Waste to Energy: An Emerging Trend
The Chambers Creek Regional Wastewater Facility in Pierce County, Wash. represents an emerging trend in the renewable energy market: transforming waste into energy. Wastewater treatment plants (WWTPs) are increasingly recognized as community resources for electricity, fertilizer, and heat, as waste to energy projects become commonplace in a sustainable economy.
A national leader in renewable energy and water/wastewater construction, Mortenson Construction is handling the expansion of the Chambers Creek Regional Wastewater Facility to increase its production of digested methane gas, which is one of the most effective and efficient ways for new or upgraded WWTPs to generate energy for surrounding communities.
The expansion adds two anaerobic digesters (for a total of five) and new digester gas-fueled steam boilers to heat the plant — thereby substantially reducing the reliance on external energy sources. The energy produced at Chambers Creek will be used to heat the plant year round and create 40 dry tons of fertilizer a week.
"We strongly believe that the transformation of waste into energy is a huge opportunity that will transform the renewable energy market and have a positive impact on communities," said Jim Yowan, Vice President, Mortenson Construction. "Wastewater is a continuous source of energy that will only increase over time. Many of the technologies which are needed to transform waste to energy exist today. Now is the time to tap into this underutilized resource."
According to the Water Environment Research Foundation, wastewater contains up to ten times the energy needed to treat it — providing a network of distributed, decentralized energy sources which are already constructed and piped.
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WWTPs are currently responsible for approximately 1.5-percent of total U.S. energy consumption. For some municipalities, this translates to 30 to 40-percent of the total electricity bill. Since the need for wastewater treatment will only increase with population growth, closing the energy loop is rapidly becoming a primary focus of many municipalities.
Some newer WWTPs are even net energy-positive, producing enough power through a combination of microbial activity, efficiency improvements, and mechanical modifications to offset the energy needed to operate. For example, a WWTP in Sheboygan, Wis. produces more energy than it needs to operate through a series of biogas-fueled micro-turbines and the implementation of a co-digestion program.
WWTPs can be sources of hydropower, capturing and redistributing the energy produced as water circulates throughout a plant. Some cities currently utilize the heat in wastewater much like a geothermal heat pump, resulting in billions of bulk gallons that are cool in the summer and warm in the winter.
Expansion of the Chambers Creek Regional Wastewater Facility is scheduled to be complete in the spring of 2016.
SOURCE Mortenson Construction
Major move forward for UK’s nascent marine energy sector
Although the industry is small and the technologies are limited, marine-based energy systems look to be taking off as “the world’s most powerful tidal turbine” begins grid-connected power generation at the European Marine Energy Centre.
At around 74 metres long, the turbine single-handedly holds the potential to supply the annual electricity demand to approximately 2,000 homes within the UK and offset 2,200 tonnes of CO2 per year.
Orbital Marine Power, a privately held Scottish-based company, announced the turbine is set to operate for around 15 years in the waters surrounding Orkney, Scotland, where the 2-megawatt O2 turbine weighing around 680 metric tons will be linked to a local on-land electricity network via a subsea cable.
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Described as a “major milestone for O2” by CEO of Orbital Marine Power Andrew Scott, the turbine will also supply additional power to generate ‘green hydrogen’ through the use of a land-based electrolyser in the hopes it will demonstrate the “decarbonisation of wider energy requirements.”
“Our vision is that this project is the trigger to the harnessing of tidal stream resources around the world to play a role in tackling climate change whilst creating a new, low-carbon industrial sector,” says Scott in a statement.
The Scottish Government has awarded £3.4 million through the Saltire Tidal Energy Challenge Fund to support the project’s construction, while public lenders also contributed to the financial requirements of the tidal turbine through the ethical investment platform Abundance Investment.
“The deployment of Orbital Marine Power’s O2, the world’s most powerful tidal turbine, is a proud moment for Scotland and a significant milestone in our journey to net zero,” says Michael Matheson, the Cabinet Secretary for Net-Zero, Energy and Transport for the Scottish Government.
“With our abundant natural resources, expertise and ambition, Scotland is ideally placed to harness the enormous global market for marine energy whilst helping deliver a net-zero economy.
“That’s why the Scottish Government has consistently supported the marine energy sector for over 10 years.”
However, Orbital Marine CEO Scott believes there’s potential to commercialise the technology being used in the project with the prospect of working towards more efficient and advanced marine energy projects in the future.
“We believe pioneering our vision in the UK can deliver on a broad spectrum of political initiatives across net-zero, levelling up and building back better at the same time as demonstrating global leadership in the area of low carbon innovation that is essential to creating a more sustainable future for the generations to come.”
The UK’s growing marine energy endeavours
This latest tidal turbine project isn’t a first for marine energy in the UK. The Port of London Authority permitted the River Thames to become a temporary home for trials into tidal energy technology and, more recently, a research project spanning the course of a year is set to focus on the potential tidal, wave, and floating wind technology holds for the future efficiency of renewable energy. The research is due to take place off of the Southwest coast of England on the Isles of Scilly