Higher voltage is confronted with a greater resistance – PV Magazine International

From PV Magazine 2/25

The imminent direct current (DC) voltage shift from the standard of the solar industry from 1.5 kV to 2 kV, such as the previous step of 600 V, promises cost savings and efficiency profit. It will again challenge PV manufacturers and developers, which must weigh technical progress and specialist products against economic viability.

Some have already found the balance in favor of 2 kV. A 182 MW project, 2 kV was built in China in 2023 and at least one American pilot site was active in 2024.

Why 2 kv?

In principle, higher voltage makes more power transmission possible at the same or a proportionally lower electricity, while the energy losses are minimized. Higher flows require thicker cables, making increasing voltage cheaper than increasing the current.

While comparisons of electrical engineer become more difficult, since the alternating current (AC) and reactive power are considered, DC -Logic is simple: power is equal to the power hours voltage or p = IV.

That is why increasing the voltage increases or reducing the current or retains the power with less losses. For solar energy, the transition is expected to improve the energy yields by 0.5% to 0.8%.

However, energy yield is only part of the story. With 2 kV, systems can house 33% more modules per string than at 1.5 kV because the voltage trap over the modules is reduced if the same conductor is used. Shorter strings can also mean thinner copper conductors that deliver savings.

Fewer strings mean fewer “home run” power box lines between site and inverter. This brings an equipment from 10% to 15% with fewer combination boxes, connectors and cabling – and cheaper maintenance.

Manufacturers get up

However, the shift to 2 kV is not only exchanging or rearranging components. It requires an industrial crossing.

China’s Jinkosolar became the first PV module supplier that was certified by Body Ul Solutions standards for 2 kV supporting products.

“The actual core circuit of the module remains the same as a standard module. What does the higher voltage classification is that you can make the strings longer. To get the PV module up to 2 kV, UL has published guidance on the crawl [the shortest distance between two conducting points along the surface of an insulating material] and clearance [the shortest distance in the air between two conducting parts] Requirements that essentially make the module a little larger. This means that you need more material between the edge of the active circuit of the laminate and the edge of the laminate, ”said Adam Detrick, director of product management and technical services at Jinkosolar US.

“We use a unique encapsulant that can withstand the increased impulse voltage required on 2 kV. There are also small adjustments to the J-Box [junction box] And connectors. On the connector side it is usually the insulation material itself, where we have added a higher dielectric material to the plastic housing. And the J-Box has a number of raised crawls and cleaning requirements, because that tension goes up. “

Manufacturers of inverters are confronted with topography changes and loss of efficiency. Higher voltages set a greater stress on semiconductor switches, causing switch losses and influencing reliability in the long term. Inverter companies PV -Magazine Until said that the challenges are well understood.

“Technically, shifting to 2 kV is not a huge challenge. It is a matter of approval distances and ensuring that new components can withstand the raised tensions, and insulation levels must be increased, ”said Damian Perez de Larraya, head of product management and business development at ABB ownership to make inverter maker Gamesa Electric. “Plus, cooling must be updated and with water cooling that is a challenge, but one that we can come across.”

Finding components is another obstacle. “We test different strategies for our designs and topologies and we have decided what we want to build,” said Perez de Larraya. “The thing we wait for are certified components. Not in the inverter IgBTs [insulated gate bipolar transistors]That we can find, but other materials. But overall reliability may not be punished at all for 2 kV, although the efficiency of the inverter can fall a small, fractional percentage. “

Electric balance of systems (EBOs) also requires higher safety measures at 2 kV.

“The flagship of the patented trunk bus solution of shoals, the Big Lead Assembly (BLA), integrates the functionality of cable assemblies, combination and combination boxes in a single system,” said Jeff Tolnar, CEO and President of Ebos Provider Shoals Technologies, A. PV -Magazine Award 2024 winner for its 2 kV cabling. “With the release of 2 kV standards by UL, its components in our Bla system are reassessed and undergo certification to process 2,000 volts. Our rigorous factory tests ensure that our solutions not only meet certification requirements, but also exceed the safety standards of the industry. “

First disadvantage disadvantage?

Solar investors want to see proof that the transition from 2 kV will make the promised savings.

“It’s a bit early and what happens to this industry is that all players are different. The largest have their own financing and tax help sleeves and they can take a little more risk and adjust themselves earlier because they are not governed by the requirements of institutions, “said Matt Murphy, Chief Operating Officer (COO) of Greenbacker.“ Partnerships at Greenbacker for Tax and debts are very large banks, and these very large banks are usually not enthusiastic to be the first people to do something in the industry. We will see 2 kV systems by 2026 and we expect the banks and other entities and all parties around the settings to be at least at ease to the point that we start to integrate them. “

Demonstrable savings are the key. “We are a technology crossing in working and building our sites. But where we are really focused, it is that when new technology comes out that promises a higher current and cheaper installation, it is about prove that in practice. So we are not laser -oriented if it seems more cost -efficient, but does it make a project actually more cost -efficient? “said Murphy.” If we go to 2 kV, our EPCs are [engineering, procurement, and construction service providers] actually charge us less? We see less on our O&M [operations and maintenance] Contracts? There is a real difference in the industry between observed savings and actual savings. It can be much different in practice. And it will eventually prove itself through price discovery when EPCs come back to us and show that they are in it and can deliver installation savings. At the moment we cannot say it in one way or another. ‘

Jinkosolar’s Detrick said it is now up to the EPCs to design the systems and to determine whether the expected cost benefits occur. “I think EPCs and developers will be the ones who stimulate the question here,” he added.

Tawing challenges

Upgrading the capacity of solar project generation, common in the United States, can be complicated by 2 kV for tax reasons.

“In the US it can be very logical to recover sites instead of doing major maintenance,” said Murphy. “And that is really where this becomes complicated with higher voltages. For standard systems, the more more complicated and more expensive that restores these systems, so a system from 600 V to 1500 V, maybe it works, but 2,000 V pushes things. The more equipment you can reuse, the more logical it is for repetition. For a company such as Greenbacker, those recovery projects are often a no-brainer. “

Stifling regulations

Europe, Asia and Australia offer regulatory challenges to 2 kV not present in China or the United States.

In Europe, legislation from 1973 AC defines AC low voltage as 50 V to 1 kV and DC as 75 V to 1.5 kV. That is why 2 kV systems are confronted with legal obstacles. Changing the regulation would be time-consuming and require acceptance by EU member states.

Asia has a variety of high-voltage DC regulations. In Japan, the edition of the main courses is only 100 V, which means that 1.5 kV and 2 kV DC power have already been merged together, which may mean minimal fuss of a switch.

In Australia, national regulations define the high voltage as more than 1 kV AC or 1.5 kV DC. That is why 2 kV DC systems fall under the high -voltage classification and require the compliance with stricter safety regulations. Just like in Europe, this adds a new layer of complexity to the implementation of 2 kV system and is a drag of the industry.

Despite the challenges, the shift to 2 kV seems inevitable. S&P Global predictions 2 KV systems will make up 77% of the solar projects on Nuts scale worldwide by 2030, which will rise from less than 5 GW in 2026 to 380 GW. China and the United States are expected to lead the transition.

The rapid development cycles of China and large manufacturers give it a head start in the implementation of new technology, while the American market is also committed to 2 kV, whereby several companies announced certification for their products in 2024.