by Ricky Jimenez
The search for the cleanest fuel to generate electricity in the future will ultimately point to the largest untapped resource that has been here with us ever since: the tropical seas.
Dr. Dan McNamara, SJ, an astrophysicist (a scientist studying distant stars, how they are born and how they influence our solar system) said this energy resource from the tropical seas is known as Ocean Thermal Energy Convergence or OTEC.
The 70-year old Jesuit from Chicago, USA, and rector of the religious community at the Ateneo de Davao University, said OTEC is non-polluting and inexhaustible compared to the familiar sources of energy such as hydropower, solar, wind and geothermal which he said have certain limitations.
Fr. Dan has become a much sought after resource speaker among anxious Dabawenyos following earlier announcements that a coal-fired power plant to produce electricity is proposed to be put up in Davao City by Aboitiz Power, costing $400M (about P15B), providing in the process jobs for 200 people and producing 200 megawatts by 2014.
Vice Mayor Rodrigo Duterte reportedly welcomes the proposal since it will make the city attractive to more investors. However, his daughter, Mayor Sara Durterte-Carpio, said the project, like mining, will only bring more problems than benefits since it will have long-term effects in the environment.
“What the city mayor is looking for is a viable alternative to coal. She’d like to hear suggestions for an energy source that is non-threatening to public health and the environment,” Leo Avila III, city agriculture officer in charge said, qualifying the official position of the city executive.
In a recent forum arranged by a coalition of environmentalists coordinated by Barog Kalikupan Dabaw (BARKADA) at the People’s Park, Fr. Dan, using a power point presentation, said we are lucky to be in the equator (the great circle of the earth that is equidistant to the North Pole and the South Pole). This is the direct solar path which raises ocean temperatures that are ideal to make OTEC work.
“OTEC allows us to harness the tropical waters’ temperature variance from Zero degrees Celsius (about one kilometer deep on the ocean floor) to 24 degrees Celsius on the ocean surface, to produce electricity, he explained.
Citing actual working models in Hawaii, India and Tahiti, Fr. Dan said electricity produced in these coastal areas is however on a limited capacity. “OTEC technology is still undergoing studies and research, since there is more focus on the part of manufacturers of giant power plants to build for countries in temperate (colder) regions.”, he opined.
OTEC works like a conventional power plant with a turbine. The temperature variance allows for the extraction of heat which causes the working fluid to vaporize, thus turning the turbine. A tube about several meters in diameter and about one kilometer in length reaches down to the ocean floor to pick up water at close to Zero degrees Celsius, he offered a scientific explanation.
Unless an alternative to coal is soon officially submitted to the city government before 2014, Fr Dan said we just have to support the Aboitiz’ coal plant project for the moment as a compromise because we need to solve the electricity shortage right away. But when there is enough power supply, city planners and service providers should be prepared to bring in an OTEC-type technology before 2020 (ten-years from today).
Preferring OTEC over hydropower, he said the recurring prolonged drought (El Nino phenomenon) due to climate change has seriously affected the water levels of lakes and rivers in Mindanao. “We need a steady water supply to keep hydropower turbines turning. The effect is longer brownouts in many parts of the region.”
On wind power, there are no known local wind corridors strong enough to turn giant windmills (similar to those in Ilocos Norte) at a consistent rate. Solar power is way too expensive at the moment while geothermal energy from volcanic underground steam is unpredictable “you have top drill from place to place to catch enough vapor”.
Right now, OTEC technology is twice or trice more expensive than conventional power plant of the same capacity, but with more studies and researches, manufacturing costs will come down .Expenses though will be offset by eliminating the need to refuel since ocean thermal energy is inexhaustible (up to a billion years until the sun burns out of the solar system), he said
On OTEC application in the country, Fr. Dan said there is a 10-megawatt OTEC plant commissioned by the Department of Energy for Panay Island and Mindoro to be put up by a private company, Deep Water Power Philippines, Inc. There are 30 other sites identified, including Davao Oriental “It would be great to have one in Samal whose east side is known to be deep. But there’s need to make more studies on depth and temperature to see if they meet OTEC requirements”.
When told that the Aboitiz coal plant design features “a circulating fluidized bed”, he said: “We want the company to clean the coal by removing the sulfur content before burning it.
But anti-coal protesters are not convinced.”There is no such thing as clean coal”, Daryl Hannah, a movie actress and environment activist said (EMagazine, Sept-Oct 2009. Hannah even said: “Coal, the largest source of energy for electricity generation is also the largest source of carbon dioxide emissions. It is relatively cheap (if you don’t value human life) and it’s abundant, but it is the dirtiest and the filthiest source of energy around”.
Reacting to Fr. Dan’s talk, BARKADA members said this is the first time they heard of OTEC. It is like seeing light at the end of the tunnel. If OTEC is small scale at the moment, maybe we should campaign to have more hydropower plants, mini-solar, and biofuel from methane, where feasible, to help cut down on coal’s pollution in the future, Betty Cabazares, BARKADA secretariat and executive director of Kinaiyahan Foundation, Inc., noted down the group’s consensus
Ram Maxey, Edge Davao editorial consultant, quipped to this writer, “It better deliver on its promise, or OTEC will turn up just another atik (Visayan equivalent for ‘sham’).”
