Maximizing concentrating solar heat’s potential in the food industry
31st October 2018
Food processors are turning towards concentrating solar heat to help reduce fossil fuel use and save money
By Zara Maung
With around 90 percent of global industrial heat still being produced by coal, oil and gas, the potential for solar heat to provide a sustainable alternative to fossil fuels in the industrial heat sector is huge. However, current low deployment rates have been attributed to a vicious cycle – driven by low awareness of solar heat technology along with high upfront investment costs and low energy prices, which combine to produce long payback periods.
Nevertheless, manufacturers of concentrating solar heat (CSH) technology are seeing demand for CSH in food processing industries across several regions, including Europe, India and Mexico. The technology is proving especially attractive to facilities such as breweries and dairies, which warm large quantities of liquids and are able to save on fuel costs by using CSH to supplement their gas or diesel powered boilers.
Angel Mejía, CEO of Mexican CSH technology manufacturer, Inventive Power, has accrued around 60 customers in Mexico, including Nestle and Unilever, since deploying its first system in 2013. He reports that companies initially take some convincing to invest in CSH as they are unfamiliar with the technology. But once they’ve trialed his systems, he says they often look to expand their use of CSH. Ten of his current installation projects are with existing customers.
One of Inventive Power’s CSH Systems at food-pellet company PAISA
Inventive Power mostly serves the food industry – including dairy, tequila, animal feed, meat and candy production – on average providing 40 percent of a plant’s energy needs. Mejía asserts that payback on investment depends on the fuel that the CSH supplements. Clients using diesel or liquid petroleum gas (LPG) as fuel can expect a 2.5 year payback period, using the tax deduction incentive offered by the Mexican government. Those using the cheapest fuel in Mexico – natural gas sent from the U.S. – can expect a five year payback period for CSH technology, which is designed to last more than 20 years.
One of Inventive Power’s customers, feed pellet company PAISA, based in San Juan de los Lagos, Jalisco, spent 1,347,330 Mexican pesos (currently about USD 71,400) in 2015 on 80 solar collectors, over an area of 264 m2, delivering 148 kWth and 95 ºC heat. They now save 77,261 liters of liquefied natural gas (LNG) annually, saving 502,197 Mexican pesos (about USD 26,600) in fuel cost annually. This means the simple payback (e.g. without taking debt repayment back into account), could be 2.7 years.
Mejía suggests that his success comes from focusing on providing customer satisfaction. Inventive Power offers a range of deals to suit their customers’ needs, including different financing deals. Companies can make a small initial payment, then pay monthly for five years of leasing before they own the project. Another option is to pay nothing for the collectors and to just buy the thermal energy. If the system doesn’t work there is no charge, reducing the risk of adopting CSH. After 10 years the company can either pay a small amount to own the CSH system or sign a new contract for another five years. According to Mejía, the company pays almost the same as the cost for natural gas – and as the cost remains the same for 10 years – it’s a way to protect the company against fluctuating gas prices.
He also offers maintenance deals (costing two percent of capex annually) and free technology upgrades to clients. Another free service is the company’s constant remote monitoring of clients’ CSH systems to optimize power production. If power generation dips Mejía says Inventive Power will call the client to discuss how to rectify the matter.
Usually the biggest problem clients find with maintaining the system is the need to clean the mirrors every three to four weeks, says Mejía. General maintenance checks should also be done every two to three months. Inventive Power’s most critical problems came during its first installation projects, where it dealt with connection problems and some defective components. One difficult project, for Mexico’s third largest milk producer, Sello Rojo, involved working out how to connect the CSH system to the pasteurization machine. It took almost two months for process engineers to develop a connection – using automation, controllers and coding – due to the precise temperature needed for the process. Now, Mejía says the pasteurization system works more accurately than before they installed CSH.
One of Inventive Power’s CSH systems from above
Having streamlined its operations in the domestic market, Inventive Power is starting to look at installing its technology abroad.
Take up of CSH technology has been comparatively slow across the border in the U.S., which Parthiv Kurup, concentrating solar power cost and systems analyst at NREL, attributes to low natural gas prices. However, the output of the CSH system may also have played a part. The operation of the U.S.’s only food industry CSH installation, at a Lays potato processing plant, developed in Modesto, California 10 years ago, revealed that the natural gas displacement due to solar integration was 12 billion Btu/year rather than the modelled and designed 20 billion Btu/year, due to inefficient connections and lower thermal energy utilization of the CSH system.
Kurup, who is currently researching ways to make CSH a more attractive offering in the U.S., says CSH technology has improved and collector costs have decreased over the last decade. An NREL System Advisor Model (SAM) validation paper, based on a Swiss dairy where CSH is used, found that the cumulative yearly thermal energy yield of the solar field simulated through the SAM model was 194 MWh·th, corresponding to an underestimation of only 4.4% compared to the measured thermal output of 203 MWh·th.
Kurup points to India, Tunisia, Jordan and the Middle East as up and coming adopters of CSH in the food industry, where remote, high solar resource locations currently rely on high-cost diesel and bigger cost savings can be made.