China would seem to be the ideal nation to pioneer a cleaner version of district heating using solar CSP, with its densely populated cities, cold winters, commitment to a cleaner future - and its central planning.
With its huge scale, clean energy used at the district level could really have a major impact. But Saudi Arabia might prove even better.
District heat supply in new townships is one of six areas of Beijing's infrastructure construction that is to be opened to both overseas and domestic investors this year, according to Peng Bo, a spokesman for the Beijing Commission of Reform and Development, the city's economic planner.
Private investment companies would enjoy the same generous deal in terms of land, price, investment return and supporting facilities as their State-owned counterparts, and the Beijing government says it would take measures to make sure investors get a reasonable return; with a suggested IRR of 8 percent.
Could this move by Beijing - bringing in overseas investors to supply district heating - open a big new market for CSP?
GlassPoint CEO Rod MacGregor would seem like the obvious person to check with, to see if using CSP for district heating in China might make sense. He has pioneered a unique market; enhanced oil recovery (EOR), using CSP to produce just heat, not electricity.
“It’s not a crazy idea,” says MacGregor. “One of the drawbacks with traditional district heating (usually coal with CHP using the waste heat) is the power station is the big source of emissions - and it is right where the people are.”
District heating has to be close to the district. This means there is a real role for pollution-free energy, to make heat, like CSP. But on the other hand, CSP sprawls. You might need about a hundred acres, about the size of a shopping mall, to heat ten thousand homes. So staying close is a challenge, but MacGregor believes it can be done. For one thing, China is building in large apartment blocks, which are innately more efficient.
Glasspoint EOR plants are more condensed than most CSP, using about a third of the land of trough CSP and a fifth of the land of power tower systems.
“In the oil industry we tend to not move steam more than a kilometer or two, that’s kind of the maximum,” he says. “It doesn’t have to be literally next door, but it has to be near your end use.” The further you are, the more you’d spend on piping and insulation.
GlassPoint could do district heating very cheaply, because the technology is designed to just directly supply hot water or steam. EOR steam production differs from standard CSP used for making electricity. It doesn’t need to achieve the very high temperatures needed to drive turbines as efficiently as possible for making electricity.
But MacGregor believes standard CSP would make economic sense too, by shipping both its power - and its waste heat. This would be more like traditional CHP, but using sunshine.
“Today, for wet cooling, fundamentally you are throwing 60 percent of the energy away, in cooling the output steam down to liquid. You could probably put 80 percent of that heat to economic use,” says MacGregor. “If you have a use for that waste heat, like combining heat and power, for district heating, then you now have an economic value for that.”
On the other hand, the potential size of the market is limited by China’s unique situation globally. “District heating has some limitations. China has a command economy. The government says we will build a town from scratch and you will use district heating,” says MacGregor. “Whereas in most other markets, it’s individuals’ choices of how they heat their homes.”
So the size of the market is one consideration. Another is air quality.
Beijing and pollution
District heating in China is most used in the northern areas. Beijing’s dry winters average -4°C, and have very little rainfall. Winter nights get as low as -9°C.
Beijing is northern, and densely populated. So new townships skirting Beijing, designed for dense urban living, would seem ideal for solar energy for district heating - if it wasn’t for the pollution from its current reliance on coal energy.
MacGregor says older cities like Beijing would be problematic currently for this reason. Of course, once enough clean energy is added around Beijing, local pollution levels will likely drop, improving solar access.
“District heating is pretty common in the north. It’s the main source of heat in the cities for several reasons,” says Meredydd Evans, senior scientist at PNNL (Pacific Northwest National Laboratory in the US) and a frequent visitor to China and China policy expert. “There’s high demand for heat in the severely cold region closer to the Russian border. Also the density of the cities makes it more cost effective.”
Like the national government, locally Beijing has shown consistent foresight in planning for a cleaner future.
“Beijing has been a strong leader in the area of clean energy, both within the urban center, and outside of its boundaries,” says Evans. “What we’ve seen around Beijing, where there is new construction, there’s conversion of rural areas into somewhat more urbanized city. They may be extending the scale, because there’s such tremendous population growth.”
District cooling with CSP - China and Saudi Arabia
China’s summers are extremely hot, ranging from 20°C to 30°C - so it would run the CSP with chillers in summer to also provide district cooling.
MacGregor cites the attractiveness of CSP for district cooling in the Middle East, as well. He’s not alone. Saudi Arabia’s ACWA Power CEO Paddy Padmanthan, with 40 years of engineering experience, says: “From an engineering point of view; using CSP for district heating or cooling is a potential application for sure.”
“The principle is based on solar-produced steam for direct heating - or in the case of cooling; then using absorption chillers to produce chilled water.”
As he sees it, the advantages would be that the mirrors can be cost-effectively defocused to avoid overproduction in the case of overabundance of solar “fuel”, and that - at least in cooling - A/C demand in the middle east tracks closely with the sun’s heat.
It’s not for everywhere. The DNI must be good, space is a consideration, O&M is more demanding than for traditional thermal technologies, and - for heating - storage is needed for the cold of night. But for cooling - he sees a perfect fit.
“We see it as a very suitable application in the Middle East,” Padmanthan notes.
“Our primary need is cooling, and there is this near-perfect match between the time when we can abstract the heat from the sun and when we need to cool our offices, homes and factories. And of course we have more spare land.”
GlassPoint is scrambling to keep up with demand in EOR right now, so district heating and cooling is just not a current focus. But if the EOR market didn’t exist?
“Definitely,” says MacGregor. “I think it’s a nice application. Who knows. In the future, once we’ve grown up a bit and we’re able to handle the volume in our core market.”