Amid the prospect of cheap natural gas for electricity production, thanks to the major gas finds off Israel’s coast, demand for solar energy here has dulled. But this week, solar got a big boost as the Kibbutz Ketura solar park, jointly owned by Siemens AG and solar energy pioneer Arava Power, became the world’s first autonomously-cleaned solar energy production facility.
Each night, the 20-acre facility is cleaned by 100 Israeli-made robots, which brush and clean the hundreds of solar panels, generating 9 million kilowatt hours of electricity per year. It’s a technical breakthrough, said Eran Meller, CEO of Ecoppia, which built the robot cleaning crew, that could encourage more use of solar power.
Solar-produced electricity contributes just a small amount of the approximately 60 billion kilowatt hours of electricity that Israel uses each year, but the government has some ideas about how to change that – beginning with its own “house.” Earlier this year, the Knesset announced a new project that will make Israel’s parliament “the greenest in the world,” according to the Energy and Water Resources Ministry. Among other things, the project will entail installing 4,500 square meters of photovoltaic panels on the roof of the Knesset building, generating all the power the building needs to function, and then some. According to Energy and Water Resources Minister Silvan Shalom, “the Green Knesset project will be a source of pride for Israel and will inspire other countries.”
Cleanliness – or a lack of it – has proven to be one of the biggest impediments to wider adoption of solar energy. Most solar energy farms are located in deserts (as is Kibbutz Ketura, which is in Israel’s southern Arava desert) where the sun is strong, and the spaces are wide open. Both are important factors to take into consideration when building a solar energy farm, which consists of hundreds or thousands of solar panels.
Besides a lot of sun, however, deserts have lots of dust, and as that dust settles on the solar panel collectors, it reduces the panels’ efficiency – by as much as 35%, said Meller, in a process called “soling.” To clean them, park managers use water, a very scarce commodity in the desert. “Due to the expense of traditional, labor-intensive, water-based cleaning, Ketura Sun’s solar panels were only cleaned some nine times a year,” he said. “This manual panel cleaning would take up to five days, during which time the field operated sub-optimally and work crews endangered sensitive equipment. In the interim between cleaning cycles, the park suffered significant electricity production degradation due to soiling.”
Enter Ecoppia’s robot crew. Instead of using water to clean panels, the robots are equipped with microfibers, with each robot assigned to a row of PV panels. Using controlled air flow, the robots push the accumulated dirt off panels, as they glide along the surface of panels on their polyurethane-coated aluminum frame using wheels. Each robot can cover about 100 square feet of panel each minute, saving water and time. The robots are controlled by a central control panel, and can operate in tandem (starting and finishing at the same time) or autonomously, based on the instructions given by park staff.
The Ecoppia solution was the best suited to meet the needs of the Ketura solar park, according to Arava Power CEO Jon Cohen. “We conducted a thorough worldwide search for a cleaning solution that could deal with the challenging weather conditions in our solar park,” said Cohen. “Only Ecoppia’s solution showed actual significant uplift in production, while offering an extremely appealing business model.”
Ecoppia was founded in 2013, and has customers worldwide for its robot cleaning solution – the only one on the market, the company said. “We’re pleased to facilitate this important first step towards effectively growing solar park energy output at the Ketura solar park,” said Ecoppia CEO Meller. “With E4, Ketura Sun maximizes its energy generation, without the expense and negative ecological impact of water-based cleaning solutions.”