This was the April-1 post for this year. Enjoy! But don’t believe. On the other hand, it is not impossible either and perhaps, one day ?
The world is approaching an energy crisis. Oil is due to run out by 2040, and longer-lasting oil shales yield a low quality, heavy oil which is poorly suited to electricity generation. Gas will last only to 2090. Coal is too dirty a fuel to burn in large quantities, and nuclear energy has shown itself to be susceptible to major incidents, has a problem with spent fuel, and relies on scarce uranium resources. Renewable resources are growing rapidly in importance, but are intermittent, and require vast areas. The problem is most severe in Germany, which has no significant oil and gas of itself, but has decided to close all its nuclear facilities. To combat energy shortages, it is mining vast areas of brown coal (lignite), with major environmental consequences, including heavy pollution, very high CO2 emissions and devastated landscapes. Some of the open-cast mines are large enough to swallow a major city (Hambach covers more than 40 km2). But now a solution has been found. And it applies German geo-engineering to the control and harvesting of lava.
The German federal government has just announced plans to create a lava lake in the Vulkaneifel. It will bring the magma of a local volcanic field to the surface where the heat will be used to generate green electricity. The lava lake will also draw tourists to this area.
A lava lake is a long-lived, large volume of molten rock which has collected in a surface depression, normally the crater of an active volcano. Six such lakes are known in the world, at Kilauea (Hawaii), Ambrym and Yasur (Vanuatu), Erebus (Antarctica), Masaya (Nicaragua) and Nyiragongo (DR Congo). At the moment only four of these are active. A lava lake needs a constant, stable supply of lava. If the lava supply varies too much, it can either let the lake solidify (’freeze’) or destroy or drain it through volcanic eruptions, as happened in 2018 in Hawaii.
The Germans plans include drilling down to the depth where liquid magma resides, some 6 kilometers below the surface. The area of the Vulkaneifel has some volcanic activity, although eruptions are infrequent. The drilling will create the conduit. Horizontal drilling will now be used to release the magma pockets, using techniques from fracking. The magma will come up through the drill path (the ‘conduit’) and fill the lake at the top. The plan has been designed by Dr. Ernst Bosch, working at the Cologne Institute for Renewable Energy (CIRE). The work is being carried out by Hochtief and Schlumberger NV.
The lava lake will have a temperature of 900 degrees centigrade. The heat will be used to generate electricity: the 2 GW system will cover 3% of Germany’s electricity usage.
A location has already been chosen, and work has started. It is based at the military base at Gerolstein. Gravel extraction within the restricted area has created a number of depressions, several of of which are perfect for the project. The location is close to the Nürburgring Grand Prix circuit which lies directly over the most productive magma chamber in western Europe. The horizontal fracking will reach there, 20 kilometers northeast from Gerolstein.
VC understands that magma fracking has already been tested for several years. This area suffers earthquakes, and the increase over the last few years in weak quakes which was caused by the testing has not been commonly noticed, and not given rise to concerns. However, it now appears that the lava lake itself has also already been tested. A satellite image of the test site clearly shows the signs of dark lava, albeit in amounts too small to remain liquid. Access to the site is currently not allowed, although reportedly a visitor centre is being build.
The operations are waiting for the 2-GW power generation system to be completed. The lava will begin to flow in July, and will begin to produce electricity around November. The building costs are surprisingly limited, at 380 million euros, because it uses off-the-shelf technology developed for fracking, and the site was already owned by the government. The only remedial work needed on the existing gravel extraction site was the addition of a waterproof membrane and a thermal insulating layer. The membrane is required as gravel pits typically extend below the water table, and the lava should not get in contact with the water table. This is also standard technology used in the rehabilitation of open-cast mines.
Various organizations have responded to the plans. USGS commented: ‘We are immensely excited by this experiment. It shows that volcanoes are not only great for tourism, but that they can generate economic growth. In 2018 we lost the most accessible lava lake in the world. It now seems likely that in 2019 the first artificial lava lake will be formed. This is the future of volcanology.’
The famous German volcanologist Boris Behncke was more critical: ‘The technique will work, but have they considered the dangers of lava tourism? This part of Germany has cold winters, and lava and snow is a dangerous combination. You wouldn’t want tourists hurt by flying lava bombs.’ He also deplored the secrecy surrounding the operation.
German mining corporations have given expressions of support. Open cast mines are common in Germany and can reach huge sizes. The companies normally turn them into lakes at the end of their lives but that can perpetuate a pollution problem. Filling them with lava could restore the original landscape and safely lock down any polluted materials at the bottom. One mining company suggested that the cooled lava could even be used as building material and a source of rare-earth elements, thus giving the mines a second lease of life.
Other people have pointed out that the technique could also be used for the management of volcanoes at risk of erupting: by providing an open conduit before the magma rises too high, the risk of explosive eruptions can be drastically reduced. USGS has calculated that, had the technology existed at the time, it could have prevented the collapse of Mt St Helens, although not the eruption itself and the immediate area would still have been affected by lava. Once the magma reaches a depth where it becomes eruptible, it is too late for this technique and providing an open conduit would just hasten the explosion.
Germany’s Green Party, the most powerful ecological party in the world, broadly supports the experiment. They stated that it provides a clean alternative to nuclear power, which they are against, but point out it is not fully carbon neutral as lava does emit some CO2. They propose to legally require the experiment to deploy carbon-capturing technology in the lava lake. Extreme eco-warrior groups have come out against the idea, stating that it uses heat from the Earth’s core which is in finite supply and therefore not a renewable resource. They argue that over-extraction will cause the core to solidify which will hasten the disappearance of the Earth’s magnetic field. Scientists deplored this view and said that the Earth’s heat would last us billions of years.
The design will deliver a constant flow rate of 1 m3/s of lava. Initially, the lava will be kept in a narrow pit, in order to keep it hot. As the amount increases, it will cover a larger area of the gravel pit. The target depth is 20 meters. This amount of lava per second, at this temperature, provides 2 GW, ten times the power of all geothermal installations in Germany combined. The existing installations use ground water reservoirs, but these are less common in the areas where the German volcanoes are located. Water-driven geothermal plants are therefore mainly located in southwest Germany where the amount of ground heat is not as high. Water also operates at much lower temperatures. In compensation, water has a much higher heat capacity than lava. Overall, lava becomes four times more efficient than the same volume of water.
In addition, the conversion of heat to electricity is much more efficient at higher temperatures. Systems that can operate at temperatures up to 1000 centigrade already exist. The lava lake system will use a volumetric pressurized receiver system. In this system, air is compressed to 15 bar. The hot air drives the first turbine, connected to the compressor and to a generator that produces electricity. The Air comes out still with a considerably elevated temperature. It is now directed to a heat boiler which this drives a steam-cycle process. The combined system has an efficiency of 50%. It was originally designed for solar heat collectors.
The pressurised air is heated indirectly. Tubing running through the lava lake circulates air at normal pressure (1 bar). The heat exchange with the 15-bar closed system happens in the vertical entrance pipe connecting the lava lake to the generating plant. The tubing running through the lava is an extreme heat resistant stainless steel variety, made by Norres and guaranteed up to 1100 centigrade. The tubing is calculated to last about one month. It will need to be regularly replaced, by sinking new tubing into the lava lake. Unlike conventional renewable energy plants, the system can be turned off for maintenance without wasting energy, as the heat is retained in the lava lake.
It is also considered to build a heat chimney, which covers the lake, collects the rising air, and forces it through a small exit window at the top where additional turbines are placed. This only adds a few per cent to the efficiency but helps direct away any excess heat. The waste heat can also be used directly to heat houses in nearby cities such as Koblenz and Bonn.
Germany uses some 60 GW of electricity on average. Lava lakes could cover about 30 GW in total, based on the rate at which magma accumulates underneath the country. However, some geologists have proposed that siphoning off the magma will actually increase this rate, through enhanced supply from the astenosphere and through enhanced decompression melt. If this is shown to be feasible, it could provide all Germany’s electricity needs.
VC would like to find out what our readers think of this idea, being more knowledgeable on the topic than most people or the press. What do you think?