Harz Mountains-- Germany's Green Battery?
Smack in the middle of northern Germany lie the Harz mountains, a forested area of hills and low mountains stretching 60 miles east-to-west and 20 miles north-to-south. For thousands of years, this area has been mined for its natural resources: copper, iron, silver, lead, zinc and coal among others. Its copper fed the region's Bronze Age; its silver enriched royalty.
As its resources dwindled, many mines closed down and its economy worsened. Heavy metal polluted the land. During World War II, abandoned mines were utilized as underground factories which the Allies could not destroy. Production of rockets required lots of labor so the Nazis brought in slaves to live and work in the underground mines. Tens of thousands died-- 20,000 in one factory alone. After the war, when Germany was partitioned, most of the Harz mountains fell under Soviet control in East Germany. They restricted access to much of the area, constructing listening posts to spy into West Germany and watch the border for escaping East Germans. The Brocken, the highest of the Harz mountains at 3,744 feet, hosted one of the listening posts. Even after unification, the region hasn't recovered. Most of the mines have long been played out and closed. Belying its sordid past, the Harz mountains provide stunning scenery and their quaint villages draw many visitors, making tourism the region's biggest industry, but jobs are still hard to come by.
Renewable Energy's Problem
It may be, however, that all those closed mines may yet have a part to play in the region's economy. Germany is determined to expand its renewable (green) energy production. By 2035, it has targeted renewable energy to produce 35% of its energy needs and 80% by 2050. At the same time, the Germans want to reduce their reliance on nuclear power. This means greatly expanding renewable electrical production using solar, wind, wave, and other technologies. The problem with solar and wind power is reliability-- nights, cloudy days, calm days means having to fallback on good old, reliable, polluting, non-renewable oil and coal. There needs to be a cost-effective way of storing excess energy from wind and solar power for use during the night and calm days-- in other words, it has to be reliable and not intermittent. Many techniques and technologies are being investigated around the world. Batteries are used for small-scale energy storage. In Fairbanks, Alaska, which is not hooked up to a regional grid, electricity is critical when temperatures can fall to 50- or 60-below-zero. They have the world's largest battery backup-- a 1,300 ton battery larger than a football which can provide 40 million watts. Although only enough to power 12,000 residents for seven minutes, it was enough to prevent 81 blackouts. Some states in the US Midwest are investigating using excess electric production from wind farms to force compressed air into underground caverns to be tapped when needed to drive electrical turbines. Others are using excess electricity to split hydrogen and oxygen via electrolysis, getting the energy back later by using the hydrogen as fuel. There are many other ideas being explored to reach the holy grail of renewable, reliable green energy priced on a par with fossil fuel-produced energy.
Harz Mines an Answer?
It was Marko Schmidt who thought the abandoned mines of the Hartz mountains might be able to address Germany's need for reliable green energy. An industrial engineer with the Energy Research Center of Lower Saxony, Schmidt thought of storing water in tanks at the bottom of the mines and using excess electricity to pump the water up to enormous tanks or reservoirs inside the tops of the mines. Then, when needed, the water would be released, turning turbines in the mine shafts to produce electricity, much the same way dams work-- but instead of the water being lost, it would be pumped back up when the sun shone or the wind blew again. This technology is known as “hydroelectric pump storage”. Basically, the energy, or most of it, used to raise the water would be reclaimed on demand when gravity was allowed to pull it down through the generators.
The idea is gathering support, with plans in the making for a pilot project in the Wiemannsbucht mine shaft in Bad Grund, a town on the western edge of the region. Backers and entrepreneurs are seeking 200 million euro ($270 million) to build it. It could be ready in three to five years and be able to store up to 400 Megawatts, enough to power 40,000 homes for a day. While at first only working with local wind farms, such plants could eventually store electricity produced from North Sea wind turbines. Such an undertaking has very few critics. It does not pollute. It does not despoil the landscape-- everything happens underground. Just as importantly, a lot of the infrastructure is already there, in the abandoned mines. If this came to fruition, it would certainly bring about an economic revival for the area. As one district administrator said, “...we could easily become Germany's number one storage facility.” The Harz mountains could become Germany's green battery.