Can Japan and its local communities benefit from micro hydropower?

Green energy is essential for stopping the worst outcomes of climate change. Fossil fuels such as gas and carbon are a huge factor in global warming. The transition is not going to be easy for every country. Japan, in particular, relies mostly on fossil fuels for its energy needs, with nuclear power falling somewhat out of favor after the Fukushima disaster.

Small- and large-scale hydropower

Hydropower is one source of renewable energy that may help reduce dependency on gas and coal. It does not burn fossil fuels, generates little to no greenhouse gases and provides a continuous energy source. However, it does have downsides. The construction of large-scale hydropower dams can damage local environments. Hydropower plants divert natural water flow, causing problems for fish and other sea life that depend on that flow for migration and breeding. They can also affect water sediments and nutrients as well as destroy habitats.

Small hydropower, or micro hydropower, generation could be a more sustainable solution. This form of energy generation utilizes smaller water channels such as rivers and agricultural irrigation channels. The energy from the flow of falling water turns a turbine which generates electricity.

Micro hydropower can serve local communities

While it is not optimal for large-scale electricity generation, one benefit of micro hydropower is that it can serve rural, local and more isolated communities. The technology has already been applied in countries as diverse as China, Vietnam, Nepal and Afghanistan. Hiroyuki Ueda is the representative director of J-Water, or in Japanese, the Nationwide Small Hydropower Promotion Council. In a 2019 interview, he uses Nanto City, Toyama Prefecture, as an example of a smaller local community with good micro hydropower output.

The smaller scale and relatively simpler assembly of many micro hydropower generators means less environmental impact than larger-scale generators. They are also stable and economical sources of power, though the potential hydropower available varies by region. Because micro hydropower also relies on small water channels to function, the areas where they can be installed are also somewhat limited.

However, they are suitable for mountainous areas with good rivers or water sources. This applies to many regions of Japan, particularly rural and agricultural areas. There are challenges involved in promoting small hydropower, such as limited awareness and laws regulating the use of land and rivers. Yet there are also prefectures that are already making good use of the technology, including Toyama, Shizuoka, Nagano, Gifu and Kagoshima.

Compatibility with Japanese agriculture and climate

Besides mountains, generators can be installed in certain kinds of dams and sewage treatment facilities. Japan’s agricultural irrigation channels are good places for installation since rice is a water-intensive crop. Small hydropower generators have been placed in irrigation channels in Nasunogahara in Tochigi Prefecture to good results.

The water cycle is an important part of why micro-hydropower is so consistent and sustainable. Places with a good amount of rain or snowfall also have hydropower potential. In Japan, this includes places such as Hokkaido, Niigata and Nagano.

Addressing any social problem requires taking into consideration the unique circumstances of certain communities and populations. The climate crisis is no different. Micro hydropower might not be the right solution for everyone, but it can provide localized energy sources that help smaller communities and cause minimum disruption to natural environments.