California CHP Potential in 2030

Installed CHP Capacity in California
Schematic of energy flows in DER-CAM (Stadler et. al, 2010)

CEC 500-10-052, Task 2.8

The goal of this project is to stimulate in an economic and environmentally sound manner natural gas-fired combined heat and power (CHP) and combined cooling, heating and electric power (CCHP) adoption in California's medium sized commercial building sector. This project is an extension of the California CHP Greenhouse Gas Abatement project.

This analysis will not be done in isolation and will consider other distributed energy resources (DER) technologies as PV, solar thermal, electric and heat storage, which can be in competition with CHP and CCHP or supplement each other, depending on the building type and DER adoption strategy.

For this analysis the Distributed Energy Resources Customer Adoption Model (DER-CAM) from Lawrence Berkeley National Laboratory will be used. DER-CAM is a mixed-integer linear program (MILP) written and executed in the General Algebraic Modeling System (GAMS). Its objective is typically to minimize the annual costs or CO2 emissions for providing energy services to the modeled site/building, including utility electricity and natural gas purchases, plus amortized capital and maintenance costs for any distributed generation (DG) investments. Other objectives, such as carbon or energy minimization, or a combination are also possible.

The approach is fully technology-neutral and can include energy purchases, on-site conversion, both electrical and thermal on-site renewable harvesting, and end-use efficiency investments. Furthermore, this approach considers the simultaneity of results. For example, building cooling technology is chosen such that results reflect the benefit of electricity demand displacement by heat-activated cooling, which lowers building peak load and, therefore, the on-site generation requirement, and also has a disproportionate benefit on bills because of demand charges and time-of-use energy charges. Site-specific inputs to the model are end-use energy loads, detailed electricity and natural gas tariffs, and DER investment options. The diagram above shows a high-level schematic of the building energy flows modeled in DER-CAM. Available energy inputs to the site are solar radiation, utility electricity, utility natural gas, biofuels, and geothermal heat. For a given site, DER-CAM selects the economically or environmental optimal combination of utility electricity purchase, on-site generation, storage and cooling equipment required to meet the site's end-use loads at each time step.

The outputs of DER-CAM include the optimal DER/storage adoption and an hourly operating schedule for a specified year, as well as the resulting costs, fuel consumption, and CO2 emissions. The approach does not consider CHP in isolation, but rather picks optimal DER equipment combinations and their operations of typical buildings (roughly 150) in the California commercial end-use survey database (CEUS) data base (CEUS, 2006) and aggregates them to statewide results.

Aspects Considered in This Project

Berkeley lab will:

  • perform optimization runs for 2030 and update existing 2020 runs.
  • develop multiple scenarios that reflect grid decarburization, changes in equipment performance, and regulatory environment; besides CO2 emissions also NOX emissions will be considered in the DER-CAM runs.
  • consider zero net energy buildings and their impact on CHP and CCHP.
  • consider different feed-in tariffs.
  • consider the impact of CO2 pricing (e.g. cap and trade) on CHP/CCHP adoption.
  • put a special focus on the California restaurant sector since it is a major consumer of natural gas.