more than 20 GW.

BUI Power Authority Ghana has inaugurated a 1 MW pilot project at the 404 MW Bui hydroelectric dam on the Black Volta River early in 2021. A 5 MW FPV system, along with a 250 MW ground-mounted scheme beside the dam, followed this year. The intention is to eventually have a blended 65 MW system, of which the FPV component will occupy approximately 350 000m2 of water space.

Mozambique‘s state-owned power utility Electricidade de Moçambique (EDM) has issued a request for expressions of interest to seek consultants for the feasibility study for a utility scale floating PV project at the 44MW Chicamba hydroelectric power station on the Ruvue River, in Manica province, near the border with Mozambique and Zimbabwe.

The first municipal scheme in South Africa was commissioned by the City of Cape Town in October 2021. This is a proof-of-concept project installed at the Kraaifontein wastewater treatment plant WWTP), to evaluate the potential. A FPV array on one of two identical settling ponds and a small land-based array will be used over a year to determine the relative efficiency of land-based panels, with optimal tilt, against lower-tilt FPV panels, and to assess evaporation losses.

This is of interest to Cape Town’s municipality and research partners the Water Research Commission and the University of Cape Town, as land is costly and the City’s many water and wastewater facilities could provide cost-effective sites. There is currently no expectation that FPV could completely meet a WWTP’s energy needs, not least because the plants run continuously and can not be supplied in this way at night without battery storage capacity.

Solar power is attractive – even necessary – in sub-Saharan countries with insufficient fossil-fuel-based generation capacity and weak grid systems. But there is generally land available, and so in continental Africa then, FPV looks likely to be limited to hydrogenation plants, and municipal and high-value agricultural applications for the foreseeable future. Island nations with limited space and the benefit of proven marine systems will continue adding capacity.

11 In summary

FPV has developed dramatically in just 15 years, from proof-of-concept to mature, robust mass-produced technology. The first viable scheme, the 20 kW Japanese Aichi pilot, still has five years to go with its initial FiT contract. The scale is now very different. There are already numerous 250 MW+ schemes, and by 2025 South Korea will have a 5-million panel, 2,1GW FPV installation.

Asia and Europe are, and will continue to be, the largest markets through a combination of high demand, scarce accessible land in densely-populated areas and progressive tariff and permitting policies. In Europe, there is the added impetus of reducing reliance on imported fossil fuels, a process given added impetus by Russia’s invasion of Ukraine and subsequent rising oil prices.

The industry is dominated by Chinese, French, Japanese and Korean manufacturers which have expanded existing PV expertise into FPV. The unique element of FPV is the design and supply of the floating platform and the anchoring and mooring solutions, and most large companies have proprietary designs.

In Africa, and Southern Africa in particular, utility-scale FPV has narrower appeal, being limited to the augmentation of hydropower schemes and installations that preserve valuable agricultural or urban land. Space constraints are not an issue – there is plenty of land available for solar farms. FPV faces the same constraints that retard the development of renewable resources across much of the continent – a lack of grid connectivity, infrastructure and investment; appropriate electricity ‘wheeling’ agreements, historical attachment to state-owned entities and a lack of coherent forward-looking energy policies. Africa has wider energy issues that must be addressed before FPV floats on the continent.

Crystal-ball gazing is seldom productive, but … just as few people saw Bavarian protection of small-scale hydropower generation would lead to Germany becoming one of the biggest solar power markets, FPV may take another path in sub-Saharan Africa. Water-stressed countries may find that the greatest attraction of FPV lies in reducing evaporation losses of scarce water. Time will tell.