Heiner Markhoff, GE Water & Process Technologies, USA
Heiner Markhoff, president and CEO of GE Water & Process Technologies
It is often said that an economy runs on oil, but it could also be said it runs on water. Simply put, electricity is needed to power the economy, however in most cases power cannot be generated without water. Conversely, electricity is needed to treat water. It is therefore critical that we consider the nexus between water and power. In a world where water is an increasingly scarce resource, policies supporting the conservation and recycling of water for power generation must become an urgent international priority.
The Kyrene water reclamation plant in Arizona, USA utilizes a ZeeWeedTM membrane filtration system
It is estimated that 15 per cent of freshwater worldwide is used for industrial purposes. Oil companies calculate that they use between 7-10 barrels of water to process one barrel of crude oil from the well to the gas pump. But as the industrial sector grows, so will demand for power and water.
Power plants circulate significant volumes of water in the process of generating electricity, but actually consume a small amount of water relative to other uses in the modern world. In the United States, for example, water demands related to electricity production have almost tripled since 1995, and nearly 90 per cent of all industrial water is used for the generation of power. And in France, power generation has become the largest consumer of water. In the European Union as a whole, energy production accounts for 44 per cent of total water abstraction.
It is clear that water reuse is not as prevalent as it is should be. We believe the industry can reuse much more water than it does today. One effective way to achieve water savings is to co-locate water treatment facilities and power plants. In addition, it is clear that we can harness more municipal wastewater to provide for industrial needs. Rather than municipal wastewater plants treating and discharging water back to a receiving stream, by adding an incremental treatment process, either at the wastewater plant or at the industrial plant, this water can meet the needs of many industrial processes, including power plant cooling.
A US Department of Energy sponsored study looked at 110 new power plants proposed for construction in 2007. It found that municipal wastewater treatment plants located within a 40 km radius of the proposed power plants could easily satisfy 97 per cent of the power plants’s cooling water needs. Moreover, reusing water often reduces energy consumption in and of itself. A 1000 MW power plant, which installs a water reuse system for cooling-tower water recovery will reduce the energy otherwise needed to produce, distribute and treat fresh water by a net 15 per cent.
The expanded Kyrene facility is helping the US state of Arizona to solve its water shortage problem
Incentives to collocate municipal wastewater treatment plants and power generation plants in the future would go a long way towards providing innovative sources of water, reducing freshwater withdrawal and energy consumption. However, while advanced water reclamation technologies already exist, the motivation to deploy them often does not. Today, it is often less expensive for plant operators to pull water from a river or a well, or even to draw potable water from a municipal system, than to treat and reuse it.
Barriers to water reuse and water recycling systems come in many forms: technological, financial, and regulatory. In fact, regulations intended to protect the public or programmes providing services to the community may have the unintended effect of discouraging or even preventing voluntary water reuse.
One of the biggest barriers to water recycling is a municipal, state, or regional water code that does not recognize the use of recycled water. Local regulations requiring that all water used in the community meet potable water standards can hinder or prevent water reuse.
In the global power generation sector, policy incentives have been primary drivers for growth in renewable energy capacity. Similar legislation and incentives to jump-start the widespread deployment of new water recycling technologies are now needed. Incentives are particularly important since new technologies are often more expensive compared with current technologies, which have developed infrastructure and economies of scale.
Water recycling and reuse is most common in communities that face limited water supplies. A number of countries around the world have enacted incentives to encourage more reuse. Many of their responses combine aggressive water conservation measures with water recycling initiatives to address current, as well as future water scarcity. Education and outreach is, for example, generally perceived as critical to advancing water recycling, not only to encourage its use, but also to overcome any public concerns about the safety and quality of recycled water.
The opportunity to achieve these goals is within our reach. Technology advances in both power generation and water treatment are already reducing the amount of water necessary to produce electricity. The cost of new technologies has declined, making water security, through diversification of water sources, a reality.
New generation membranes and improved management practices have contributed to reducing the cost of seawater desalination by a factor of three in the past decade. The cost of producing desalinated or decontaminated water through reverse osmosis (RO) is around $0.45-0.60 per m3 and has become cost effective for many countries with critical water security conditions.
Ignore the power-water linkage at your peril
Global water use is expected to rise by up to 30 per cent in developing countries and more than ten per cent in industrialized countries by 2025. The population living in water-stressed areas is set to double over the period 1995-2025, and by 2030 some two-thirds of the world’s inhabitants may experience moderate to high water supply concerns. At the same time, global electricity demand is expected to double by 2030.
Ignoring such linkages between water and energy are likely to become increasingly counterproductive, especially in social, economic, and environmental terms. Energy and water truly are co-dependent resources, critical to the functioning of modern economies and to life itself. We must respect this inter-dependent relationship so that we can better manage the ways we acquire and use these resources. In doing so, we shall build a foundation for more long-term growth in the years ahead.
At GE, we also see the importance of achieving water and energy efficiencies across our own portfolio of businesses. With respect to energy, we have committed to reducing our greenhouse gas emissions by 30 per cent on a normalized basis allowing for projected growth of our businesses or one per cent in absolute terms from 2006 to 2012. In addition, we have committed to reducing our water consumption by an absolute 20 per cent during the same time frame. At the same time, we are working with our customers around the world to help them achieve similar efficiencies.
In addition, GE is doubling its level of investment in clean research and development from $700 million in 2005 to more than $1.5 billion by the year 2010. This research effort is focused on helping our customers meet pressing energy and water challenges.
Water-related issues often lead power plants to operate at sub-optimal levels and increased cost. To meet such challenges there is a broad array of water solutions tailored to power generation applications. They enable customers to maximize output and profits through more productive processes, fewer outages, less maintenance, reduced costs and assured environmental compliance.
Water is used for many processes in a power plant, but owners and operators of power generation assets may underestimate the impact water-related issues have on a plant’s overall output, reliability, availability and cost. The right mix of water chemistry, equipment and services is critical for operational, financial and environmental performance.
One example is the mobile water treatment plant GE supplied to a UK power plant on an emergency basis. The plant’s regular supply of demineralized water was disrupted, and without a 90m3/h supply of water for a high-pressure boiler, it would have had to shutdown.
A nearby river was a potential solution but its fluctuating quality made water treatment difficult. We built a temporary mobile modular treatment system that was tested and fully operational within four days of arrival on-site, manned by GE field service representatives. The river water was dosed with acid, biocide and coagulant, then was sent to a 50 m3 contact tank. From there it was pumped onto two MobileFlowTM filter trailers and then sent to two GE MobileROTM units running at 90 per cent rejection (the level of filtration) and 70 per cent water recovery rates. The treated water’s quality exceeded customer expectations.
Advanced cooling is another key concern. The pressures to achieve improved reliability and performance of cooling water systems while reducing cost have always existed. When left uncontrolled, corrosion and deposition can lead to unscheduled maintenance and turnarounds, production bottlenecks and significant capital expenses. Further without effective processes and treatment to control microbiological growth, businesses could expose their employees and community to health risks.
Today, this is all compounded by an ever increasing need to reduce water consumption and be a better environmental steward.
How Much Water Does It Take to Make Electricity?
Remember when you were a kid and your parents made a big fuss about turning off the lights when you left a room? Who knew that, besides adding to the monthly electric bill, keeping a single 60 W lightbulb lit for 12 hours uses as much as 60 litres of water?
Researchers at the Virginia Water Resources Research Center, in the US, have found that fossil fuel fired thermoelectric power plants consume more than 500 billion litres of fresh water per day in the United States alone. That translates to an average of 95 litres of water to produce 1 kWh of electricity. Why so much?
Water plays a number of roles in energy production, including pumping crude oil out of the ground, helping to remove pollutants from power plant exhaust, generating steam that turns turbines, flushing away residue after fossil fuels are burned and keeping power plants cool1.
GE’s desalination plant in Spain is providing Benidorm with a dependable supply of water of consistent quality
By far the greatest need for water comes from the cooling of turbines in the thermal power plant. The amount of water required depends on the type and size of power plant, and especially on the kind of cooling. The two main types are ‘once-through cooling’, in which water is used to cool the turbines and then discharged directly back to a waterway or pond, and ‘tower cooling’ in which the turbines are cooled and the hot water is sent to a cooling tower, reused several times and eventually discharged from the plant.
One of the advantages of tower cooling is that water is discharged back to waterways at a much cooler temperature, thereby protecting aquatic ecosystems and downstream water uses. Another advantage is that it allows the recycling of water within the power plant, and this means that tower cooling requires less than three per cent of the water withdrawals of once-through cooling per unit energy produced. Although tower cooling requires much lower withdrawals, it consumes twice as much water per unit of energy as once-through cooling because much more water is evaporated in the cooling towers2.
GE’s Advanced Cooling Solution (ACS) is a series of packaged technologies to monitor, control and maintain cooling systems with greater efficiency, reliability, and predictability. It lowers total cost of ownership and minimizes the environmental impact of plant operation. The ACS combines state-of-the-art TrueSenseTM monitoring/control capabilities with patented GenGardTM chemistry and the most complete portfolio of filtration solutions and other products for sidestream softening, filtering and wastewater reuse.
Water use can be a significant issue in energy production, particularly in areas where water is scarce because conventional power plants also use large amounts of water for the condensing portion of the thermodynamic cycle. For coal fired plants, water is also used to clean and process fuel.
GE offers solutions to other water related power plant concerns as well. When dealing with the issue of water scarcity, our technologies enable the use of industrial wastewater, municipal wastewater, seawater/brackish water, surface and groundwater. For ultrafiltration (UF), GE provides a complete membrane package, including one of the industry’s most experienced team of specialists and the broadest range of packaged UF and RO systems for boiler feedwater.
With regard to effluent quality, our Advanced Biological Metals Removal Process (ABMetTM) uses naturally occurring microbes to chemically reduce and precipitate target compounds out of solution or to convert them into their harmless chemical components. An example would be turning nitrate into nitrogen gas. It is the only commercially proven technology for removing low-level selenium and heavy metals from discharged wastewater streams, such as from fluidized gas desulfurization.
And for fuel and combustion solutions, GE offers a variety of approaches to help fossil plant owners reduce slagging and fouling, improve combustion, abate coal dust, improve emissions, and manage vanadium corrosion.
We believe that even governments in water scarce regions are looking for ways to expand water recycling and reuse. On 28 May last year, GE issued a white paper entitled ‘Addressing Water Scarcity Through Recycling and Reuse: A Menu for Policymakers,’ which draws on representative examples from around the world.
Heiner Markhoff is president and CEO of GE Water & Process Technologies. The company brings together experienced professionals and advanced technologies to solve the world’s most complex challenges related to water availability and quality, increased productivity and cost reduction, and environmental regulations. The business also has the unique capability to deliver integrated solutions in concert with other GE Energy business units.