Davis could be carbon-neutral by 2035; community energy choice is key

From Davis Enterprise, July 5,2015

report final

Download the report as a PDF

By aggressively pursuing renewable energy — mainly solar and wind — and reducing energy use through energy-efficiency improvements to existing buildings, Davis could eliminate its direct carbon footprint by 2035. This is 15 years earlier than the carbon neutrality goal established by the city’s Climate Action and Adaptation Plan.

This is one of the conclusions of the DavisFREE report, a road map for implementation of Davis’ Climate Action Plan, recently submitted to the California Energy Commission, which funded most of the study. (FREE stands for “Future Renewable Energy and Efficiency.”)

The report showed that if all suitable rooftop space was covered by solar photovoltaic cells (PV), the result would be enough energy to supply 4 1/2 times the city’s residential electric power needs. Installing PV on some suitable city-owned land would produce enough surplus electricity to cover non-residential needs and even to export to other cities through the utility grid. And this does not include high-quality wind sources in the Sacramento-San Joaquin Delta that are within easy reach of Davis.

But wind and solar energy are variable and must be coupled with an extensive network of storage capacity to ensure that it is available when needed to meet demand. This could be, in part, vehicle batteries of plug-in cars and trucks.

But the report indicated that this is both the best and worst of times to realize this potential. It’s the best of times because solar and wind energy prices have dropped to the point of being competitive with conventional sources. Cost of storage capacity is not far behind.

And it’s the worst of times because many of the incentives — such as tax credits or the ability to sell surplus energy — are threatened. A variety of disincentives are being proposed by investor-owned utilities, such as fees for solar customers.

Community choice of energy sources, the report concluded, is the key to overcoming current and future impediments. The city is hiring a consultant to study the feasibility of Davis setting up a Community Choice Energy (CCE) agency similar to successful models currently operating in Marin and Sonoma counties. These CCEs offer customers a high proportion of green energy at a lower price than PG&E, and — for a surcharge — even 100-percent locally produced renewable energy.

A CCE could, for example, build local solar gardens and sell shares to residents and businesses that cannot accommodate solar panels on their on their property. Under current regulations, this is not allowed. Like Marin County, Davis could keep energy dollars at home by moving toward 100-percent locally produced renewable energy as a major economic stimulus for the area.

An analysis of potential for energy efficiency concluded that Davis must target existing buildings, since there will be relatively little new highly energy-efficient construction for the foreseeable future. A detailed analysis of existing building stock, segregated by vintage — years built — and other characteristics is provided.

A package of “good, better, best” energy-efficiency upgrades is proposed — with “best” including solar energy, which would result in “zero net energy” usage in homes. All packages could be cost-effective.

A marketing approach is outlined for community groups, such as Cool Davis and the Valley Climate Action Center, to use in promoting energy upgrades. DavisFREE, working with the city and PG&E, developed a highly detailed geographical information system database of energy use in Davis down to the level of neighborhoods of 20 to 30 homes.

Another analysis shows that solar water heaters — domestic, commercial and pool — can significantly reduce natural gas combustion and greenhouse gas emissions at the source. Currently, they are available at the lowest prices ever, taking into account the incentives available from PG&E, state and federal governments. Residential solar water heaters — which typically reduce natural gas usage by 30 percent or more — could cost as little as $1,100, after incentives.

Mayor Dan Wolk hailed the DavisFREE work as the next step on the road to a carbon-free Davis: “The city has adopted a Climate Change and Adaptation Plan, but we needed the specifics of what measures would be practical and efficient in achieving our goals. We have that now. The citizen task force which drafted our plan knew it could be done. Now we know how. Our job is to follow through with implementation.”

The city of Davis was the grant recipient, and Valley Climate Action Center managed the project. Richard Flood was the project manager. Leading consultants were Gerry Braun of Integrated Renewable Energy Systems Network, Rob Hammon of BIRAenergy consultants, UC Davis Energy Institute, DVN/GL-KEMA consultants and Jonathan Gemma of Aztec Solar.

Links to the full report are available at climateactioncenter.org.

— Mark Braly is a Davis resident and president of the Valley Climate Action Center.