Eva Augsten, Contributor
March 29, 2013 | 1 Comments
HAMBURG -- Five years ago it seemed possible that solar water and space heating would break through into the mass market. Oil and gas prices were rising quickly and collector manufacturers had invested in larger production lines. But the successes of 2008 have not continued since. According to the latest projections by BDH, the German heating industry association, German plumbers installed 1.2 million square meters of solar collectors in 2012. This is 5 percent less than in 2011 and 40 percent less than in the boom year of 2008.
Applications in which water and space are heated in family houses are typical uses of solar thermal systems in Germany, forming 95 percent of the market, according to BDH statistics. But at the same time, they are the most expensive application, and there is little that the solar industry can do about that. “Even giving away collectors for free would only reduce the total cost of a solar water heating system by 6 percent for the end consumer,” estimates Bernd Hafner of the heating equipment producer Viessmann. More than half of the costs of a domestic solar water heating system lie on the installer's side. Naturally the solar industry is trying to overcome the problem by working on simpler systems but the potential for cost reduction is limited and the situation may even get worse for solar thermal. With ever cheaper PV systems and high surpluses of solar electricity in summer, even water heating with PV might become cheaper than solar thermal within a couple of years.
If solar thermal is to play a major role in the energy revolution, a new market is needed urgently. Industrial and commercial applications seem to be a field that is worth cultivating. Many of them need heat all year round at low temperatures. Large solar fields, planned and installed by specialized companies could lead to significant cost reductions, as has been demonstrated by Danish district heating plants. For several years solar process heat has been discussed at conferences, described in papers and investigated in pilot applications, but the consumer response has been hesitant.
In summer 2012, as the development of solar thermal energy was falling short of expectations, the German government agreed on new subsidies, especially for solar process heat. Solar plants of collector area 20-1000 m2 that provide heat for commercial and industrial processes now receive a 50 percent subsidy of the net investment. The new subsidies are part of the Marktanreizprogramm (MAP), which is the responsibility of the Federal Office of Economics and Export Control (BAFA). “The new incentives for commercial and industrial process heat go beyond the classical MAP incentives for water and space heating,” says Ralph Baller, head of division at BAFA. “We call it MAP 2.0.” This might give solar process heat a decisive push.
Huge Potential for Solar Process Heat
In 2011 a group of scientists including Professor Klaus Vajen from Kassel University published what was then the most comprehensive study of the potential for solar heat in industrial processes in Germany. The nation's industry consumes more than 508 TWh of heat per year, it reported. Equivalent to the yield of more than 1 billion m2 of solar collectors, based on figures from 2012 it would take a thousand years to produce and install these.
Unfortunately it is precisely those industries that have the highest energy demand that require the highest temperatures. Examples are metal production and processing, so solar is out of the game in their case. But, on the other hand, more than 20 percent of the industrial heat demand in Germany is for warm water, space heating and industrial processes that require temperatures lower than 100°C, so these applications could be supplied by standard solar collectors.
In absolute numbers the biggest demand for low temperature heat is in the chemical industry. Some chemical processes such as the production of ammonia or the cracking of naphtha need high temperatures, but side processes that require low temperatures are numerous. More than 15 TWh of heat below 100°C is needed annually for washing, drying and concentration processes, and another 8 TWh for hot water and space heating in the chemical industry, say Professor Vajen and his team.
The situation in the food and beverage industry is different but probably even more promising. The overall heat consumption here is only 28 TWh, including 17 TWh below 100°C. Pasteurization of milk and other liquids needs temperatures between 60°C and 145°C, blanching and scalding of vegetables and meat needs 45°C-95°C, drying processes start at 40°C and cleaning of production equipment is usually done at temperatures of 60°C-90°C. “In the short term the food and beverage industry is the most promising for solar thermal process heat,” says Vajen.
Based on the temperature profile for heat demand in various industries, the scientists determined that there is a theoretical potential for solar heat of 130 TWh. This includes processes with a temperature below 250°C, so in this case special collectors will be needed. A lot of this heat can be provided by efficiency measures such as recovering waste heat from electrical or high-temperature processes. And many low temperature processes are powered by electric heating elements directly incorporated in the machinery.
“For some plastic moulds, for example, there is no alternative available on the market that would work with direct heat except electricity,” explains Vajen. And even if the integration in the process is feasible, some companies simply have no space for solar collectors.
Vajen and his team assume that these restrictions eliminate 60 percent of the theoretical potential for solar process heat. For the remaining 40 percent, they consider a plausible average solar fraction to be 30 percent. This means that solar could cover 3 percent of the heat consumption of Germany's industry, or 16 TWh a year, which is the equivalent of solar collectors of total area 40 million m2. Based on installation figures from 2012, it would take more than 30 years for the country to fulfill this potential.
New Sales Structures Needed
With the potential determined, the challenge is now to offer the customer the product they want. This is not as simple as it sounds. Most solar companies are used to selling collectors but industrial customers are not interested in shiny sun catchers; they want low-cost heat.
The few solar companies that are already successful in the process heat business have adapted to this market structure. They offer turnkey solar plants and work closely with the engineering companies that deliver machines and other equipment to the industry. For example, Ritter XL Solar has teamed up with Eisenmann, a large provider of paint shops. They call their partnership the Green Alliance for Sustainable Production. Eisenmann's main business is the automotive industry. Painting cars requires huge amounts of heat that Ritter XL Solar can provide easily with its vacuum tube collectors. The alliance's first common project was a solar-fuelled paint shop for the radiator manufacturer Zehnder in Switzerland. For all of their plants, Ritter XL Solar and Eisenmann guarantee their customers a certain solar yield.
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