By Joseph Nyangon
How California’s New Rooftop Solar Mandate Will Build Additional Value for Its Customers
The boldest new plan yet to increase electricity generation from noncarbon-producing sources has been announced by California. Highly regarded as a trendsetter and vanguard of progressive energy policies, California became the first state to require solar power installed on all new homes. The requirement makes rooftop solar a mainstream energy source in the state’s residential market. Adopted by the California Energy Commission (CEC) as an update to the state’s 2019 Title 24, Part 6, Building Energy Efficiency Standards , the solar mandate obligates new homes built after Jan. 1, 2020 to include photovoltaic (PV) systems.
These standards represent a groundbreaking development for clean energy. Single-family homes and multifamily units that are under three stories will be required to install solar panels. The biggest impact may prove to be the incentive for energy storage and the expected uptake in energy efficiency upgrades which could significantly cut energy consumption in new homes.
But not everyone is celebrating. Critics warn that the requirement could drive up home prices overall, further exacerbating already high housing costs in the state. For instance, in a letter to CEC, Professor Severin Borenstein of the Haas School of Business at UC Berkeley warned that such a plan would be an “expensive way to expand renewables” to achieve clean energy goals . But in its order, CEC argued that the new rooftop solar mandate would save homebuilders and residents money in the long-term and cut energy-related greenhouse-gas emissions in residential buildings.
Few solar firms, homebuilders, efficiency experts and local governments fully understand the significance of the mandate. Buildings-to-grid integration experts speak of “turning residential solar into an appliance,”—the merging of rooftop solar, home energy management, energy storage, and data analytics into the next generation of high performance buildings that is expected to usher in a new era of sustainable development.
How could this new solar mandate help improve grid management so that these ‘new power plants’—clusters of buildings integrated to the grid—can respond quicker to load signals like water heating or home entertainment and thereby contribute to better system reliability? Of course, there are a lot for stakeholders to grapple with between now and 2020 as they come up with compliance solutions to address these opportunities. But this gap, especially, poses a significant challenge in how the new California’s Title 24 codes will affect the clean energy industry.
On the delivery side, First Solar Inc.—a U.S. panel manufacturer—and Sunrun—the largest U.S. residential-solar installer—could be major beneficiaries of the new building codes considering their established market positions in the state. The U.S. Energy Information Administration’s Annual Energy Outlook 2018 puts the mid-point estimate of installed solar capacity required to meet the state’s ambitious ‘50% by 2030’ renewable portfolio standard (RPS) target at around 32 GW (Figure 1). California currently has an installed solar capacity of 18.6 GW, indicating that it has only until the beginning of the next decade to find technical, business, and policy solutions to realize a 50% increase in installed PV capacity. Considering that the core elements of the requirements are now technically locked in, greater cooperation with solar industry players is needed for the success of this bold energy vision.
Here are suggestions of what needs to be done to succeed. Provision of today’s electricity services is fundamentally dependent on its transmission, distribution, and storage (TD&S) systems; these functions include business activities that support construction, operation, maintenance and in this case, overhaul California’s electricity infrastructure. According to the 2018 U.S. Energy and Employment Report (USEER), national employment in TD&S including retail service was approximately 2.35 million in 2017, with nearly 7% growth expected in 2018, mostly in manufacturing, construction, installation/repair, and operation of TD&S facilities . Using these national figures as rough benchmarks for job generation, the new solar building mandate represents a major growth opportunity for the solar industry. However, there are transmission implementation challenges that could occur in the future. Orders 890 and 1000 by the Federal Energy Regulatory Commission (FERC) require transmission providers to treat demand resources comparably with transmission and generation solutions during transmission planning. Which means that a clarification is required of whether onsite generation under Title 24 would count toward compliance with FERC’s orders.
With proper distribution and transmission planning coupled with the fact that new homes will have better efficiency overall, California could reap significant benefits from the solar mandate and pioneer in mainstreaming non-wire alternative business models associated with solar distributed generation systems. Deferring and reducing costs to capacity upgrades for distribution and transmission under a distributed utility regime, is one example. For this reason, California regulators would need to anticipate and address compliance issues that could result during the implementation period, such as concerns regarding flexibility measures, the estimated number of homes that would comply with the codes, and year-on-year market bottlenecks that may occur without rapid change in business models. Further greater stakeholder engagement and partnerships with the building industry, universities and research organizations will be needed to track progress on single–family and multi-family solar development.
Another key step is to improve the revenue model for all generation technologies to reconcile with long-term contracts. In recent years, as solar power grew in the Western Electricity Coordinating Council region, and particularly in California, future prices of solar electricity became uncertain. Today’s electricity prices are set based on the variable cost of the marginal technology. Because technologies like rooftop solar, once built have near-zero marginal costs, this could put downward pressure on long-term electricity prices. Good news for customers and the economy! But payment for TD&S may be of risk. States have been solving this problem by implementing long-term fixed pricing systems, either through power purchase agreements (PPA) or capacity mechanisms, which carry the full-price risk of the technology. California (and New York) has proposed new revenue models that balance the pace of improvement in technology cost and revenue returns. Still, adjustments in the revenue model may be necessary in the future.
The logic behind California’s solar mandate is to reposition the market so that the bulk of generation will increasingly come from customer-sited equipment. This is significant: rooftop solar is one of the most effective customer-sited solutions for accelerating a decentralized grid and greening our electricity supply. Apart from the anticipated long-term cost-reductions to the grid, we can infer that CEC may have been guided by the growing market potential of rooftop solar when crafting the new building code energy-efficiency standards. As to the question of economic viability of the standards to the grid, detailed study is needed to take into account direct and indirect impacts.
Recently, there has been mention of the mounting problem widely known as the “duck curve”—that is, the sun shines only during the day which means that the solar energy cannot meet the system’s demands when the sun goes down or cloud cover disrupts solar energy system output. This phenomenon can force utilities to ramp up non-solar generation, thereby undermining some of the benefits of a low-carbon strategy. This concern raises a question: What happens to the value of solar energy produced as new additional capacity grows? Over-generation? Because retail competition is still limited in volume to support the anticipated market growth under the new standards, the value of the additional solar generation could decline. Furthermore, the grid would need to be prepared to anticipate and handle any over-generation. CEC is aware of the duck curve problem and included a compliance credit for energy storage in the Title 24 codes to address the issue. But this may not be enough. Options for maximizing on-site solar use should be sought as capacity grows. In addition, while greater electrification of buildings is noteworthy for the utility business model, without offering incentives to residential solar producers, for instance, in the form of affordable construction materials that socializes costs over all ratepayers and introduces new products and services that guarantee long-term profitability, the latest round of CEC building codes could raise significant grid management issues and market uncertainties thus exacerbating the duck curve problem. In brief, the role of utilities in interconnecting these ‘power plants’ and managing any over-generation issues will become more critical.
Growth from the new solar mandate and steps taken to incentivize storage and energy efficiency upgrades may not produce profits for utilities in the short term. But adoption of the Title 24 codes offers utilities opportunities for greater electrification and enables them to search for cost-effective pathways to reduce carbon emissions. In a study of grid decarbonization strategies in California, Southern California Edison (SCE) found that a clean power and electrification path can provide an affordable and feasible approach to achieving the state’s climate and air quality goals . While the cost of managing the grid is an important consideration for utilities like SCE, approval of the new solar mandate is an important reminder of the changing utility industry. Power companies are developing new ways to extract value from emerging distributed solar technologies and expand customer choices. The success of the Title 24 codes will depend to a significant degree on supportive regulation. With billions of investments required for grid modernization to address the aging infrastructure issues, finding a sustainable operating model that enables utilities to recuperate costs through rates is fundamental. This is a long-term proposition and power companies should treat it as such.
Despite the challenges discussed above, California’s new Title 24 mandate represents the boldest and most inspiring building energy efficiency standards by any state to date. No doubt the questions surrounding future electricity rates, grid management issues, retail competition, investments in TD&S, design of long-term contracting via PPA mechanisms, and the impact on housing prices require significant attention. But this solar mandate can be an unprecedented energy-problem solving strategy that turns every home into a power plant as solar becomes more mainstream.
 Rulemaking on 2019 Building Energy Efficiency Standards: https://energy.ca.gov/title24/2019standards/rulemaking/
 Email response by Severin Borenstein regarding new building energy efficiency standards rulemaking to mandate rooftop solar on all new residential buildings: https://faculty.haas.berkeley.edu/borenste/cecweisenmiller180509.pdf
 The 2018 U.S. Energy and Employment Report was prepared by the Energy Futures Initiative (EFI) and the National Association of State Energy Officials (NASEO): https://static1.squarespace.com/static/5a98cf80ec4eb7c5cd928c61/t/5afb0ce4575d1f3cdf9ebe36/1526402279839/2018+U.S.+Energy+and+Employment+Report.pdf
 The Clean Power and Electrification Pathway: An exploration of SCE’s proposal to help realize California’s environmental goals: https://www.edison.com/content/dam/eix/documents/our-perspective/g17-pathway-to-2030-white-paper.pdf