A group of Massachusetts lawmakers who visited Canadian hydroelectric facilities in March were ferried there on the dime of a public utility company that runs a power line between Quebec and Ayer, according to documents obtained by the Herald.

The cadre of elected officials, which was made up of three senators and eight representatives, touted the three-day trip as an “alternative energy fact finding” mission.

A spokesperson for Senate budget writer Michael Rodrigues initially told the Herald that senators were responsible for paying for their transportation, lodging, and expenses.

But a batch of ethics disclosures show part of the trip’s tab, including flights to and from and meals at various sites, was picked up by Hydro-Quebec Energy Services, a U.S. affiliate of the public utility company Hydro-Quebec that runs a power line between Canada and Ayer.

Each of the lawmakers disclosed that Hydro-Quebec Energy Services paid for $1,308 in trip-related expenses, according to copies of the ethics disclosures on file with the State Ethics Commission and House Clerk’s Office.

In an ethics filing dated March 11, or two days before the trip, Rodrigues said he planned to visit Hydro-Quebec facilities in Canada to “learn about the interconnections supporting the New England power system,” including the power line that runs to the Sandy Pond substation in Ayer.

“The commonwealth faces a number of challenges in energy policy, including, but not limited to, the high energy costs facing residents and the need for a reliable, competitively priced supply of electricity,” the Westport Democrat said. “Touring Hydro-Quebec’s facilities will inform my work in the Massachusetts Senate in this area and support future policymaking to address the energy challenges facing the commonwealth and its residents.”

Rodrigues, along with Sen. Jacob Oliveira, a Ludlow Democrat, and Sen. John Cronin, a Fitchburg Democrat, disclosed in respective ethics filings that Hydro-Quebec Energy Services covered $1,050 in airfare between Montreal and Radisson, $103 for ground transportation, and $155 for meals.

The spokesperson for Rodirgues — who also told the State House News Service in March that senators were paying for transportation, lodging, and expenses — said the senator’s ethics disclosure filed ahead of the trip “is correct and contains a full account of the trip’s expenses and how they were paid.”

“This disclosure was filed with the State Ethics Commission before the start of the trip, as required by the Ethics Commission’s regulations. The information I provided to the State House News Service on March 14 was incomplete, but this was an unintentional error on my part,” the spokesperson said in a statement to the Herald.

In a statement to the Herald, a spokesperson for Hydro-Quebec said it has regularly paid for elected public officials to visit its facilities.

“As a result of our regular dialog with Massachusetts lawmakers, it was a natural outcome for HQ to extend this invitation, as we have in the past,” the spokesperson said. “It is essential for elected leaders in New England to see and understand the source of so much of the region’s electricity.”

The spokesperson said the company is not looking to expand services in Massachusetts but is focused on completing construction of “New England Clean Energy Connect,” a transmission line that is expected to bring over 1,000 megawatts of hydroelectricity to New England over 20 years.

“By the end of this year, Hydro-Québec expects to begin deliveries of energy under a power purchase agreement signed in 2018 with Massachusetts electric distribution companies, pursuant to the Massachusetts Green Communities Act,” the spokesperson said.

Other lawmakers who traveled to Canada argued the trip had value for their constituents.

House budget chief Aaron Michlewitz of the North End said in a March 13 disclosure that the visit promoted state interests because “it will strengthen my understanding of the energy issues, particularly reliability and cost, that have a direct impact on my constituents and our state.”

A spokesperson for Michlewitz said any costs not covered by the public utility company were covered out of his own pocket.

The conflict of interest law generally prohibits public employees from accepting gifts or gratuities worth $50 or more that are given to them because of their official position, according to the State Ethics Commission.

But there are some exceptions to the general prohibition.

Elected officials can accept travel expenses paid by or reimbursed by certain outside entities if they determine their “acceptance of the travel serves a legitimate public purpose and that the public purpose outweighs any non-work related benefit, and they file the relevant disclosure,” according to the State Ethics Commission.

Rodrigues, Cronin, and Oliveira indicated in their disclosures that they believed they were engaging in an “activity that serves a legitimate public purpose, i.e., it is intended to promote the interests of the commonwealth, a county, or a municipality.”

“Such public purpose outweighs any special non-work related benefit to me or to the person providing the reimbursement, waiver, or payment,” their forms read.

The trip started March 13 with a dinner in Montreal, according to an itinerary included in Rodrigues’ filing. The next day, lawmakers were shuttled and flown to and from the hydroelectric facilities where they were provided lunch, the itinerary showed.

The lawmakers traveled to Varennes, Canada on March 15 to visit the Hydro-Quebec Research Institute before being returned to Montreal through arranged ground transportation, according to the itinerary.

The legislators who were selected to travel to Canada hold key posts in the Legislature.

Michlewitz and Rodrigues are the two lead budget-writers in their chambers and chair the powerful House and Senate Ways and Means Committees, which both serve as clearing houses for major bills.

Also on the trip were Reps. Jeff Roy of Franklin, Danielle Gregoire of Marlboro, Kathleen LaNatra of Kingston, Mark Cusack of Braintree, Michael Kushmerek of Fitchburg, Meghan Kilcoyne of Clinton, and Michael Finn of West Springfield.

Roy previously served as the chair of an energy-focused committee last session but was moved to a low-level leadership position in the House this legislative term.

Gregoire serves in House leadership while Lanatra is co-chair of the House Committee on Federal Funding, Policy, and Accountability. Cusack co-chairs the Telecommunications, Utilities, and Energy Committee with Kushmerek as vice chair.

Kilcoyne is the vice chair of the Health Care Financing Committee while Finn is the co-chair of the Bonding, Capital Expenditures, and State Assets Committee.

Oliveira sits on multiple committees, including the Senate Ways and Means Committee, and is the vice chair of the Election Laws Committee.

Cronin also sits on the Senate Ways and Means Committee, and is the co-chair of the Emergency Preparedness and Management Committee and Public Safety and Homeland Security Committee.