Last June 2019, the Luzon grid was recently placed under red alert status, meaning that the available energy supply was only just enough for the peak demand with very little reserve margin. Given the ever-increasing hunger for electricity, the country aims to swiftly add to their power supply while keeping in mind how this would affect climate change. Because of this, the path towards renewables is often encouraged due to its reputation of being clean and emitting little to no greenhouse gases. Though renewable energy has its benefits, it is essential to examine the bigger picture wherein much of its environmental impacts stem from other phases of its life cycle.

One of the major contributors to the renewable energy supply of the Philippines would be hydropower, comprising of around 12% in 2015. The concept behind this RE technology is fairly straightforward, wherein the volume of water flow and elevation of the reservoir are major factors in determining electricity output. Generally, the water would flow through a penstock and would turn the blades in a turbine which would produce the electricity.

As of 2019, the Philippines has around 3600 MW of installed hydropower, mostly from large-scale hydro. Since hydropower is known for its energy stability and electricity price reduction, this would be a go-to source to explore for many large stakeholders. In constructing the reservoir dams however, the displacement of local communities as well as ecosystem disruption is inevitable. With this, more people are turning towards run-of-the-river hydropower (ROR) due to its relatively smaller environmental impact as well as minimal capital costs.

ROR projects must be located on rivers that have sufficient head and constant substantial flow rate to generate electricity. With this, there is no need to build large dams to hold water, thus energy is produced following the flow of the river body. In some cases, smaller scale dams may be built for same day use water storage. On average, the efficiency of ROR systems would range between 65% to 90% and these can be classified based on their capacity, usually ranging from micro (<100 kW), mini (100 kW- 1 MW), and small (1-50 MW).

Given its benefits, it is strange how the ROR technology is not as utilized in the country as compared to solar and wind. Under the Feed-in-Tariff rates for renewables, run-of-river hydro has been lowered to PhP 5.87/kWh (effective 2018), however the quota of 250MW has not been reached until today. Hopefully more studies on this type of hydropower can be conducted in the future so we may harness its potential for the growth of the Philippines.