Many renewable energy technologies, such as wind and solar farms, require enormous amounts of land if deployed at scale, putting them in competition with other land uses, including agriculture. Critical factors in siting mega-solar plants are access to sunlight, solar irradiation, available land, market demand, local expertise, land prices and sufficient transmission infrastructure. Factors that slow down siting for large mega-solar plants include insurance, ownership, permitting, California Environmental Quality Act (CEQA) compliance and zoning problems.
The San Mateo County Energy and Water Strategy 2025 provides a detailed strategy of the county’s vision to transition to cleaner energy and water use. It focuses on optimizing energy use by deploying smart design and technologies in existing buildings. It also focuses on pilot projects using new energy-storage and microgrid technologies, load balancing in real-time, decarbonizing both the supply and demand, expanding electric vehicle infrastructure, better leveraging data, and addressing financing and funding issues. The strategy aims to enhance indoor and outdoor water conservation through policy, education and best practices. It also prioritizes the development and use of water data and expanded use of on-site recycled water, along with utility-supplied recycled water.
Potential actions for implementing this energy and water strategy include installing solar electric panels, wind turbines and solar hot water systems; developing cogeneration and alternative fuel at city facilities; and investing in clean energy systems by providing rebates and by reducing or eliminating permit fees altogether. Several cities in San Mateo County have installed or plan to install solar electric systems in government facilities.
One example of at-scale solar PV application in San Mateo County is the 200-megawatt utility-scale Wright Solar Facility in Los Banos (in California’s Central Valley), which broke ground in October 2018. Peninsula Clean Energy began providing more solar power to San Mateo County from the Wright Solar Project in January 2020, when it went online. It is, as of to date, the largest renewable energy installation ever built for a Community Choice Aggregation agency, consisting of 650,000 4-by-2-foot solar panels.[1] PCE has an exclusive 25-year power purchase agreement (PPA) with Wright Solar Park LLC to buy all of the facility’s electricity to power more than 100,000 San Mateo County homes. Image credit – here.
Community Microgrids and Mobile Microgrids
Another example of using solar PV to advance energy solutions for communities in San Mateo County is the Hoover Solar Emergency Microgrid (SEM). Microgrids support community energy needs with better economics, reliability and resilience while reducing carbon emissions. A microgrid is a local energy grid which can get disconnected from the traditional grid and operates autonomously. The U.S. Department of Energy describes a microgrid as “a group of interconnected loads and distributed energy resources within clearly defined electrical boundaries that acts as a single controllable entity with respect to the grid. A microgrid can connect and disconnect from the grid to enable it to operate in both grid-connected or island mode.”
Julie Cart of CalMatters explains, “A microgrid can be as simple as a single home operating on its own solar power, or a complex series of connections between a power source and distribution lines to end users. It can run a business, a neighborhood or even a city. It can be any size and may be fueled by renewable energy stored in batteries, or by generators run on a conventional fuel such as diesel.”
Microgrids are subsets of power systems, designed to operate both in parallel with the main grid and independently of it, in an island or independent mode, as needed. During outages, a microgrid can be decoupled from the main grid and run in a standalone, islanded mode, ensuring continuous power supply within the microgrid. Microgrids can provide combined heat and power (CHP), using the waste heat from making electricity to heat buildings that are connected to them. As they have local generation, they reduce peak demand on the overall grid and are relatively economical due to absence of delivery tariffs paid to maintain the larger grid.
The major benefits of an SEM are cost savings on a customer’s utility bill from energy usage reduction, load shifting and demand charge reduction, as well as the ability to act as a valuable community resource in case of a natural disaster. These benefits are all on top of building overall energy resilience. The two key challenges hindering SEM uptake are inadequate feed-in tariffs [2] and the lack of integrated design tools that combine demand charge reduction with off-grid response. To learn more about SEM utilizing residential and working spaces, click here.
An example of a well-functioning community microgrid in San Mateo County is the Stanford Redwood City microgrid. It leverages the resources of a top-tier research university and showcases how distributed energy resources (DER) can be configured to provide energy cost savings and resilience for campuses and buildings nationwide. The Stanford campus in Redwood City is a smaller-scale version of the Stanford Energy System Innovations (SESI) at Stanford’s main campus in Palo Alto. SESI has grid-sourced electricity and has an efficient electric heat recovery system. Stanford University’s goal is to become 80% carbon-free by 2025.
Stanford Redwood City is a new, two-phase real estate development of more than a dozen buildings located in the disadvantaged Stambaugh-Heller neighborhood within the city. This community microgrid is for a large campus with multiple buildings and meters as well as highly customized energy solutions for central heating and hot water, while the ownership model is representative of a nonprofit site owner/project beneficiary. To read more about Stanford’s journey toward clean energy transition, go here. To learn more about Stanford’s SESI project, click here.
Credit: Stanford University
The Hoover School, located in Redwood City, operates year-round to serve 700 students with approximately 100 staff employees. A full-service cafeteria, after-school programs and summer camps make Hoover an important community resource. Hoover School’s SEM design criteria have already incorporated energy-efficiency retrofits that allow for a properly sized solar PV system to be designed and installed without risk that the system may be oversized. The school also enjoys a Red Cross emergency shelter designation. The goal of this SEM is to provide power continuity in case of short-term (minutes-long) to long-term (days-long) outages.
Overview of Redwood City’s SEM sites. Credit: Peninsula Advanced Energy Community
Burlingame Solar Carport: In November 2019 Burlingame became the home of one of the largest dual-axis solar carports in the country, with each of the six trackers supporting up to 100 solar panels.
Dual-Axis Solar Carport, Burlingame.
The tracker captures light earlier in the morning and later in the evening than does a fixed tilt array, which enables it to yield 45% to 60% more energy than a fixed-tilt solar array using the same number of solar panels, at a cost of about 50% less.[3] The dual-axis design also outperforms single-axis trackers, with a 20% energy boost. The Mechatron [4] array used in this solar carport provides a levelized cost of energy (LCOE) at 7 cents per kilowatt-hour (kWh), compared with an estimated LCOE of 24 cents for a fixed-tilt design, and it will deliver a return on investment in less than four years. There are plans to add several EV charging stations, each of which can recharge up to nine vehicles. This tracking solar carport system charges electric vehicles and provides 90% of the power needed at Kahala Tower, an office building near the San Francisco International Airport.
Photo Credit: Solar Power World Online
References
[2] A feed-in tariff (FIT) program typically guarantees that customers who own a FIT-eligible renewable electricity generation facility, such as a rooftop solar photovoltaic system, will receive a set price from their utility for all of the electricity they generate and provide to the grid. Click here for more information. [3] https://cleantechnica.com/2019/11/14/burlingame-ca-inaugurates-unique-dual-axis-solar-carport/ [4] Mechatron M18KD-20