Chinese ICT solutions giant Huawei has continued its expansion into the PV industry with the unveiling this week of its smart PV solution at a 7.8 MW solar park in Germany.
The Lansweiler-Reden PV plant, owned and operated by Germany’s Greencells Group, is a utility-scale installation at a former mining site in Western Germany. Connected to the grid in May, it was one of Huawei’s first smart PV plants in Europe, and pv magazine was invited along to see the system in operation.
The 7.8 MW plant has been built using Huawei’s SUN2000 string inverters rather than the more traditional central inverter. The use of 300 string inverters across the site affords the site owner greater control and monitoring of the plant, generating a 5% higher yield and a 50% better maintenance efficiency for the same cost as a central inverter.
Steven Zhou, Huawei’s PV inverter solution sales director for Europe, told pv magazine: "The price of this inverter installation is equal to the system costs of a traditional central inverter, but the strings give you a better yield and more control."
Lined up ten in a row, and with 60 inverters for each 1.56 MW substation of the plant, these low impact string inverters each connect to five streams, with each stream accounting for 20 modules. The connection to the transformer requires no DC cables, which further lowers costs, and weighing just 48kg each they can be easily installed and replaced should a problem arise, the company said.
Huawei, which claimed more than 3% of global inverter revenue share in Q2 2014, was also keen to demonstrate the inverters’ durability, running live weather replication tests on the site. Built with IP65 protection, the inverters were able to perform at peak in extreme heat, when doused with continuous rain, and even in salt mist conditions.
"The multi-MPPT increases power yields and reduces the impact of shading," said Zhou, who added that the inverters deliver an 80% quicker fault detection rate, meaning less down-time should an inverter fail.
Huaweis GM of smart PV plant solution, Yingtong Xu, also spoke of how a string inverter set up for utility-scale applications such as this one addresses a number of problems not alleviated by central inverters.
"The string inverters have a smart battery, remote monitoring capabilities and are connected via Huaweis 4G LTE wireless network, which offers a wider monitoring reach, better data for analysis and, overall, a higher power ratio," said Xu.
The synergy between Huawei’s traditional strengths in telecommunications, allied to its recent foray into the solar world, is what sets the company apart from competitors, added Alison Finch, Huaweis business development director for U.K. and Ireland.
The company’s use of string inverters for large-scale installations is growing globally. In the first six months of the year, Huawei shipped 500 MW of inverters mostly string inverters in China, and is on course to reach 3 GW of global inverter shipments (including central inverters) by the end of Q1 next year.
"We calculated that using string inverters for this installation worked out around $0.01-$0.02/W cheaper than central inverters," said Andreas Hoffmann, CEO of Greencells Group, which owns and operates the plant. "There is no need for a DC container box, or DC cables, which lowers hardware costs, while the installation was easier and less traffic-heavy, which saved on upfront soft costs."
One benefit of string inverters, Huawei argued, is in post-installation maintenance. The company, which currently has around 7,000 staff in Europe, can operate a much more cost-effective after sales service. By using string inverters rather than central inverters, there are no upfront service contracts, while replacement of faulty inverters is quicker and easier. "A normal, on-the-ground local technician can easily replace an inverter, which means the system is down for less time," said Xu.
String inverter global growth
Huawei’s evident backing of the string inverter option for utility-scale installations is likely to be mirrored by other leading companies around the world according to the latest data from IHS. While central inverters are currently and will remain the dominant option globally between now and 2018, by that date the amount of string inverters installed worldwide will have reached 24 GW (up from 10 GW currently).
Further, IHS’ Cormac Gilligan said that the price of a string inverter will fall sharply over the next four years to around $0.10/W closing a current gap of around $0.08/W when compared to central inverters.
In terms of deployment type, IHS forecast that string inverters will come to dominate the commercial installation sector, rising from 35% of installations in 2013 to 50% of all installations by 2018. At utility scale, string inverters will account for around 20% of the market by 2018, added Gilligan.