00:00Being a reporter is fun, but not always.
00:05Okay, let's do it.
00:07I think that's beyond next level.
00:10Today we want to find out how entire residential areas can be heated with this icy cold water.
00:16With a heat pump. A fairly large one.
00:19I don't hear anything.
00:21It's minus one degree. It feels like a thousand needles in my leg.
00:26And I thought I'd just see how cold this water really is.
00:29Bad idea. It really hurt.
00:33Heat for homes and industry requires more energy than any other sector.
00:37The majority from fossil fuels.
00:41So, for the climate, emissions need to be reduced.
00:44To make the building sector more sustainable, there's no getting around heat pumps, large or small.
00:49They convert energy from the air, water or earth into heat.
00:54Around 300,000 people live in Mannheim directly on the Rhine, and the river plays a special role today.
01:04The magic is happening in this.
01:06The local energy provider is producing electricity and heating through a mix of fossil fuels and cold water.
01:15In this region, it still comes primarily from climate-damaging coal.
01:20I meet Felix Haack, an energy manager at the MVV Energy Group.
01:31The site where we are located is part of the Mannheim coal-fired power plant.
01:36It emits an estimated 1% of Germany's CO2 emissions per year.
01:41But that should change soon.
01:44Millions of liters of water flow through the Rhine,
01:47which is several times the amount of heat Mannheim needs, even at such cold temperatures.
01:54It's now 6 or 7 degrees Celsius, so physically, there's still enough heat in it.
02:02We're now in the anteroom, and we need to take our earplugs because it's really loud in there.
02:07This deafening giant machine is a flow heat pump.
02:10800 liters of river water are pumped through here every second.
02:15This generates heat for around 3,500 households.
02:22This is where the river water from the Rhine comes in and goes into the large heat exchanger, the evaporator,
02:28where it then transfers the heat to the refrigerant.
02:31Okay, let's take a step back.
02:33Here's what happens in the pipes.
02:35The water is cold, but it's warm enough to vaporize a refrigerant at very low temperatures.
02:41This gas then expands.
02:43An electric pump compresses the gas.
02:46That generates heat.
02:48It's like a bicycle pump.
02:50The more you pump, and the higher the pressure goes,
02:53the more heat is released.
02:56It's like a bicycle pump.
02:58The more you pump, and the higher the pressure goes,
03:01the hotter the pump becomes.
03:03The heat is then used to heat water or air.
03:06The coolant, therefore, releases the energy and becomes liquid again,
03:10and the whole process starts all over.
03:13This method is three times more efficient than heating with a gas boiler.
03:17It not only works with river water,
03:20but also with energy from the air or the ground on a large and small scale.
03:25Ideally, the electricity for the heat pump should come from green energy,
03:29but even if it comes from fossil fuels, it's still more sustainable.
03:34The principle of a heat pump isn't new at all.
03:37It's based on a concept which has existed for a very long time
03:41and on a technology which most of us have at home.
03:45A refrigerator.
03:47In the 19th century, there was a high demand to cool things.
03:51Ice blocks were even imported from far away.
03:54In 1859, Frenchman Ferdinand Carré developed one of the first commercial cooling systems.
04:01It works just like a heat pump, only the other way around.
04:05It transports the heat from inside to outside.
04:09Later, another machine made the headlines, the air conditioner.
04:13It was originally invented to solve moisture problems in the paper industry.
04:18It wasn't until later that the heat pump had its big moment.
04:22The pride and joy of the man of the house is the weather control center.
04:27A center that puts you in charge of the electric heating and air conditioning
04:32and the electronic air filtering of the entire house.
04:36After the Second World War came widespread electrification and new lifestyle expectations.
04:42Heat pumps fit into the picture well.
04:45But as many people still used cheap oil and gas for heating, they didn't really catch on.
04:50Today it's different.
04:52So now we're going to see the heat storage from where the heat is being distributed over the entire city.
04:59That's the thermos flask. 43,000 cubic meters of water.
05:05Okay, wow. How much is that in liters?
05:0843 million liters.
05:12That takes a while to fill.
05:16In Mannheim, most of the heat still comes from coal, only 3% from the river.
05:21However, that will soon change as the coal-fired power plant is expected to be shut down by 2033.
05:30We want to go even bigger.
05:32We want 50,000 households to be supplied with river water heat pumps.
05:37That means a tenfold increase in the next few years.
05:42From an environmental perspective, there is a theoretical problem with river heat pumps.
05:47If heat is extracted from the river, cooler water is returned later.
05:52However, the quantities here are so small that the temperature in the river only changes minimally, according to MVV.
05:59But now imagine all along the river Rhine, all the major cities there, wanting to cover their entire heat demand,
06:05including industrial plants such as the BASF or covestro plants along the river Rhine,
06:11that might use water for heat pumps for their processes.
06:16And suddenly you get an issue.
06:19In Mannheim, the heat is distributed above and below ground via a district heating network.
06:25In Germany, around 15% of all buildings are now heated in this way.
06:30And the largest part of this could be covered by large heat pumps that make coal and gas redundant.
06:36But it's still a niche market.
06:38The model is the Swedish capital Stockholm, where around 90,000 homes are heated with wastewater.
06:44In Mannheim, the city's climate targets and state subsidies for the construction of the plant were decisive factors for the changeover.
06:52Their goal is to produce almost completely clean heat by 2030.
06:57The heat pumps won't cover all of that, but will be one important component to eventually shut down the dirty coal power plant behind me in the near future.
07:06Whether large or small, heat pumps are sustainable and can make regions, cities and individual buildings less dependent on fossil fuels.
07:16And they even work in winter.
07:18All right, I made it.
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