Seeking to diffuse peak power demands, the Caribbean Utilities Company will make major changes, starting this month, to its renewable energy program ahead of a report about allocating resources during the next 30 years.
The changes, according to CUC and regulators at the Utilities and Competition Office, will include raising the 9 megawatt cap on the Consumer Owned Renewable Energy program, known as CORE, reducing some payments to program subscribers, expanding the size of private solar arrays – called “distributed energy resources” – and allowing them to connect to the national electricity grid without belonging to CORE.
The company says further changes will follow in January when it announces fresh charges for demand billing customers – temporarily limited to large commercial enterprises.
The changes come as CUC meets steadily rising power demands – reaching a record 105.6 megawatts on Aug. 29, according to its third-quarter report earlier this month – and makes increasing investments to meet them. In July 2016, for example, the utility commissioned two new 18.7 MW diesel generators, costing $85 million, designed to last 25 years.
CUC said it will accompany its new “demand billing” scheme, based on a consumers’ highest use of power in any given month, by efforts to diffuse peak demand and control consumption, reducing pressure on both generation and distribution assets.
The scheme took shape last summer when CUC installed “smart meters” in all 29,000 customer premises, recording consumption in 15-minute intervals. Starting in January, CUC will bill its large commercial customers according to the greatest consumption in any quarter-hour interval during the month.
If consumers can spread consumption to alternate hours, however, they can reduce spikes in demand – and peak-hour charges. The company declined to say if the scheme would ultimately extend to residential clients.
The plan, explained Louis Boucher, deputy executive director for energy and utilities at the Utility Regulation and Competition Office, “has been under consideration for quite some time; there were several iterations and back-and-forth agreements and disagreements with CUC. The first iteration was submitted by CUC in mid-December 2015.”
For the moment, the price of a kilowatt hour of electricity will remain the same for most consumers, but CUC and OfReg will announce new rates in January for its 129 “large commercial clients” – defined as those using 38,800 kWh per month for three consecutive months, according to CUC.
Part of the scheme to mitigate peak demand involves changes to CORE, which requires privately owned solar-energy systems to be connected to Cayman’s transmission and distribution grid – unless the owner wishes to go “off grid,” abandoning the system entirely.
CORE subscribers sell their power to CUC, then buy it back as required at discounted rates. The program, started in 2011, has a strict 9 MW limit, however, allocated between commercial and residential clients, and 1 MW reserved for government. The size of residential solar systems has been limited to 10 kilowatts, ensuring individuals produce no more power than their own peak load.
Both the regulator and the utility say, however, they will raise the 10 kW limit on system size, raise the 9 MW cap and allow distributed energy resources unaffiliated with CORE to connect to the grid “because the new demand rate billing mechanism will enable infusion of DERs on the grid,” Mr. Boucher said.
“This is one of the consumer benefits of the new demand rate structure,” said CUC spokeswoman Pat Bynoe-Clarke. “It is designed to allow customers to save money on their bills by managing both energy and demand usage.”
“Customers wanting to have DER systems outside of the CORE program will have the demand rates available to them as soon as the program is finalized between CUC and OfReg,” she said, adding that the demand rates “will be completely different” from CORE rates, and will “be rolled out in a phased-in approach for large commercial customers in January 2018.”
She did not say what the new CORE cap or subscriber rates might be, while Mr. Boucher said no decisions had been made about limits to distributed energy resource sizes. CUC and OfReg are scheduled to start discussions this month.
Non-CORE distributed energy resources may also help CUC boost renewable-energy contributions to the power grid, recommended in the company’s Integrated Resource Plan, commissioned in August 2016 to study energy and market trends for the next 30 years. CUC has released selected portions of the plan, and officials expect full publication by the end of the year.