Chances are you've recently come across a story heralding solar panels, wind turbines, or energy storage as the solution to preparing our power grid for a low-carbon future. Each of these technologies will move us toward this goal, and we must utilize every opportunity at our disposal to get there.
Soon, millions of people will be living in cities that are maintained by renewables and will be charging batteries to both balance those renewables and power activities throughout our everyday lives -- including our daily commute. It's crucial that we start preparing our grid now for what lies ahead, while also fixing some of today's biggest issues. Finding a truly sustainable solution means looking beyond just one potential "magic bullet" answer to considering the energy landscape from a bird's eye view.
Understanding the Grid and Why It Needs to Change
The grid is constantly being subjected to spikes in energy usage and is structured to accommodate our worst-case maximum demands. This is typically during the hottest days of summer when air conditioners cities-wide go on full blast and energy consumption is at its max. Summer brownouts and blackouts are a significant risk during these high levels of consumption that can push many grids to their limit or beyond.
Often, renewables such as solar are at their highest output during these times, but this generation isn't guaranteed due to what is called "intermittency," whereby generation drops unexpectedly. When this happens, traditional generation would be required to ramp up to compensate and maintain quality of supply. The problem: Carbon-based power plants cannot ramp up quickly enough to cover the shortfall. An extreme example of this is when a renewable generator goes from 100 percent output to 0 percent output in a matter of minutes, but large-scale generators can only change load by a small percentage per hour. This leaves a difficult gap to fill.
Traditionally, utilities have turned to "peaker plants" to supplement supply at a premium cost since they spend large parts of the year, or even multiple years, in idle. This is a poorly utilized asset that utilities, business owners, tenants, rate payers and consumers are paying for. Chemical battery storage has been seen as the savior to the intermittency problem and an alternative to peaking generators. Battery costs have continued to fall and will no doubt be a critical part of the future smart grid. However, we need to consider a range of other mechanisms that may allow us to speed the transition and reduce costs even further.
The Energy You Don't Use
The cheapest energy is the energy you don't use in the first place. Taking a look around a modern office, we see one of the biggest impacts and contributors to modern energy savings -- LEDs. LEDs in our lighting and computer monitors have made a sizable impact on efficiency. The next step is to implement the next level of savings by finding faults, installing efficient appliances and a range of other measures.
It is interesting that despite our efforts to reduce waste, improve efficiency and introduce more renewables to the grid, the need for energy storage persists.
Energy Storage by Many Means
Energy storage has become a hot topic usually mentioned in conjunction with renewables. While batteries are the most discussed type of building-level storage, they are expensive and might not be the right fit for every building or region.
Chilled and hot water thermal storage tanks, compressed air storage, and ice banks represent viable and affordable alternatives to battery power. These can be installed for significantly less than a battery, cost less per kWh and can easily have more than double the lifespan. Consider that 1,000 liters of water can store around 10kWh of energy at practically no cost, whereas a battery of similar size can cost more than $10,000 once fully installed.
By storing energy in the medium which it is used, such as ice for cooling, these systems offer better round-trip efficiency -- a measure of the amount of energy lost between charge and discharge -- than battery storage, which is around 75 percent. However, before buildings start implementing storage, they should be aware of the storage they already have.
Let Your Building Do the Work
It may be surprising, but the building itself can be treated as a storage device. When efficiently utilized, a building's infrastructure -- all bricks, concrete, steel and wood -- can serve as a resource. A building's mass can trap cooling and heating, keeping a building comfortable during interruptions to renewable output.
Intelligent energy management systems can help with this by making automatic adjustments to operations based on a building's characteristics and other real-time conditions so buildings run at optimal efficiency. These systems take into account typical energy usage patterns and other variables such as signals from the utility, weather forecasts and occupant comfort to make adjustments to heating and cooling operations that generate huge savings. By using artificial intelligence, the software is able to map out a path to savings that would otherwise not be possible.
This technology is more than just a logic-based, pre-determined-response set up. It is able to understand the situation the building and grid are facing and make changes that are beneficial 10-15 moves into the future instead of making changes for instant gratification that could void a future opportunity.
Integrating For a Sustainable Future
It's this type of intelligence that needs to be in place before adding other systems to a building and the grid to ensure that all platforms work in harmony with each other. Buildings that can control lighting, HVAC and storage through a unified system will benefit the overall grid by making sure that technologies aren't working against each other.
What is happening within the building is a microcosm of what should also be happening within the entire grid. Every building will need to work together in the future. What's efficient for one building in the moment might not be best for the grid in the long-term. With a connected system in place, buildings will be able to see the complete energy landscape in its entirety and make decisions that will benefit itself as well as the greater good of the grid.
Looking to the Future
According to IHS Automotive, worldwide production of EVs will increase by 67 percent this year. The charging of these vehicles adds yet another variable to how energy loads should be shaped within buildings. If everyone plans on charging their cars during the work day, this could cause an even higher peak demand. If we all charge in the morning, it could add a new peak to our grid. We need to plan for this eventuality.
Our energy future is poised to become unprecedentedly complex with this widespread adoption of electric vehicles (EVs), further integration of renewable energy sources and more. Having intelligent software in place that can serve as a central point for all energy decisions within a building will make adaption to future changes easier. EVs will become just another variable. The same principle applies to renewable energy. By looking at weather patterns, it knows when solar will be producing less and can make adjustments before the drop-off in generation happens.
This complex symphony conducted by artificially intelligent systems will usher in a new era of smart cites. These self-sufficient, grid-responsive networks created within buildings, between buildings and in collaboration with the utility they work with, will ensure consistent energy usage, stable demand, a thriving electric grid, and most importantly, an attainable, sustainable future.