'Waste to Energy' in T&T

If the Government of Trinidad and Tobago (GOTT) is to be taken seriously about its commitments to achieving 10% renewable energy production by 2021 then we must all get behind them and make sure it is not just “empty words”. Trinidad and Tobago’s electricity consumption in the year 2014 was approximately 866 MWh. In 2016, the largest electricity consumer, Arcelor Mittal, closed its factory which greatly reduced the amount of electricity the power generation companies needed to supply. Due to this the electricity to be produced by renewables to make up the 10% of the nation’s power has also significantly decreased making it easier to achieve. There are many various technologies available that are relevant to Trinidad and Tobago such as wind, solar and biomass that can generate power but the GOTT has chosen to explore the potential of a ‘waste to energy’ power plant.

There has been a serious problem in the way we dispose of our waste in Trinidad and Tobago. The landfills at Forres Park, Beetham and Guanapo are all operating over the maximum capacity and waste being produced over the years have been increasing. The average daily intake of waste are 490 tonnes, 928 tonnes and 270 tonnes respectively at these landfills. Instead of just dumping our garbage at landfills which can pollute the surrounding environment, we can put it to greater use, such as, to generate electricity. One might wonder, “how is this classed as a form of renewable energy?”. The basic principle behind renewable energy technologies is to convert natural resources into some form of useful power. The waste that is generated every day from households and businesses can be sorted and placed into an incinerator or gasifier to drive turbines to generate power.

Forres Park landfill (courtesy Trinidad Express)

‘Waste to energy’ power plants operate 24 hours a day and 7 days a week. This form of renewable energy is not intermittent in nature and can be taken advantage of any hour of the day. Waste is transported to the plant by trucks which dump it into a large collection area to be mixed to keep the consistency of waste being used for incineration or gasification. The waste is then added as required to the incinerator which can reach temperatures between 1000˚C and 1200˚C. The heat generated is used to convert water in the furnace walls to steam. This high pressure steam is sent to turn turbines, which then drives a generator to produce the electricity. Not all the waste can be incinerated and the remaining material called ‘bottom ash’ is made up of metals such as aluminium and copper along with sand. These are cleaned and separated with the metals being sent to scrap iron recycling plants and the sand, which can be useful in the asphalt and concrete industries, are sent out to the relevant companies. 

2D model of processes inside a 'waste to energy' power plant 

However, the challenging part of the entire process is what will be done to the toxic gases generated which are extremely harmful to the environment. The gases are first filtered so that flying particles are collected and taken out at an early stage in the process and can also be used as a filling material in asphalt. The rest of gasses are further filtered in a closed loop water system and pure steam is then released into the air via a chimney. Only 1% of the materials entering the plant is not used and it is to be disposed of safely at the landfill so it does not pollute underlying aquifers.

A ‘waste to energy’ plant that can convert 880 tonnes of waste per day can generate up to 20MW of power or more. This is possible as our total waste collected per day is 1688 tonnes. There are many reasons to seriously consider the avenue of investing in a ‘waste to energy’ power plant as the heat generated by the plant can also be used in the desalination of sea water. Many jobs will be created during the construction and the operation of the plant as well as the reduction in the space required to store waste in our landfills.

Nevertheless, in order to successfully accomplish this project, policies will have to be revised to accommodate the integration of renewable energy technologies into our electricity grid system. As well as, a system should be in place where citizens sort the waste before collection at households by placing different waste in allocated waste bins, so that recyclable waste is not transported to the power plant. Furthermore, since there has been steady increase year after year in waste production citizens must exercise greater caution with their contributions in order to reduce.

So Trinidad and Tobago are you ready?