Renewable energy refers to the energy that is generated mostly from natural resources. Alternatively, they can be generated from processes that can be constantly replenished. This is not a new technology as misconceived by many. Harnessing the power of nature has been used for heating, transportation, lighting, and more since long. The only new thing is that today we have innovative and cheap means of capturing and utilizing these resources.
But, a few decades ago, nobody would’ve guessed that one day we will be using filthy sewage as a source of renewable energy.
Alternative energy is a term used for an energy supply that’s an alternative to using fossil fuels. Generally, it suggests energies that are unconventional and also have low environmental effect. The term option is used to contrast with fossil fuels according to several resources. By most definitions other energy does not harm the environment, a distinction that separates it from renewable energy which may or may not have significant environmental impact.
But today we utilize wastewater to create energy because global warming is catching up with us and we’re running short of time. And of course, there’s plenty of sewage around anyway. Take a look at the UK and US for instance; the numbers of plants that have undertaken the sewage to energy treatment facilities are not few at all. More of these are emerging with time.
What is Biomass?
Biomass, is a renewable natural matter, and can consist of biological material derived from living, or recently living organisms, such as wood, waste, and alcohol fuels. One major source of biomass is the sewers, which is great because it means that as these waste components which would have otherwise cause sewer blockage if large amounts are left untreated, are being targeted as a useful source of energy.
Wood energy is derived both from harvested timber as a fuel and from wood waste solutions. Waste energy can be produced from municipal waste, manufacturing waste, and landfill gas. Biomass alcohol gas, or ethanol, is derived almost exclusively from corn.
What is Biodiesel?
Biodiesel is fuel made from plant oils that can be utilized in diesel engines. They are typically made of renewable organic raw materials such as soybean or rapeseed oils, animal fats, waste vegetable oils or microalgae oils.
How is energy from sewage generated?
Sludge-to-methane is the most common method of generating energy from sewage, and this treatment has the most mature technology for the purpose today. Yes, we’ve learned in school that methane is a greenhouse gas and that it produces carbon dioxide on combustion. But don’t fret; sewage generated methane that is present in a blocked main drain line does not add on to any greenhouse gases, hence not to the issue of global warming. It’s the same with the case of biofuels.
Why? Because the methane that is produced as a part of the carbon cycle of sewage treatment. Hence this method is opted by quite a few plants, such as the one in Reno, Nevada.
Real plants powered by renewable energy
- England has a plant called the Oxfordshire where they treat sewage from fourteen million Thames Water customers. It further generates methane gas which is identical to natural gas in its chemical composition, which can be used for cooking and heating. As of 2011, this plant was supplying natural gas to over 200 households. Thereafter, shocked by the results, the UK’s national gas grid conducted a study which estimated that if similar plants operated in all of the 9,600 waste treatment facilities which were spread across the nation, it could supply 15% of the UK’s demand for natural gas.
- There is biogas fired power plant at the Western Treatment Plant in Melbourne which generates electricity through the combustion of biogas, which is confined under covers placed over sewage treatment lagoons. The plant uses biogas to meet almost all of its electricity needs. It generates around 71,500 MW of clean energy each year approximately, which avoids 87,000 tonnes of carbon dioxide emission through the combustion of fossil fuels. When there is more energy produced than required, it is stored in the electricity grid for future consumption.
- Another plant in Melbourne which uses the biogas is the Eastern Treatment Plant. Most of the electricity consumption is powered by biogas including cooling and heating. The seven of the plant’s generations also run on Biogas.
- Come to Colorado, and the city of Grand Junction will shock you. There is a Persigo Wastewater Treatment Plant which processes 8m gallons of human waste into renewable natural gas, also known as biomethane. This is used to fuel about 40 fleet vehicles.
- One of the most enormous renewable energy projects happen to be in Southern California where sewage is used to produce electricity, heat, and hydrogen for cars. Here again, methane is produced first which is then used in a fuel cell to generate electricity where hydrogen is generated as a byproduct. This hydrogen is then used in a fuelling station to supply electric cars that run on hydrogen.