Renewables have gained strong market penetration in recent years – so much so that the Trump administration’s love affair with coal and other fossil fuels will not slow down the momentum. Cities and businesses are adopting aggressive goals to achieve 100 percent renewables. Furthermore, renewable energy is good business. It is an expanding industry that employs nearly 3.5 million Americans.
Solar is popular on both the consumer and utility sides of the meter, while wind remains more of a utility scale resource. According to the Solar Energy Industry Association, solar has experienced an annual average growth rate of 68 percent during the past decade. Energy storage is growing in popularity on both sides of the meter.
According to Greentech Media and the Energy Storage Association, 41.8 megawatts of energy storage were deployed across the U.S. in the third quarter of 2017. This represents 46 percent year-over-year growth, and 10 percent growth over the second quarter of 2017. Greentech Media expects the U.S. energy storage market to grow to roughly 2.6 gigawatts by 2022, almost 12 times the size of the 2016 market.
Incentives and rebates have certainly helped spur growth. Solar continues to enjoy a 30 percent federal tax investment credit through 2019 and energy storage that charges directly from solar is eligible for the same tax credit. Any home or business owner with a tax appetite can get 30 percent off the total cost of their solar plus storage system.
How does storage work? Energy storage captures sun power from solar panels during their limited production hours, so it can be used later in the day when the sun is not shining and the grid is stressed by heavy evening use. This strategy is known as solar self-supply. Other strategies include:
- Renewable Energy Smoothing – storage brings predictability to intermittent renewables such as solar and wind.
- Demand Charge reduction – Commercial & Industrial (C&I) facilities often see a large portion of their bill (40-50 percent) in the form of demand charges. Demand is a surcharge based on the 15 to 60 minutes of highest intensity energy use during a billing cycle. Discharging batteries during times of peak demand targets one of the most expensive charges C&I customers face.
Energy storage can also keep solar operating during an extended power outage, providing much needed resiliency. We need look no further than last hurricane season in the Southeast, Puerto Rico and the Caribbean to appreciate the need for resiliency.
In normal operations, energy storage can be tied to charge off the grid, or directly from solar panels. By having the capability to switch over to a Microgrid capability during a power outage, solar can continue to generate clean energy and provide back-up power through the use of batteries and, in some cases, generators. This approach works for homeowners as well as C&I facilities that lose millions of dollars in production during an extended outage.
Keeping essential facilities running like hospitals, nursing homes and community shelters is crucial during a natural disaster such as a hurricane, tornado, earthquake or other cataclysmic event. Properly designed energy storage systems with intelligent optimization software can do just that.
Depending on the desired strategy, energy storage can be sized first by looking at the building consumption patterns, the tariff structure and the ongoing energy-use profile. If resiliency is a key objective, it is important to determine the size of critical loads that must remain operational during a disaster. This approach can be used for modeling back-up loads for businesses or individual homes. Intelligent software can model a range of scenarios.
How to move from concept to practice when considering grid resiliency
The city of San Francisco received a U.S. Department of Energy grant to create a roadmap for deploying solar with storage for resilience.
The primary goals of the project were to accelerate the deployment of solar nationwide and create a roadmap for using solar as a viable tool for energy security in the event of an emergency. Here are the steps that the project team followed:
- Researched San Francisco’s current disaster preparedness plans with respect to electricity needs of buildings.
- Facilitated stakeholder engagement through the formation and management of a working group.
- Developed an approach for using existing solar systems during an outage.
- Developed a solutions roadmap that addressed technical and economic barriers.
- Developed an emergency load assessment tool.
- Disseminated a Best Practices Manual to regional, state and national networks.
In Spring 2017, the project team released SolarResilient.org, a free online calculator created to help size batteries to ensure a building has enough power to run critical loads during emergencies. The calculator allows building owners, energy professionals and city departments across the country to develop preliminary solar plus storage equipment sizing estimates on a portfolio of buildings so they can incorporate optimum scenarios into their energy resilience strategies.
