An Integrated Market for Electricity and Natural Gas Systems with Stochastic Power Producers

In energy systems with high shares of weather-driven renewable power sources, gas-fired power plants can serve as a back-up technology to ensure security of supply and provide short-term flexibility. Therefore, a tighter coordination between electricity and natural gas networks is foreseen. In this work, we examine different levels of coordination in terms of system integration and time coupling of trading floors. We propose an integrated operational model for electricity and natural gas systems under uncertain power supply by applying two-stage stochastic programming. This formulation co-optimizes day-ahead and real-time dispatch of both energy systems and aims at minimizing the total expected cost. Additionally, two deterministic models, one of an integrated energy system and one that treats the two systems independently, are presented. We utilize a formulation that considers the linepack of the natural gas system, while it results in a tractable mixed-integer linear programming (MILP) model. Our analysis demonstrates the effectiveness of the proposed model in accommodating high shares of renewables and the importance of proper natural gas system modeling in short-term operations to reveal valuable flexibility of the natural gas system. Moreover, we identify the coordination parameters between the two markets and show their impact on the system's operation and dispatch

Determining Utility System Value of Demand Flexibility From Grid-interactive Efficient Buildings

This report focuses on ways current methods and practices that establish the value to electric utility systems of distributed energy resource (DER) investments can be enhanced to determine the value of demand flexibility in grid-interactive efficient buildings that can provide grid services. The report introduces key valuation concepts that are applicable to demand flexibility that these buildings can provide and links to other documents that describe these concepts and their implementation in more detail.The scope of this report is limited to the valuation of economic benefits to the utility system. These are the foundational values on which other benefits (and costs) can be built. Establishing the economic value to the grid of demand flexibility provides the information needed to design programs, market rules, and rates that align the economic interest of utility customers with building owners and occupants. By nature, DERs directly impact customers and provide societal benefits external to the utility system. Jurisdictions can use utility system benefits and costs as the foundation of their economic analysis but align their primary cost-effectiveness metric with all applicable policy objectives, which may include customer and societal (non-utility system) impacts.This report suggests enhancements to current methods and practices that state and local policymakers, public utility commissions, state energy offices, utilities, state utility consumer representatives, and other stakeholders might support. These enhancements can improve the consistency and robustness of economic valuation of demand flexibility for grid services. The report concludes with a discussion of considerations for prioritizing implementation of these improvements

The emergence of markets in the natural gas industry

As countries have deregulated prices and lowered entry barriers in the natural gas industry, many new participants have emerged, promoting competition in the newly created markets. The increased competition has benefited everyone through more efficient pricing and greater choice among natural gas contracts. Four distinctstructural models have emerged in the industry's restructuring. The traditional model (a vertically integrated industry) has been increasingly replaced by models that decentralize the industry along horizontal and vertical lines. With increasing decentralization, regulation of the industry focuses on the pipeline transportation and distribution, the industry segments with natural monopoly characteristics. Regulation aims to protect both end users and participants in the deregulated segments from the market power of companies operating in the monopolistic segments. As a result of deregulation, two major markets emerge: the natural gas market (which facilitates the trading of natural gas as a commodity) and the transportation market (which enables market participants to trade the services needed to ship natural gas through pipelines). Competition and open entry are crucial for these two markets to function efficiently. The transportation market is affected by the market power of pipeline companies, but resale of transportation contracts brings competition to this market and facilitates the efficient allocation of contracts. Intermediaries and spot markets promote efficient pricing and minimize transaction costs. Markets have become more complex with deregulation, and trading mechanisms are needed to ensure the simultaneous clearing of natural gas and transportation markets at minimum cost to the industry. Two main trading models guide transactions: the bilateral trading model (which relies on decentralized bilateral negotiated between market participants) and the poolco model (which relies on a centralized entity to coordinate transactions). Properly applied, both models lead to the same outcome. The bilateral trading model has dominated because of its simplicity of implementation, but the poolco model has great potential once problems of sharing and processing information are addressed.Environmental Economics&Policies,Water and Industry,Economic Theory&Research,Markets and Market Access,Oil&Gas,Water and Industry,Oil Refining&Gas Industry,Markets and Market Access,Access to Markets,Oil&Gas

Integration Costs Revisited – An economic framework for wind and solar variability

The integration of wind and solar generators into power systems causes “integration costs” – for grids, balancing services, more flexible operation of thermal plants, and reduced utilization of the capital stock embodied in infrastructure, among other things. This paper proposes a framework to analyze and quantify these costs. We propose a definition of integration costs based on the marginal economic value of electricity, or market value – as such a definition can be more easily used in economic cost-benefit assessment than previous approaches. We suggest decomposing integration costs intro three components, according to the principal characteristics of wind and solar power: temporal variability, uncertainty, and location-constraints. Quantitative estimates of these components are extracted from a review of 100 + published studies. At high penetration rates, say a wind market share of 30–40%, integration costs are found to be 25–35 €/MWh, i.e. up to 50% of generation costs. While these estimates are system-specific and subject to significant uncertainty, integration costs are certainly too large to be ignored in high-penetration assessments (but might be ignored at low penetration). The largest single factor is reduced utilization of capital embodied in thermal plants, a cost component that has not been accounted for in most previous integration studies