In 2013, the City of Palo Alto Utilities (CPAU) committed to providing 100% carbon neutral electricity, defined as purchasing an amount of electricity from non-carbon-emitting sources (such as solar PV, wind, landfill gas, or small- and large-scale hydroelectric) that matches the total amount of electricity demand within our City on an annual basis.
To achieve this, CPAU has contracted for the construction of 13 new renewable energy generation facilities in California: five landfill gas, six solar, and two wind. These facilities allow CPAU to meet over 50% of Palo Alto’s electricity demand with renewable energy sources. During a year of normal or high rainfall, CPAU’s long-term contracts for carbon free hydroelectric power also meet at least 50% of electricity demand, enabling us to deliver 100% carbon neutral electricity.
Again, 100% carbon neutrality is an annual goal. Our ability to meet electricity demand with carbon free supply on a daily basis depends on factors such as the amount of available sunshine, wind, and hydroelectric power. In a dry year and/or on a cloudy day, renewable and hydroelectric energy supply may be insufficient to meet demand. On those days CPAU may have to buy market power from the grid, which includes unspecified sources that could be carbon-emitting generation facilities. On other days, CPAU has excess renewable and hydroelectric supply and sells the surplus energy to the market, replacing carbon-emitting generation and reducing emissions of greenhouse gases (GHGs) into the atmosphere.
Over the course of one year, Palo Alto achieves carbon neutral electricity by matching the number of megawatt-hours of electrical energy that Palo Altans use with an equal number of megawatt-hours of energy purchased from CPAU’s contracted renewable and hydroelectric generating sources This is likely in an average or high rainfall year, but in a dry year with low hydroelectric generation CPAU’s contracted sources may not provide enough non-carbon-emitting energy to achieve carbon neutrality. In that case, CPAU would purchase Renewable Energy Certificates, or RECs, which are equal to the environmental attributes of renewable energy, to ensure that 100% of our electricity demand is matched by renewable or hydroelectric supply and is carbon neutral. View an EPA video explaining RECs.