Contents lists available at ScienceDirect The Electricity Journal journal homepage: www.elsevier.com/locate/tej Unintended consequences of Northern Ireland’s renewable obligation policy Destenie Nock ⁎ , Erin Baker University of Massachusetts, Amherst, United States ARTICLE INFO Keywords: Electricity network Power grid Wind Renewable energy Delivery Learning ABSTRACT Northern Ireland’s Renewable Obligation Policy radically increased the amount of small and micro-scale re- newable energy generation in the country, putting strain on the small and somewhat isolated grid. We review the impacts of the policy on the generation mix, and the resulting impacts on the power grid. We discuss a range of mitigation methods, and conclude with a recommendation that countries consider flexible policies to provide incentives for stability along with renewable energy. 1. Introduction By 2020 Northern Ireland hopes to source 40% of its final electricity consumption from renewable resources (RaISe and L & RS, 2013). To help support these goals, in 2005 the country instituted the Northern Ireland Renewables Obligation (NIRO) policy, similar to the 2002 Re- newable Obligation (RO) policy in Great Britain. Both of these schemes are a part of a UK-wide market for renewable obligation certificates (ROCs), which are the primary policy mechanism for increasing the level of renewable generation capacity in the UK. In Great Britain the RO policy led primarily to increases in the level of large-scale genera- tion, as intended (Bassi et al., 2012; Hain, 2005). Northern Ireland hoped for a similar response to their policy: the Department of En- terprise, Trade and Investment (DETI), stated that the purpose of in- creasing the ROC support for solar “is to get 100 MW–200 MW of large- scale solar PV into Northern Ireland. That will contribute to our targets, enhance our security of supply and ease costs to the consumer” (DETI, 2014b). The result of the ROC, however, was different: small- and micro- generation (SMG), with capacities between 11.05 kW and 5 MW, and below 11.05 kW respectively, increased by 365% between 2012 and 2014. This put significant pressure on the reliability and cost-effec- tiveness of the small and poorly interconnected Northern Ireland grid. While other countries have provided incentives for, and seen increases in, SMG, Northern Ireland is of particular interest since it has a rela- tively small grid with a high renewable energy target. While the entire UK RO program closed to new generation on March 31, 2017, there are lessons to be learned by looking at this case study. In this article, we complement previous work discussing the RO policy in Great Britain (Mitchell and Connor, 2004; Mitchell et al., 2006) by providing a retrospective look at a broadened RO policy in Northern Ireland. Other papers have addressed the impacts of SMG as part of other challenges, such as distributed generation (DG) more generally (Barker and De Mello, 2000; Ochoa et al., 2006; Silva et al., 2016), including concerns with specific integration methods, such as the “fit and forget” technique (Strbac, 2007). We examine the impacts of the rapid increase in the level of uncontrolled SMG in Northern Ireland, which was deployed using “fit and forget.” The remainder of the article is organized as follows. Section 2 de- scribes the NIRO policy. Section 3 discusses the impact of the NIRO on deployment of SMG. Section 4 reviews the impacts on the power system resulting from the significant increase in SMG. Section 5 discusses po- tential mitigation methods, followed by conclusions and policy im- plications in Section 6. 2. The Northern Ireland renewable obligation policy The power systems in Northern Ireland and the Republic of Ireland make up the island's wholesale electricity market, the Single Electricity Market (SEM). The SEM is regulated by the SEM-Committee, made up of representatives from the two electricity regulators on the island, playing a role similar to the Federal Energy Regulatory Commission in the U.S. (RaISe and L & RS, 2013). While the island is connected in one Energy Market, the two countries have retained separate grids con- nected by four tie-lines and interconnectors. As of 2015, there were 840,000 electricity customers in Northern Ireland, supplied by three conventional power plants using coal, oil, and natural gas, totalling 1645 MW, and 694 MW of non-SMG renewable technologies (including wind, solar, hydro, biomass, and anaerobic digestion, with wind pro- viding the bulk of the capacity). In comparison, the peak demand for http://dx.doi.org/10.1016/j.tej.2017.07.002 ⁎ Corresponding author. E-mail address: destenienock5@gmail.com (D. Nock). The Electricity Journal 30 (2017) 47–54 Available online 03 October 2017 1040-6190/ © 2017 Elsevier Inc. All rights reserved. MARK