Sustainable Power: Coming of Age
What growing pains do you need to consider before selecting your sustainable power option?
Sustainability, defined as meeting current needs without impact to future needs, is the new “it girl” of the business world: everyone wants to be seen with her. Many retail and industrial companies are looking at these solutions to enhance their green initiatives and coupling these efforts with diversity and inclusion policy changes to enhance their corporate environmental, social, and governance goals and share stock valuations. But just like growing up, when we construct anything, even with sustainability in mind, change happens.
In our favorite 80s classics, the cool kids (sustainability) and the nerds (impact) are at odds yet ultimately triumph together. Our goal when selecting sustainable options is to make the impact to future needs less overall than what it would be otherwise. Sustainability is a multi-avenue approach, but here we will focus on electric power alternatives. What are your options for sustainable power, and what do you need to consider before making your selection?
Since before the industrial revolution, we have used hydropower in one form or another. Examples include a water wheel to turn a sprocket, belt drive to mill grains, or dam to drive large turbines. Windmills, too, have been used in the same capacity and more recently attached to alternators. These all require the movement of water or wind across a series of fan blades to drive an alternator to produce electricity.
A new twist on this is what is called “pumped power.” This is a situation where water is transferred between upper and lower reservoirs to generate power through a series of turbines. The water flows downhill through the turbines to generate power and out into the lower reservoir. Then under low demand, the pump house moves the water back to the upper reservoir. This could also be deemed as a kinetic power solution with the upper reservoir as a kinetic battery.
The impact of hydropower is the control of the natural water flow by damming rivers and flooding the land behind to form a lake. The positives are flood control, a water reservoir for surrounding communities, power generation, and the ability to transport goods up and down the river. The negative is the effect of the construction of the dam and its infrastructure on the environment.
Modern wind power generation is now a long way from the windmills that Don Quixote was chasing. Today’s power generation from wind is really a modern marvel of engineering. If you have never driven by one of the trucks hauling a 120-foot long windmill blade down the road, it is quite impressive. More impressive is to see a field of these become visible in the distance and approaching them to realize the comparative size of these structures to yourself. Even more impressive is the 1.5 to 2 megawatts of power many of these can generate, enough power for about 50 households per windmill! The offshore fields that are being developed will have nacelles capable of generating even more power, upwards of 5 megawatts per unit being discussed. The drawback here is the amount of space needed to construct these fields of windmills. A field of windmills requires acres with power infrastructure and accessible equipment for operations and maintenance.
Solar power: This is when Molly Ringwald and Anthony Michael Hall become friends. Solar power can be applied to just about any structure we want. The energy from the sun is immense, and as long as it is out and shining, power is generated through the photovoltaic (PV) cells in the panels. There are two application types: residential and commercial. In residential applications, there are the classic solar panels that come to mind, but there are also applications on the market that look more like a shingle. Solar hot water generators are yet another form of this power source that can provide an alternative to or supplement the hot water system in the home and even for radiant floor heating.
The beauty of solar in a residential application is the ability to spin the meter backwards at home. That means you would be generating more power than you are using thus lowering your utility bill and helping reduce the strain on your local electric grid. The operations and maintenance of the system is very simple as there are no real moving parts. At the risk of sounding like a RONCO commercial, you can “set it and forget it” in most applications. Many solar providers are also touting the ability to have solar as a backup power source. This is where things really become interesting. We can store the energy collected and use it during an outage or when the sun is not out. Often called a solar generator, these systems use the solar panels to generate the electricity and a battery bank to store that energy and dispense it as needed.
Commercial and utility application of solar is a much bigger effort. Picture the solar farms with rows and rows of panels covering acres of land. Some of these are “active” where the panels track the sun through the daytime sky to maximize energy collected, and some are “passive” and stationary. There is another solar application that consists of a series of mirrors and lenses that focus on the sun at a single point, superheating a media to produce steam, and spin a turbine to generate electricity. The size of these applications limits them to specific areas when sunshine can be unobstructed for the longest amount of time (horizon to horizon). Commercially, there are thousands of square feet of rooftop space on many low-rise office buildings and warehouses that could be accessed for PV panel installation.
Kinetic power generation comes in a few different applications being used. One is in the form of wave energy that moves a wing up and down as the wave passes or spins a propellor when tides roll in and out to drive a generator to produce electricity. Another form of this that has been put into operation is using the Archimedes principal of lifting force. Imagine a bicycle chain vertically submerged in a column of water with a sprocket at the top and at the bottom. The pins of the chain are hollow vessels and are injected with air at the bottom sprocket, forcing them to rise. At the top sprocket, they turn over and begin to fill with water on the way down. The bottom sprocket is connected to a generator that uses braking force to generate power and control the rotation of the chain.
Also known as geothermal, thermal energy solutions have been used for heating and cooling for some time now. My current home has a water source heat pump to heat and cool our home. Power generation using the earth’s energy is a different level of geothermal heat energy collection. In this application, superheated water from the earth is used to spin a turbine and generate electricity. Then it is returned to the earth to be reheated by its core for reuse. To put it simply, the water again is used to spin a turbine to generate electricity.
While all of these sustainable power applications have their place in the effort to replace dependence on fossil fuels, the drawback is the lifecycle assessment that determines the impact of implantation on the environment. Specifically, the impact of collecting the raw materials to produce the equipment, constructing facilities, performing operations and maintenance, the demo and disposal, the recycling of the spent materials, and the recovery of any energy from those spent materials.
Just as we learned in those coming-of-age films, appearances don’t always reflect reality. Sustainable power options are not one-size-fits-all. Take into consideration the physical space, available resources, expected results, and impact on your surrounding environment before making your choice. APTIM can help you through the decision making and implementation processes. Contact us today.
Senior Project Manager III
APTIM. In Pursuit of Better.
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