The Alberta Utilities Commission on Feb. 11 approved an application from Maxim Power for a second new gas-fired unit at the H.R. Milner coal plant site, with this latest unit needed to support the coal unit when new greenhouse gas limits kick in.
Maxim Power has been approved to construct and operate an 86-MW cogeneration plant called M3 at its Milner site, approximately 20 kilometers north of the town of Grande Cache, Alberta. The proposed power plant M3 would consist of two 43-MW General Electric LM6000 aero-derivative gas turbine generators, each equipped with a heat recovery steam generator and related auxiliary equipment.
Maxim presently owns and operates a 150-MW coal-fired unit called M1. Maxim also holds an approval to construct and operate a 520-MW natural gas-fired power plant, designated as the HR Milner Expansion Project Amendment (M2). Maxim in 2011 received approval to construct M2 as a coal-fired unit. But then in 2014 it was approved by the commission for the fuel switch at M2 to gas. Maxim cited new federal government greenhouse gas emissions legislation and the low cost of natural gas as drivers for the alteration.
Maxim stated that Environment Canada’s federal greenhouse gas regulation, which came into force in September 2012, has stringent performance standards for coal-fired generators. The regulation requires new coal-fired generators to meet the standard of 420 tonnes of carbon dioxide per gigawatt hour by July 1, 2015. The regulation also requires existing coal-fired power plants to be in compliance with this new standard. Maxim submitted that, in accordance with the federal greenhouse gas regulation, the existing coal-fired power plant M1, that was built in 1972, would be required to cease or end its base load operation by Dec. 31, 2019, and would then only be allowed to operate as a standby unit and to burn coal at a capacity factor of 9% per year as of Dec. 31, 2029. Maxim also submitted that in accordance with the provincial regulation, a Best Available Technology Economically Achievable (BATEA) would be required to be installed on the coal-fired power plant M1 by Jan. 1, 2023.
To meet the requirements of federal and provincial regulations, Maxim stated that it proposed to build M3 to enhance the current energy output at the Milner site. M3’s gas turbines would be used to drive the electric generators and the exhaust energy to be produced from the gas turbines would be converted to steam in the heat recovery steam generators. The steam would be piped into the existing coal-fired M1 and expanded in the steam turbine to generate electricity, which would displace a portion of the coal-sourced steam. Maxim said that this process would allow M1 to reduce the amount of coal that it presently burns, reducing its greenhouse gas emissions.
The natural gas for M3 would be supplied via an expansion of the supply service from the TransCanada pipeline system. Maxim stated that it plans to commence construction in the second quarter of 2015 and begin operation in the third quarter of 2016.
Maxim stated that it would reduce the greenhouse gas emissions and increase the power output from the HR Milner generating station by using the steam to be generated from M3 in the existing M1. Maxim submitted that a net increase of electric power output would be approximately 84 MW, with a total net capacity of 228 MW. The total emissions of carbon dioxide (CO2), nitrogen oxides (NOx), sulfur oxide (SOx) and particulate matter would be reduced.