Cheap and clean PV is the fastest growing source of electrcity in the EU, with an estimated 406 GW of cumulative capacity as of the end of 2025, according to SolarPower Europe. The reason is clear. According to the European Commission, the cost of solar power decreased by 82% between 2010 and 2020. This dramatic reduction has made solar energy the most competitive source of electricity in many parts of the EU. Indeed, last year almost half of all electricity in the EU came from renewables and more than a fifth of this came from solar alone.
It’s a similar situation in the USA and in parts of Asia too. Recent analysis from the US Solar Energy Industries Association (SEIA) reports that US total solar installed capacity is about 248 GW. Top states include California, which now hosts close to 52 GW of solar generation, supplying almost a third of the state’s power. Long the US leader, California is rapidly being caught up by other states, such as Texas, Arizona and Florida. Texas, for example, is in second place for total solar production and added the most utility-scale solar capacity nationwide in 2024. Additional solar installed capacity in the state is expected to exceed 41 GW over the next decade, doubling solar installed capacity, which currently stands at around 41.5 GW.
The SEIA notes that just a decade ago, only three states had more than 1 GW of solar capacity installed. Today, there are 33 states that can boast more than that threshold. There are plenty of indications that, given favourable conditions, this remarkable growth will continue. Some 10.8 GW of new solar capacity was installed across the US in Q1 2025, for example. However, while solar is evidently cheap, clean and flexible, its very success is also creating challenges.
The solar challenge
Considering the remarkable and sustained growth of distributed energy generation, such as solar, one of the key issues is integration of such capacity within the existing grid infrastructure. With significant increases in solar power, conventional current flows, which previously ran from large, centralised power plants out towards the local distribution network, are reversing. Large volumes of distributed roof-top solar, for example, are feeding power from the edges of the network. At the same time, utility-scale solar projects are feeding in power via their networks. Collectively this is introducing congestion into the transmission grid.
The International Energy Agency (IEA) has drawn attention to the major impact this congestion is having, citing the example of The Netherlands, where it says grid congestion has become a major bottleneck impeding the energy transition. They note that the country has seen impressive growth in renewable electricity generation, with solar PV capacity growing 500% between 2018 and 2023, driven mainly by rooftop installations. However, while solar capacity was booming, grid capacity did not follow suit. In addition, a net-metering arrangement offers payment for all the power delivered to the grid, irrespective of supply and demand as well as the market price. The outcome is a system which does not incentivise solar PV to attempt to meet the needs of system and instead favours generation of the maximum volume possible. The IEA says this has resulted in grid congestion and delays in expanding or upgrading the system. It points out that in early 2025, there were around 10 000 large users and 7500 generation projects larger than household-scale PV waiting to connect to the grid. In 2022, the Netherlands transmission system operator, TenneT, spent EUR388 million on grid congestion management and similar trends are being seen elsewhere in Europe and in the US too.
One alternative to huge investments in bolstering grid infrastructure by either reconductoring existing transmission corridors or building entirely new transmission lines is to use the existing assets in a smarter, more efficient and effective way with the application of grid enhancing technologies. By deploying novel technology, additional network capacity can often be quickly found at a fraction of the cost.
Grid enhancing, not grid building
One of the most attractive grid enhancing technologies is known as dynamic line rating (DLR), which can be used to more accurately establish safety margins for conductors. In many jurisdictions, the capacity margins for any cable span are highly conservative and are based on a worst-case scenario model designed to ensure reliability in all weathers. These margins are based largely on factors such as ambient temperatures. Broadly, the higher the temperature of a conductor the more susceptible it is to sag, which reduces clearance, potentially allowing energised lines to arc and also to come into contact with objects such as trees or vehicles. Such sagging is particularly significant in the context of solar power given that higher solar irradiation implies both higher ambient temperatures and a simultaneous increase in the power generated. The outcome under conventional static line ratings, which are generally set on a seasonal basis, is that just as solar capacity peaks, the line ratings needed to export that power to end users are falling to a minimum.
Instead, with its far more sophisticated approach, DLR can not only take into account the solar radiation and the temperature of the conductor but also other factors, such as the wind, which has a cooling effect. More detailed and granular analysis allows the net outcome of all these cumulative influences to be included to generate a far more accurate assessment of a conductor’s real time condition and thus maintain all safety considerations while still allowing a conductor to potentially carry substantially more power.
Ampacimon, for example, deploys a patented sensor technology to generate accurate data from individual conductors or sections of the network, giving an unprecedented level of detail in real time. Fitted with accelerometers, the sensors are powered using induction from the conductor current. They measure the wind speed as well as the conductor vibration frequency and by analysis of the vibration spectrum they can be used to accurately estimate the sag and the perpendicular wind speed at the conductor. Wind behaviour is complex and it can be subject to major variation on a micro-terrain basis. However, while even minor errors in estimates of the conditions can potentially have a major impact on power line ratings, by taking a physical measurement on the specific conductor span, accuracy in assessing actual conditions is dramatically improved.
These measured data are also coupled with accurate weather forecasting to present an assessment of likely wind characteristics, overall conductor condition and accurate predictions of the capacity for many hours ahead. The probabilistic machine learning methods deployed in the Ampacimon model are used to overcome many of the shortcomings that forecasting models present, especially at low wind speeds. With its accurate forecasting and a wealth of hard data, Ampacimon’s DLR system can allow power lines to transport as much as 40% more power in comparison with operations under the standard static line rating regime.
The real-world benefits of DLR
Already widely deployed in Europe and America, in a recent year-long project in Japan, a DLR system from Ampacimon was installed on a transmission line span crossing a large river. This line connected high power photovoltaic facilities and the study observed the behaviour of the currents, conductor temperatures, wind speeds and dynamic ampacities using real time data gathered from the Ampacimon sensors deployed on the conductor. The analysis was conducted over a one-year period and it was confirmed that at no point did the conductor temperature reach the maximum allowable 90°C. At most, the conductor was pushed up to 75°C during the course of the trial while often carrying currents that exceeded the static rating by 100 A. This substantial improvement in carrying capacity was achieved in real time without relying on the predictive elements of the Ampacimon solution and thus delivered a highly accurate method of maximising current carrying capacity.
Simulations were also performed to assess how much energy the DLR system could save by reducing PV curtailment on the assumption of a gradual increase in the output of PV plants connected to the transmission line. This analysis confirmed that adding an additional 20 MW of PV would result in a total of 40 hours’ worth of curtailment when using DLR. In comparison, relying on the static line rating would result in curtailments for a total of 576 hours. The number of hours of curtailment would therefore be reduced by 93% using real time DLR.
Clearly then, a DLR system can significantly increase PV power output by reducing the need for curtailment. Grids usually have more physical capacity available when real world and real time conditions are carefully considered.
