[OPINION] Renewable energy technology for energy transition

Sustainability in the context of electricity supply means utilizing generation sources that have the lowest possible negative effect on the environment in terms of greenhouse gas emissions and other impacts. Many of those who advocate for the “energy transition” stop there, promoting renewable energy (RE) sources such as solar and wind as replacements for conventional fossil fuel-powered capacity, but affordability and reliability must be considered.

The energy transition must be viewed as an effort toward providing energy security for the Philippines, where energy demand is met by an energy supply that is balanced between sustainability, accessibility, reliability, and affordability.

To achieve this, the Philippines must apply efforts toward decentralizing generation, improving demand efficiency, encouraging energy conservation, and above all, applying a mix of generation technologies that are fit for purpose.

This means that the available capacity, at whatever scale it is used, provides sufficient base load power, regulating reserve power to ensure transmission system stability and contingent reserves to meet supply deficiencies. Using generation technologies in combination makes the best use of the advantages each offers while compensating for their disadvantages, such as the intermittent nature of solar and wind power.

Solar Photovoltaic (PV)

On a grid scale, solar PV is rather inefficient, despite its obvious advantages of being completely emissions-free and using costless fuel in the form of sunlight. Solar has a large footprint — approximately 1 hectare per megawatt of capacity — and has a low capacity factor, averaging 20% to 25%. Solar equipment also has a limited lifespan, generally about 25 years, at which point it must be replaced; this creates an additional environmental problem of large amounts of mostly unrecyclable waste.

However, solar PV is well-suited to smaller, localized power systems, particularly when used in line with battery storage systems that can provide electricity at stable frequencies, including at night when solar power is unavailable. Examples are single homes or commercial buildings and distributed energy systems, where individual solar installations on a small scale such as a village or neighborhood are interconnected to form a microgrid.

Wind Power

Like solar, wind has the advantages of being emissions-free and using free energy from the environment, but it also has the disadvantages of intermittency — although this can be managed somewhat better than for solar with the type of turbine equipment used — and a relatively low capacity factor.

The Philippines does have a great deal of potential offshore wind capacity, however, so if wind power is used with energy storage systems, it can be a reliable source of supply. Its biggest drawback is perhaps its cost, which according to data (2023) from Lazard is higher on a levelized basis at the utility-scale than both solar and geothermal, and higher than conventional combined-cycle gas generation.

Geothermal

Thanks to its volcanic geographic origins, the Philippines has abundant geothermal resources, estimated to be about 4.6 gigawatts in total, of which 1.9 GW already is being utilized as installed capacity. Unlike solar and wind, geothermal power can be used for baseload supply.

However, its disadvantages are relatively high development costs — Lazard’s calculations of LCOE do not take into account exploratory costs for locating new wells, something the energy monitor does acknowledge — and the fact that it is only available here in the Philippines in limited areas. In those areas, however, geothermal can be a reliable baseload around which a supply of RE capacity can be built, and of course, it can contribute some clean supply to the national grid.

Biomass and Waste-to-Energy

Although most RE advocates would not consider these to be the same thing — waste-to-energy is considered emissions-heavy, although it does not necessarily have to be if designed properly — in engineering terms they are, and they are the closest thing to a direct replacement for conventional coal, gas, or oil-fired generation, as biomass or consumer waste, is simply a substitute fuel.

The biggest handicap for either type is fuel. Biomass that relies on agricultural waste may be subject to seasonal availability, and using purpose-grown crops is disfavored here in the Philippines as it is seen as compromising the country’s already tenuous food security. Waste-to-energy plants also may not have a consistent supply of fuel, particularly since reducing solid waste through recycling and other conservation measures is a national-level objective. However, in areas where sufficient and reliable fuel supplies are available biomass or waste-to-energy plants can provide baseload support for other RE systems.

Energy Storage Systems

The most commonly used energy storage systems currently are battery installations, and these are quite reliable, though they are limited in duration. Current battery technology, primarily lithium-ion batteries, has a relatively low energy-to-mass ratio, and there are growing concerns about the future availability of raw material resources. Like solar and wind equipment, batteries also have a limited lifespan and present a solid waste disposal problem. However, battery storage can compensate for the intermittency of solar and wind installations, with that capability being progressively more reliable the smaller the scale of the connected distribution system.

Another form of energy storage that is being applied in some parts of the world is pumped hydro storage, where an RE installation such as a wind farm powers pumps to fill a reservoir that can be drawn down to provide hydroelectric power when needed. Here in the Philippines, the available areas where pumped hydro facilities could be built are quite limited, and because of this – as well as the high cost of development – it is unlikely that pumped hydro would be put to widespread use.

Other clean energy technologies that may be considered in the future, perhaps in the next 10 to 20 years, including nuclear energy, particularly small modular reactors (SMRs); and tidal power, which could be installed in a few locations throughout the Philippines; and hydrogen fuel cells, which are most applicable to vehicles, but could also be used as small-scale energy storage systems. Energy technology continues to evolve, with reliability and efficiency steadily improving, so the next decades may very well present new alternatives to meet the Philippines’ energy security needs. – Rappler.com

Ruth Yu-Owen is the Renewable Energy and Energy Efficiency Committee chairperson of the European Chamber of Commerce of the Philippines (ECCP)